Transcript Document

Hydropower ‘Good Practice Guide’
Supplement to EA Hydropower manual
Dr John Aldrick
HO Water Resources Regulation manager
PRESENTATION CAVEATS

The slides showing hydrographs and flow duration curves were
prepared to illustrate the impact a hydropower scheme may have on
flows in the depleted reach. A range of different river types were
used, as indicated in the title of each slide.
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The hydrograph shows the gauged flow, without hydropower, the
flow in the depleted reach with abstraction for hydropower, and the
flow for hydropower (and other amenity purposes in the hydropower
leat etc).The percentile flow values (Q50,Q95 values) used are for
illustrative/investigation purposes.
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This work has shown that there are further principles that can be
drawn out and developed regarding the setting of hydropower
abstraction/flows in the depleted reach. These will be developed
further as part of the 'Good Practice Guidance'.
Environment Agency
Policy on Hydropower
The Agency strongly supports the Government’s
targets for the use of renewable energy. (10% - 2010,
20% - 2020)
BUT
 The Agency recognises both potential benefits &
environmental impacts of small-scale hydropower
 The Agency seeks to work constructively with the
hydropower industry to balance the benefits/impacts
of hydropower
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“We’re only borrowing
the water, so what’s the big deal”
Agency regulatory regime
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Strong legislative and environmental constraints
which guide us
Range of matters to take into account
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Water Resources permit
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e.g. water resources, fisheries, flood risk, water quality, navigation,
Abstraction Licence/Impoundment licence/sec 158 agreement
Hydropower proposals test the Water Resources
mandate to balance the needs of the developer
and the environment
Abstraction Licence
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Quantity that can be abstracted
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Residual flows in deprived reach
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measurement/control of abstraction & flows
Operating/control agreement
Time limited licence (normally 12 years to CAMS Common End Date)
Fish Screening requirements
Fish Pass requirements
Derogation agreement ?- (quirk of legislation?)
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Max. Instantaneous, hourly, daily, annual
Allows some further upstream abstraction
No abstraction charge if < 5Mw
Hydropower issues
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Location
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Volume/timing
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environmental sensitivity
local impact
Residual flows

deprived reaches

flow measurement
Fisheries
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turbines

