IFI CAPACITY ENHANCEMENT PROJECT MP TO IP NETWORK COMPRESSION

17th October 2012

Phil Winnard Project Engineer CNG Services Ltd.

WHY DO WE NEED IN-NETWORK COMPRESSION ?

BIOMETHANE PRODUCTION - DEMAND ISSUE

• Typically AD plants are sited in rural areas with MP or IP connections – Grid does not always have enough demand related capacity – Around 30 to 40% of plants constrained by this

• BM plants have to run at almost continuous rate as the AD digestion process is continuous.

Continuous Biomethane Production Variable gas demand profile

PRODUCTION / DEMAND EXPLAINED

• Seasonal and diurnal demand profiles combine to create periods of very low demand; night time in summer months – May be less than 1% for a few

hours at night on a domestic network

• Hence BM produced at steady rate cannot be absorbed

• Compression required for very low demand periods

• Energy usage approx. 2 to 3% of gas energy compressed.

THE CONCEPT

• Compressor selected and module designed to achieve delivery upstream of excess supply (Biomethane Plant) over local demand (Seasonal minimum)

IP - 7 Bar nominal)

Other 7 bar to 2 bar off-takes - typical

7 bar to 2 bar off-take Normal flow

Compressor Reverse flow – say 100m3/hr

2 bar customer off-takes - typical

MP - 2 Bar nominal)

Biomethane source – say 100m3/hr

THE PILOT PROJECT OBJECTIVES

• To prove the principle of increasing the “effective” capacity of a Medium Pressure network to support Biomethane plants that would otherwise be constrained and hence uneconomic

• To design, build and test safe systems of operation to ensure a safe and secure gas supply at all times whilst running the Compressor

THE PILOT COMPRISED

• Concept design • System modelling for trial location selection • Development of compressor, pipes and supply

points network modelling tool • Detailed design engineering and G17 appraisals

/approvals including mechanical, electrical, instrumentation and control disciplines

• Equipment sourcing • Module fabrication and installation with associated

power and control • Operational test in service

PROJECT TIMELINE

• Original feasibility study Dec 2009 for NGN using IFI funding. Theoretically confirmed concept to be viable

• Agreed two further stages required – Pilot field trial, precursor to – Apply to actual project

• NG and NGN agreed joint approach summer 2011 • Work began Sept 2011 • Pilot study at Skipton completed August 2012 • Final report and Open day to be completed by September

2012 • 12 MONTHS FROM CONCEPT TO IMPLEMENTATION

WHAT ARE THE DESIGN ISSUES?

DESIGN PRINCIPLES

1. Ensure a continued safe and secure gas supply whilst the Compressor is operating

2. Ensure the Compressor is effective in moving excess gas production over demand

DESIGN PRINCIPLE – SUPPLY SECURITY

• Compressor module designed so that : – Medium pressure system cannot be drawn down

below a safe minimum

– Intermediate pressure system cannot be pressurised above a safe maximum

SUPPLY SECURITY – MP - LOW PRESSURE

• Compressor module low pressure protection : – Pressure transmitter trips out Compressor when MP low point is reached

– Mechanical slam shut device closes when MP low – low point is reached

Gas flow To PLC To PLC

Discharge pressure

transmitter (High

pressure)

Suction pressure

transmitter (Low

pressure)

Suction Slam Shut (Low - Low pressure)

Discharge Slam Shut

(High - High pressure)

SUPPLY SECURITY – MP - LOW PRESSURE

• Compressor module low pressure protection : – Pressure transmitter trips out Compressor when MP low point is reached

– Mechanical slam shut device closes when MP low – low point is reached

Gas flow To PLC To PLC

Discharge pressure

transmitter (High

pressure)

Suction pressure

transmitter (Low

pressure)

Suction Slam Shut (Low - Low pressure)

Discharge Slam Shut

(High - High pressure)

SUPPLY SECURITY – IP – HIGH PRESSURE

• Compressor module designed so that : – Pressure transmitter trips out Compressor when IP high point is reached

