Tidal Power - Regensw
Bristol Channel Tidal Technology Overview 6 October 2011
All photographs, drawings and graphics copyright of their originators, whose permission to reproduce is gratefully acknowledged.
Tidal Energy Options • Tidal Power – Tidal Range (store and release) • Tidal Barrages
• Low Head Barrages
• Tidal Lagoons
In Practice • Tidal Range • 240MW successfully operating at La Rance Barrage, France • Uses standard turbine technology • Can operate in a variety of modes – ebb only, ebb and flood, with or without supplementary pumping • Reduces flows though barrage so tidal prism is also reduced, particularly for ebb generation • Most expensive when first built, now cheapest on EdF system with 60+ years of operation to come
Tidal Energy Options • Tidal Power – Tidal Stream (tidal currents) • Tidal Fences and Arrays (MCT, Atlantis, OpenHydro, DeltaStream etc)
• Venturi Fences (VerdErg’s SMEC)
In Practice • Tidal Stream • 1.2MW successfully operating at Strangford Lough, N Ireland • Demonstration Project • Supplies into grid and achieving load factors of c 60% • Significant environmental monitoring programme in place • Expensive but its producing energy and providing useful lessons to inform downstream development
Tidal Power in the UK • Department of Energy and Climate Change (DECC) • Severn Tidal Power Feasibility Study – 2008 to 2010 • Severn Embryonic Technologies Scheme (SETS) - 2009 • North West Tidal Energy Feasibility Studies • Mersey (Peel Energy) – 2009 to 2011 • Solway (Solway Gateway) - 2009 • Duddon (Briatin’s Energy Coast – West Cumbria) - 2010 • Tidal Stream Demonstrators • Strangford Lough - 2007 • Open Hydro and Atlantis @ EMEC - 2010 • Pulse Tidal on Humber - 2008
Current Status • Severn Tidal Power October 2010: “No strategic case at this time”, “may revisit in 2015”
• Mersey Power June 2011: “Not viable under the current Renewables Obligation”
• Duddon and Solway 2010: No significant action since completion of feasibility studies.
• Tidal Stream •
2011: Several demonstration projects but no commercial arrays. Strangford Lough (1.2MW) generating into the grid £20m from Government as part of the £200m innovation fund announced in 2011
Electricity Generation to 2050 Electricity Generation (GWh/yr)
80% reduction in 1990 CO2 emissions by 2050
900,000 800,000 700,000 600,000
Today – 7% from renewables
500,000 400,000
30% from renewables by 2020
300,000 200,000 100,000 1970
1980
1990
2000
2010
2020
2030
2040
2050
Why is Tidal Power still relevant? • •
Predictable Energy Source – requires less back-up than wind Low carbon – abundant energy resource in UK
Tidal Range Projects • Long life (120 years +) • Conventional Technologies • High initial cost (1st 30 years) • Very low subsequent cost (next 90+ years) • Downward pressure on future energy prices Tidal Stream • Less environmental impact • Export potential if UK establishes manufacturing base • Very high initial cost but potential to drive costs down as technology develops • Higher load factors than wind or tidal range projects • Life similar to offshore wind (20 – 25 years)
Tidal Power Challenges Tidal Range Projects • Environmental Impact • • • • •
Geomorphological change Fish Sedimentation Water quality changes Salt marsh and habitat loss
• Socio-economic impacts • Ports • Construction impacts
• Scale • Cannot be developed incrementally – all or nothing
• Initial Financing • Initial financing would require subsidy greater than current ROC’s • Longer term value not recognised
Tidal Power Challenges Tidal Stream Projects • Environment • Modest impacts but still require monitoring
•
Socio-economic impacts • Navigation • Construction impacts
•
Initial Financing • Initial financing would require subsidy greater than current ROC’s
•
Cost • Expensive in terms of cost per MW installed • Difficult to access and maintain • Relatively short asset life (20 – 25 years)
•
Technology • Not yet commercialised • Reliability • Manufacturers financially stretched during pre-commercialisation phase
What have we learned from Severn and SETS studies?
All photographs, drawings and graphics copyright of their originators, whose permission to reproduce is gratefully acknowledged.
