innovation in global power

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A technicaljournal by

ParsonsBrinckerhoff

employeesand colleagues

Issue No. 68 August 2008

http://www.pbworld.com/news_events/publications/network/

Also in this Issue: PB Redesigns Composting Machine;

Laying out a Swim Lane Diagram Using Microsoft Powerpoint or Visio;

Working with Text in Adobe Acrobat

Innovation

in Global

PowerNuGas Steam Cycles

HeatMap of

HotRocks

3 MW Mini Hydro Station


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Guest Editors for thisissue: Katherine Jack-son and Arthur Ekwue.

Guest Technical Reviewers:John Douglas, Ferrel Ensign,Steve Loyd, Chris Meadows,Brian Van Weele, andJohn Wichall .

Special thanks to Paul Kenyonand Matthew Chan for theirassistance.

Cover photo (lower right):Tony Mulholland

Note: Soon after distribution,this issue will be availableon the Web athttp://www.pbworld.com/news_events/publications/network/Issue_68/68_index.asp

PB Network #68 / August 2008 2

Innovation in Global PowerInnovation in Global PowerIntroduction (Burton) ...........................................................3

GENERATION

THERMAL ACHIEVING NEW EFFICIENCIES,REDUCING CARBON EMISSIONS

Best Practices Across a Range of Technologies (Kenyon)..4

The Effect of Carbon Capture and Storage andCarbon Pricing on the Competitiveness of GasTurbine Power Plants (Cook)..................................................5

The NuGasTM Concept: Combining a Nuclear PowerPlant with a Gas-fired Plant (Willson, Smith).................8

PB Inspections Help To Ensure Power Plant Safety(Gray) .................................................................................................11

Project Brief: Using Monte Carlo Techniques toSize a Power Station (Emmerton).....................................13

Project Brief: Energizing Singapores Economy (Gill)........13

Combined Heat and Power for USAs LargestResidential Development (Bautista, Swensen)............14

Ensuring Continual Power Supply for New York

City Hospitals (Krupnik, Andrews) ....................................16Changes to Chiller, Boiler and HVAC Lower Energy

Consumption at a University Campus (Choi)............18

Power Terminology: Units and Conversions(Ebau) .................................................................................................20

HYDROPOWER NEW TECHNOLOGIES, NEWCONSIDERATIONS

Does Hydro have a Future? (Wichall).......................................21

Pumped Storage Technology: Recent Developments,Future Applications (McClymont, Reilly)........................22

Planning for Mini Hydro in Distributed Generation(Mulholland)....................................................................................25

Developing, Engineering and Licensing a NewHydropower Dam (Chan, Schadinger)...........................27

Developing Hydropower Resources in Greenland(Kropelnicki,Tucker, Shiers).....................................................30

Successful Relicensing of a Federally RegulatedHydropower Project (Bynoe, Shiers, Williamson,Plizga)..................................................................................................32

Using OASIS Software to Model Water Allocationfor Hydropower Generation Projects(Shiers, Williamson,Tsai) ..........................................................35

Dam Safety: State-of-the Art MethodologyDemonstrates that Costly Dam Remediation isNot Needed (Greska, Mochrie) .........................................38

Deck Slot Cutting and Tainter Gate RemediationExtend Safe Operations of a HydroelectricDam (Buratto, Plizga, Shiers).................................................41

RENEWABLES THE RISKS, CONCERNS ANDPOTENTIAL

The Growing Power of Renewables (Loyd) .............44

Renewable EnergySustainable Economy? (Cook)........45

Test Bed to Turnkey: Introducing New ThermalRenewable Energy Technologies (Burdon) ...................48

Realising the Power Potential from Hot Rocks(Curtis) ..............................................................................................51

Project Brief: Tidal Power (Kydd) .........................................53

Converting Landfill Gas to High Btu Fuel (Lemos)...........54

Photovoltaics,With a Focus on Spain* (Lejarza)..........56

TRANSMISSION AND DISTRIBUTION

TRANSPORTING POWER ACROSS THE GRID

Electricity Transmission, Building on 120 Years ofExperience (Ekwue)...................................................................58

Meeting the Need for Reliable, Cheaper and Non-polluting Electricity in Cambodia (Parkinson,Roe).........59

Rehabilitation and Reconstruction of Abu DhabiTransmission Network (Jayasimha)...................................62

HVDC Transmission Strengthening in SouthernAfrica (Tuson)......................................................................................63

Assessing Transmission Network Condition: 3DData Capture and Reporting (Reynolds)......................66

DISTRIBUTING POWER TO USERS

The Wide Range of Distribution (Douglas)....................68

Research & Innovation: Using Dynamic ThermalRatings and Active Control to Unlock DistributionNetwork Capacity (Neumann)...........................................69

Upside Down! How Innovation in DistributionNetworks is Challenging Tradition (Neumann) .........72

A Survey of Power System Packages for DistributionNetwork Analysis (Ekwue, Roscoe, Lynch) ..................75

Improving 11 kV Network Performance in Al Ain(Nikolic).............................................................................................77

Energy Demand Management Programs inWestern Sydney (Duo)............................................................79

PLANNING AND THE ROLE OF REGULATORS

Planning and Regulating Power Infrastructurein a World of Change (Stedall) ...........................................81

Asset Replacement: The Regulators View (Douglas)...........82

New Zealand Energy StrategyA Plan for aSustainable Nation (Barneveld)...........................................86

Power Articles in PB Network, NOTES, andPowerlines (Chow) ...................................................................89

DEPARTMENTS

Networking: PB Redesigns a Composting Machinefor Improved Operations (Alts)* ....................................91

Water Factory Will Help to Address Water

Shortage Concerns (Hodgkinson) ....................................94Swim Lanes Part 2: Laying Out a Swim Lane Diagram

using Microsoft PowerPoint or Visio (Sloan)................94

Computer Tutor: Working with Text in AdobeAcrobat Pro: Copy text to other softwareapplications, use built-in OCR, make correctionswith the TouchUp Text tool (Hinshaw) ..........................99

PlanetWise: Going Green: Walking the Walk!!(Sammut).......................................................................................101

In Future Issues/Call for Articles................................102

The Net View: Fishing Power (Clark)....................104

TABLE

OF

CO

NTE

NTS

* La edicin en lengua espaola del presente artculo est disponible en la direccin Web de PB Network.


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Innovation in Global Power


3 PB Network #68 / August 2008

I

NTR

ODUCT

ION

This issue ofPB Networkfocuses on the power expertise that PB provides to clients around the

world. There continues to be a rapid rate of change in the global power industry as it responds

to a range of external drivers, including governmental and regulatory targets, fuel price changes,

rising equipment costs and environmental pressures. These changes are happening at the same

time that the demand for electrical power world-wide continues to accelerate at unprecedented rates.

PBs ability to innovate has become increasingly important to power clients looking for solutions

and a competitive advantage in this rapidly changing environment. Reducing carbon emissions

through using more efficient and lower carbon forms of generation, a greater interest in extending

the l ifetime and capacity of existing power assets, and a requirement to squeeze more into

existing land space must all be key to helping ensure a sustainable future

One of PBs stated values is to work with our clients to contribute to their success, and

a number of the articles demonstrate how we are using innovation to do this, including:

Information about the advice we are currently providing to the UK government on carbon

capture and storage

The creation of the NuGas concept that can improve thermal efficiencies to unprecedented

levels by combining nuclear power generation with a small combined cycle gas fired plant

The development of designs for high-temperature hot dry rock power generation in Australia

PBs role in the research and development of a distribution network active thermal controller

that uses local meteorological data to calculate real time equipment ratings and control network

power flows.

Other articles demonstrate how PBs engineers have successfully applied novel thinking to solving

problems on a range of projects, including:

Increasing the lifetime of hydropower dams

Ensuring that New York City hospitals continue to operate during power blackouts

Developing a 3D asset data capture system for transmission networks; and developing demand

reduction strategies.

Another of PBs stated values is to share knowledge with our colleagues to deliver profes-

sional excellence. PB Networkand the Practice Area Networks (PANs) all assist with achieving

this goal, and I would like to thank all of the PANs, authors, reviewers and the editing team who

have contributed to this issue. In the spirit of sharing knowledge with our non-power colleagues,

we have included a list of standard power terminology, definitions, and conversion factors (Ebau,

page 20). Colleagues have shared over 30 other power articles in recent PB Networks, NOTES,

and Powerlines (see list on pp. 89-90).