– Mechanical slam shut device closes when IP high – high point is reached

Gas flow To PLC To PLC

Discharge pressure

transmitter (High

pressure)

Suction pressure

transmitter (Low

pressure)

Suction Slam Shut (Low - Low pressure)

Discharge Slam Shut

(High - High pressure)

SUPPLY SECURITY – IP – HIGH PRESSURE

• Compressor module designed so that : – Pressure transmitter trips out Compressor when IP high point is reached

– Mechanical slam shut device closes when IP high – high point is reached

Gas flow To PLC To PLC

Discharge pressure

transmitter (High

pressure)

Suction pressure

transmitter (Low

pressure)

Suction Slam Shut (Low - Low pressure)

Discharge Slam Shut

(High - High pressure)

COMPRESOR TRIP IN

• Compressor module low pressure protection : – Pressure transmitter trips in Compressor when MP high point is reached

Gas flow To PLC To PLC

Discharge pressure

transmitter (High

pressure)

Suction pressure

transmitter (Low

pressure)

Suction Slam Shut (Low - Low pressure)

Discharge Slam Shut

(High - High pressure)

CIRCULAR FLOW

7 bar to 2 bar off-take Normal flow

Compressor Reverse flow

Potentially no effect on moving excess gas from Biomethane Production

CIRCULAR FLOW

• Modifications to PRS Auxiliary system

Solenoid valve

Pilot regulator safety device

THE COMPRESSOR HYDROVANE

COMPRESSOR OPERATION

Vacuum trip

Unloader valves

NRV

COMPRESSOR OPERATION

PLC DESIGN KINGSTON CONTRACTS

PLC CONTROL FUNCTIONS

Biomethane Plant

Compressor

PRS

IP - 7 Bar

MP – 2 Bar

PLC

MP Low Pressure Points

MIMIC DISPLAY

• PLC display showing system device status

CONTROL FUNCTIONS

• Compressor starts on high set point MP pressure • Compressor stops on low set point MP pressure • Compressor stops on high filter differential pressure • Compressor stops on high outlet temperature • Compressor stops on Low – Low MP pressure – indicates

Slam Shut closed • Compressor stops on High – High IP pressure – indicates Slam

Shut closed • Regulator solenoid valve closes and opens on Compressor

start and stop – indicates closed or open • Compressor stops on low MP system extremity pressure

DESIGN CONTROL

DESIGN RESPONSIBILITY MATRIX

• Each of the design disciplines was subjected to the Northern Gas Networks G17 review process a matrix of disciplines and responsibilities is shown as follows:-

Discipline Design responsibility G17 appraisal /approval

Mechanical CNG Services / Automated

Flow Controls GPS Systems

Hazardous area CNG Services GPS Systems

Electrical Technica Ltd Technica Ltd (Chinese wall)

Instrumentation Kingston Contracts Ltd Kingston Contracts Ltd (Chinese wall)

PLC Design Kingston Contracts Ltd Kingston Contracts Ltd (Chinese wall)

Civil Northern Gas Networks Northern Gas Networks

SKIPTON PILOT

PILOT OBJECTIVES

• To check the functionality of the Compressor and its control equipment under varying supply and demand conditions.

• To provide data for validating the network model

SITE SELECTION

• Four sites compared in NG and NGN networks • Skipton offered best combination of ease of

connections for compressor, adequate site access and relatively simple MP network

• Low seasonal demand of segregated network fits neatly into commercially available compressor module (100m3/hour)

NETWORK SNAP SHOT

NEWTWORK SCHEMATIC

KEIGHLEY

SKIPTON

SNAYGILL

PLAN IMPLEMENTATION

Implementation of the plan was subject to the following: • G17 appraisal, approval and user acceptance of the following

components:- – Mechanical design – Hazardous area design – Electrical design – Instrumentation design – PLC design – Civil Engineering design

• Acceptance/approval of the prepared non-routine operational

(NRO) procedure • Sign off of actions identified in the HAZOP

FILED TRIAL RESULTS

FIELD TRIAL RESULTS –NO EFFECT ON IP

• The graph shows the Intermediate pressure network recorded pressure during the period of the trial. The operation of the compressor is shown to be making very little impact on the IP network pressure.

