south west water experiences of pumped storage · 2015-01-08 · allers wtw maundown wtw (wessex...
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Presentation by
South West WaterExperiences of Pumped Storage
Jo RobinsonResources AnalystSouth West Water
Overview
• Pumped Storage Explanation • SWW Pumped Storage Schemes• Developing a Scheme• Pumped Storage Operation• Conclusions
Pumped Storage
• Making use of higher winter river flows to aid reservoir refill
• Maximising effective catchment area• Reservoir no longer just dependant on natural
refill• Useful for multi-season reservoirs which have
potential to be more susceptible to successive dry winters
Pumped Storage
• Can be operated as long as flow is available (subject to licences)
• Enables water to be taken from reservoir at a greater rate during summer knowing that it can be topped up in winter if required
• Reduces risk of low reservoir levels the following summer which could lead to customer restrictions, drought orders/permits and poor reservoir water quality
The effect of pumped storage on a 24 month drought
pum
ping
perm
itted
pum
ping
perm
itted
pum
ping
perm
itted
J F M A M J J A S O N D J F M A M J J A S O N D1975 1976
0%
100%
ReservoirStorage
Storage increase due to pumping
But…
• Schemes are expensive – high energy consumption
• Schemes are subject to environmental constraints– potential impact on flows required to help
fish migration– potential loss of natural variation in flows– potential impact to water quality in reservoir
SWW Pumped Storage Schemes
Pumped Storage Scheme
Developing a PS Scheme
Case Study:WimbleballReservoir
Wimbleball Supply/Demand Balance
New Water Resource Solutions
• Increasing groundwater supplies
• Axe Valley Reservoir
• Wimbleball Pumped Storage Scheme
Wimbleball Pumped Storage Scheme
Pumps water from Exebridge back to the reservoir
We no longer have to rely on natural inflow alone
Allers WTW
Maundown WTW(Wessex Water)
Pynes WTW
Wimbleball Reservoir
TIVERTON
EXETER
Exebridge
Licence Application
Need to demonstrate that the whole water strategyhas been considered by showing:• Below economic level of leakage• Potential infrastructure enhancements have been
carried out• Water conservation is being promoted• That having done all this there is still a need to
take water from the environment via pumped storage
Licence Application
Scheme Construction
Main Elements of the Scheme
• Weir• Intake screens• Pumping station• Water main• Tunnel • Outfall structure
Weir is 21m wide and used for:• raising the water level to enable intake to operate• measuring the flow to ensure licence compliance
Exebridge Weir
Intake Screens
9m long coarse trash screen with 6mm slots to screen large debris
• 8 Johnson passive screens with 3mm slots
• Screens are “fish friendly”but block easily
Johnson Passive Screens
Site of ExebridgePumping Station
Exebridge Pumping Station
Tunnel
Wimbleball Reservoir Outfall
Environmental Considerations
Fish Movement Studies
Environmental sensitivity of pipeline routes
Pumped Storage Operation
CollifordPS Outfall Structure
Deciding when to Pump
• Period of licence eg Wimbleball Nov – Mar• Licence availability
– Daily licence– Annual licence (not always x365 daily)– Licence may be used in conjunction with
abstractions for public water supply
Reservoir Pumping Zones
DCP Zone ADCP Zone BDCP Zone CDCP Zone DConsider Winter Pumping
0
2500
5000
7500
10000
12500
15000
17500
20000
01/0
1/06
01/0
2/06
01/0
3/06
01/0
4/06
01/0
5/06
01/0
6/06
01/0
7/06
01/0
8/06
01/0
9/06
01/1
0/06
01/1
1/06
01/1
2/06
Rem
aini
ng N
et S
tora
ge (M
l)
0
10
20
30
40
50
60
70
80
90
100
Rem
aini
ng N
et S
tora
ge (%
)
Wimbleball Pumping Zones
Reservoir Storage Projections
0
2500
5000
7500
10000
12500
15000
17500
20000
01/0
1/06
01/0
2/06
01/0
3/06
01/0
4/06
01/0
5/06
01/0
6/06
01/0
7/06
01/0
8/06
01/0
9/06
01/1
0/06
01/1
1/06
01/1
2/06
01/0
1/07
01/0
2/07
01/0
3/07
01/0
4/07
01/0
5/07
Rem
aini
ng N
et S
tora
ge (M
l)
0
10
20
30
40
50
60
70
80
90
100
Rem
aini
ng N
et S
tora
ge (%
)
196 2 19 63 1964 1965 1966 1967 1968 19 69 1970 1971 1972 1973 19741975 19 76 1977 1978 1979 1980 1981 19 82 1983 1984 1985 1986 1987198 8 19 89 1990 1991 1992 1993 1994 19 95 1996 1997 1998 1999 2000
Abstract as required
Consider implementationof bans on non-esssential
use of water
Consider implementation of hosepipe bans & drought
Initiate regular contacts with the EA and increase publicity
Wimbleball Indicative Projected Storage 06/07
A series of possible outcomes which can provide an indication of the probability of various states of storage occurring in the future.
Autumn leaf clogging reduces volume pumped
Operational Issues
Riparian and fisheries interests
Intake Protection
• Water quality monitoring instruments and triggers to avoid abstraction of poor quality water
• Regular maintenance and calibration
• 24 hr site manning• Awareness of pipeline
delivery times • Rapid notification and
shutdown in the event of a pollution incident
Deciding when to Stop Pumping
• Once a PS scheme is shut down it is difficult to restart
• Important to have a controlled shut down• Pumping zones – has target storage been
reached? • Weather forecasts• Have licence constraints been reached?
0
2000
4000
6000
8000
10000
12000
14000
16000
18000
20000
22000
Date
Rem
aini
ng N
et S
tora
ge (M
l)
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Rem
aini
ng N
et S
tora
ge (%
)
DCP Zone ADCP Zone BDCP Zone CDCP Zone DConsider Winter Pumping2006 Net Storage
Net Capacity 21320 Ml
Consider Winter Pumping
Storage without pumping
Actual storage with pumping
Use of Wimbleball Pumped Storage in 2005/06
Conclusions
• Secures reliable supplies– reduces the risk of hose pipe bans– reduces the risk of drought orders affecting the
environment
• More effective use of an existing asset• Requires careful operational management
– to minimise pumping costs– to avoid adverse environmental effects– can require constructive dialogue with
stakeholders
Colliford Reservoir
Questions
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