Katherine Jackson and Arthur Ekwue were the guest editors who compiled all the articles and

developed the framework for the publication. The guest reviewers who helped hone the technical

content were John Douglas, Steve Loyd, Chris Meadows, John Wichall, Paul Kenyon, Brian Van

Weele, and Ferrel Ensign. This issue was sponsored by PBs Power business units globally and

by four of PBs power PANs (conventional thermal generation; high voltage transmission and

distribution; power system planning, analysis, and restructuring; and renewable energy sources).

Eric Burton

Managing Director, Power International

Newcastle, UK


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The public awareness of climate change and energy issues has risen dramatically in the last two to

three years. There appears to be growing acceptance of the need to be energy smart and to

reduce carbon emissions.

An example is the identification of energy savings by finesse of thermal cycle. The NuGas

concept and the energy efficiency projects at Co-op City and the SUNY campus in Brockport,

New York combine an already efficient plant in a way that gains an extra advantage. The process

for cleaning the steam and evaporator units at the Keppel Energy Plant in Singapore reduced

on-site time and improved steam and water quality during commissioning. These are elegant

no-cost or low-cost solutions that were developed by thinking that went the extra step.

The demand for increasing thermal efficiencies in our power plants is pushing up temperatures,

making it even more important to ensure safe design and operation of these facilities. Stewart

Gray has developed an expertise in hazardous areas engineering due, in part to having witnessedmany instances of people not understanding the rules and vocabulary involved, and he knows of

the severe consequences that can result. His ar ticle highlights some of the steps engineers can

take a various stages to help ensure such disasters do not occur.

The paper on carbon capture and storage gives insight to a dilemma facing many of PBs clients.

The world-wide management of carbon dioxide emissions to the atmosphere is crucial to slowing

the rate of global warming. This can be achieved by combinations of improved efficiency in

combustion of fossil fuels, moves to low-carbon or carbon-free fuels, or carbon capture. At present

carbon capture is not mandated but this may arise, just as happened with reduction of nitrogen

oxides emissions (NO and NO2). As with Renewable Energy Certificates, a market may develop

to provide incentives to clean operators, funded by penalties on those with less clean processes.

PB is well placed to assist its clients in this topical and important area of technology.The use of Monte Carlo techniques is a novel approach to optimize generation capacity for a

random load profile. The team went beyond traditional engineering analysis, reduced uncertainty

and provided the client with increased confidence in PBs appraisal. Other PB teams can adopt

this approach to determine the most economical technical solution yet minimize the risk of a

shortfall in installed capacity.

The emergency power generation project for hospitals in New York City applied PB expertise

and good practice to solve a real and serious issue with old and inadequate life-safety

equipment. The projects required improvement work to progress on old, dispersed,

sometimes poorly documented infrastructure without disruption to essential services.

These articles illustrate projects and technologies with a range of complexity, but each team hasa depth of expertise and knowledge to assist clients in its sector.

Please see page 89 for a list of many additional thermal generation and carbon reduction articles

from past PB publications.

Paul Kenyon

Engineering Manager, Newark, New Jersey


GENERATION:Thermal Achieving New Efficiencies, Reducing Carbon Emissions

Best Practices Across a Range of Technologies


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Thermal Achieving New Efficiencies, Reducing Carbon Emissions

Current thinking is that atmospheric CO2 concentrations must be stabilised at 450 parts per

million by volume if we are to at least slow down, if not stop, global warming. This goal will

require a reduction in greenhouse gas emissions by a factor of four to five in the industrialised

nations. Whilst there is a continued and necessary focus on the development, improvement

and implementation of renewable and carbon-neutral power generation technologies and the

adoption of energy efficiency measures, there is a large gap in the short and medium terms

in the level of carbon reductions that can be delivered through these routes alone.

The power generation industry produces about half the worlds CO 2 emissions, so it offers

considerable opportunity for introducing large-scale emission reduction technologies. Current

global debate is focussing on the development of carbon capture and storage (CCS), which

can extract 85 percent to 95 percent of the CO2 produced by a fossil-fuel power generation

facility. Even though carbon capture reduces a plants thermal efficiency, meaning that the use

of fuel per unit of electricity produced increases, the overall carbon reduction is still highabout 80 percent to 90 percent. The effectiveness of carbon capture technology on power

plant emissions is illustrated in Figure 1.

CCS technologies impact the cost of electricity generation, however, so if we are to move

forward with this technology, it is important that we consider the impact of carbon pricing on

lifetime costs, the attractiveness of the technology to investors, and how varying the carbon price

will affect the competitiveness of gas turbine plant with other methods of power generation.

Carbon Capture Technologies

The main carbon capture technologies under development are classed as either

pre-combustion or post-combustion. The one pre-combustion and two post-combustionoptions available, which represent the first generation of commercial carbon capture, are

shown in Figure 2 and reviewed below.

Pre-combustion. The fuel is first reformed into more basic constituents by its reaction

with oxygen. The fuel can be solid, such as coal, petcoke or biomass; liquid, such as a heavy

fuel oil; or gas, such as natural gas. The resultant product, known as syngas (synthetic

gas), contains mainly carbon monoxide and hydrogen. Other constituents include some

methane, some carbon dioxide, hydrogen sulphide and many other minor compounds

including ash if a solid fuel is used. Ash is usually in a fused form and easily separated

from the syngas. The syngas is treated to convert the carbon monoxide to carbon dioxide

that is removed in a chemical absorption process, leaving a predominantly a high purity

hydrogen gas stream suitable for compression, transportation and long-term sequestration.

The main plant components of the pre-combustion reformation and capture stages are considered

to be proven technologies, although there will be some process engineering required to bring

these to the scale required for large scale CCS. Some further operational

proving of the gas turbine for use on hydrogen fuel is required before

the process can be regarded as being a normal operational procedure.

Post Combustion. A post combustion carbon capture plant can

use the same fuels as a pre-combustion capture plant. The fuels are

combusted in either conventional boiler plant or, if suitable, in gas

turbine plant. The flue gases are treated to remove particulate matter

The Effect of Carbon Capture and Storage andCarbon Pricing on the Competitiveness of GasTurbine Power Plants By Dominic Cook, Newcastle-upon-Tyne, UK, 44 191 226 2203, [email protected]

Carbon capture and storage

presents an opportunity for

the continued use of fossil

fuel in power generation

whilst mitigating its contri-

bution to carbon emissions.

But at what cost? Will elec-

tricity still be affordable?

Will the technology be

attractive to investors?

The author explains thecapture and transport/

storage processes, explores

the answers to these ques-

tions, and tells about some

considerations clients will

face when deciding whether

or not to implement CCS.

Figure 1: Effectiveness of CarbonCapture.

Figure 2: Carbon Captureand Storage Schematic.


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1 A number of possible chemicals can be used. Amine, ammonia, and potassium bicarbonate are just a few.2Imperial College, Potential for Synergy between renewables and Carbon Capture and Storage.



and sulphur dioxide, and to reduce nitrogen oxides before

entering the carbon capture process. The carbon dioxide is

absorbed into a chemical solution1to remove it from the flue

gas,which is then emitted to atmosphere. The carbon dioxide

gas is removed from the absorbent, compressed and trans-

ported for long-term sequestration. The challenge with this

technology is the need to scale up to utility-size capture.

Oxyfuel. An oxyfuel plant is one in which the fuel is

combusted in oxygen supplied by an air separation plant

rather than air. The resulting flue gases are purified to remove

particulate matter and sulphur dioxide, and to reduce nitrogen

oxides. Some of the captured carbon dioxide is recycled and

mixed with the oxygen feed to the boiler plant to control

combustion temperature. The remaining carbon dioxide is

then purified, compressed and transported to long-term storage.

The aim of oxyfuel development is to use as much of the

existing and proven equipment as possible; although some

issues remain relating to the control of combustion tempera-tures within the boiler and the scaling up of air separation

plant to the size necessary for use in power plant applications.