screens

fish-passes
Good Practice Guide
Appendix to Agency Hydropower Manual
To provide starting point for evaluating schemes
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Checklist for criteria that may require EIA work
Principles for setting Residual flow
Flow measurement
Screen/turbine relationship
Principles of screen design
Hydropower Good Practice Guide
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Being developed by EA/Hydropower Working Group
Aims to :
 provide Agency/developers with a consistent
approach, common language and practical advice
 clarify the Agency position and promote awareness
But it won’t :
 answer all your Hydropower development issues
Agency Hydropower Manual(2003) available on website
Environmental site list audit
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Checklist indicates factors that need to be considered
Red boxes need
further work
Notes provide
further guidance
Water Resources
Conservation
Chemical/physical
water quality
Biological Water
quality
Fisheries
Flood Defence
tick box
YES
A Water Resources Checklist
NO
Note
No.
Is the scheme non-consumptive i.e. will 100% of any water abstracted be returned to
the water course from which it was taken?
1
Is the scheme being built on existing infrastructure?
2
Will the turbine be placed directly within the weir / water course rather than in a
separate channel?
3
Is there a flow-depleted channel?
4
Is there a flow-depleted weir?
4
Is it intended to increase the height of the impoundment?
8
Do surveys reveal any existing abstractions, including unlicensed ones, which will
be derogated by the proposal? (1)
5
Is there an EA gauging station in the depleted reach or nearby that is likely to be
affected by the scheme?
5
Will the developer accept a derogation consent within the proposed licence?
7
Deprived reach Flow
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Flow to be left in deprived reach between intake
and discharge - (how much?)
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To meet fisheries, ecological, amenity, riparian,
navigation needs
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Dependant on environmental sensitivity
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May depend on the length of the deprived reach
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May vary with flow or season (eg migratory fish)
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Flow measurement or control
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Decisions impact on economics/viability of scheme
Hydropower
Large river Q50-Q95
1400
1300
Long Term Natural
1200
?
1100
Flow Ml/d
Q50/Q95 2.01
1000
Hydro 1
900
Hydro 2
800
700
600
500
400
300
200
100
Don hydropower
0
10000
0
10
20
30
40
50
60
70
80
90
Flow Excedence %ile
Long Term Natural
Qn50
Qn95
Hydro 1
Gen vol 1
1.00
10.00
30.0
1000
40.00
50.00
60.0
70.00
80.00
90.0
95.00
Date
Aug-94
Jun-94
Apr-94
Feb-94
Dec-93
Oct-93
Aug-93
Jun-93
Apr-93
Feb-93
Dec-92
Oct-92
Aug-92
Jun-92
Apr-92
Feb-92
Dec-91
Oct-91
Aug-91
Jun-91
Apr-91
Feb-91
Dec-90
Oct-90
Aug-90
Jun-90
Apr-90
Feb-90
98.00
Dec-89
100
Oct-89
Flow (Ml/d)
20.0
99.0
100.00
8808.6
2922.5
1762.1
1220.4
956.3
787.4
674.2
586.8
503.1
431.6
392.2
349.4
327.5
275.2
100
Hydropower
Large river Q50-Q100
1400
1300
Long Term Natural
1200
?
1100
Flow Ml/d
Q50/Q95 2.01
141% more hydropower
1000
Hydro 1
900
Hydro 2
800
700
600
500
400
300
200
100
Don hydropower
0
0
10000
10
20
30
40
50
Long Term Natural
Qn50
Qn95
Hydro 1
Gen vol 1
1.00
10.00
30.0
40.00
1000
50.00
60.0
70.00
80.00
90.0
95.00
Date
Aug-94
Jun-94
Apr-94
Feb-94
Dec-93
Oct-93
Aug-93
Jun-93
Apr-93
Feb-93
Dec-92
Oct-92
Aug-92
Jun-92
Apr-92
Feb-92
Dec-91
Oct-91
Aug-91
Jun-91
Apr-91
Feb-91
Dec-90
Oct-90
Aug-90
Jun-90
Apr-90
Feb-90
Dec-89
98.00
Oct-89
Flow (Ml/d)
20.0
100
60
70
80
90
Flow Excedence %ile
99.0
100.00
8808.6
2922.5
1762.1
1220.4
956.3
787.4
674.2
586.8
503.1
431.6
392.2
349.4
327.5
275.2
100
Hydropower
Spaty river Q50-Q95
1400
1300
Long Term Natural
1200
GES A2
1100
Hydro 1
Hydro 2
1000
Qn95
Qn50
900
Flow Ml/d
Q50/Q95 6.86
116% more hydropower if Q100
800
700
600
500
400
300
200
Kilgram hydrograph
100
0
1000
0
10
20
30
40
50
60
70
80
90
Flow Excedence %ile
900
Long Term Natural
800
1.00
Qn95
10.00
20.0
Hydro 1
Q50 - Q95
1831590
600
30.0
40.00
500
50.00
400
60.0
300
70.00
80.00
200
90.0
100
95.00
98.00
Date
Oct-92
Oct-91
Oct-90
0
Oct-89
Flow (Ml/d)
700
Qn50
99.0
100.00
10583.2
3603.2
2116.2
1407.2
957.0
657.1
471.7
316.4
200.6
127.1
95.8
70.6
55.7
33.4
100
Hydropower
Large Chalk river Q50-Q95
1400
1300
Long Term Natural
Q50/Q95 1.75
1200
GES A2
1100
Hydro 1
Hydro 2
1000
Qn95
Qn50
Flow Ml/d
900
800
700
600
500
400
300
Chalk hydrograph
200
100
1000
0
0
900
30
40
50
700
1.00
Hydro 1
Q50 - Q95
gen Q
600
10.00
20.0
30.0
500
40.00
400
50.00
60.0
300
70.00
80.00
200
90.0
100
95.00
Date
Aug-94
Jun-94
Apr-94
Feb-94
Dec-93
Oct-93
Aug-93
Jun-93
Apr-93
Feb-93
Dec-92
Oct-92
Aug-92
Jun-92
Apr-92
