In order to have a frame of reference for later articles in this series, I thought I’d give you the summary of what Professor David J C MacKay thinks future U.K. could look like if it were to make an attempt at a carbon-free society. This is just his take on what demand will look like and his Plan E (the most economically affordable plan).
In the five plans for the future, transport is largely electrified. Electric engines are more efficient than petrol engines, so the energy required for transport is reduced. Public transport (also largely electrified) will be better integrated, better personalized, and better patronized. There will be a few essential vehicles that can’t be easily electrified, and for those we will make our own liquid fuels (for example biodiesel or biomethanol or cellulosic bioethanol). The energy for transport is 18 kWh/d/p of electricity and 2 kWh/d/p of liquid fuels. The electric vehicles’ batteries will serve as an energy storage facility, helping to cope with fluctuations of electricity supply and demand. The area required for the biofuel production would be about 12% of the UK (500m2 per person), assuming that biofuel production comes from 1%- efficient plants and that conversion of plant to fuel is 33% efficient. Alternatively, the biofuels could be imported if we could persuade other countries to devote the required (Wales-sized) area of agricultural land to biofuels for us.
In all five plans, the energy consumption of heating is reduced by improving the insulation of all buildings, and improving the control of temperature (through thermostats, education, and the promotion of sweater-wearing by sexy personalities). New buildings (all those built from 2010 onwards) are really well insulated and require almost no space heating. Old buildings (which will still dominate in 2050) are mainly heated by air-source heat pumps and ground-source heat pumps. Some water heating is delivered by solar panels (2.5 square metres on every house), some by heat pumps, and some by electricity. Some buildings located near to managed forests and energy-crop plantations are heated by biomass. The power required for heating is thus reduced from40 kWh/d/p to 12 kWh/d/p of electricity, 2 kWh/d/p of solar hot water, and 5 kWh/d/p of wood.
The wood for making heat (or possibly combined heat and power) comes from nearby forests and energy crops (perhaps miscanthus grass, willow, or poplar) covering a land area of 6 million hectares, or 1000m2 per person; this would correspond to 35% of the agricultural land of the
UK, which has an area of 2800m2 per person. The energy crops would be grown mainly on the lower-grade land, leaving the higher-grade land for food-farming. 1000m2 of energy crops will yield 1 oven dry ton per year, which has an energy content of about 10GJ; of this energy, about 33% is lost in the heat delivery process or required for production and transport. The final heat delivered is 5 kWh/d per person. In these plans, I assume the current demand for electricity for gadgets, light, and so forth is maintained. So we still require 18 kWh(e)/d/p of electricity. Yes, lighting efficiency will be improved by a switch to LEDs for most lighting, but we’ll have increased the number of gadgets in our lives, for example video-conferencing systems to help us travel less.
So the total consumption of electricity under this plan goes up (because of the 18 kWh/d/p for electric transport and the 12 kWh/d/p for heat pumps) to 48 kWh/d/p (or 120GW per UK). This is nearly a tripling of UK electricity consumption. Where’s that energy to come from? Let’s describe some alternatives. Not all of these alternatives are ‘sustainable’ as defined in this book; but they are all low-carbon plans.
Producing lots of electricity – the components to make lots of electricity, our plan will use some amount of onshore and offshorewind; some solar photovoltaics; possibly some solar power
bought from countries with deserts; waste incineration (including refuse and agricultural waste); hydroelectricity (the same amount as we get today); perhaps wave power; tidal barrages, tidal lagoons, and tidal stream power; perhaps nuclear power; and perhaps some ‘clean fossil fuel’, that is, coal burnt in power stations that do carbon capture and storage. Each plan will aim for a total electricity production of 50 kWh/d/p on average – I got this figure by rounding up the 48 kWh/d/p of assumed average demand.
Some of the plans that follow will import power from other countries. For comparison, it may be helpful to know how much of our current power is imported today. The answer is that, in 2006, the UK imported 28 kWh/d/p of fuel, – 23% of its primary consumption. These imports are dominated by coal (18 kWh/d/p), crude oil (5 kWh/d/p), and natural gas (6 kWh/d/p). Nuclear fuel (uranium) is not usually counted as an import since it’s easily stored.
