190 likes | 455 Views
Tidal Power Projections. Tom Beagan 24 th February 2005. The Tidal Resource. The UK has a significant proportion of the world’s tidal power It can be harnessed in 2 forms: Tidal Barrage Tidal Stream. Tidal Barrage. Requires a tidal basin at least 5m tidal difference
E N D
Tidal Power Projections Tom Beagan 24th February 2005
The Tidal Resource The UK has a significant proportion of the world’s tidal power It can be harnessed in 2 forms: • Tidal Barrage • Tidal Stream
Tidal Barrage • Requires a tidal basin • at least 5m tidal difference • Few suitable sites in the world • La Rance (right) only large one, 240MW capacity • Potential for an 8460 MW barrage across the Severn
Tidal Barrage Benefits • Continuous electricity source • Pollution free (except construction) • Low cost after completion Limitations • High capital cost (resulting in high cost of electricity) • Environmental impact: sediment flows, species migration • Hinders navigation • Visual impact • Can’t control peak generation time
Tidal Stream • The newer method of tidal generation • Devices placed in strong tidal streams around UK • Possible devices: • ‘Seagen’ (right) up to 1MW • Stingray (aerofoil) 150KW
Tidal Stream Benefits • Small environmental and visual impact • Large Potential resource in UK waters • No pollution Limitations • Technology in early stage of development • Devices expensive = expensive electricity • Tidal streams are a long way from large populations • Electricity loss through transmission • Low load factor 39% average (carbon trust)
The Future for Tidal Barrage Hmmm! Artists impression of the proposed Severn barrage
The Future for Tidal Barrage There are 3 large barrage proposals in UK • The Severn – 8640 MW by far the largest in UK • The Mersey – 700MW • Orkney Churchill Barriers – 300MW Several smaller proposals • Duddon estuary (Cumbria) – 100MW • Wyre estuary (Lancashire) – 63.6 MW • Conwy (North Wales) – 33.4 MW • Loughor (Swansea) – 5 MW
Why aren’t they being built? • Mainly financial reasons • Severn 8.6GW scheme ‘uneconomical’ • High capital costs and few jobs after completion • Electricity will be too expensive • Environmental reasons • Large opposition from pressure groups • Extent of possible damage unknown • Big risk • Turn towards Tidal Stream • Interest is building • Acquiring more funding and investment
What can we expect from barrage? • Unlikely to be any sizeable schemes between now and 2030 except maybe Orkney (existing barrier) To increase likelihood • Need a reduction in capital costs • Improvement in power capture efficiency • Possible tidal lagoon in Severn? FOE Projection • 2010 – 0 MW • 2015 – 0 MW • 2020 – Up to 300 MW if Orkney gets go ahead • 2030 – 300 MW
The Future for Tidal Stream The future is bright! • Size of resource 22 TWH/yr most recent prediction • Most advanced design is double turbine ‘seagen’ capable of over 1 MW capacity • 300 KW single turbine being tested in Bristol Channel currently outperforming expectations by 27% Problem? • High cost of technology currently over £2M for a single unit • Funding gap, businesses can’t afford to build prototypes
The Future for Tidal Stream Solution • Aug ’04 Marine Renewables Development Fund to be set up • Grants of £5M to suitable investors Result • 1 MW prototype Tests and technological improvements • Grid connected ‘farm’ of 3-5 devices Tests • Tidal farm will grow to 20+ devices Tests • Several farms will be created in different sites • Improved technology will bring prices down, large growth
Tidal Stream Projections Carbon trust total tidal stream extractable: • 22 TWh/year • That requires a 2.5 GW supply • This will need 6435 double turbines (LF 39%) Can we do this by 2030? • That’s 257 Seagen a year from now until 2030 I don’t think so!!!
What can we expect? • 2010 – 1 Seagen (1MW) probably grid installed • 0.39 MW = 0.01 PJ • 2015 – 25 Seagen grid operational • 9.75 MW = 0.31 PJ • 2020 – 100 operational • 39 MW = 1.23 PJ Capital cost cheaper, Each unit now 1.5 MW • 2025 – 350 operational (around 50 per year) • 205 MW = 6.46 PJ • 2030 – 750 operational (around 80 per year) • 439 MW = 13.8 PJ
Stream plus Barrage • Orkney tidal barrage (300MW) likely by 2020 • Load factor around 23% • Therefore 69 MW = 2.18 PJ 2020 –3.14 PJ 2025 –8.46 PJ 2030–16 PJ But this is an optimistic projection!
Conclusion • Large margin for error • Projections rely on results of testing • Transmission costs not accounted for • Hydrogen? • Main barrier FINANCIAL