Severn Tidal Power • Technically Feasible Options
B3
L3d
B4
Cardiff to Weston Barrage
Bridgwater Bay Lagoon
Shoots Barrage
8,640MW
3,600MW
1,050MW
14.4 to 16.7 TWh/a
5.6 to 6.9 TWh/a
2.6 to 2.8 TWh/a
Ebb only
Ebb & Flood
Ebb only
2021
2023
2019
Severn Tidal Power • Technically Feasible Options – Costs in £bn Option:
Cardiff – Western Barrage
Bridgwater Bay Lagoon
Shoots Barrage
Base Cost
17.6
9.2
3.3
Habitat Costs (2:1):
1.3
0.2
0.3
Mitigation Costs (upper bound):
1.2
0.6
0.6
Total Cost:
20.1
10.0
4.2
Contingency Costs:
3.2
1.9
0.5
Total inc contingencies:
23.2
11.9
4.7
Energy Cost (£/MWh @3.5%)
73
88
83
Energy Cost (£/MWh @10%)
211
248
228
SETS Proposals 3 shortlisted by DECC for match funding in 2009: • Tidal Fence – IT Power • Tidal Bar – Rolls Royce • Venturi Fence - VerdErg
SETS Proposals IT Power’s Tidal Fence
SETS Proposals IT Power’s Tidal Fence • 19km twin fence arrangement • Extracts power during ebb & flood tides • Circa 400MW and up to 800 turbines • 0.88 TWh/year • Capex £1.97bn • Energy Cost £200 and £300/MWh @ 3.5% and 10% respectively
Environmental and Navigation •
50mm change to water levels
•
Open access for ships through 650m wide, two-way navigation channel
•
Low level impact (in comparison with Severn Tidal Power alternatives)
Project Timing •
pre-construction 8-10 years (including technology proving scheme)
•
construction 4 years – once technology commercially available and fence system has been demonstrated
SETS Proposals Rolls Royce’s Tidal Bar
SETS Proposals Rolls Royce’s Tidal Bar • •
New variable pitch, low fixed speed, contra-rotating turbine. Installed capacity 4.5MW / turbine at 11 metres scalable up and down to suit estuary environment. • Static head: • Tip speed:
• • • • • •
3m 9m/s
Concept at pre-prototype stage 20% longer structure than conventional barrage to accommodate over 1000 turbines (5,800MW) Capital cost on Cardiff to Weston alignment: £18.75bn (provisional) Energy Yield 17TWh/a (excluding pumping) Requires gearbox so maintenance costs higher Energy Costs £100 and £200/MWh @ 3.5% and 10% respectively
Environmental and Navigation • Potentially reduced environmental impact due to greater flow transfer, lower operating head and slower blade rotation • Requires 1,000 ha of compensatory habitat • Requires barrage structure with navigation locks Project Timescales • 17 year development and construction timeframe
SETS Proposals
SETS Proposals VerdErg’s Venturi Fence •
Venturi Fence with electricity generated in a secondary circuit using conventional propeller turbines.
•
Generation is a function of head drop across unit and velocity of current
•
Primary flow passes through Venturi Fence accelerating and causing a pressure drop that sucks water through the secondary circuit and turbines
•
Lab tested but concept not yet at demonstration stage
•
Capital cost on Cardiff to Weston alignment: £14.5bn (provisional)
•
Energy Yield 9.6TWh/a (provisional) from 7,500MW on Cardiff to Weston alignment
•
Energy Costs £100 and £200/MWh @ 3.5% and 10% respectively
Environmental and Navigation •
Potentially reduced environmental impact due to greater flow transfer and lower operating head
•
Fish may be damaged as main flow accelerates through venturi slots
•
Requires 3,500 ha of compensatory habitat
•
Requires navigation locks as it effectively barrages estuary
Project Timescales •
18 year development and construction timeframe
SETS Proposals Summary Option:
IT Power: Tidal Fence
Rolls Royce: Tidal Bar
VerdErg: Venturi Fence
Cost (£bn)
1.71
16.3
12.6
Contingency Costs (£bn):
0.26
2.45
1.9
Total inc contingencies (£bn):
1.97
18.75
14.5
Energy Yield (TWh/a):
0.88
16.8
9.6
Energy Cost (£/MWh @3.5%)
196
107
118
Energy Cost (£/MWh @10%)
307
200
226
Severn Tidal Power Conclusions Conventional Technologies •
Land Connected Lagoons offer reasonable energy yields with lower impact on ports and environment than barrage solutions but at 20% greater energy cost
•
Potential for further sites to be evaluated to reduce costs
SETS Solutions •
Technology at early stage of development with long development timeframes but could be competitive with conventional technologies
•
Most mature technology (Tidal Fence) is expensive in cost of energy terms but has least environmental impact - could abstract more energy but with greater environmental and navigation impact
•
Rolls Royce turbine technology could be used in lagoons as well as barrages
•
Tidal Bar and Venturi Fence required navigation locks
All photographs, drawings and graphics copyright of their originators, whose permission to reproduce is gratefully acknowledged.