In all five plans I will assume that we scale up municipal waste incineration so that almost all waste is incinerated or recycled rather than landfilled. Incinerating 1 kg per day per person of waste yields roughly 0.5 kWh/d per person of electricity. I’ll assume that a similar amount of agricultural waste is also incinerated, yielding 0.6 kWh/d. Incinerating this waste would require roughly 3GW of waste-to-energy capacity, a ten-fold increase over the incinerating power stations of 2008. London (7 million people) would have twelve 30MW waste-to-energy plants like SELCHP in South London. Birmingham (1 million people) would have two of them. Every town of 200,000 people would have a 10MW waste-to-energy plant. One good side-effect of this waste incineration plan is that it eliminates future methane emissions from landfill sites.
SELCHP cost £85 million so the cost of the nation’s 100 new 30MW incinerators might be £8.5 billion (£140 per person). In all five plans, hydroelectricity contributes 0.2 kWh/d, the same
amount as we get from hydro today. Electric vehicles are used as a dynamically-adjustable load on the electricity network. The average power required to charge the electric vehicles is 50GW (20 kWh/d/p). So fluctuations in renewables such as solar and wind can be balanced this load, as long as the fluctuations are not too big.
Daily swings in electricity demand are going to be bigger because of the replacement of gas for cooking and heating by electricity. To ensure that sudden surges in consumer demand of 50GW lasting up to 2 hours can be covered, all the plans would build new pumped storage facilities like Dinorwig. 100GWh of storage is equal to ten Dinorwigs.
Before presenting Plan E(conomics), Professor MacKay provides four other plans that are fairly well summarized here. Below is a graphical breakdown of how energy generation in the five plans breaks down. Plan E, describe below, is on the far right.
Plan E stands for ‘economics’. On a level economic playing field with a strong price signal preventing the emission of CO2, we don’t get a diverse solution, we get an economically optimal solution that delivers the required power at the lowest cost. And when ‘clean coal’ and nuclear go head to head on price, it’s nuclear that wins. (The capital cost of regular dirty coal power stations is £1 billion per GW, about the same as nuclear; but the capital cost of clean coal power, including carbon capture and storage, is roughly £2 billion per GW.) Solar power in other people’s deserts loses to nuclear power when we take into account the cost of the required 2000-km-long transmission lines. Offshore wind also loses to nuclear, but I’ve assumed that onshore wind costs about the same. My final plan is a rough guess for what would happen in a liberated energy market with a strong carbon price.
Wind: 4 kWh/d/p (10GWaverage) (plus about 500GWh of associated pumped storage facilities). Solar PV: 0 kWh/d/p. Hydro, waste incineration: 1.3 kWh/d/p. Wave: 0 kWh/d/p. Tide: 0.7 kWh/d/p. Nuclear: 44 kWh/d/p (110GW). Total: 50 kWh/d/p.
This plan has a ten-fold increase in our nuclear power over 2007 levels. 110GW is roughly double France’s nuclear fleet. I included a little tide because I believe a well-designed tidal lagoon facility can compete with nuclear power. In this plan, Britain has no energy imports (except for the uranium, which, as we said before, doesn’t count).
Without having done the math yet I suspect that the United States’ plan will not look like any of these plans. We will use our own Plan E of course. Or, at least that will be the plan that I will recommend. There is absolutely no reason not to leave the choice of technologies to the market. There is absolutely no reason to pay more for energy than we have to provided that the choices are carbon comparable. Nuclear aside, maybe.
The point being, the United States has far more cost efficient wind and solar resources available to us than Britain. As you can see, three of MacKay’s Plan for Britain involve setting up vast solar installations in northern Africa and piping the electricity across Europe into England. Ultimately he doesn’t see that as politically or economically feasible. We will have such problems in the desert south-west.