Has Professor MacKay FRS, Chief Scientific Advisor to DECC, underestimated Britain's potential for Renewable Energy?
Today, The Times has claimed that Britain’s potential renewable resources are insufficient to meet demand, and therefore that Britain needs new nuclear plants. This is reported as having been stated by the new Chief Scientific Advisor to DECC, Professor David MacKay FRS, the author of the free online book: Sustainable Energy Without the Hot Air – though it appears that The Times invented this quote. Nevertheless, the claim that Britain cannot live on its own renewables, is also made in his book.
However, the claim is not true.
On the professor’s own (underestimated) calculation of Britain’s renewable potential, it is possible for Britain to power itself from wind and solar. Current energy demand (heat, transport & electricity), is 98kWh per person per day (245GW), and the professor’s book identifies 68kWh/d (170GW) of wind onshore and offshore, and 55kWh/d (137.5GW) from photovoltaics, which together gives 123kWh/d (307.5GW). That means that even ignoring wave, tidal, geothermal and biomass, Britain’s renewable potential supply just from solar and wind substantially exceeds our energy demand.
In short, it’s a mythconception to say that Britain needs any nuclear at all (or renewables in other countries’ deserts) to decarbonise its energy supplies. It’s a mythconception to say that Britain’s potential renewable resource is insufficient to meet demand. And the numbers bear that out.
For example, here’s a scenario, which would allow Britain to generate energy equivalent to 100% of its demand from renewables alone, with no net import of energy or fuel.
Supply = 190GW
Note that the figures given below are for average power delivered, not the maximum capacity that would be installed. For example, the 10GWe of electricity from biomass would come from 40GWp of peak installed plant, running at 25% load factor. The 78GWe of electricity from offshore wind would come from about 240GWp peak capacity of installed wind turbines.
- 3GWe of geothermal
- 10GWe of biomass, built as 40GWp to run at a mean 25% load factor
- 20GWth of solar-thermal heating
- 10GWe of photovoltaics
- 10GWe of wave
- 5GWe of tidal stream
- 4GWe from tidal barrages
- 78GWe of offshore wind
- 50GWe of onshore wind
Giving 190GW mean supply of energy, of which 43GWp is dispatchable electricity-on-demand.
Demand = 190GW
- 245GW: current demand
- -25GW reduction by electrifying the car fleet: electric vehicles are much more energy efficient, so although electricity demand from the grid would increase by about 10GW, the energy demand from petrol would decrease by about 35GW, giving a net decrease in energy consumption of 25GW
- -30GWth reduction by insulating the housing stock properly
Thus reducing demand from its current 245GW to 190GW at most.
Halving total energy demand to 125GW is realistic, using the panoply of cost-effective energy-efficiency measures; but here, I’ve just taken a figure that’s roughly the 20% savings that we’re already committed to delivering by 2020. It will generally be far cheaper to push much further on the energy efficiency than that 20%, because reducing demand reduces the balancing, transmission & storage requirements, as well as reducing the required installed generation capacity.
- electric district heating with large thermal stores;
- 100GW of interconnectors to the continent, by building all of the offshore wind off the east and south coasts along HVDC interconnectors to the continent
- decarbonise the 20GWp of backup generators, and connect them all into the smart grid, giving 20GW of emergency reserve.
- smart grid: smart heating + smart electric-vehicle charging with V2G + smart appliances for those that don’t object to their appliances helping to minimise the household electricity bill (fridge, freezer, laundry, dishwasher).
- 2 more Dinorwigs onshore; and more offshore too, in the form of IOPAC energy islands, which would also be built along the interconnectors. This is the technology in the proposals for the Dutch Masterplan for the North Sea, and the Danish Green Power Island.
There are lots of reasons to believe that the renewable resource is far higher than the Professor estimates, too.
The potential wave resource is around 80GW (source: ETSU R-122 “New and Renewable Energy: Prospects in the UK for the 21st Century: Supporting Analysis”), with a theoretical potential harvest rate of 80%, giving 64GW: Professor MacKay assumes a 25% harvest of a 40GW resource, giving 10GW.
On offshore wind, the book assumes that:
- none of the waters between 50m and 700m depth will be used;
- two-thirds of the waters between 0 and 50m cannot be used for offshore wind, because of shipping (that’s some pretty big shipping!);
- wind yield from current offshore wind farms is representative of the offshore resource as a whole.
However, I do not believe that any of those assumptions withstand scrutiny.
- The Norwegians are piloting floating turbines in waters 100-700m deep, right now.
- Of course you’d need some waters for shipping; but small boats are quite happy to travel between turbines in offshore wind farms; meaning that turbine-free shipping lanes are needed just through the channel and between the major ports, for tankers and container ships.
- The DTI’s Renewables Atlas shows that the available energy offshore in wind is on average far higher than at the current operational offshore windfarm sites.
Elsewhere on this site, I show that the UK offshore wind resource is 2 Terawatts mean power, if the book’s assumptions are removed.
The numbers do show that Britain’s potential renewables resource is way more than sufficient to meet demand.