Hydropower

1
Hydropower Good Practice GuideSupplement to EA
Hydropower manual

• Dr John Aldrick
• HO Water Resources Regulation manager

2
Environment Agency Policy on Hydropower
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.
• 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/investi
  gation purposes.
• 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'.

3
Environment Agency Policy on Hydropower

• The Agency strongly supports the Governments
  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

4
Were only borrowing the water, so whats the
big deal
5
Agency regulatory regime

• Strong legislative and environmental constraints
  which guide us
• Range of matters to take into account
• e.g. water resources, fisheries, flood risk,
  water quality, navigation,
• Water Resources permit
• Abstraction Licence/Impoundment licence/sec 158
  agreement
• Hydropower proposals test the Water Resources
  mandate to balance the needs of the developer and
  the environment

6
Abstraction Licence

• Quantity that can be abstracted
• Max. Instantaneous, hourly, daily, annual
• Residual flows in deprived reach
• 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?)
• Allows some further upstream abstraction
• No abstraction charge if lt 5Mw

7
Hydropower issues

• Location
• environmental sensitivity
• Volume/timing
• local impact
• Residual flows
• deprived reaches
• flow measurement
• Fisheries
• turbines
• screens
• fish-passes

8
Good Practice Guide

• Appendix to Agency Hydropower Manual
• To provide starting point for evaluating schemes
• Checklist for criteria that may require EIA work
• Principles for setting Residual flow
• Flow measurement
• Screen/turbine relationship
• Principles of screen design

9
Hydropower Good Practice Guide

• 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 wont
• answer all your Hydropower development issues
• Agency Hydropower Manual(2003) available on
  website

10
Environmental site list audit

• Checklist indicates factors that need to be
  considered

tick box tick box A Water Resources Checklist Note No.
YES NO A Water Resources Checklist 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

• Red boxes need further work
• Notes provide further guidance
• Water Resources
• Conservation
• Chemical/physical water quality
• Biological Water quality
• Fisheries
• Flood Defence

11
Deprived reach Flow

• Flow to be left in deprived reach between intake
  and discharge - (how much?)
• To meet fisheries, ecological, amenity, riparian,
  navigation needs
• Dependant on environmental sensitivity
• May depend on the length of the deprived reach
• May vary with flow or season (eg migratory fish)
• Flow measurement or control
• Decisions impact on economics/viability of scheme

12
HydropowerLarge river Q50-Q95 Q50/Q95 2.01
13
HydropowerLarge river Q50-Q100 Q50/Q95 2.01
141 more hydropower
14
HydropowerSpaty river Q50-Q95 Q50/Q95 6.86116
more hydropower if Q100
15
HydropowerLarge Chalk river Q50-Q95 Q50/Q95
1.75
16
HydropowerLarge Chalk river Q50-Q100 Q50/Q95
1.75152 more hydropower
17
Hydropower50-50 flow split2/3rds of power
18
Deprived reach Flow principles?

• Q90-95 default Hands Off Flow
• Q30/50 HOF potentially available for hydropower
• Length of deprived reach
• 50/50 flow split?
• Limited impact on flow variability
• 2/3rds of hydropower
• Q50/Q95 lt 3 (high baseflow) may have economic
  advantage of using Q100 if very short deprived
  reach

19
Fisheries

• Turbines
• screens
• Migration
• spawning
• Habitats Directive

20
Turbines, screens, conservation

• Conservation issues (HD, SSSI etc) impact on
  overall scheme
• Fish friendliness of turbines
• Screen specification

21
Fish friendly turbines?

• Crossflow
• Francis
• Kaplan
• Archimedean screw
• Waterwheel

22
Fish screens

• Mostly physical
• wedge wire, mesh,bar
• Fish screens are expensive
• Recent RD
• Mesh size
• flow velocities

23
Fish Screen - principles

• 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
• Tail race screens on salmonid rivers

1 3 6mm
16 25 50 Crossflow
Kaplan/
Screw/
Francis
Waterwheel
10/ 12.5
24
Fish migration

• Fish passes
• may involve retro-fit
• also likely to be costly
• New weirs
• Salmonid rivers first

25
Applicants should expect the Agency to

• 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

26
Applicants should not expect the Agency to

• 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

27
The Agency expects the applicants to

• 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

28
Conclusions

• 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