5.80

6.00

6.20

6.40

6.60

6.80

7.00

13:30 13:59 14:28 14:57 15:25 15:54

Whinny Gill Outlet, Skipton Inlet

Skipton 7 bar Inlet Pressure Whinny Gill 7 bar Outlet Pressure source

FIELD TRIAL RESULTS – MP TRACE

• The graph shows a plot of the Medium Pressure network pressure at Skipton. Notes on the graph shown the effect on the MP network as the compressor trips in an out.

FIELD TRIAL RESULTS SUMMARY

• The study has successfully tested the design concept including the operational and safety engineering principles.

• The challenge going forward is to apply the current design into a fully operationally reliable solution for demand management of excess Biomethane on a real project

MODELING TOOL OVERVIEW TSC SIMULATIONS

MODELING TOOL FUNCTIONALITY

• Predict the time when the Compressor will start / stop

• Predict pressure distribution at customer off-take nodes during compressor operation

Lowest pressure node goes green

DIURNAL PROFILE

MODELING TOOL OVERVIEW - RUN MODES

• The modeling tool has two running modes as follows:- • Steady state mode • Dynamic mode

The Accuracy - Speed bar allows increased speed in dynamic mode by sampling data at less frequent intervals

STEADY STATE MODEL RESULTS –SKIPTON – 14% Demand

Biomethane Flow

Compressor triggers

Demand reducing

MODELING SEQUENCE – DYNAMIC

Biomethane Flow

Effective demand and regulator flow reducing

Network Low Point Pressure

Compressor trips in and out 2X

Note: The network low point node position changes as shown on the following slide

MODELING SEQUENCE – NETWORK LOW POINTS

• The location of network LOW POINTS will change due to the transient effect of the Compressor starting and stopping.

LowPressureNodeName LowPressureValue SkiptonCompLow Pressure Node Name Low Pressure value Compressor flow SCMH

Model Time Calc Cycles CNG:CNG Maths:Low_Pressure_Node:1000011 CNG:CNG Maths:Low_Pressure_Value:1000011hh:mm:ss Pa

02:14:16 639189 22100190000264 291199.0659 002:14:17 639268 22100190000264 291203.6595 002:14:18 639347 22100190000264 291208.3118 002:14:19 639426 22100190000264 291212.9642 002:14:20 639505 22100101080004 291218.8447 002:14:21 639584 22100190000264 291222.269 002:14:22 639663 22100190000264 291217.3598 -40.8299160102:14:23 639742 22100190000264 291205.2952 -88.8612533902:14:24 639821 22100190000264 291191.469 -135.686959402:14:25 639900 22100190000264 291169.5341 -183.703571502:14:26 639979 22100110011004 291137.1001 -231.104563302:14:27 640058 22100190000264 291110.2572 -238.106012502:14:28 640137 22100190000264 291091.1808 -238.090455502:14:29 640216 22100190000264 291061.7184 -238.066247902:14:30 640295 22100190000264 291027.9059 -238.038557402:14:31 640374 22100190000264 290997.5977 -238.013807802:14:32 640453 22100190000264 290970.903 -237.992010202:14:33 640532 22100190000264 290941.9668 -237.968312802:14:34 640611 22100190000223 290911.1911 -237.943440602:14:35 640690 22100190000264 290881.5743 -237.9189148

SUMMARY

• Insert the diurnal demand profiles • Carry out Steady State runs are then carried

out at the lower end of the seasonal demand profile

• Once the Compressor trigger demand has been identified a Dynamic run is carried The results of the Dynamic run will enable a plot to be made of the Compressor activity, low point pressures and locations