Carbon Dioxide Transport and Storage

Transport. Captured carbon dioxide is transported to a long-

term storage location by either pipeline, truck, train, or boat,

although only pipeline would be feasible for the quantities

resulting from large-scale power generationmillions of tonnes

per year. The pipeline could transport carbon dioxide in the

gaseous phase, at pressures below 71 bar, or at higher pres-

sures where the carbon dioxide is present as a supercritical

fluid giving benefits from lower frictional losses. The scale issuch that a new pipeline infrastructure would be needed.

Storage. Storage of carbon dioxide is assumed to be in

geological formations, such as depleted oil and gas reservoirs,

deep saline aquifers and unmineable coal seams. These

formations need to provide storage with negligible leakage

to ensure that the carbon is sequestered over geological

timescalesthousands, if not tens of thousands of years.

The estimated global potential for the storage of CO2 in

these various sinks is detailed in Table 1. As would be expected,

the capacities for the oil/gas and coal storage options areconsiderably smaller than those for the saline aquifers.

Even with the present global carbon dioxide emissions of

about 25 billion tonnes per year, the available storage capacity

extends for about 55 years to about 435 years. Whilst

this is not a solution, it does provide us with a temporary

breathing space in which to find and implement alternative

means of energy provision to satisfy human, social and

economic aspirations.

TechnologyAnalysis andLifetime Cost ofGeneration

For the purposes of

reviewing the position

of gas turbine technol-ogy within a carbon

constrained world, it was

necessary to identify those

power generation technologies where gas turbines will

continue to have a use and, importantly, the competitor

technologies. The technologies reviewed included:

Coal supercritical pulverised fuel plant with flue gas

desulphurisation with and without carbon capture

Coal integrated gasification combined cycle plant (IGCC)

with and without carbon capture

Gas fired combined cycle plant with low NOx burner

technology with and without carbon capture New generation nuclear power plant.

Our analysis considered the impact of carbon and capital

on the lifetime cost of electricity generation. The extent to

which carbon pricing feeds through to the cost of electricity

generation depends on the amount of free allocations

provided by government to individual plants. Given that

different allocation methodologies will be adopted in different

countries globally, it was considered to be of more value to

assume no allocations and that the full cost of carbon flows

through to the end electricity generation cost.

The level of carbon captured within the carbon captureoptions will be specific to each plants detailed design. The

costs associated with the transport and storage of carbon

were based on various reference sourcesan indicative

value of $10/ton CO2 sequestered was used.2 The Capital

costs and operation and maintenance costs were based on

those observed in the market and included adjustments for

the recent increases in the underlying materials costs, such as:

Steel: 35 percent increase since 2002

Copper: 400 percent increase since 2002

Nickel: 400 percent increase since 2002.

The analysis showed that the addition of carbon captureand associated transport and storage charges added about

35 percent to 63 percent to the lifetime cost of electricity

generation. Introducing a carbon cost payable by the

generation plants for all CO2 emitted increased the electricity

costs across the board, as would be expected. For example,

if a $25/ton charge were placed on all CO2 emissions, the gap

between non-carbon capture and carbon capture would be

narrowed to 6 percent to 22 percent due to the proportion-

ately larger impact the carbon cost has on the non-CCS plant.


Table 1: Estimated Capacity ofCO2Storage Options.

(Source: IEA-GHG, 2004)


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Figure 3 shows that the carbon costs incurred by unabated

generation increase the cost of generation significantly whilstmaintaining the mix of generation technologies to coal, gas

and nuclear. There did not appear to be a clear winner.

Where Are We Now?

A number of CCS projects of varying sizes are underway

around the world. The European Union (EU) projects are

shown in Figure 4. As can be seen, only three are identifiedas being operational with the bulk being in the planned stage.

These projects will be implemented at various times up to

2015, with the majority scheduled for delivery around 2010.

The fact that these development projects are moving forward

is a step in right direction; however, there is a need to accelerate

this if we wish to contain the global concentrations of

atmospheric CO2 below the 450 ppmv level that is presently

given as our target.

Other Opportunities

A carbon capture plant had been considered to date as

being inflexible in its operation and less able to respond to

short-term changes in electricity demand. This view is changing,

however, with recent studies considering the specific capabilities

of the power generation plant and the carbon capture plant

separately. With this new view comes the potential to

include additional carbon storage on post-combustion capture

plants, a change that will allow additional power to be provided

from the generator in response to system events, such astransmission system faults, power station forced outages, or

spikes in demand. This change could provide valuable flexibility

services to the transmission system operator when rapid

response to system events is required.

In the case of pre-combustion plant, whether the fuel is coal

or gas, the hydrogen fraction of the syngas could provide the

beginning for establishing a hydrogen economy. This would

be prior to the commercial realisation of nuclear fission. It

would also be applicable in countries that do not have sufficient

insolation (incident solar radiation) or available land area to

drive large solar plant that could be used to generate hydrogen.

Summary

The technology relating to carbon capture is progressing

and reaching a point where it is at a pre-commercial stage.

The mechanisms to allow the costs associated with carbon

emissions to incentivise investment in carbon capture plant

are beginning to emerge, but they will need a strong political

will to ensure that the costs associated with carbon emissions

become sufficient to tip the balance in favour of carbon

capture. This political decision will need to take into

account the extent to which the end customer incurs

additional charges and the rate at which any additional costsare introduced into the economy. This is a balancing act

and it will have a time constant associated with it. It must

be remembered, however, that:

CCS IS NOT A SOLUTION ITS A STOP GAP!


Figure 3: Relative costs of plant with and without carbon capture.

Figure 4: Carbon Capture projects in the European Union.

Dominic Cookhas 20+ years of utility and consultancy experience in the power industry. He has been involved in regulatory audits and the development of powergeneration plant, and in providing advice to financial institutions. His publications included Powering the Nation in June 2006 and he is presently involved with theUK government on the carbon capture competition.

Note: This article was adapted from a paper presented at the annual conference of the Institute of Diesel and Gas Turbine Engineers (IDGTE) in November 2007.

across the board, as would be expected. For example, if a

25/ton charge were placed on all CO2 emissions, the gap

betweennon-carbon capture and carbon capture would be

narrowed to 6 percent to 22 percent due to the proportion-

ately larger impact the carbon cost has on the non-CCS plant.


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PBs power specialists in the UK have developed and patented a completely new concept

for high-efficiency electricity generation. This ground-breaking development, called NuGasTM,

combines the advantages of nuclear power generation with a smaller combined cycle gas turbine

(CCGT)-based power technology to create a low-cost, highly reliable hybrid system that:

Increases output and thermal efficiencies to levels that are far higher than even the most

ambitious forecasts

Achieves a simple, safe and effective interface between the cycles.

Improved performance comes from better use of heat in the steam cycles of the CCGT and

nuclear plant where currently unavoidable large temperature differences prevent the maximum

work being obtained from the heat. By linking a CCGT with the low-temperature steam cycle

typical of a nuclear power plant, these temperature differences can be reduced significantly,

releasing additional power output without going outside conventional design conditions.

Because NuGasTM enhances thermodynamic cycle design rather than changing operating conditions

to improve efficiency, it introduces no new technology risks in its implementation. This is a

significant advantage over the more complex and unproven technologies being introduced for

new gas turbine designs as engineers pursue ever higher temperature operation.

NuGasTM can be used either for retrofitting existing nuclear stations or for new-build installations.

While the new-build design allows for maximum optimization, the retrofitted option will

enable rapid return on investment with minimal impact on normal day-to-day operation

of the existing nuclear plant during construction of the CCGT unit.

Improving Thermal Efficiency

When analyzing a nuclear power station design, the question often asked by non-engineers or

scientists is why cant you convert all the heat generated in the reactor into electricity? For

example, the thermal efficiency of the latest pressurized water reactors (PWRs) is just 37 percent.

Even if there were no losses in the system, the maximum Ideal Efficiency would still be well

below 100 percent. For a PWR operating at an upper steam temperature of 540F (280C),

the maximum possible efficiency would be just 45 percent. The way to push the Ideal Efficiency

up is to increase the upper temperature in the cycle, which is why gas-cooled high temperature

reactors are again being considered.

