Future Projections: Tidal Power in the UK

Alice Sheppard

24th February 2005

Proposals

2 options: 1. Tidal barrage2. Turbines

• Tidal Energy at 10 most promising sites 36 TWh/year (House of Commons, 2001).

• Total resource ~50TW/year (1994)• Severn Barrage: 17TWh/year (1994)• Bi-direction turbines, capacity 60MW, cost

£79m

Hopes for Tidal Power

• £348m allocated towards R&D over 4 years (Patricia Hewitt)

• Technology still “in infancy”: – >30 years ago predictions made for 10MW turbines– 43 wind farms operating in 1997

• Technological barriers “could be overcome” if engineering funded (House of Commons)

• Lifetime ~ 120 years for barrage• Low maintenance cost (0.5%/year)• More predictable than wind• Could promote local employment and recreation

Potential Disadvantages

• Construction costs– Severn Barrage: at least £800m (1981), 7% overheads cost– Electricity price could be 14p/kWh (1994)– “Limited scope for cost reduction” (1994)

• No output until construction complete• Adverse effect on local area:

– Redirecting/treating sewage effluent ~£120-230m– Additional sea defence ~£10m

• Essentially long-term project so undesirable to “market forces”; “no significant economies of scale”

• After £12.1m allocated to DTI/DE programme funding before March 1993 & 150 projects, none commissioned

Optimistic Projections: Turbines

• In theory, could install 20 turbines/day. Installation 3-4 weeks, so say 20 every 3 weeks, starting from March this year, each 1MW:

• 2005 =220MW =6.93PJ/year• 2010 =2920MW =91.98PJ/year• 2015 =5720MW =180.18PJ/year• 2020 =8520MW =268.28PJ/year• 2030 =11,320MW =356.58PJ/year

Pessimistic Projection: Turbines

• Energy Papers 46 and 62 do not even mention turbines: worst possible outcome 0PJ/year.

• What is most likely? Depends upon:– Future use of nuclear fuel– Willingness of government to invest in R&D– Engineering– Success in other countries

Optimistic Projection: Barrages

• 30 potential sites have been identified in the UK, 90% of generation to take place at 8 sites

• Total resource 50TWh. If all this could be used by 2030, 180PJ/year could be produced.

• Gross Energy Consumption projected in 2030: 15,894PJ (assuming a 1.7% yearly growth since 2003)

• In theory, therefore possible to supply 20% of current energy consumed in England and Wales (1994)

• No information available on rates of construction, or start/finish dates. Projection assumes finish date 2030.

Pessimistic Projection: Barrage

• Energy Paper 62, March 1994: Predicts zero construction between 2005 and 2025: “limited scope for cost reduction”, “no significant economies of scale” etc.

• May be 0 PJ generated by 2030.• Assuming construction starts 2025, no electricity would

be generated that year• If the Severn Barrage was completed by 2030,

generating 17TWh: 61.2PJ/year, or <4% of projected energy demand by 2030

Realistic scenario: Probably pessimistic - no development plans at present or change from intention to delay any construction until 2025.