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.

The UK’s potential renewable resource

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.

7 comments on “Has Professor MacKay FRS, Chief Scientific Advisor to DECC, underestimated Britain's potential for Renewable Energy?

  1. For Britain as the country with the biggest wind, wave and tidal resource in Europe to go down the new nuclear route is, quite frankly, ludicrous.

    I have been campaigning (more or less actively and in various roles and wearing different hats) for energy efficiency and renewables and against nuclear power for 20 years, and I was pleased to read in the UK Nuclear News last Friday that the UK new nuclear-build programme is wobbling (see http://www.adamsmith.org/blog/regulation-and-industry/new-uk-nuclear-build?-200910024214/). Hopefully it will continue to wobble, topple over and be consigned to the scrapheap of history in the not too distant future.

    On a related note, my biggest fear in the context of the recent German election was an emerging pro-nuclear movement that would push for the construction of new nuclear power plants in Germany, although fortunately it seems public anti-nuclear opinion in Germany is so strong that no-one would actually seriously suggest a new nuclear-build programme. An article in the current edition of Nuclear Monitor (see http://www.hetranslation.co.uk/files/NM695.pdf) would suggest that new nuclear is definitely off the agenda in Germany, and the worst case scenario under the new government seems to be an extension of the operating licences for some of the existing plants.

    I sincerely hope that Germany will continue on its path to become “The World’s First Major Renewable Energy Economy” (see http://tinyurl.com/Renewable-Energy-Economy and that Britain will follow suit, notwithstanding continuing efforts from various sides to undermine such an enlightened route.

  2. Claverton)

    Paul Mott wrote:

    > As to “money going abroad for the kit”, that’s equally true for wind
    > turbines isn’t it ?

    It is at the moment, because as was made clear at the recent Vestas
    closure, Britain has failed to *commit* to building sensibly large
    quantities of new wind. Across the industry it seems quite well
    accepted now that the more building and construction you do close to the
    farm site, the cheaper it gets. Enercon look to be pushing this line now.

    If Britain were to commit to installing 3-10GWp of wind a year, the
    factories will spring up within two years. If we continue to mess
    around on the issue as we have been doing for decades now, most
    renewables infrastructure finance will continue to go elsewhere.

    Britain’s offshore know-how from north sea oil means it could become the
    world leader in offshore wind. Our wave, tidal stream and tidal barrage
    resources are all sufficiently large for us to become the world’s first
    resort of expertise in every single one of those areas.

    And yes, it most certainly does matter whose pockets the money goes
    into. Internal investment vs external expenditure. A pound spent on UK
    manufacturing will get turned into UK consumer expenditure, UK tax
    revenue, and exports.


    And now a quick report back to the list, from my email discussion with
    Professor MacKay last night.

    He pointed out that on p114 of his book, he says:
    “We’ve established that the UK’s present lifestyle can’t be sustained on
    the UK’s own renewables (except with the industrialization of
    country-sized areas of land and sea).”
    This does contradict p233, which says:
    “Just like Britain, Europe can’t live on its own renewables.”

    I don’t like the term “industrialization” here. Hasn’t the oil & gas
    industry *already* industrialised the North Sea? And onshore, what
    about pylons and post-war agricultural practices? Haven’t they already
    industrialised the countryside? It seems to me to be a value judgement
    to say that those *weren’t* industrialisation, but that wind farms are.
    Maybe they both are. Maybe neither are. But those are all subjective

    In reference to The Times quote from him that “Britain could never live
    on its own renewables.”, David noted that The Times invented most the
    quotes in the article that it attributes to him. No surprise really,
    about The Times: I’m sure that at some time, many of us have suffered
    press abuse in this way.

    He agreed that:

    * a 100% UK renewables scenario is possible;

    * the wave resource is much larger than presented in his book, due to
    the large proportion of wave energy that doesn’t reach British coasts,
    but is instead out in the deep waters: mostly in the Rockall /Icelandic
    spur, but I’ll note here that there’s some off the SW coast too;

    * a tidal barrage does *not* generate twice as much energy in two-way
    operation as one way; in theory, it can generate some more in two-way
    than one-way; but in practice, there’s little difference;

    * two grids – one for intermittent supply + non-time-sensitive demand,
    one for everything else – is not a solution to the question of
    variability; rather, it makes things worse, not better.

    * the offshore wind resource becomes much larger than presented in his
    book, as and when the floating turbine is proven. The pilot one is
    operating right now;


  3. Prof. Mackay does include in his book a theoretical yield from PV of 55kWh/d. However, he also suggests that the practical issues involved in delivering that quantity of PV in a ‘useful’ time scale renders it impractical as a solution to our energy needs.

    Britain certainly has a renewable potential that far exceeds our current energy use. Ideally, by the year 2050 we will be delivering much of our energy from renewable sources. Unfortunately, the issue now is one of time. We simple don’t have time to wait until we can produce all our energy from renewable sources.

    I’m not for a minute suggesting that we should do anything other than push renewables as hard as we possibly can. But we need to take a pragmatic look at the gap between the potential and the short term practical reality.

  4. This contention would be valid if every MWh was consumed at the nanosecond of generation. Adding up random MWh(e) from renewables is a flawed approach. As with any number of random events you will ALWAYS get coincident null points where no electricity is generated from wind, wave, tidal, solar, hydro etc so there has to be 100% backup when these null points occur.

    Hence you do need nuclear to provide low carbon backup for low carbon intermittent systems which is a nonsense in itself. Why bother with renewables at all if you are going to be building nuclear to provide secure supplies anyway?

    response from Andrew Smith

    I do discuss balancing in the article, where I provide sufficient backup mechanisms, to complement the 43GWp of zero-carbon thermal plant

  5. Dear Andrew H Mackay,

    I am afraid your conclusions and understanding are wrong. Andrew Smith is not a moron as he and other people in the Claverton Network have modelled in detail the interaction of renewable energy with variable supply and your statement is simply not true ie that you need 100% back up. You need to read the UKERC report on intermittency to understand this, and to look up the article on wikipedia – Intermittent Energy Energy source – http://en.wikipedia.org/wiki/Intermittent_energy_source .
    If you search on this site and look up what Dr Gregor Czisch has studied exhaustively, for 7 years you will see that renewables can provide continuous electric power at the same price as power is now without 1005 back up.
    Look at Dr David Elliots papers, two of them at: http://tx1.fcomet.com/~claverto/cms/?dl_id=384 and you will see various scenarios renewable energy.

  6. Dear Peter Cross,

    One of the things the Claverton group has discussd in great detail is how quickly UK could build things. It is pretty obvious to most people that renewables can be built far more quickly than nuclear – you just take a couple of years to build a tower, turbine and blade factory, then you can churn the stuff out. One only has to look at the WW2 precedents where Liberty ships plus a whole lot of other things – tanks, heavy guns,aircraft, concrete defences were being built at a fantastic rate.
    We in the Claverton Group are only too keen to look at various future scenarios but from a fact based perspective.

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