PROJECT PROFILEPROJECT PROFILE

THE UTILITY GRID ASS TAND-BY POWER

PROJECT PROFILE

Located outside of Rochester, New York State, US,Harbec Plastics produces highly engineered, customplastic parts for customers in the medical, auto-

motive, consumer goods, and other industries. Thecompany makes every effort to minimize waste throughre-use and recycling, even saving floor scraps which,combined with plastic granules and other waste products,are re-melted to produce long-lasting, decay-resistantplastic lumber.

Likewise, energy efficiency is another of the company’spriorities. The 40,000 sq. ft (3700 m2) facility uses an arrayof microturbine systems to produce high-quality,uninterrupted power and heat for space heating andcooling. Some of the power is even used to charge thecompany’s fleet of electric vehicles, further reducing airand noise pollution.

The company, which now has 100 employees, wasoriginally a machine shop performing various welding andfabricating processes; by using computer numericalcontrolled (CNC) machinery this has now developed intothe production of high-value, customized tools – instead ofhigh volume, mass-produced parts. After developingexpertise with computer-controlled metalworking equip-

ment, the company found the same techniques applied tothe growing market for plastic parts.Today, it makes use ofmore than 200 polymer blends to produce high-tolerance,specialty parts using engineered resins and complexinserting processes.

ON-SITE POWER

Harbec supplies complex, one-of-a-kind parts withextremely short lead times. Being dependent on a largenumber of CNC spindles and numerous CAD stations, theworst possible problem the operation faces is a powerfailure. Even during a momentary grid outage or voltageproblem, the sophisticated sequences that the CNCmachines are performing are lost, requiring 6–8 hours toreprogram and restart. If the cutter on the CNC damagesthe part being made, days of work in process may be lost.Multiply this problem by the 30 CNC machines conductingthese processes, then add the loss of at least one hour ofproduction time to reset each of the many otherproduction machines, and the cost of lost raw materials,and the implications of a power failure, start to becomeclear.

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The worst possible problem faced by a manufacturing facility in

the state of New York used to be power interruptions. Even a

m o m e n t a ry power event would be as damaging as a long outage,

as days of work in process would be lost and computer numeri-

cal controlled machinery and other production equipment would

need to be re p rogrammed and reset. Earlier this year a new, micro-

turbine-based power, heat and chilling system was installed.

STEVE GILLETTE reports on that new system and its performance.

The Harbec Plastics plant

THE UTILITY GRID AS STAND-BY POWER

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Microturbines are scaled down turbine engines with integratedgenerators and power electronics. They are generallycharacterized by having often only one rapidly moving part(moving at 100,000 rpm) supported either by air- or liquid-lubricated bearings. The microturbine generates high-frequencyAC power that is rectified by a power electronics package intoutility grid-quality, three-phase 400–480 V AC. Microturbines canoperate on a wide variety of gaseous and liquid fuels, and haveextremely low emissions of nitrogen oxides (although factoryrated at full load at ‘less than 9 ppmV NOx @ 15% O2’, Capstonemicroturbines operating on natural gas have been independentlymeasured at less than 3 ppm by the California Energy Commissionand by the Cambridge Energy Research Associates). Electricalefficiency of microturbines is in the 25–30% range. Although thelatest combined cycle gas turbines can achieve maximum outputefficiencies nearing 60%, the US Environmental ProtectionAgency and the Department of Energy notes that average powerplant efficiency in the country is 34%. Since 5–10 points of that islost in transmission and distribution, the national average mayactually be about the same as that of on-site microturbines.

Large-scale combined cycle turbines use ancillary heat toincrease efficiency to 50–60%. Ancillary heat from microturbines

can be used on-site for water and space heating, process drying,food processing and absorption chilling. Doing so delivers a totalsystem efficiency of at least 70%, and use of the exhaust streamfor process drying, greenhouse heating/CO2 supplementation andsimilar tasks yields efficiencies exceeding 90%.

Capstone Turbine Corporation began shipping microturbinesin December of 1998. As of September 2001, Capstone had soldmore than 1800, 30 kW and 60 kW microturbines, primarily inNorth America, Japan and Europe. Capstone’s nearest competitorwas Honeywell Power Systems, which had produced a total ofabout 300 of their 75 kW Parallon microturbines. However, earlierthis year Honeywell recalled, or disabled in situ, all their Parallonsystems and have said that they were unable to capturemicroturbine market opportunities as well as hoped.

Two significant players planning to offer microturbinesystems later this year are Ingersoll-Rand and Turbec (the latter isa co-operative venture of ABB and Volvo). The 70 kW Ingersoll-Rand PowerWorks microturbine will use a two-shaft design thatmay have some advantages in secondary mechanical driveapplications. The 100 kW Turbec T100 will have a pre-integratedheat exchanger to deliver a claimed 30% electrical efficiency andan 80% total system efficiency.

Microturbines

In June 1999 Harbec experienced three such outages,and company President Bob Bechtold was concerned thatsomething had to be done. The criteria he outlined for analternative system included the following:

• The system must be the facility’s primary source of power.Since even a momentary power event was as damaging asa lengthy one,stand-by generation was not adequate.B a t-tery UPSs cannot respond properly to the inrush currentof the firm’s many high-horsepower motors. The on-sitesystem must instead be a continuous source of power tothe facility, with some level of redundancy. If the on-sitesystem failed, as well as the redundant system, the gridwould serve as the final back-up. Since the on-site systemnormally operates independently of the grid,the odds ofboth failing simultaneously are extremely low.

