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David MacKay

@david-mackay · 27 positions · 0 changes of mind

Physicist. Professor at the University of Cambridge from 1995 to his death in 2016, Chief Scientific Adviser to the UK Department of Energy and Climate Change from 2009 to 2014. Wrote Sustainable Energy — without the hot air (2008), which he published free at withouthotair.com.

David MacKay did not write this page.

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  1. If everyone does only a little to help solve a big problem, the collective result will still be only a little.

    A more realistic mantra is: if everyone does a little, we’ll achieve only a little.

    Sustainable Energy — without the hot airinference.org.uk 1st of 27 in this piece

  2. Climate change is at its core an energy problem, since burning fossil fuels for energy is the main driver of emissions.

    So to fix climate change, we need to sort out a new way of getting energy. The climate problem is mostly an energy problem.

    Sustainable Energy — without the hot airinference.org.uk 2nd of 27 in this piece

    energy

  3. Covering the windiest 10% of Britain with windmills could generate about 20 kWh per day per person, roughly half the energy used driving an average car 50 km a day.

    if we covered the windiest 10% of the country with windmills (delivering 2 W/m2 ), we would be able to generate 20 kWh/d per person, which is half of the power used by driving an average fossil-fuel car 50 km per day.

    Sustainable Energy — without the hot airinference.org.uk 3rd of 27 in this piece

    energy

  4. Britain's onshore wind resource, though large, is not as large as the country's energy consumption.

    Britain’s onshore wind energy resource may be “huge,” but it’s evidently not as huge as our huge consumption.

    Sustainable Energy — without the hot airinference.org.uk 4th of 27 in this piece

    energy

  5. Airplanes are already almost as energy-efficient as they could possibly be, so no redesign will radically improve their efficiency.

    planes are already almost as energy-efficient as they could possibly be. Planes unavoidably have to use energy for two reasons: they have to throw air down in order to stay up, and they need energy to overcome air resistance. No redesign of a plane is going to radically improve its efficiency.

    Sustainable Energy — without the hot airinference.org.uk 5th of 27 in this piece

    energy

  6. Photovoltaic panels will keep getting cheaper and less energy-intensive to manufacture over time.

    I am sure that photovoltaic panels will become ever cheaper; I’m also sure that solar panels will become ever less energy-intensive to manufacture, so their energy yield ratio will improve.

    Sustainable Energy — without the hot airinference.org.uk 6th of 27 in this piece

    solarenergy

  7. Biofuels cannot supply enough energy to matter for a country like Britain or to replace all transport fuels.

    I think one conclusion is clear: biofuels can’t add up – at least, not in countries like Britain, and not as a replacement for all transport fuels.

    Sustainable Energy — without the hot airinference.org.uk 7th of 27 in this piece

    energy

  8. Switching off a phone charger when not in use saves only a negligible amount of energy compared to overall consumption.

    Obsessively switching off the phone-charger is like bailing the Titanic with a teaspoon.

    Sustainable Energy — without the hot airinference.org.uk 8th of 27 in this piece

    energy

  9. Wave power is unlikely to play a significant role in solving Britain's sustainable energy problem, though it may suit small remote-island communities.

    While wave power may be useful for small communities on remote islands, I suspect it can’t play a significant role in the solution to Britain’s sustainable energy problem.

    Sustainable Energy — without the hot airinference.org.uk 9th of 27 in this piece

    energy

  10. Britain cannot live on its own renewables under its current lifestyle and consumption levels.

    But realistically, I don’t think Britain can live on its own renewables – at least not the way we currently live.

    Sustainable Energy — without the hot airinference.org.uk 10th of 27 in this piece

    energy

  11. British people tend to oppose large-scale renewable energy projects even while supporting renewable energy in principle.

    People love renewable energy, unless it is bigger than a figleaf. If the British are good at one thing, it’s saying “no.”

    Sustainable Energy — without the hot airinference.org.uk 11th of 27 in this piece

    energy

  12. Hydrogen is a hyped-up bandwagon that is unlikely to help with our energy problems.

    I think hydrogen is a hyped-up bandwagon. I’ll be delighted to be proved wrong, but I don’t see how hydrogen is going to help us with our energy problems.

    Sustainable Energy — without the hot airinference.org.uk 12th of 27 in this piece

    energy

  13. Hydrogen-powered cars will ultimately use about as much energy as today's average fossil-fuelled car.

    my prediction is that after all the “zeroemissions” trumpeting is over, we’ll find that hydrogen cars use just as much energy as the average fossil car of today.

