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Hydropower ‘Good Practice Guide’ Supplement to EA Hydropower manual

Hydropower ‘Good Practice Guide’ Supplement to EA Hydropower manual. Dr John Aldrick HO Water Resources Regulation manager. PRESENTATION CAVEATS.

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Hydropower ‘Good Practice Guide’ Supplement to EA Hydropower manual

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  1. Hydropower ‘Good Practice Guide’Supplement to EA Hydropower manual Dr John Aldrick HO Water Resources Regulation manager

  2. 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/investigation 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 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

  4. “We’re only borrowing the water, so what’s 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 < 5Mw

  7. Hydropower issues • Location • environmentalsensitivity • 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 won’t : • answer all your Hydropower development issues • Agency Hydropower Manual(2003) available on website

  10. Environmental site list audit • Red boxes need further work • Notes provide further guidance • Water Resources • Conservation • Chemical/physical water quality • Biological Water quality • Fisheries • Flood Defence • Checklist indicates factors that need to be considered

  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-Q100Q50/Q95 2.01141% more hydropower

  14. HydropowerSpaty river Q50-Q95Q50/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 < 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 R&D • 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

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