Tidal Energy Options • Tidal Power – Tidal Range (store and release) • Tidal Barrages
• Low Head Barrages
• Tidal Lagoons
In Practice • Tidal Range • 240MW successfully operating at La Rance Barrage, France • Uses standard turbine technology • Can operate in a variety of modes – ebb only, ebb and flood, with or without supplementary pumping • Reduces flows though barrage so tidal prism is also reduced, particularly for ebb generation • Most expensive when first built, now cheapest on EdF system with 60+ years of operation to come
Tidal Energy Options • Tidal Power – Tidal Stream (tidal currents) • Tidal Fences and Arrays (MCT, Atlantis, OpenHydro, DeltaStream etc)
• Venturi Fences (VerdErg’s SMEC)
In Practice • Tidal Stream • 1.2MW successfully operating at Strangford Lough, N Ireland • Demonstration Project • Supplies into grid and achieving load factors of c 60% • Significant environmental monitoring programme in place • Expensive but its producing energy and providing useful lessons to inform downstream development
Tidal Power in the UK • Department of Energy and Climate Change (DECC) • Severn Tidal Power Feasibility Study – 2008 to 2010 • Severn Embryonic Technologies Scheme (SETS) - 2009 • North West Tidal Energy Feasibility Studies • Mersey (Peel Energy) – 2009 to 2011 • Solway (Solway Gateway) - 2009 • Duddon (Briatin’s Energy Coast – West Cumbria) - 2010 • Tidal Stream Demonstrators • Strangford Lough - 2007 • Open Hydro and Atlantis @ EMEC - 2010 • Pulse Tidal on Humber - 2008
Current Status • Severn Tidal Power October 2010: “No strategic case at this time”, “may revisit in 2015”
• Mersey Power June 2011: “Not viable under the current Renewables Obligation”
• Duddon and Solway 2010: No significant action since completion of feasibility studies.
• Tidal Stream •
2011: Several demonstration projects but no commercial arrays. Strangford Lough (1.2MW) generating into the grid £20m from Government as part of the £200m innovation fund announced in 2011
Electricity Generation to 2050 Electricity Generation (GWh/yr)
80% reduction in 1990 CO2 emissions by 2050
900,000 800,000 700,000 600,000
Today – 7% from renewables
500,000 400,000
30% from renewables by 2020
300,000 200,000 100,000 1970
1980
1990
2000
2010
2020
2030
2040
2050
Why is Tidal Power still relevant? • •
Predictable Energy Source – requires less back-up than wind Low carbon – abundant energy resource in UK
Tidal Range Projects • Long life (120 years +) • Conventional Technologies • High initial cost (1st 30 years) • Very low subsequent cost (next 90+ years) • Downward pressure on future energy prices Tidal Stream • Less environmental impact • Export potential if UK establishes manufacturing base • Very high initial cost but potential to drive costs down as technology develops • Higher load factors than wind or tidal range projects • Life similar to offshore wind (20 – 25 years)
Tidal Power Challenges Tidal Range Projects • Environmental Impact • • • • •
Geomorphological change Fish Sedimentation Water quality changes Salt marsh and habitat loss
• Socio-economic impacts • Ports • Construction impacts
• Scale • Cannot be developed incrementally – all or nothing
• Initial Financing • Initial financing would require subsidy greater than current ROC’s • Longer term value not recognised
Tidal Power Challenges Tidal Stream Projects • Environment • Modest impacts but still require monitoring
•
Socio-economic impacts • Navigation • Construction impacts
•
Initial Financing • Initial financing would require subsidy greater than current ROC’s
•
Cost • Expensive in terms of cost per MW installed • Difficult to access and maintain • Relatively short asset life (20 – 25 years)
•
Technology • Not yet commercialised • Reliability • Manufacturers financially stretched during pre-commercialisation phase
What have we learned from Severn and SETS studies?
All photographs, drawings and graphics copyright of their originators, whose permission to reproduce is gratefully acknowledged.