    Sustainable Energy — without the hot airinference.org.uk 13th of 27 in this piece

    energy

  14. Switching to electric cars is already a good idea, even before the electricity supply is greened.

    So I conclude that switching to electric cars is already a good idea, even before we green our electricity supply.

    Sustainable Energy — without the hot airinference.org.uk 14th of 27 in this piece

    energy

  15. Heat pumps are more efficient than condensing boilers even when the heat pump's electricity comes from a natural-gas power station.

    Heat pumps are superior in efficiency to condensing boilers, even if the heat pumps are powered by electricity from a power station burning natural gas.

    Sustainable Energy — without the hot airinference.org.uk 15th of 27 in this piece

    energy

  16. The price of nuclear power is dominated by construction and decommissioning costs, not fuel costs.

    nuclear power’s price is dominated by the cost of power-station construction and decommissioning, not by the cost of the fuel.

    Sustainable Energy — without the hot airinference.org.uk 16th of 27 in this piece

    energy

  17. Nuclear power is dangerous, but not uniquely so among energy sources like coal, oil, and wind.

    Nuclear power is not infinitely dangerous. It’s just dangerous, much as coal mines, petrol repositories, fossil-fuel burning and wind turbines are dangerous.

    Sustainable Energy — without the hot airinference.org.uk 17th of 27 in this piece

    energy

  18. Nuclear waste is only a minor worry compared with the other forms of waste being left to future generations.

    I feel nuclear waste is only a minor worry, compared with all the other forms of waste we are inflicting on future generations.

    Sustainable Energy — without the hot airinference.org.uk 18th of 27 in this piece

    energy

  19. Assuming the nuclear fusion problem will be solved is reckless, even though estimating fusion's potential power output is still worthwhile.

    Fusion power is speculative and experimental. I think it is reckless to assume that the fusion problem will be cracked, but I’m happy to estimate how much power fusion could deliver, if the problem is cracked.

    Sustainable Energy — without the hot airinference.org.uk 19th of 27 in this piece

    energy

  20. Ramping up electric vehicles alongside wind power, roughly 3,000 vehicles per 3 MW turbine, with smart charging, would go a long way to solving the problem of wind fluctuations.

    If we ramp up electric vehicles at the same time as ramping up wind power, roughly 3000 new vehicles for every 3 MW wind turbine, and if we ensure that the charging systems for the vehicles are smart, this synergy would go a long way to solving the problem of wind fluctuations.

    Sustainable Energy — without the hot airinference.org.uk 20th of 27 in this piece

    energy

  21. Reducing emissions from oil and gas matters less than coal, because supplies of both are expected to decline over the next 50 years anyway.

    Trying to reduce emissions from oil and gas is of secondary importance because supplies of both oil and gas are expected to decline over the next 50 years.

    Sustainable Energy — without the hot airinference.org.uk 21st of 27 in this piece

    energy

  22. Free markets alone cannot solve environmental and energy problems; legislation, regulation, and taxation are also necessary.

    So, while markets may play a role, it’s silly to say “let the market handle it all.” Surely we need to talk about legislation, regulations, and taxes.

    Sustainable Energy — without the hot airinference.org.uk 22nd of 27 in this piece

    energy

  23. Europe cannot meet its energy needs from renewables alone and will need nuclear power, solar power from deserts elsewhere, or both.

    Just like Britain, Europe can’t live on its own renewables. So if the aim is to get off fossil fuels, Europe needs nuclear power, or solar power in other people’s deserts (as discussed on p179), or both.

    Sustainable Energy — without the hot airinference.org.uk 23rd of 27 in this piece

    solarenergyEurope

  24. Solar thermal water heating is a practical technology that works in most of the world.

    Solar thermal water heaters are a no-brainer. They will work almost everywhere in the world.

    Sustainable Energy — without the hot airinference.org.uk 24th of 27 in this piece

    solar

  25. Using tree planting to reverse climate change is not workable because it would require country-sized land areas.

    If anyone proposes using trees to undo climate change, they need to realise that country-sized facilities are required. I don’t see how it could ever work.

    Sustainable Energy — without the hot airinference.org.uk 25th of 27 in this piece

  26. Air-source heat pumps are the best heating choice for most people.

    I therefore suggest air-source heat pumps are the best heating choice for most people.

    Sustainable Energy — without the hot airinference.org.uk 26th of 27 in this piece

    energy

  27. For most materials, embodied energy per unit weight is at least about 10 kWh per kg, similar to fossil fuels' energy density by weight.

    For most materials, the embodied energy per unit weight is greater than or equal to 10 kWh per kg – the same as the energy per unit weight of fossil fuels.

    Sustainable Energy — without the hot airinference.org.uk 27th of 27 in this piece

    energy