The opposition to the continuing existence of a largely fossil-fuel based economy can be loosely divided into two key groups: The first propagate that a reliance on coal, oil and gas should be replaced with the exploitation of renewable energy sources, such as wind, solar and biomass; The second group support the growth of atomic energy, and envision a future society where hydrocarbon power plants are replaced by nuclear alternatives. It is frequently asserted, by members of both groups, that the two approaches are incompatible with each other – that we are faced with an either-or decision. We can either take the ‘nuclear option’, or go for an entirely renewable energy future. I personally believe that both positions are false. The evidence that I have seen leads me to the conclusion that nuclear and renewables can not only work well together, but an energy solution including elements of both would be more economical and have a higher chance of success than relying on one source of energy alone.

Let’s start by looking at some of the advantages and disadvantages of nuclear and renewable energy.

The UK has large, windy shores. The physicist David J.C Mackay identified the offshore regions around the British Isles as a very promising source of energy in his excellent book on energy. We can safely say that a key advantage of renewable energy sources, such as offshore wind, is its huge abundance. In the book mentioned above, it is calculated that there is sufficient energy in the winds around the UK to provide all of our energy needs.

Mackay also identified the key disadvantages of most renewables – variability in output, and also the amount of land needed to be exploited to supply a given amount of energy. The physicist calculated that approximately one-third of the waters around the UK would need to be filled with wind turbines to make a serious dent in our fossil fuel replacement needs.

Obviously, wind power on this scale will pose logistical, material and public acceptability problems.

The recent report by the UK’s Committee on Climate Change found that even when exploiting a range of renewable sources in tandem (solar, wind, etc), there are periods in which output will drop to virtually zero.

There are solutions to the later of these two problems at least – large scale energy storage, such as dams or batteries, or producing a large scale multi-national ‘supergrid’. Another, perhaps much easier solution would be to simply combine a large scale build of renewables with nuclear energy.

One of the biggest advantages of nuclear energy is that it is highly reliable. Your average nuclear reactor in the UK will provide the full nameplate output around 90% of the time. This is an impressive figure, and is a bit better than most coal and gas plants, and way better than even the most reliable wind farms (around 40%).

However, not only can a nuclear power plant run on a continual, round-the-clock basis, it usually has to be run uninterrupted, in order to remain economically viable. When in the nuclear power business, the largest cost is constructing the plant in the first place, the so called ‘overnight capital cost’. To justify this enormous investment, the operator of a nuclear power plant usually has to run it on a 24/7 full-power mode. Forget waste and safety, this is real downside of nuclear energy.

Keeping in mind what we have just discussed, consider the following graph. It represents the fluctuation in electricity demand over a few days in the UK. Note how there is a value below which demand never falls (which actually isn’t even represented on the graph). This is often refereed to as the ‘baseload’. Also note how there are ‘peaks’ in demand on a daily basis.

It has been argued that the baseload demand would be difficult to satisfy with variable output sources of power, such as renewables. Indeed, the solutions for ‘smoothing’ the output of wind, solar etc, such as building storage dams, batteries, or a ‘supergrid’, are highly expensive and time consuming. An ideal candidate to provide baseload capacity seems to be nuclear power, due to its continual output.

Can nuclear also provide the power required to satisfy the peaks in demand? Yes, it could, but remember that the output of a nuclear power plant can not be varied substantially and remain economically viable. So the further we move nuclear power up those peak demand curves, the more money we potentially waste.

This is where luck is on our side. It just so happens that those peaks in demand, which occur when a substantial number of people are getting home from work and turning on they’re TV sets, kettles etc just so happens to coincide with when the sun is setting and it’s starting to get cold and windy. Got any ideas as to what the ideal solution here is? I don’t think I really need to spell it out.

It is arrogant to suggest that the solution to our energy woes is based on a single source. We’re going to need to exploit the factories that are tooled up for making wind turbines and reactor vessels. We’ll probably need to throw in some Carbon Capture and Storage plants too for back up, and don’t forget energy efficiency.

In conclusion, the advantages and disadvantages of nuclear power and renewables such as wind are equal and opposite – one is highly reliable, yet mostly stuck on all the time, the other variable. It just so happens that about half our energy demand resembles the output of one source and the other half resembles the output of the other. Therefore, an energy mix based on both renewables and nuclear is not only possible, it’s desirable, pragmatic and economic.

We have a huge task ahead – can we please stop arguing, bang out an energy plan, and just get on with it?

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