Temperatures have been pushed up also in fossil fuelled power plants, and the most modern

coal-fired super-critical boilers can achieve a thermal efficiency of 44 percent. This level is now

being exceeded when two cycles are combined, such as the CCGT, where temperatures are

around 2300F (1200C) and a thermal efficiency of 57 percent can now be achieved. Thedesire to raise system efficiencies beyond current levels has proven challenging, however.

Despite considerable investment in research and development, it appears that significant

incremental improvements are becoming more expensive and harder to achieve without

sacrificing reliability.

By combining current nuclear and CCGT technologies. NuGasTM raises thermal efficiencies to

unprecedented levels. Under this concept, the two separate power generation systems can operate

in tandem as a single combined unit on the same site. In the case of breakdown or planned

maintenance, either the nuclear plant or the gas turbine-powered unit can revert to independent

operation, thereby maximizing availability of power and minimizing upset to the power networks.

The NuGasTM Concept: Combining a Nuclear PowerPlant with a Gas-Fired PlantBy Paul Willson, Manchester, UK, 44 161 200 5210 [email protected]; andAlistair Smith, 44 161 200 5114, [email protected]

Nuclear power is experi-

encing renewed interest

around the world because

of its low carbon emissions

and affordability. As with

other thermal generation

technologies, however, its

thermal efficiency is limited.

PB has developed a new

concept that combines

current nuclear technologywith combined cycle gas

turbine technology to

achieve unprecedented

levels of thermal efficiency.

The authors explain how

it works and how it can be

implemented in new instal-

lations or in retrofitting

existing nuclear stations.


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The basic concept would allow a large nuclear power plant

with a typical output of 800 to 1700 MWe to be combined

with a 300 MW CCGT generating unit. Linking the steam-

cycles of the two plants enables them to operate as an

integrated power production unit and reduces losses of

potential output, increasing total efficiency. Cycle efficiency

gains enable the CCGT to contribute an increased output for

no additional fuel, with the efficiency of converting the energyin the gas to electricity increased to about 62 percent.

How NuGasTMWorks

Although a CCGT system has a high thermal efficiency, it

relies on using the heat from the exhaust gases of the gas

turbine to boil water to produce steam that drives the

turbine. As the exhaust gases cool, water is evaporated in

the boiler tubes but temperature differences of up to 400F

(200C) arise in the boiler due to the large amount of heat

needed to evaporate the water. These temperature differences

limit the potential work that can be extracted from thesteam, reducing the output of the steam cycle.

The NuGasTM cycle overcomes this limitation by borrowing a

small proportion (typically 10 percent) of the steam from the

nuclear steam cycle (point A on Figure 1). The dry saturated

steam is superheated using the exhaust heat of the gas

turbine. The high temperature steam (B) is then used to

drive a separate conventional condensing steam turbine to

provide additional output from the plant. Superheating steam

rather than boiling water enables a much lower temperature

difference to be maintained in the heat recovery system,

maximizing the value of the energy recovered.

The heat in the gas turbine exhaust flow between about

570F and 320F (300C and 160C) is recovered via a high

temperature economizer (C) to generate high temperature

feedwater, which is returned to the nuclear cycle (D),

ensuring that the inlet temperature to the steam generator

is maintained close to the design value.

The heat in the gas turbine exhaust below about 320F (160C)

(E) is used to heat part of the condensate from the high

temperature steam turbine (F) before it is deaerated and

returned to the nuclear cycle feed pumps (G). The remainingcondensate from the high temperature steam turbine is

returned to the nuclear cycle condensate system (H).

The flows of energy around the cycle differ somewhat to

those in a conventional CCGT. Figure 2 shows a simplified

Sankey diagram for the NuGasTM cycle, including the energy

exchanges between the CCGT and PWR cycles shown along

the lower edge of the diagram.

Identifying the separate performance of the CCGT cycle

when it is linked to the PWR cycle requires that the design

PWR energy balance be maintained. Thus, the CCGT returns

power to the PWR to compensate for the reduction in

output due to the borrowed steam and returns rejected

heat in the CCGT cooling water to the PWR to account

for the reduced heat rejection from the nuclear turbine

condenser. The diagram therefore shows the additional

energy input, the additional losses and the additional power

generated by the cycle, demonstrating its high efficiency.

Safety Considerations

Downstream failure is limited. The extraction of steam

from the main steam system has the potential to disturb

reactor operating conditions. However, the PWR system isdesigned to allow for a 10 percent step change in flow to the

main steam turbine without exceeding the appropriate limits

for a frequent operating condition. It is likely, nevertheless,

Figure 1: Schematic Combination of the Steam Cycles. Figure 2: Simplified Sankey Diagram for NuGas Cycle.


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that a suitably qualified shut-off valve and additional bypass

valves would be needed to limit the potential impact of any

downstream failure in the NuGasTM cycle.

Installation risks are minimized. The interconnection

design minimizes installation risks and ensures that the main

plant is unaffected by maintenance of the NuGasTM plant and

that CCGT operation can continue independently of reactoroperation. This is fundamental, as significant costs would be

charged by the grid operator for increasing the loss of gener-

ation resulting from a single fault. In addition, the project

economics would be adversely affected if the availability of

either plant was to be degraded by the linking of the cycles.

Safety case is maintained. NuGasTM raises overall efficiency

by enhancing the thermodynamic cycle rather than changing

operating conditions, so in addition to being inexpensive, it

introduces no new technology risks in its implementation.

The plant design incorporates additional systems to control

high temperature steam flows linking the nuclear and CCGTunits, ensuring that the integrity of the nuclear safety case is

maintained.

To ensure that all the additional hazards associated with the

introduction of the CCGT are assessed, a full HAZOP has

been carried out to ensure that risks are well within the

currently assessed fault scenarios.

New Build

Currently, the two leading candidate PWR designs for new

nuclear construction are the Evolutionary Pressurized Water

Reactor (EPR) from AREVA with a nominal power rating of

1600 MWe and the Westinghouse AP1000 reactor with an

output of around 1140 MWe. Either the EPR or AP1000

could be integrated with a NuGasTM cycle to offer extra

capacity with the highest possible efficiency for fossil fuel

conversion without significantly increasing the loss of output

in the event of a reactor trip.

If the NuGasTM concept was applied to an AP1000 with a

nuclear plant electrical output of 1140 MW, the combined

plant would have an output of approximately 1470 MW for an

additional capital cost of around $250 million ($800 to $1000

per incremental kW). The cost of the NuGasTM integration is

approximately $50 million, which can be considered to offer

additional capacity with no additional fuel burn. Pessimistically

at a fuel price of $7/MMBTU, a cost that is conservatively

below current levels and below recent longer term forecasts,

the investment to combine the plants would have a typical

payback time of less than three years. At higher gas prices,

the benefits are increased and the payback period

correspondingly reduced.

Backfit

The renaissance of interest in new nuclear power plants will

mean that by 2015 and beyond more nuclear plants will be

brought on-line, but for the next seven years utilities waiting

for their new nuclear plants to be licensed and built may be

faced with a generating capacity gap. Some utilities are,

therefore, considering building interim plants with a low capital

cost and rapid construction times, characteristics of the

CCGT. Building a CCGT and combining it with an existing

nuclear power plant can provide a rapid method for increasing

power generation capacity with exceptionally high thermalefficiency, making it far more profitable than stand-alone

CCGTs. The necessary connections to the nuclear steam

cycle can be readily made during the refuelling outages on

the nuclear plant, thereby minimizing disruption and cost.

A further key advantage for the NuGasTM concept arises

where the nuclear plant has increased operating margins

such that more heat can be emitted by the reactor. In some

cases this extra output cannot be converted to electricity

as the existing steam system cannot operate at significantly

higher rates. Because the NuGasTM cycle increases steam

utilization capability by at least 10 percent, it can use excesssteam without expenditure or shutdowns for costly steam

cycle upgrades, making the NuGasTM conversion even more

attractive financially.

Conclusion

By re-examining power generation options and focusing on

improving efficiency to reduce carbon emissions, it has been

possible to developing a novel concept that brings together

the best aspects of nuclear and gas-fired power generating

technologies. The concept is now being developed with

utilities and plant vendors, with a target of going into servicebefore 2013.