• The system must have extremely low emissions . The ISO14000 certified company’s commitment to an environ-mentally benign system ensured that investigationfocused on wind power, fuel cells and microturbines.

• The system must be efficient.The company envisioned usinga system that would recapture waste heat from power gen-eration for use in space heating, process drying and evenspace cooling.

• The system must be commercially available, and econom -ically feasible.

As far as Harbec was concerned,microturbines fulfilled allof these criteria.

THE HARBEC SYSTEM

Electrical and mechanical design firm IBC Engineeringwas enlisted to evaluate the electrical loads of the building,and selected the number of microturbines. Nearly all of the25 Capstone Turbine systems were mated with a heatrecovery boiler; each boilers using the exhaust heat fromfour microturbines to generate 100ºC (210ºF) water. Totalsystem efficiency exceeds 70%. (A webcam view of thesystem is at www. h a r b e c. c o m / l p / s t i t c h e d _ r e s u l t _ c o g e n . h t m l )

Generator

Generatorcooling fins

Exhaustoutlet

Recuperator

Combustionchamber

Recuperatorhousing

Compressor

Air bearings

Turbine

FIGURE 1. Cutaway of the Capstone 330 MicroTurbine

THE UTILITY GRID AS STAND-BY POWER

In the winter, the hot water is routed to a radiant floorheating system built into the concrete slab of Harbec’swarehouse area. This warehouse was added as part of anoverall remodel that included the on-site power system,and is the first industrial warehouse in the US to complywith the LEED standard for ultra-efficient construction.LEED – Leadership in Energy and Environmental Design– is a system managed by the US Green Buildings Council,and is designed for rating new and existing buildings. Theenergy efficiency-enhancing features include the use ofrecycled materials, daylighting, twice the insulation used in

typical construction, and heat from the microturbines asthe source of space heating.

It is also advantageous to use the microturbine heatduring the non-heating season. The facility had no airconditioning, so a cooling system was designed using hotwater to fire an absorption chiller that generates chilledwater. The chilled water is piped to a fan-coil system thatnow air conditions Harbec’s warehouse and productionareas. Thus, air conditioning is made available with nearzero electrical load. And added benefit is an integrateddesiccant that reduces humidity and eliminates a materialsdrying process that had been a routine cost during thehumid summer months.

System performanceThe system ran and has continued to run well throughoutthe summer months.This is the period historically plaguedby power outages, and during which the facility’s powerload is at its highest. Harbec uses a number of sophisti-cated production devices that have sensitivity to very briefvoltage sags and other power quality events which wouldhave no perceptible impact on lighting, PCs and so on.

The system has worked reliably,and one additional Model330 has been added for a small capacity increase, bringing thetotal to 25 units.The workforce has been especially pleased tobenefit from their ‘electricity-free’ air conditioning as therewas no air conditioning at the company prior to thisi n s t a l l a t i o n . The system is also used for drying of rawm a t e r i a l s, thus streamlining a Harbec production process.The Harbec installation

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THE UTILITY GRID AS STAND-BY POWER

Harbec has secured a natural gas contract with T X Uthat delivers fuel to the facility at an average cost ofU S $ 6 . 8 5 / M c f. At this rate, the value of the hot waterrecovered from the microturbines equates to $0.03/kWh .Net of this recaptured heat, power is generated forapproximately $0.074/kWh , compared to the mean gridprice of approximately $0.105/kWh . At the time of writing,long-term natural gas contracts are available in many parts of the USA for about $4/Mcf; at that rate, the perk Wh cost would net at less than $0.05/kWh . Th i sdifferential will pay for the capital cost of the system evenwithout outage cost avoidance. More importantly, H a r b e cwill have achieved certainty in its source of power,and known costs for the foreseeable future. This issignificant in an environment of growing uncertainty aboutthe reliability and cost of grid-supplied power.With slightlyhigher electrical efficiency and hotter exhaust temperature,C a p s t o n e ’s newer microturbine models would provideeven more favourable economics with just half the numberof systems. Incentives for CHP installations available inseveral parts of Europe and the Americas make furtherimprovements to the return-on-investment picture.

C O N C L U S I O N

All businesses, but especially continuous processmanufacturers, require a continuous supply of high-qualitypower. When even momentary disruptions result in lostwork-in-process, down time and missed deadlines, on-sitepower systems provide an economically attractive

alternative to avoid such financial losses. Microturbinesare among the proven technologies capable of providing acontinuous source of high-quality power with near-zeroemissions and extremely little maintenance. Couplingthem with heat recovery and providing thermal energy forspace and process conditioning makes these systemsextremely energy efficient.

Even greater total system efficiencies – exceeding 90%– are possible when the exhaust is used directly in processdrying. Since Capstone systems use no liquid or chemicallubricants or coolants, there is no exhaust streamcontamination to foul sensitive materials. (One Capstonedistributor, Advantica in the UK, has even engineeredaward-winning installations in which the exhaust stream isported directly into horticultural greenhouses.)

The economics of on-site power with heat recoveryenable businesses to achieve an extremely reliable powersupply from a system whose energy economics can pay foritself. In these times of volatile electricity prices, on-sitegeneration systems enable companies to budget forexactly what their electricity will cost. Such systems arecreating a positive working environment at businesses likeHarbec Plastics.

Steve Gillette is Capstone’s Director of CHP Applications.Fax: +1 818 734 5320e-mail: sgillette@capstoneturbine.comweb: www.microturbine.com

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