In my last major blog I described how the UK needed to phase out the domestic gas grid if government was to have any hope of meeting its legal obligations under the Climate Change Act, and also its aspirations for aviation emissions – which policy presumably informs their thinking on a third runway.
The piece concluded that we need either to spend £20-£40Bn a year every year on upgrading household energy efficiency, or we needed to build 1 GW of new carbon free generating capacity every four months between 2015 and 2050, or some combination of the two. This blog, the second in the series, will take a look at how we might actually achieve this – in a way that is both practical and affordable. The final part will look at paying for it.
To do this I am going to have to try unashamedly to pick some winners. I make no apologies for trying, Whatever the current orthodoxy about not picking winners in case you pick losers, I think that position is deeply flawed. The destruction created by climate change won’t wait for political consensus or technological development. You cannot negotiate with physics – we might have 20-40 years in which we have to rearrange our entire global energy system – but probably no more. Given that the life of the public and private assets we need to transform is 50-100 years (think of the national grid, the gas grid, or a nuclear power station) we need to make decisions now.
Of course we might pick a course of action and then find that a new technology comes along that makes all our efforts seem obsolete and expensive. That is not a cause for regret, but a matter for celebration – the ultimate cost of decarbonising will be lower than we initially expected. But if that technology doesn’t come along – then not acting now will be the cause for the deepest regrets possible – compromising the only atmosphere we have on the only planet we can hope to live on. On that basis let me go forwards where angels fear to tread!
In order to make any sense of carbon free energy for heating we need to first think about energy storage. Energy storage is expensive – a recent study in the Maldives showed that energy stored from solar panels in the daytime and released at night was over twice as expensive as energy used as it was generated. The problem becomes much worse if you try to store energy for long periods. Consider a simple battery used to store 1kWh of electricity in the day and release it at night. It gets used 365 times a year. On the other hand a battery that stores 1kWh of electricity in the summer and releases it in the winter gets used only once a year – even though it costs the same to buy. Gas is the main exception to this rule in the UK: we use old oil and gas reservoirs as cheap storage.
Clearly building 100 new nuclear power stations to meet 100% of our heating needs would be daft – even if we could do it. The issue isn’t safety , or waste, but simple economics. Heat is only needed for a few months a year – so those power stations will only be able to sell power in the winter. All summer they will lie idle – full of fuel, and able to generate electricity at more or less zero marginal cost, that we can neither use nor store. Ultimately we will need a fair number of them – but the fewer we build the better.
Wind is a much better resource as it is reasonably correlated with winter and the timing of our heating loads. Wind turbines generate almost twice as much electricity in the winter as they do in the summer – though of course they can’t be relied upon to match supply and demand day by day and hour by hour. There will be some times, such as with a settled high pressure system over the UK, when they deliver nothing just as heating demand peaks.
Solar is the least useful resource. Heat will dominate our electricity needs in the future, and we need it in the winter when we get least sunshine. Once we have sufficient nuclear and wind plant to meet our winter needs we are likely to end up with more electricity than we need in the summer – just when solar is delivering at its best. It does seem odd, therefore, to subsidise solar power at a higher rate than wind power – or even to subsidise it at all.
Whatever mix of wind and nuclear we finally choose will be expensive, and imperfectly able to match supply and demand. This brings us to focusing on the houses themselves. Energy efficiency has the great advantage that it will reduce dramatically the seasonal power demand peaks. It is much easier to build and manage a grid whose peak demand is only 50% more than the baseload, than one whose peak is 200% of the baseload. Furthermore, good choice of technology in our homes means we will be able to use smart metering to regulate heat demand from moment to moment – as the Danes are already doing on the island of Bornholm. In a highly efficient house, heat is lost slowly so short term variations in the heat available should have little impact on comfort or convenience.
Nonetheless, even with a fair mix of new nuclear, wind and efficiency, demand matching will still be a problem – for which gas is usually seen as the easy fix. This is where things get interesting, and speculative, but where good decisions could make a huge difference.
The reality is that we are unlikely to be able to build wind farms and nuclear power stations anywhere near as fast as we need. Nor are we likely to be able to refurbish our housing stock fast enough or thoroughly enough to meet our 2050 targets. What we desperately need is a transitional step, that is easy to implement using existing infrastructure, but that can be phased out over time without the economic pain of retiring expensive capital plant before the end of its economic life.
The technology that offers us a ‘get out of jail free’ card is the Solid Oxide Fuel Cell (SOFC). SOFCs take methane, from natural or bio-gas, and convert it into electricity at high efficiency. The best of these can operate at electrical efficiencies of over 60%, and at the same time generate useful high grade heat. The special feature that makes them interesting, though, is that they can be arranged to produce, as exhaust, a near pure stream of CO2. Conventional power stations produce CO2, but it is mixed with large quantities of Nitrogen. If the CO2 is to be removed from the exhaust gas and pumped underground for storage – as a way of developing climate friendly power – then up to 15% of the electricity generated by the power station can be consumed by the process. Large scale SOFC plants would avoid this step – giving us efficient electricity generation at potentially low cost – with easy carbon capture at no extra cost or penalty in power loss.
Unfortunately we can’t do this right away – the technology is not ready, the costs are too high, and the supply chains are not there. However the technology is ready for putting SOFCs into a domestic setting. At least one firm1 has a dishwasher sized 2kW domestic unit for sale that offers over 60% electrical efficiency, plus enough heat to meet the hot water needs of the average house. By putting these into our homes we could immediately achieve many things. The first of these is that we could overcome the imminent shortage of electricity that we face in the next few years as old nuclear and coal plants are forced to shut. The second is that by putting SOFCs in our homes as micro-‘combined heat and power’ stations we would immediately reduce our GHG emissions.
Most importantly though, we could start to build a large and cost effective supply chain. At present SOFCs are highly priced because they sell in such small volumes, but the true cost of building them in high volume is surprisingly low. The expensive bit is the intellectual property, not the materials and manufacturing.
Once we had built enough domestic units we could develop slightly larger installations, perhaps initially for use with biogas, where we could instantly increase the electrical output of anaerobic digesters by 50-100% through the simple efficiency gains compared to conventional generators.
Finally, once a supply chain was well established, costs were well down, and experience was plentiful, we could start to use the units in medium sized gas fired power stations – and capture the exhaust gas for pumping underground and safe storage. This may not be a long term solution, but it would buy us a few extra decades to build what we need. It would also leave us with a legacy of gas plant that, whilst not perfectly despatchable, could at least be modulated to balance our grid. By this stage the domestic units would have long since paid for themselves and been retired – so leaving no legacy of stranded assets.
So in summary – forget solar – it’s a red herring. Wind and nuclear will ultimately form the staple replacement for our gas grid – but that will happen more slowly that we would like. In the interim, let’s spend the very modest amounts of money needed to drag SOFCs from niche expensive technology into the mainstream, and eventually into the larger power stations where it can generate cost effective power and enable carbon capture and storage at an affordable cost. Oh, and that lets us take advantage of all this new fracked gas at low cost too.
- Ceramic Fuel Cells Ltd, in Melbourne, Australia [↩]