Paul Willson, Deputy Director of Engineering, Generation within PBs power and energy business in Manchester, has worked for PB and its predecessors for more than 25years. He leads the Development and Emerging Technology Group, which is responsible for independent power and water project development and for innovations. Paul

is co-inventor of the NuGas technology.

Alistair Smith, Director of Nuclear Services for PB based in Manchester, has worked in the nuclear power industry for 27 years and has worked on all phases of thenuclear plant li fecycle covering design, construction, operation and decommissioning. He is the chairman of the UK Institution of Mechanical Engineers Nuclear Power

Committee, chairman of the Nuclear Industry Associations industrial group, and is a spokesman for the UK nuclear industry.


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In modern thermal power plants fuelled by either oil or gas, fuel handling processes give rise

to situations where electrical equipment could cause an explosion due to a hot surface or a

spark. Indeed, there have been several incidents in the past where lives have been lost and

plant destroyed. Places where these situations arise are termed hazardous or classified areas.

Special engineering practices designed to prevent explosions in these areas are available.

These practices are often misunderstood and applied incorrectly, however, expert supervision

should always be used at a project start-up to ensure such engineering practices are imple-

mented properly. The following information is based on the experiences of some of PBs

workers in this field, particularly our assessments of power plant installations and our ensuring

that relevant codes and practices, local statute and insurance requirements are adhered to.

Applicable Codes or Practice

The code or practice applicable to each installation is normally determined by its locality,

although the several different practices applied worldwide have many similarities. The mostcommonly applied codes are International Electrotechnical Commission (IEC) 60079 Electrical

apparatus for explosive gas atmospheres and National Fire Protection Association (NFPA) 70

National Electrical Code. Both define sets of special precautions (types of protection) required

for electrical equipment in hazardous/classified areas using some very definite vocabulary.

Choice of Types of Explosion Protection

It is important to establish the extent of hazardous areas that exist at an early stage of any

plants design. These areas are customarily delineated using a plan called a hazardous areas

layout drawing. While it is always best to install the electrical equipment elsewhere, doing so

is often unavoidable.

All electrical equipment installed in a hazardous area requires explosion protection. IEC60079 defines nine types of such protection. Of these, the three types of protection most

commonly found in modern power plant are:

Flame proof enclosure (type d). This technique limits the effect of an explosion. Parts

that could cause an explosion are placed inside a special enclosure that is strong enough to

contain an internal explosion (Figure 1). The resulting hot gasses exit through a specially

machined path that is relatively long and narrow. As they exit they are cooled sufficiently

to avoid spreading the explosion outside.

The main uses for this type of protection are electrical power equipment, switches, etc.

While this is a well known technique, it is somewhat less readily available than other s. It

is also expensive and requires special installation rules.

Increased safety (type e). This technique (Figure 2) prevents explosions. Parts that could

cause an explosion are made with a superior degree of safety, including long creepages and

clearances, and temperature limitations. Its main use is for junction boxes. This technique is

well known, readily available, and inexpensive. Its use requires observation of special design

and installation rules.

Intrinsic safety (type i). This technique (Figure 3) also prevents explosions. The circuit

is arranged so the amount of energy that can flow into the hazardous area is limited and

incapable of causing an ignition. Normally, energy limiting barrier devices used in the safe

area contain zenner diodes or optical isolators to achieve the energy limitation. Care needs

to be taken to ensure that the hazardous area part of the circuit cannot store large amounts

of energy (i.e., use of low capacitance cables).

PB Inspections Help to Ensure Power Plant SafetyBy Stewart Gray, Bangkok, Thailand, 66 (0) 2343 8866, [email protected]

The author provides some

insight into the application

of engineering to prevent

explosions and fire in highly

hazardous areas of power

plants fuelled by oil or gas.

Acronyms/Abbreviations

IEC: Internat ionalElectrotechnicalCommission

Figure 1: Schematic of theprinciple of a flameproofenclosure.

Figure 2: Schematic of theprinciple of increased safety.

Figure 3: Schematic of theprinciple of intrinsic safety.


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The main uses of type i are for instrumentation, telecom-

munication devices, and similar equipment. It is well

known, inexpensive and readily available, but special design

and installation rules need to be followed. Two categories

of intrinsic safety are available. Category ia, which provides

the highest degree of explosion protection available,

ensures safety under two faults. Category ib ensures safety

under a single fault.

Design and Assembly Stage Inspections

Inspections of the installation need to be conducted through-

out the stages of its life cycle in accordance with IEC 60079.

Design Stage. Inspections should start at the design stage

by means of design review because mistakes identified at this

stage are almost always easier and less costly to rectify.

Factory Assembly Stage. When factory assembly of skid

mounted equipment is completed and after the factory has

conducted its own inspection, an inspection done by our

team is advantageous. Whilst this does not present a

comprehensive picture of the final installation, it can often

show mistakes, and corrective measures can be planned

during shipping to the construction site.

Final Construction Inspection

A final construction inspection, along with possible rectifica-

tion of any mistake, is mandatorybefore explosive fluid can

be introduced to the plant. The objective of the inspections

is to verify the installation complies with the applicable code

of practice. In the case of IEC 60079, this requires ensuringthat the appropriate components were selected and that

they were installed correctly. Discovery of an installation

mistake at this stage may lead to project time delay.

Verification of Explosion Protection. The first part of

any inspection work is to make sure that the equipment is

explosion protected in conformance with IEC 60079. Whilst

it may be labelled with compliance information, a visual check

of labelling is not enough. It is necessary to obtain a copy

of the original certificate of conformance and use this as

the inspect ion star t-point . The inspector should check

the cer tif icate validi ty, cross check the cer tificate againstequipment labels and verify the installation method complies

with the requirements as stated in the certificate.

Use of Check Sheets. It is good practice to record the

outcome of the inspection using check-sheets. The minimum

points to be considered are peculiar to each type of protection,

as summarised in the box below. In addition, the check-sheets

should contain a record of each items certificate number.

The methods used are straightforward; however, each item of

plant has its own peculiarities and some of these are often

overlooked. The importance of this matter dictates that an

expert lead the inspection at this stage.

Minimum Check Points for Installation of

Three Common Types of Explosion Protection

Flame proof enclosure installation (type d). The EEx d label is correct. The cover has been fitted correctly. The serial number on the cover and base unit match (if applicable). Cable entries are by means of EEx d certi fied gland (special rule

for enclosure > 2 litre size), EEx d certified plug or stopper, EEx dcertified cable bushing/termination or sealed conduit.

All conduits are wrench-tight with at least five full threads engaged. Any reducer used is certified.

Increased safety installation (type e).

The EEx e label is correct. Any breather is of an approved type (see certificate schedule).

Any breather is installed in correct face.

Any unused cable hole is sealed properly.

All terminal screws are tightened, including spare terminals.

Insulation is within 1 mm (0.04 inch) of the terminal throat.

If mineral-insulated copper clad (MICC) cable is used, an EEx egland is applied.

The glanding technique maintains IP54 (washers may be used).

There is no more than one conductor per clamp, unless a specialjoint is used.

Terminal creepages and clearances are within specifications.

Terminal temperatures will not exceed the temperature of thecomponent certificate.

All terminals and accessories have been installed per themanufacturers recommendations.

Terminal ratings do not exceed their label.

Intrinsic safety installation (type i).

The barrier is installed in safe area (may be in zone 1 area if insideEEx d enclosure).

The EEx marking is correct on the barrier and device, if applicable.Wiring has been segregated. Enclosures are protected to at least IP20.

Earthing has been connected in accordance with the EEx certificate.

Wiring properties are consistent with EEx cer tification. If a colour code is applied, the colour used is light blue.

Related Web Sites:

Additional information about the use of electrical equipment inhazardous areas is publicly available at numerous certification body

and specialist manufacturers Web sites, including: http://www.baseefa.com/ http://www.mtl-inst.com/ http://www.ptb.de/index_en.html http://www.stahl.de/en/start.html

Stewart Grayis a principal engineer with more than 30 years project engineering experience, including 10 in a construction-based consulting role. With his detailed knowl-

edge of the subjects of safety and inspections, he has identified a variety of hazardous area installation errors on behalf of several clients before their plants went into service.

In most cases, these errors were attributable to incorrect material selection or inappropriate installation techniques.


