Intermittency
"But what if the wind stops blowing? What if the sun stops shining? How can we rely on renewables then?"
These are the questions frequently posed by those who believe that we need nuclear power to support a low carbon electricity system. But read on and you will see that nuclear is not the solution.
The UK's demand for electricity varies through out the day, and across the year. The energy industry needs to be able to match that demand in order to prevent power cuts. Currently this is managed through temporarily increasing the output from gas-fired and coal-fired power stations when demand rises1. Renewable sources of energy that rely on the weather (wind, wave, and solar power) do not have the option to temporarily increase their output.
However there is more than one way to manage the mismatch between supply and demand. In fact there are lots of ways, and if employed correctly we can consistently and reliably supply the UK's electricity needs through low-carbon resources without resorting to nuclear power.
It is possible to manage supply through increasing output from biogas-fired power stations2 or hydro-power3. In the same way that coal and gas provide a spinning reserve now, biogas can provide a carbon-neutral reserve in the future. We can also smooth out the overall output of wind energy by spacing the wind farms far apart – that way they're not all vulnerable to the same gusts and lulls in the wind. Another way to manage supply during emergencies is to import renewably-generated electricity from our European neighbours. And in case you're worried that this is a costly solution, it's worth bearing in mind that the export of the UK's renewable electricity is likely to earn us £6.37 billion a year in the future.4
But even more crucially than this, the Secretary for Energy and Climate Change (Rt Hon Chris Huhne), recognises and admits that nuclear power is not suitable for bridging the gap between demand and supply. On 15th September 2010, in an oral evidence session at Westminster with MPs from the Energy and Climate Change Committee, Huhne said of nuclear power that "it is not economic to turn it up and down". To keep a nuclear power plant running at half capacity and then to turn it up to full capacity when wind power drops would be prohibitively expensive, and so nuclear cannot be used to fulfil this role.
But we don't need to always manage the supply, we can manage the demand as well. By using our electricity intelligently we can make the most of our resources at the optimal time. For example well-established dynamic demand technologies are able to respond to reduced electricity supply in the national grid by turning off non-essential appliances for a few minutes, such as your fridge or your air-conditioning, before turning them on again when supply rises. The technology is cheap and simple, and would even save you a small amount of money each year on your fuel bills.
Indeed, with increased renewables in the UK grid the availability of electricity might even be better suited to the way in which we will use electricity in the future. With more wind energy at night, charging up our electric cars overnight will be even easier.
So there it is, a non-nuclear future would not be a future of power-cuts, it would be a smart future of intelligent energy use, where electricity supply would be more than sufficient to meet our needs.
1. Having these power stations running on standby is extremely inefficient and costs about £80 million per year
2. Zero Carbon Britain 2030: A new energy strategy, Centre for Alternative Technology 2010, page 239
3. ibid, page 271
4. ibid, page 273