Wessex Water – Overview

• One of ten water and sewerage companies in England and Wales

• Over 10,000 square km’s area

• Overall performance recognised independently as one of the best

LOCATION & CUSTOMER BASE2.5m Sewerage

customers

• 1.35m sewerage only

• 1.1m water and sewerage

• 0.13m water only

Wessex Water – Overview

Water Supply 123 treatment plant, 366 pumping stations

11,000 km’s water main

Wastewater 392 treatment plant, 1,314 pumping stations

15,000 km’s sewers

Wessex Water – Energy costs• Energy is one of the largest operational costs

- average electrical use is about 27 MW = one 747 jet engine output – 0.06% of all UK average demand of 39 GWe

- Clean Water treatment and supply ~ £4m

- Wastewater collection and treatment ~ £6m

• CHP generation is about 4.5 MW continuous

• Also 30 standby diesel engines, totaling 18 MW used routinely to support National Grid, 4 minute start up and paralleling.

Wessex Water Diesel Engines

Operator interface page: General Map showing some of the LM sites.Operator interface page: General Map showing some of the LM sites.

Wessex Water Load Management System

• One central point of control via a master PLC based at Avonmouth and a set specific PLC at each of the generators controls the system.

• Day to day control of each sets availability and visibility of status – from anywhere

• instantaneous call off by NGC and constant reporting of output

• scheduled runs instructed 1-3 hours ahead from BGT/Centrica

• Triad avoidance instructed 7 hours ahead

Wessex Water Load Management System

NGC Computer on the left, operator interface on the right Can dial in remotely via lap top.NGC Computer on the left, operator interface on the right Can dial in remotely via lap top.

Wessex Water Load Management System

Operator interface page: Overview Page showing first 14 sets with various status’s simulated.Operator interface page: Overview Page showing first 14 sets with various status’s simulated.

Wessex Water Load Management System

S CA D A

PLC

MODEM

PLC

MODEM

MODEM

MODEM

MODEM

N a tio n a l Te le p h o n e Ne t wo rk (B T )

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

W e s s e x W a t e r L o a d M a n a g e m e n t G e n e ra t o r P L C 's

L o a d M a n a g e m e n t M a st e rP L C

The Master Controller has 4 modem connections to enable 4 sites to be contacted at once, hence speeding up the operation of an immediate start request.

The Master Controller has 4 modem connections to enable 4 sites to be contacted at once, hence speeding up the operation of an immediate start request.

Wessex Water Load Management System

Master Control PLC, with its 4 modems.Master Control PLC, with its 4 modems.

4 Modems

Wessex Water Load Management System

Load Management control panel, with the door open. Showing the PLC controller etc.Load Management control panel, with the door open. Showing the PLC controller etc.

Wessex Water Load Management System

Typical Site: In the background we see the Generator, in the foreground we see the Generator controller and the Load Management control panel.

Typical Site: In the background we see the Generator, in the foreground we see the Generator controller and the Load Management control panel.

Generator

Load Management Control Panel

GeneratorControl Panel

Wessex Water Load Management System

S C A D A

PLC

MODEM

PLC

MODEM

MODEM

MODEM

MODEM

Na t io n a l T e le p h o n e Ne t wo rk (B T )

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

PLC

MODEM

W e s se x W a te r L o a d M a n a g e m e n t G e n e ra to r P L C 's

L o a d M a n a g e m e n t M a s te rP L C N G C Co m p u te r

MODEM

NG C D ire c t C a ll Co n n e c tio n

A direct call can be initiated from the NCG SRD dispatch computer.A direct call can be initiated from the NCG SRD dispatch computer.

BGT/Centrica• BGT send their running request to us via an SMS message.

• We confirm receipt by return of automatic email.

• Every day the system sends data regarding our capacity to BGT via automatic email.

• Whenever the system has a run, the local operators are sent an automatic SMS message telling them that a run is about to start.

• This enables them to monitor and reminds them to keep there eye on the fuel levels.

Wessex Water Load Management System

• Earnings from the system are based on 4 factors.

• Reserve Service availability fee and running payment.

• BGT/ Centrica capacity and running payment.

• Triad avoidance.

• Income from export.

• The expected profit is in the region of £250K.

Wessex Water Load Management System

Site kW Output

Portbury Wharf 245

Radipole 1 675

Radipole 2 675

Sutton Bingham690

West Huntspill 550

Weston super Mare 1 700

Weston super Mare 2 700

Weston super Mare 3 650

Black Rock 1 640

Black Rock 2 640

Corfe Mullen WTW 450

Kingston Seymour 1 640

Kingston Seymour 2 750

Weymouth 1 750

Weymouth 2 750

34 Sets spread across 24 Sites totalling 18 MW

Site kW OutputAshford 470Blackwell Hams 480Chilton Trinity 650Clevedon 270Durleigh 470Empool 500Frome 340Fulwood 610Holdenhurst 1 600Holdenhurst 3 385Minehead 1 260Minehead 2 390Poole Inlet 390Poole RSPS 800Poole BAF 750Portishead 380Swanage STW 800

Poole inlet pumping station – 390kW + fuel tank

Small set maybe 150kW

1MW containerised set, fuel in background

Testing diesels off load

• Very quickly ruins the engine – maybe 50 hours.• Under loaded means low cylinder pressures and

temperatures• Soot forms clogging rings and hard carbon scrapes bores• Injectors clog with soot• Diesels must be run at full load once a month to ensure

they work.• Reserve Service is the ideal way.• In 1987 storms, 50% of Thames Generators failed to start

or stay running.

Costs

• Maybe £3k to fit PLC to set• Paralleling maybe £5k• Tidying up set (noise, fuel) maybe £5k

• So for a 1MW set…£13/kW• 50 kW…maybe £260/kW• Running costs - fuel 10p/kWh

- maintenance -0.5p/kWh

Types of capacity on the system

• 57GW in use at peak winter demand• NGT likes to have 8.5 GW spare but not running• 1.5 GW or spinning reserve – can come on in 20 –

30 seconds.• 2.25 GW of Frequency Service loads• 2.25 GW of Reserve Service diesels etc• 2 GW? Fast response plant • Dinorwig and Ffestiniog 2 GW in 15 secs

How is reserve service used?

• Say a 660 MW turbine trips• Under frequency relays on Frequency Service customers

trip up to 660 MW of load – off for up to 20 minutes.• NGT issued Reserve Service call for 660 MW which is

available within 20 minutes• When available, Frequency Service loads are re-connected• Frequency Service relays re-armed• Some hour or so later, Frequency Service diesels are stood

down by then replaced with new levels of large power stations.

How much more is there?

• Wessex has 550 generators of capacity 100MW.• We only use 18MW• Could use others but diminishing returns – still worth

doing.• Nationally there are 20 GW of diesels• Could all be utilised with right incentives• Frequency Service could be applied to a one kW deferrable

load in every 20m homes – 20GW• Freezers, fridges, storage heater, immersion heater• A one kW Stirling micro-CHP in every home gives 20 GW