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In early 2007, PB was selected to assist one of the worlds largest port owner-operators to

determine the least-cost approach to meeting the power needs of a proposed container port

development in Pakistan. The major electrical loads of a container port are the quay cranesused for loading and unloading container ships. The client required our power specialists to

determine whether a stand-alone power station would be more economical than using on-board

quay crane diesel motors. The key challenge in sizing the power station was to deal with the

uncertainty associated with the loading pattern of 16 quay cranes. The electrical loads of

these cranes var y with their duty cycles, and the total load varies with the number of cranes

in operation In turn, this, is dependent on the rate of arrival/departure and the capacity of the

container ships.

Our team combined engineering and Monte Carlo techniques to successfully deal with this

problem. Monte Carlo is a method of analyzing stochastic processes, which are those governed

by laws of probability, that are so difficult that a purely mathematical treatment is not practical.1

Client feedback indicated that this technique was the most convincing method they had seen

used in the industry, whereas solutions based on traditional engineering methods only were

judged to be unreliable or conservative.

Project Brief: Using Monte Carlo Techniques toSize a Power Station By Mike Emmerton, Hong Kong, 65 6290 0737, [email protected]

1 Two earlierPB Networkarticlestell how Monte Carlo techniques

were used in risk management.Please see:

Project Risk Management andMadrids New Airport by PaulCallender, Issue 51, January 2002,pp. 56-58 and on line at http://www.pbworld.com/news_events/publications/network/issue_51/51_24_callenderp_madridairport.asp.

A Risk Assessment and Analysisfor an Existing Water ConveyanceTunnel by Kyle Ott and Joe Wang,Issue 51, January 2002,pp. 38-40, 43 and on line athttp://www.pbworld.com/news_

events/publications/network/issue_51/51_17_ottk_riskassessmentanalysistunnel.asp

Mike Emmerton is a management consultant who has been with PB since 2004.

PB acted as owners engineer to Keppel Energy for its development of the Keppel Merlimau

Cogen power plant, a 500 MW combined cycle facility on Jurong Island in southwest Singapore.

The plant now supplies power to the Singapore grid, and has provision to feed process steam

to chemical plants that are due to be part of the evolving petrochemical industry on the island.

Construction began in March 2005. Our management team ensured that everything was in

place well ahead of the schedule set by the turnkey contractor, an effort that helped lead to

the plant seeing provisional acceptance in April 2007.

The project adopted the acid cleaning method, which replaced the usual steam-blow procedure.

This resulted not only in a shortened timetable, but in improved qualities of steam and waterfor commissioning.

Our team also helped to meet stringent regulatory requirements. The plant was the first

independent power project to comply with Singapores Energy Market Authority (EMA) rules

following deregulation of the countrys electricity market in 2003.

Project Brief: Energizing Singapores EconomyBy Kamaljit Gill, Singapore, 65 6533 7333, [email protected]

Kamaljit Gill is a senior mechanical engineer who has been with PB since 2005. He was the lead mechanical engineer supervising the installation and construction of GTs,ST, HRSG, piping, tanks and balance of plant equipment on site, including chemical cleaning, steam blowing and performance testing of turnkey systems. He was also review-ing engineering design documents and drawings from contractors, monitoring schedules and quality of execution during site implementation to ensure that the plant complieswith contractual requirements. Kamaljit was also a member of the commissioning team, supervising, internal commissioning activities - conducting internal and regulatorytesting, reliability runs and performance guarantee testing.

Related Web Sites:

http://www.keppelenergy.com/

http://www.ema.gov.sg/

http://www.pbworld.com/


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PB was engaged as prime consultant to upgrade the central boiler/chiller plant at the largest

cooperative residential development in the USA, which is named Co-op City. Located inNew York Citys borough of the Bronx, Co-op City is home to approximately 55,000 residents.

It consists of 15,372 residential units in 35 high-rise buildings and seven clusters of townhouses,

three shopping centers, parking garages, schools, and houses of worship (Figure 1).

Riverbay, the corporation that manages Co-op City for the residents, wanted to make a number of

improvements for greening the complex. These included: upgrading the central plant, improving

the buildings energy efficiency, extending the existing waste recycling schemes, and introducing

water-conserving technologies. The objectives of the central plant upgrades were to reconfig-

ure the systems to optimize steam and energy utilization during peak and off peak seasons;

make the development self-sufficient for heating, cooling, and power; and lower emissions.

The Existing Boiler/Chiller Plant

The existing plant had been configured as a thermal plant with electric generation to provide

for the parasitic loads of the plant. As studied, the plant comprised the following, all of which

were fired on No. 6 (residual) fuel oil:

A central boiler plant with combined gross steam generating capacity of approximately

442 tonne/hour (975,000 lbs/hr).

One high-pressure boiler 34.5 barg (500 psig) with rated capacity of 138 tonne/hour

(305,000 lbs/hr).

Two low-pressure boilers.

Four multistage steam turbine driven centrifugal chillers, each with original rating of

6,250 tons refrigeration.

During spring and fall when there is li ttle requirement for heating or cooling, the steam

demand may be as low as from 4,536 kg/hr to 13,608 kg/hr (10,000 lbs/hr to 30,000 lbs/hr),

while winter peak heating demand can be more than 226,800 kg/hr (500,000 lbs/hr). Steam

is used for domestic water heating all year round, chilled water production in the summer,

and space heating in the winter. The old 7.5 MVA steam turbine generator (STG) had not

been operational since 1996, and the superheated steam from the high-pressure boiler was

now directed to the pressure reducing/de-superheater station and

low-pressure header to supplement the low pressure boilers

steam supply.

The electrical loads were supplied from Consolidated Edison

Company of New York, Inc. (Con-Ed), the local utility. The loadranged from an annual average demand of 12 MWe to a peak

demand of 23 MWe.

Configuration Study and Critical Analysis

PB provided a configuration study and critical analyses that

recommended installation of combined cycle gas turbine (CCGT)

cogeneration plant to replace the existing electrical supply from

Con-Ed and to meet the thermal demand of the complex.

Included were a combined heat and power (CHP) study, chiller

upgrade study, cooling tower study and miscellaneous plant upgrades.

Combined Heat and Power for USAs LargestResidential DevelopmentBy Dennis Bautista and Eric Swensen, New York, New York, 1-212-613-8840, [email protected]

The project described inthis article started as

refurbishment of a central

heat/chill plant to include

combined heat and power

(CHP) for a baseload of

approximately 26 MWe.

The majority of CHP in USA

is heat matched with top-up

electrical power from the

utility provider. Our teamidentified benefits for an

over-size (40 MWe) CHP

plant able to export up to

16 MWe to the utility grid.

Figure 1: View from the refurbished cooling tower showingsome of the Co-op Citys 35 high rise buildings in thebackground.

Related Web Sites:

New York State EnergyResearch and DevelopmentAuthority (NYSERDA):

http://nyserda.org/default.asp Riverbay Corporation:

http://www.riverbaycorp.com/newrb


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The CCGT system selected by the client from options

presented by PB went beyond the straight replacement of

plant. It was designed for flexibility of operation and retained

usable equipment where possible. Although the majority of

CHP in the USA is heat matched, an oversize (40 MWe)

plant with power-export capability was selected. This oversize

system (Figure 2) included:

Two new 13 MWe gas turbine generators, each with a

heat recovery steam generator (HRSG), fired on natural

gas as primary fuel or No. 2 (distillate) oil as back up fuel.

A new 15 MWe extraction condensing steam turbine

generator. This generator uses the existing condenser,

which has a maximum steam capacity of 29,483 kg/hr

(65,000 lb/hr). Consultation with the original equipment

manufacturer confirmed sufficient capacity.

The two existing central plant low-pressure boilers, which

will continue to operate on No. 6 (residual) fuel oil.

A new dual fuel (gas/oil) packaged boiler rated at 68 tonne/hr

(150,000 lbs/hr) that will provide further flexibility.

The PB CHP study started in May 2004 and was completed

in October 2004. Following the study and configuration

analysis, PB performed owners engineering services to procure

the gas turbine and award an engineer, procure, construct

(EPC) contract. The contract was awarded April 2006 and

construction commenced in June 2006. The installation was

completed in early 2008 and, at the time of writing, was

ready for testing and final Con-Ed approval of the intercon-

nection arrangements. The final EPC cost was $67 million.

