Transcript Tidal Power Projections - University of East Anglia

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 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
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