QUESTIONS

IFI CAPACITY ENHANCEMENT PROJECT

Economic/Regulatory/Safety Review

17th October 2012

Iain Ward CNG Services Ltd

Project Purpose and Characteristics

• Estimates are that around 30% of potential biomethane injection projects have a low demand/capacity issue

• Often no use for CHP waste heat and hence not having gas grid capacity is bad in CO2 and efficiency terms

• Within Grid compression will alleviate injection capacity issues in most such projects – Potential for all pressure tiers (design changes but principles the same) – Expected most applications in 2 to 7 bar grids, some to high pressure (20 - 30

Bar) – Significant contribution to potential projects and Biomethane volumes

• Significant costs savings by having a local connection to nearest grid and a remote compressor (compared to running high pressure pipeline)

• Skipton project has proved that this is a viable option that can be taken forward by GDNs subject to regulatory approval

What is not affected by the compression option?

• No gas quality, odorant or CV issues as all are managed at the entry point • The compression plant will be remote from the biomethane entry point

– Only in rare circumstances will they be near each other – At Skipton, compression plant is 2km from simulated biomethane entry point

• In addition, as per any normal biomethane injection project, the injection can be expected to be typically > 95% reliable but <100% (European experience) – The GDN cannot rely on BM injection as a backfeed to a capacity constrained

network and hence BM cannot contribute to overall network capacity enhancement

Stage 1. Compression Option Feasibility

• First, identification of the capacity constraint – GDNs can do this although it is appreciated that their network models are not designed

to provide summer minimum flows – Also, GDNs have limited flow data from the network

• If there is a capacity shortfall, Feasibility Study required: – Flow characteristics?

• Inlet and outlet pressure, Flow range, Expected running hours per year

– Is there a site available to install the compressor • Land available? Electricity supply? Likely to receive planning consent?

– What type of compressor? • Cost (capex and maintenance) Design? (one machine or two)

– Impact on the network • Transient and steady state impact of the compressor

• Study expected to take 6 weeks, cost around £10- 20K (though costs will not be known until the GDNs carry out such a Study) – Aim of the Feasibility is to indicate go/no-go

Stage 2. Compression Plant Design and Build

• Following Feasibility Study, Biomethane Producer can decide that they want the GDN to implement the project

• Design and Build Agreement – Cost likely to be in range £100 - £500k – Time likely to be around 9 months

• Network Entry Agreement

– The normal capacity provisions will be supplemented to address the additional capacity provided by the compression system

– Details to be agreed – eg there may be a base load of low demand capacity that is increased with the installation of a compressor, if the compressor fails the lower capacity level will still be maintained

– Likely to be additional comunications between the producer and the GDN in relation to maintenance, emergencies etc

Stage 3. Operations and Maintenance

• Site specific, new technology for GDNs

– Resource, training and operability issues – Site response, standards of service – Remote monitoring by System Control

• Possible that GDN would contract out compressor maintenance in short term to specialist companies as few installations and specialist work – However, controls are similar to ones that GDNs already have

Funding of the Compression Option

• At present, one funding option: – GDN funds and operates as per other network assets – Receives capital contribution for design and construction (as if it was a

gas connection) – Goes into GDN asset base with a zero RAV – Charges O&M costs to the BM project shipper

• UNC mod 391 facilitates charging for this (now approved by Ofgem, target date for implementation is April 2013 subject to Xoserve review)

• O&M charges to be based on forward estimate of running hours based on network analysis model

• Standards of Service

– GDN to have standards of service in relation to biomethane projects and the ones that apply to compression to be developed

• Liabilities – Limited liabilities at present under UNC with any changes developed in

discussion with the GDNs/Ofgem

Conclusions

• Physical design using Skipton as basis is technically sound and can be adopted

• Funding by biomethane producer is the only option available today – O&M charged to shipper via UNC Mod 391