Chiller Upgrade

The other major component of our plant work was a

configuration study and engineering services to upgrade

the existing central chil ler plant. The goals were to

increase efficiency and reliability with construction that

minimized the impact on the existing system. The primary

features of the existing central chiller plant were:

Chillers. Four Worthington multistage steam turbine

driven, centrifugal chillers, each with original rating of

6,250 tons refrigeration.

Turbine Drives. The multistage steam turbine drivers

were each rated 2,289.3 kW (3,070 hp), designed for10.3 barg (150 psig) steam supplied from the existing

central boilers.

Performance. Design chilled water flow rate was 37 8

liter/minute (10,000 gpm) each.

The main components of the chiller plant upgrade were:

Replacement of the chiller unit driveline to a more efficient,

single-stage turbine. The new driveline lowered the output

of each chiller to 5,000 tons (total combined capacity of

20,000 tons), but improved chiller efficiency by 33 percent.

New high efficiency tubes for the evaporators, condensers

and steam condensers. A new digital control system.

The chilled water plant configuration study and engineering

was undertaken in September 2004. The upgrade of the

chiller plant commenced in summer of 2006 and was completed

a year later. The final EPC cost was $12 million. The chiller

plant efficiency was improved from the existing steam rate

consumption of approximately 15 lb/ton-hr to 10 lb/ton-hr

Other Supporting Tasks

Several other tasks included in our scope supported Riverbay

Corporations goal to increase efficiency and reduce emissions.

Some of them are discussed here briefly.

Cooling Tower. The existing five-cell Marley mechanical

draft evaporative cooling tower was refurbished to address

the additional heat rejection from the new cogeneration plant.

Switchgear. A short circuit and protection relay coordination

study indicated that upgrading of the existing switchgear was

required. The new 13.2 kV switchgear includes individual

generator circuit breakers, connection to the new plant

switchgear and parallel operation with the Con-Ed utility.

The switchgear was installed by the client.

Financial Grants. We investigated the availability of grants

and successfully applied to the New York State Energy

Research and Development Authority (NYSERDA), a public

benefit corporation created in 1975 to help reduce New

York States fossil fuel consumption.

Figure 2:Combined cyclegas turbine(CCGT) plantrepresentativeof installationat Co-op City.

Dennis Bautista was lead mechanical engineer on the Co-op City project. He is a former PB employee.

Eric Swensen, an assistant vice president and senior engineering manage, has extensive experience in power engineering, ranging from initial feasibility studies and

conceptual design, through detailed design, construction, and commissioning.


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The Northeast Blackout of 2003, the largest power outage in North American history, revealed

poorly performing stand-by emergency generators and emergency power distribution systemsat some of New York Citys hospitals. This event led NYC Health and Hospital Corporation

(NYC HHC), the owner, to have feasibility studies performed for upgrading emergency power

systems at several of its major hospitals and diagnostic and treatment centers. The following

year the Dormitory Authority of the State of New York (DASNY), which acts as NYC HHCs

agent, retained PB to validate the aforementioned feasibility studies and to develop design and

construction documents for upgrading the emergency systems at nine hospitalsBellevue,

Coler, Elmhurst, Goldwater, Gouverneur, Harlem, Lincoln, Queens and Woodhulland three

diagnostic and treatment centersCumberland, Segunda Ruiz Belvis, and Morrisonia.

Bellevue, Elmhurst, Harlem and Lincoln Hospitals received priority over the other facilities

because they serve as Level 1trauma centers.1 At the time of writing (May 2008), Bellevue

and Elmhurst Hospital projects were in the middle of the contractor bidding process.

PBs role was similar for each hospital:

Investigate the site.

Measure and record existing running loads.

Perform load analysis.

Provide a study report to document findings and recommendations to address system

deficiencies.

Meet and correspond with local utility companies to request upgrades in utility services.

Provide bid documents and construction support services to upgrade emergency

systems, including replacing and adding generators; synchronizing generator switchgear;

and incorporating bypass isolation type transfer switches, emergency distribution

switchboards and panelboards. Provide bid documents and construction support services to address code violations

associated with the existing emergency systems and to connect code-required HVAC

equipment to emergency power.

Design Challenges

General Challenge. Implementing electric power upgrades within active hospital facilities

is challenging, and it is essential that electric power be maintained during construction. Even a

partial loss of power can cause severe operational problems along a chain of activities:

Power loss to lighting systems can make it impossible to dispense medicine accurately,

carry out precise medical laboratory work or perform surgical procedures.

Power loss to refrigerators storing tissue, bone or blood can leave the facility without

crucial resources.

Power loss to essential life support equipment, such as heart pumps, medical vacuum

pumps, dialysis machines, and ventilators, can result in loss of life.

Developing design and construction documents that virtually eliminate interruptions to

electric power during construction was paramount. Thorough up-front planning was essential

so that these documents incorporate effective strategies for minimizing the impact of

construction on hospital operations.

We exercised just such careful planning for the NYC HHC facil ities, and included language for

sequencing construction into design and construction documents for each one. During the

Ensuring Continual Power Supply for New YorkCity Hospitals By Ross Krupnik, New York, New York, 1-212-613-8889, [email protected]; and

Warren Andrews, Atlanta, Georgia, 1-404-364-2650, [email protected]

Several of New York Cityshospitals and diagnostic

and treatment centers

needed upgrades to their

power systems to ensure

they would maintain services

during power outages. The

author tells about much of

the research and planning

PB conducted for these

upgrades and, equallyimportant, for ensuring that

interruptions to power

were minimized during

construction.

Ross Krupnik, an electrical engineer,has a B.S. degree with a double major-electrical and computer engineering,and biomedical engineering. Hecompleted his advanced studies inelectrical engineering in June 2008.Ross joined PB in 2006 and served as

an engineer on the hospital studiescovered in this article.

Warren Andrews, a senior engineeringmanager and PB vice president, wasprogram manager for the New YorkCity hospitals project. He specializesin power design. Warren has beenwith PB since 1997.

1 Level 1 trauma centers offer themost comprehensive emergencymedical and surgical servicesavailable to patients sufferingtraumatic injuries.

Related Web Sites:

Dormitory Authority of theState of New York:www.dasny.org

New York City Health and

Hospitals Corporation:www.nyc.gov/hhc


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planning phase, our team:

Performed detailed surveys and consulted with facility

administrators, maintenance and operation staff and other

personnel to gain a thorough understanding of specific

functions in each area of each facility

Identified and documented the location of all essential

equipment, and critical and life-safety loads Identified the local source of normal and emergency power

serving all these loads

Identified areas in each facility that would serve as swing

space for locating temporary power distribution equipment.

This planning allowed us to produce drawings specifying

construction phasing for accurate, detailed equipment

removals and relocations and for temporary power. It also

enabled us to identify windows of opportunity for scheduled,

short-duration interruptions of power to minimize impacts

on facility operations.

Bellevue Hospital. After our analysis of the existing and

planned electrical loads, we discovered that the hospitals

existing four 400 kW generators and one 600 kW generator

could not accommodate a total failure of the normal electrical

power feed from the local utility. We proposed:

Replacing the 400 kW generators with four new 725 kW

generators and one 1500 kW generator to provide

enough power for the existing and future loads. These

would be installed and synchronized with the remaining

600 kW generator.

Replacing the existing emergency switchgear.

Modifying and upgrading 35 of the 47 existing automatictransfer switches (ATSs) to accommodate future loads.

Upgrading various systems, including the fire pump, fire

detection system, fire alarms, and alarms for medical gas

and vacuum systems.

Various components of the emergency electrical equipment

are located throughout the hospital rather than at centralized

locations. Further, Bellevue Hospital is Americas oldest

public hospital, and now has little room for larger equipment.

We collaborated with facility management and the manufacturer

of the switchgear, ATSs, and generators to fit the equipment

in the available space. (For example, once we determinedhow much space was available for switchgear, manufacturers

worked within those restrictions to develop switchgear

frames (boxes) that fit.) The four 725 kW generators will

be installed on the 13th floor close to the existing 600 kW

generator, while the 1500 kW generator was planned to be

installed in the sub-cellar. The paralleling switchgear for these

generators is on the 13th floor.