Feb-92
Dec-91
Oct-91
Aug-91
Jun-91
Apr-91
Feb-91
Dec-90
Oct-90
Aug-90
Jun-90
Apr-90
Feb-90
Dec-89
98.00
Oct-89
0
60
70
80
Qn50
Qn95
Flow (Ml/d)
20
Flow Excedence %ile
Long Term Natural
800
10
99.0
100.00
1350.3
841.1
736.7
658.1
583.3
529.7
468.4
420.5
374.0
330.8
303.3
274.1
259.9
218.2
90
100
Hydropower
Large Chalk river Q50-Q100
1400
1300
Long Term Natural
1200
GES A2
1100
Hydro 1
Hydro 2
1000
Qn95
Qn50
900
Flow Ml/d
Q50/Q95 1.75
152% more hydropower
800
700
600
500
400
300
200
100
Chalk hydrograph
0
0
900
Long Term Natural
800
30
40
50
1.00
Qn50
10.00
Qn95
700
20.0
Hydro 2
Q50 - Q100
genQ
600
30.0
40.00
500
50.00
60.0
400
70.00
300
80.00
90.0
200
95.00
100
98.00
Date
Aug-94
Jun-94
Apr-94
Feb-94
Dec-93
Oct-93
Aug-93
Jun-93
Apr-93
Feb-93
Dec-92
Oct-92
Aug-92
Jun-92
Apr-92
Feb-92
Dec-91
Oct-91
Aug-91
Jun-91
Apr-91
Feb-91
Dec-90
Oct-90
Aug-90
Jun-90
Apr-90
Feb-90
Dec-89
99.0
Oct-89
Flow (Ml/d)
20
60
70
80
90
Flow Excedence %ile
1000
0
10
100.00
1350.3
841.1
736.7
658.1
583.3
529.7
468.4
420.5
374.0
330.8
303.3
274.1
259.9
218.2
100
Hydropower
50-50 flow split
50
Long Term Natural
GES A2
2/3rds of power
Hydro 1
Hydro 2
Qn95
Qn50
50% split
40
Flow Ml/d
30
Hydropower Chalk hydrograph
20
50
Long Term
Natural
Qn50
10
Qn95
40
0
Hydro 1
Q50 - Q95
0
20
30
40
50
1.00
10.00
20.0
20
30.0
40.00
50.00
60.0
10
70.00
80.00
90.0
Date
Aug-94
Jun-94
Apr-94
Feb-94
Dec-93
Oct-93
Aug-93
Jun-93
Apr-93
Feb-93
Dec-92
Oct-92
Aug-92
Jun-92
Apr-92
Feb-92
Dec-91
Oct-91
Aug-91
Jun-91
Apr-91
Feb-91
Dec-90
Oct-90
Aug-90
Jun-90
Apr-90
Feb-90
95.00
Dec-89
0
60
70
80
50%split
Oct-89
Flow (Ml/d)
30
10
Flow Excedence %ile
gen Q
98.00
99.0
100.00
53.6
32.7
24.8
19.7
15.6
12.7
10.5
8.8
7.5
6.3
5.5
4.8
4.4
3.3
90
100
Deprived reach Flow – principles?
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Q90-95 default Hands Off Flow
Q30/50 – HOF potentially available for hydropower
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Length of deprived reach
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50/50 flow split?
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Limited impact on flow variability
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2/3rds of hydropower
Q50/Q95 < 3 (high baseflow) may have economic
advantage of using Q100 if very short deprived reach
Fisheries
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Turbines
screens
Migration
spawning
Habitats Directive
Turbines, screens, conservation
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Conservation issues (HD, SSSI etc) impact on overall
scheme
Fish friendliness of turbines
Screen specification
Fish friendly turbines?
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Crossflow
Francis
Kaplan
Archimedean screw
Waterwheel
Fish screens
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Mostly physical
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wedge wire, mesh,bar
Fish screens are
expensive
Recent R&D
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Mesh size
flow velocities
Fish Screen - principles
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13
Inlet velocity – ideally 0.25-0.3m/sec (at an angle to
the flow) – leading to a
By-wash – to enable fish to escape
Mesh size/turbine type
6mm
Crossflow
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10/ 12.5
16
25
50
Kaplan/
Screw/
Francis
Waterwheel
Tail race screens on salmonid rivers
Fish migration
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Fish passes
 may involve retro-fit
 also likely to be costly
 New weirs
 Salmonid rivers first
Applicants should
expect the Agency to:
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Provide clear guidance on the licensing process
Highlight key issues for environmental assessment
Have an understanding of hydropower
Provide information it has available
Be consistent
Provide timely responses, with explanations
Applicants should not
expect the Agency to:
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collect and analyse supporting data
carry out the environmental assessment
accept inadequate data or assessments
give a binding view based on incomplete information
design the scheme
contravene its statutory duties
The Agency expects
the applicants to:
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to know their site, its environment and their objectives for
the scheme (background)
consider and design their proposals carefully
consider options/alternatives
make early contact with the Agency and continue such
throughout the process
appreciate the legislative and other constraints
provide quality, focused environmental assessments
provide appropriately detailed plans and drawings to
support any applications
Conclusions
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Good Practice Guidance has not had final sign-off
Will not answer all questions
Provides ‘starting point’ for decision making
Requires trialling/evaluation
The Agency will move to National Permitting in 2008