Severn Tidal Power • Technically Feasible Options
B3
L3d
B4
Cardiff to Weston Barrage
Bridgwater Bay Lagoon
Shoots Barrage
8,640MW
3,600MW
1,050MW
14.4 to 16.7 TWh/a
5.6 to 6.9 TWh/a
2.6 to 2.8 TWh/a
Ebb only
Ebb & Flood
Ebb only
2021
2023
2019
Severn Tidal Power • Technically Feasible Options – Costs in £bn Option:
Cardiff – Western Barrage
Bridgwater Bay Lagoon
Shoots Barrage
Base Cost
17.6
9.2
3.3
Habitat Costs (2:1):
1.3
0.2
0.3
Mitigation Costs (upper bound):
1.2
0.6
0.6
Total Cost:
20.1
10.0
4.2
Contingency Costs:
3.2
1.9
0.5
Total inc contingencies:
23.2
11.9
4.7
Energy Cost (£/MWh @3.5%)
73
88
83
Energy Cost (£/MWh @10%)
211
248
228
SETS Proposals 3 shortlisted by DECC for match funding in 2009: • Tidal Fence – IT Power • Tidal Bar – Rolls Royce • Venturi Fence - VerdErg
SETS Proposals IT Power’s Tidal Fence
SETS Proposals IT Power’s Tidal Fence • 19km twin fence arrangement • Extracts power during ebb & flood tides • Circa 400MW and up to 800 turbines • 0.88 TWh/year • Capex £1.97bn • Energy Cost £200 and £300/MWh @ 3.5% and 10% respectively
Environmental and Navigation •
50mm change to water levels
•
Open access for ships through 650m wide, two-way navigation channel
•
Low level impact (in comparison with Severn Tidal Power alternatives)
Project Timing •
pre-construction 8-10 years (including technology proving scheme)
•
construction 4 years – once technology commercially available and fence system has been demonstrated
SETS Proposals Rolls Royce’s Tidal Bar
SETS Proposals Rolls Royce’s Tidal Bar • •
New variable pitch, low fixed speed, contra-rotating turbine. Installed capacity 4.5MW / turbine at 11 metres scalable up and down to suit estuary environment. • Static head: • Tip speed:
• • • • • •
3m 9m/s
Concept at pre-prototype stage 20% longer structure than conventional barrage to accommodate over 1000 turbines (5,800MW) Capital cost on Cardiff to Weston alignment: £18.75bn (provisional) Energy Yield 17TWh/a (excluding pumping) Requires gearbox so maintenance costs higher Energy Costs £100 and £200/MWh @ 3.5% and 10% respectively
Environmental and Navigation • Potentially reduced environmental impact due to greater flow transfer, lower operating head and slower blade rotation • Requires 1,000 ha of compensatory habitat • Requires barrage structure with navigation locks Project Timescales • 17 year development and construction timeframe
SETS Proposals
SETS Proposals VerdErg’s Venturi Fence •
Venturi Fence with electricity generated in a secondary circuit using conventional propeller turbines.
•
Generation is a function of head drop across unit and velocity of current
•
Primary flow passes through Venturi Fence accelerating and causing a pressure drop that sucks water through the secondary circuit and turbines
•
Lab tested but concept not yet at demonstration stage
•
Capital cost on Cardiff to Weston alignment: £14.5bn (provisional)
•
Energy Yield 9.6TWh/a (provisional) from 7,500MW on Cardiff to Weston alignment
•
Energy Costs £100 and £200/MWh @ 3.5% and 10% respectively
Environmental and Navigation •
Potentially reduced environmental impact due to greater flow transfer and lower operating head
•
Fish may be damaged as main flow accelerates through venturi slots
•
Requires 3,500 ha of compensatory habitat
•
Requires navigation locks as it effectively barrages estuary
Project Timescales •
18 year development and construction timeframe
SETS Proposals Summary Option:
IT Power: Tidal Fence
Rolls Royce: Tidal Bar
VerdErg: Venturi Fence
Cost (£bn)
1.71
16.3
12.6
Contingency Costs (£bn):
0.26
2.45
1.9
Total inc contingencies (£bn):
1.97
18.75
14.5
Energy Yield (TWh/a):
0.88
16.8
9.6
Energy Cost (£/MWh @3.5%)
196
107
118
Energy Cost (£/MWh @10%)
307
200
226
Severn Tidal Power Conclusions Conventional Technologies •
Land Connected Lagoons offer reasonable energy yields with lower impact on ports and environment than barrage solutions but at 20% greater energy cost
•
Potential for further sites to be evaluated to reduce costs
SETS Solutions •
Technology at early stage of development with long development timeframes but could be competitive with conventional technologies
•
Most mature technology (Tidal Fence) is expensive in cost of energy terms but has least environmental impact - could abstract more energy but with greater environmental and navigation impact
•
Rolls Royce turbine technology could be used in lagoons as well as barrages
•
Tidal Bar and Venturi Fence required navigation locks