• Actual projects needed to allow the GDN to establish consistent processes , costs , contracts etc – It is not completely straightforward and needs significant management

input in short term • This area should be one where GDNs can show innovation and

provide significant environmental benefits

Safety Regulation

Installation Characteristics

• Within Grid compression will comprise a dedicated unit sited distant from the Biomethane input point – Power and throughput defined by analysis of network demands at low flows and rate of

Biomethane input – Network modelling at low flows to predict running hours and required operating range – Site selected by network flow patterns, available space and power supply availability,

existing sites provide best opportunity and required security

• Plant will operate automatically between pre-set pressure values when activated

• Operation for a few hours only during low flow times e.g. summer nights • Remote visibility via telemetry, remote shut down capability • Mechanical protection against over- and under-pressure in both affected

networks • Design subject to G17, uses commonly available equipment

Compliance review, compliances required

• GS(M)R and G(COTE)R relating to Gas Composition – No gas quality, odorant or CV issues as all are managed at the entry point

• Engineering Standards and good practice – Engineering design follows established procedures – Except for the compressor itself, the plant comprises standard components – Same design codes, engineering standards and cops applied – Specific standards for electrical supply, rotating machinery etc

• Safety Case – Gas Transporters Safety Case required by GS(M)R – Describes the plant in use and how the network is operated – Provision for compressor plant therefore required – Requires review against each GDN Safety Case to ensure correct references and inclusions – A generic review has been completed as part of the Skipton trial

• Summary of generic review is that there are no material impacts – Some edits/insertions required to add compressor plant and related items – Most changes relate to Biomethane in general, and not specifically the compressor

plant – 14 identified review points

Safety Case; specific impacts Safety Case Reference

2. Operations Undertaken 3. Plant and premises 4b. Procedures for O&M

5. Risk Assessment

Suggested Change

• Additional paragraph to cover conveyance of gas from BM plant to consumers.

• Include ref to BM injection plant and compressor

• Diag to show embedded BM connection • Add section to describe BM/Compressor plant • Insert ref to compression plant within the grid • Specialist contractor access for maintenance of

specific plant e.g. the compressor • List of sites to include BM injection and

compressor site(s) • Reference site specific risk assessment relating

to BM injection points and effects of on/off flow changes

Safety Case; specific impacts Safety Case Reference

7. Employee Competence 10. Health and Safety Communication 12. Co-operation 13. Gas Escapes and Investigations

Suggested Change

• Extend list to cover policy and procedure for specialist maintenance

• GDNs must advise and test emergency response by BM producers including instruction from Incident Controller and/or NEC

• BM suppliers must be aware and able to co-operate with GDN and emergency instructions

• Amendment needed for actual measurement arrangements at BM entry points

• Must reflect relationship between BM supplier and GDN

• References to include dedicated NEAs for BM entry points

• Needs to include reference to BM entry points

Safety Case; specific impacts Safety Case Reference

15. Content and Characteristics of Gas 16. Continuity of Supply 17. Adequate Pressure at end of Network. 18. Gas Supply Emergencies Abbreviations and Glossary

Suggested Change

• Verify inclusion of references to embedded input points as well as NTS offtakes, including arrangements for assurance/verification.

• Change required for specific BM monitoring regime e.g. slight relaxation of CV measurement accuracy

• Include references to relevant commercial agreements, update operating strategy, inclusion of BM in demand forecasting, explicitly state no capacity claims made for BM inputs or compressor installations.

• Review and if necessary update for plant settings and specific pressure monitoring, list sites with within-grid compressor installations

• Include explanation of compressor operation in emergency conditions.

• Update as required

Conclusions

• Adopting standard design and appraisal/review procedures enables demonstration of compliance with engineering standards in common use –uses existing GDN skill set

• Consideration to specific aspects of the Compressor required • Review of Safety Case indicates limited changes and no

Material impacts – Recommended (and expected) that each GDN arranges specific review

of own SC in case of differences – Some consequent actions to ensure demonstration

• Therefore no technical barriers to implementation

QUESTIONS