Keeping the lights on

George Monbiot’s latest column (originally published in the Guardian) analysing UK electricity demand and supply raises a number of issues.

George modestly says he is not qualified to carry out this analysis. I’m not any more qualified, but I suggest it is only the facts that require expert input, not the analysis itself, a large part of which is simply a matter of addition.

I’ve spent some considerable time since buying yesterday’s Guardian poring over the numbers and I feel I have to gently chide George for his presentation being even more confusing than necessary.

I suggest that a clearer approach would be to consider first the total amount of power that the UK can generate by renewable means.

Then let’s consider what would need to be done to ensure that peak requirements can be met. This should include what measures can be taken to reduce the peak consumption.

Finally we should think about what spare capacity is necessary.

1. Power generation capacity
According to the DTI the UK currently uses about 400,000 GWh of electricity a year. I do not share George’s optimism that this can be significantly reduced. Currently it is increasing. We should also not consider electricity generation in isolation. In particular, solutions to reduce CO2 emissions from the transport sector are likely to require increased electricity generation, either to power public transport or to power cars directly or indirectly (if electricity is used to produce hydrogen, for example). I suggest that we assume instead that we can maintain this demand at a constant level.

From the figures in the article the UK could generate power as follows:
· 100,000 GWh from offshore wind;
· 58,000 GWh from onshore wind;
· 53,000 GWh from wave power;
· 36,000 GWh from tidal stream machines;
· 24,000 GWh from tidal lagoons;
· an unknown amount from sunlight;
· 17,000 GWh from willow plantations;
· 6,000 GWh from hydro power;
· 5,000 GWh from landfill gas.

That is, a total of 299,000 GWh + solar. Not too bad at all.

I’d like to make a few points, though:
· I don’t buy into any of the supposed limitations on expanding offshore wind power electricity generation beyond 100,000 GWh per year. GM notes that “shallow water with a firm seabed” is required. Surely this is just an engineering problem – why can’t they be built on floating platforms, for example? We seem to be able to overcome similar problems to extract oil from the most hospitable environments. I suggest that with sufficient market demand this problem will be solved. The need to stay out of the paths of migrating birds is debatable and of military exercises just lame. Furthermore, on the internet I find a report Sea Wind East report by AEA for Greenpeace. This stated (in 2002) that by 2020 84,000 GWh of offshore windpower could be produced from the resources of East Anglia alone! Elsewhere on the Web I find the UK’s accessible wind resource estimated at 340 TWh, i.e. 340,000 GWh pa. Can anyone comment on the true potential for wind power generation in the UK?
· the production of 17,000 GWh pa by 2030 from willow plantations is just not going to happen. Apart from being ecological barbarism, I calculate that this will require a minimum of 400,000 hectares of suitable land. This is presumably in addition to the 1.25 million hectares required to meet the UK’s Renewable Transport Fuel Obligation (see GM’s article “Fuel for nought”, Guardian 23/11/04, also available online on his site as “Feeding Cars not People”). I suspect some double-counting as DEFRA statistics suggest there are only 680,000 hectares of set-aside land in the UK. The 5.7 million hectares mentioned in “Fuel for nought”, refers to the total arable land in the UK, all of which (it seems) is being used to grow crops or has been rotated to pasture (or is fallow). We need to eat. Furthermore, the willow will require fertilization, herbicides and (inevitable in a monoculture) pesticides. It also requires huge amounts of water. Quite apart from all this, in the limited time I have had available, my internet surfing suggests that those countries, such as Canada and Sweden, where willow is currently being used for power are at least 10 years ahead of the UK in trialling specific varieties, but still at a scale of 1,000s rather than 100,000s of hectares. In most cases the production of willow seems to be a by-product of using the crop to get rid of polluted water. Besides all this, isn't there a good chance the climate will change significantly during the 25 year lifetime of the crop, shortening its useful life and undermining the viability of the investment? Indeed, if this were a financial investment, my advice would be “avoid”.
· we need to understand the potential of local electricity generation using solar power and wind turbines. Can anyone comment on this? [It is a non sequitur in GM's article that electricity from sunlight should not be counted because ... "it isn't produced when we need it most" as he goes on a couple of paragraphs later to assume the development of energy storage facilities].

OK, so we’re 101,000 GWh short, (or 118,000 if we forget the willows).

2. Peak capacity
Apart from the absolute amount of power we can generate, we also have the problem of meeting peak demand, as GM stresses in his article. It seems to me that this problem is not totally insoluble.

First, the article is mistaken when it says: “The need for spare capacity could be greatly reduced if we managed demand rather than supply…”. In fact it’s the peak that would be reduced. (The need for spare capacity will instead depend on the technologies used.). Matching of demand to supply must clearly be investigated. For example, according to DTI figures, the biggest single industrial user is the chemical industry, at 23,000 GWh per annum. How much of this could be moved to times when sufficient power is available? Remember, the supply of wind-power is predictable in advance.

Second, it should be noted, as Graham Sinden of Oxford University points out, that the profile of wind energy production matches demand reasonably well: it peaks in winter and during the day, for example.

Third, we already manage peak demand in two ways: we use pumped storage facilities and we import power. According to DTI figures, pumped storage is 75% efficient, so George is being pessimistic when he assumes 50% efficiency for storage. Could such facilities be expanded? Even if expensive, wouldn’t this be more desirable than building nuclear power stations?

Importing and exporting power seems an even more attractive method of smoothing out peaks and troughs in supply. Over a large enough area the wind will always be blowing somewhere. It seems an expansion of international power transmission infrastructure has not been sufficiently allowed for. The whole climate change debate is conducted as if it is a separate problem for each individual state. In fact, it’s a global problem and requires global solutions.

3. Spare capacity
As we’ve already seen, the need for spare capacity will depend on the technologies used. It seems to me that, because nuclear power generation is “lumpy” – with a few facilities each generating vast amounts of power- and the safety concerns so serious, a solution with a high proportion of nuclear power will require most spare capacity, to allow for power stations to be closed for maintenance for long periods. It may also be necessary to allow for unplanned maintenance. Conversely, wouldn’t the need for spare capacity be much reduced if we rely more on renewable energy?

Conclusions
I have no over-riding objection to nuclear power. After all, we’re already importing electricity produced using French nuclear power and a nuclear accident in France is likely to affect me in the south of England at least as much as one in Scotland. Like other forms of power it is risky, and these risks need to be taken account of in a full cost analysis. Such analyses seem to show that it is an expensive way to generate power and even if it did make us self-sufficient, this is a mistaken objective: we have to trade to survive anyway. I also understand there are not unlimited supplies of uranium ore. We need to factor into our calculations what happens to costs if there is worldwide construction of nuclear power stations over the next 20 years or so. The numbers suggest to me that before we make a decision we must get a better understanding of the potential for electricity generation by offshore wind power. An exercise should be carried out to consider what we would do if we couldn’t build any new nuclear power stations.

Even if we do opt to build more nuclear power stations, there are several steps which can be taken to reduce their number:
· extend real-time pricing mechanisms to better match demand to supply;
· invest in facilities to store power, for example further pumped storage facilities;
· invest further in international power transmission infrastructure.

I’d certainly like to see a clearer analysis before I concede that it’s necessary to build more nuclear power stations.

Finally, there’s really no reason why one of most densely populated places on the planet (the UK) should be self-sufficient in power. I’d hate to think that we’re building nuclear power stations because politicians find that an easier solution than building infrastructure to ensure that renewable forms of power can be fully exploited - and perhaps having to do deals with other European countries!