Toward the end of the design process, DASNY asked that we

revise our design for the sub-cellar 1500 kW generator to

offer it more protection against flood damage. We raised the

generator six feet (2 m) and placed it on a new platform. It will

be supported in an areaway next to an on-ramp along the

FDR Drive, a heavily traveled highway on Manhattans east side.

The 47 ATSs are located in electrical rooms throughout the

hospital. Our engineers had to arduously examine the available

riser space to determine where the replacement switchescould be located. This effort required the engineers to visit

each floor of the hospital and venture into areas that required

special security by the hospital or NYC Department of

Corrections because of the patients that occupied those areas.

Elmhurst Hospital. As was the case at Bellevue, Elmhurst

Hospitals current generators could not accommodate a total

failure of the normal electrical power feed from the local utility.

We proposed installing generators at three locations, each with

different setups, and making additional upgrades, as follows:

Replacing one 350 kW generator with a new 600 kW

generator and synchronizing it with an existing 400 kWgenerator

Replacing another 350 kW generator with a new 600 kW

generator

Synchronizing three existing 600 kW generators with one

new 1500 kW generator

Upgrading 16 of the 30 existing ATSs and adding five new

ATSs to accommodate future loads

Upgrading various systems, including the fire pump, fire

detection system and fire alarms.

The generators at the three locations will be activated basedon the particular load that was lost and the size of the

power outage. If for some reason the local generator cannot

supply enough load, it will activate and synchronize with the

1500 kW generator. This built in redundancy helps to assure

that patients, doctors, and hospital staff will not notice the

change from normal to emergency power.

While Elmhurst is not as tall a building as Bellevue and has its

emergency power equipment at three centralized locations,

these locations are located at nearly opposite ends of the

hospital. This configuration requires that cable between the

generators and paralleling switchgear be run through the

cable support system in the sub-basement. The conduit runs

are layered many times over and noticeably reduce the height

of portions of the sub-basement corridors. An electrician at

this hospital told us that the supports for the conduit had to

be replaced recently because the weight of the conduit caused

the supports to buckle. This reduced the available space for

new conduit and made it more challenging to run new feeders.

PB worked closely with facility management and its electricians

to make the most efficient use of the hospitals remaining

space for new feeders and equipment.


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PBs power specialists have been working with New York Power Authority (NYPA) for more

than a decade to undertake energy conservation designs for college campuses, municipalitybuildings and state office buildings throughout New York State. At the State University of New

York (SUNY) campus at Brockport, New York, we developed improved systems and plant that

reduced energy consumption, enhanced the reliability of campus systems and increased the

comfort and safety of building occupants. Some of the key features of this work included:

Introducing a distributed chilled water loop that linked individual chillers in various

buildings to increase part-load efficiency

Linking boilers in individual buildings to improve their use and extend boiler life by

reducing cycling.

Getting Started

The Brockport campus is comprised of 40 buildings, most of which are 30 to 50 years old.

We assessed these buildings and their chiller, boiler, and heating, ventilation and cooling

equipment for potential energy conservation measures. Our team conducted an extensive

data collection on the campus equipment to perform cooling and heating load calculations.

An economic analysis (life-cycle cost analysis) was performed using Building Life-Cycle Cost

(BLCC) 5.2 software, which was developed by the National Institute of Standards and Technology

under the Federal Energy Management Program (FEMP). The software methodology complies

with American Society for Testing and Materials (ASTM) international standards related to

building economics as well as FEMP guidelines for economic analysis of building projects.

We developed a number of energy conservation measures (ECMs) that were subsequently

ranked based on payback and client preference. The college approved seventeen of them,and PB provided the detailed design and construction management for the work.

Distributed Chilled Water Loop

A key energy savings was obtained on the chiller system providing air conditioning (AC) for

the buildings. The campus had eight electricity-driven water-chillers located in individual buildings.

Many of the chillers were either oversized or inadequate for the required duty. By their nature,

constant speed chillers operate most efficiently when the cooling load is close to the chiller

capacity. They become less efficient in part load use, which is the majority of the cooling season.

We designed an underground chil ler water loop running in concrete tunnels to connect the

individual chillers into a distributed chilled water plant. This technique, normally adopted onlyin centralized plant systems, improved utilization of the installed capacity and increased the

seasonal efficiency. Fewer chillers run during partial load conditions, so the lives of individual

machines will be prolonged and efficiency increased. System redundancy improved also, and it

was possible to install additional air handling units without the addition of new chillers.

Installation of underground piping is always a challenge and this case proved to be no exception.

Although we had the campus underground utility records, we asked the contractor to investigate

pipe routing with ground penetration radar. We had to confirm that we would not encounter

abandoned asbestos piping that was not shown on any drawings, gas distribution lines that

were not active, or stone foundations of old houses along the way.

Changes to Chiller, Boiler and HVAC Lower EnergyConsumption at a University CampusBy Damee Choi, New York, New York, 1-212-613-8835, [email protected]

New York State has a goalof cutting energy use

in schools and other

government facilities by fif-

teen percent by 2015. Our

work at the State

University of New York

campus in Brockport illus-

trates how PB is helping

the state meet this goal.

Improvements to the boilersystem and other energy

saving measures resulted

in a six percent reduction

in energy consumption.

Acronyms/Abbreviations

AC: Air conditioning

ECM: Energy conservationmeasures

HVAC: Heating, ventilation, airconditioning

LED: Light-emitting diode

NYPA: New York PowerAuthority

SUNY: State University ofNew York

VAV: Variable air volume

VFD: Variable frequencydrive

Related Web Sites: http://www.brockport.edu/

http://www1.eere.energy.gov/femp/

http://www.astm.org/

http://www.nyserda.org/programs/state.asp


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Improving Kitchen Steam Boiler Operation

The original boiler was sized to meet the kitchen load

demand, but over time part of the steam kitchen equipment

had been converted to direct gas or electric fired equipment,

so the boiler had become oversized, resulting in extreme

short cycling and a drop in efficiency. We installed a steam-

to-water heat exchanger up stream of a direct fired gasdomestic hot water heater serving the kitchen. The system

was arranged to meet the kitchen steam demand first and,

if steam was available, to then feed the new heat exchanger.

Cold water to the domestic hot water heater passes first

through the new heat exchanger and is heated there by the

excess steam. It then flows to the direct fired heater. If the

available steam is adequate for domestic hot water production,

then the heater does not fire. If the steam boiler capacity

cannot meet the demand at this moment, then the heater

fires and heats the water to the desired temperature.

Wide Range of Additional Energy ConservationMeasures

The following energy conservation measures that we imple-

mented can often be applied to other projects.

Water Pump Control. In a number of buildings, we installed

variable frequency drives (VFDs) on the water pumps and

outside air fans to minimize the water pumping cost and

outside air conditioning costs. For example, the Tuttle North

building had five constant speed pumps that served the

heating system. VFDs were installed at these pumps and

the three-way heating coil control valves were converted tooperate as two valves to support the variable flow operation.

During the occupied hours, the pumps modulate flow to the

coil, which reduces power consumption particularly at partial

load conditions. When the building is unoccupied, the flow is

maintained at 20 percent to avoid coil freezing.

CO2 Sensors. The majority of buildings featured air handling

units that operated with a fixed amount of fresh air intake

that was independent of the building occupancy. This mode

of operation, common for building design until several years

ago, results in unneeded energy consumption. We introduced

CO2 sensors (indoor air quality sensors) that reduce thefresh air intake, and consequently, the heating and/or cooling

energy consumption, particularly when the building is only

partly occupied.

The CO2 sensors are located in the return air ducts of 56 air

handling units. They have automatic controls to modulate

their outside air dampers and exhaust dampers to suit building

occupancy. The CO2 sensor readings fluctuate depending on

building occupancy levels. The outside air is set to a minimum

rate required for the building minimum exhaust.

HVAC Upgrade. At the Metro Center, which has class rooms

and lecture halls, the HVAC system was upgraded to include a

new variable air volume (VAV) system with summer economizer.

This replaced the old high pressure air handling units and

window mounted direct expansion (DX) units. Fin tube radi-

ation installed at the building perimeter improved occupant

comfort and eliminated the need for costly reheating systems.

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