Every year the National Grid produces a statement that identifies how much UK electricity generating capacity is expected to open and to close over the next seven years. The Grid is careful to say that its ‘Seven Year Statement’ is not intended to be used as a forecast but this vital document gives clear indications of how it thinks the demand for electricity will be met over the next few years. The most recent statement, published at the end of May 2011, suggests that the Grid is becoming far more bullish about wind power – particularly offshore - and about new gas power stations.

Last year, it suggested that about 8 gigawatts of wind capacity might be constructed between this year and 2016. The number has risen to 15.5 gigawatts in this year’s review. Projected new gas plants are up from 12 GW to 13 GW. Unsurprisingly, the Grid has pushed back the date of the first new nuclear stations to 2018.

The recent review of renewable energy potential by the Committee on Climate Change estimated that the UK would have installed 28 GW of wind power by 2020. It sees slightly more onshore wind by this date (15 GW) than offshore (13 GW). The Grid’s view is very different, with a projected 18 GW offshore by 2018 and only 8 GW onshore, with very high rates of installation in offshore waters possible beyond 2015.

This is how the National Grid sees UK generating capacity in 2018.

Generating technology	Amount of potential capacity (gigawatts) in 2018

Gas (CCGT)	45, (29 today)
Coal	21, (29)
Offshore wind	18, (1)
Onshore wind	8 (2)
Nuclear	13 (11)
Other	9 (10)

TOTAL	114 (82)

The increase in total generating capacity is, of course, partly a mirage since wind power only generates about 30-35% of its maximum power, with offshore at the higher end of the range. But the National Grid is seeing nevertheless a remarkable switch towards offshore wind, a point that commentators seem not to have picked up. By 2018, if these numbers are accurate, the UK will be getting something over 20% of its electricity from wind, or average of 8-9 GW, compared to no more than 1 GW at the moment.

On the negative side, National Grid is seeing a very limited investment in grid connected tidal power, with only about 0.1 GW connected by 2018. It postulates over 2 GW of biomass power stations, meaning that even including today’s hydro-electric plants, renewables other than wind will be little more than 3 GW. The Climate Change Committee’s scenario for 2020 has a much large figure of about 10 GW, implying far more optimism about the prospects for biomass, tidal and wave.

We might see measurable amounts of solar PV by 2018 in terms of capacity, but the typical installation will perform at only about 10% of its rated power, meaning that even if 2m homes sign up to feed in tariffs the UK will struggle to get an average of 0.5 GW of power from the sun. The 2018 scenario sees 2 nuclear power stations completed during 2017/8 at Wylfa and Hinckley Point.

As an aside, National Grid forecasts show large amounts of spare electricity generating capacity as some of the coal-fired stations close in the 2015 and 2016 period. The generators are falling over themselves to install gas plants, with the winter peak maximum demand of about 60 GW almost covered by nuclear stations and by gas plants alone, with no need for any contribution from coal power at all, even from the power stations remaining open. The lights will not go out.