Scotland’s enviable renewable energy resources make the task of decarbonising our electricity much more straightforward – but that doesn’t mean easy.
Scotland’s enviable renewable energy resources make the task of decarbonising our electricity much more straightforward – but that doesn’t mean easy. Very roughly, while Scotland generates close to what it consumes in renewable energy, much of that energy is ‘non- schedulable’ (we know when the wind will blow so it can be planned, but it can’t be turned on and off to match demand) so we export a lot of it and then need to make up the balance using generation based on natural gas and nuclear. Scotland’s nuclear power plants are close to the end of their life and to decarbonise we need to replace the generation capacity of the gas turbines, but we also need to put in place energy storage so we can turn supply up at moments of peak demand.
This means that, roughly, we need to double our current renewable energy generation to meet this demand, and we need to be able to store about a tenth of this in a way we can switch on and off to meet demand peaks. But that’s not all, because to decarbonise our transport we’re going to need a lot of additional electricity. To meet that demand we need, roughly, to double again our current amount of energy generation. So in total, to completely decarbonise Scotland’s energy (and so long as we build a national district heating system) we need to roughly triple the amount of renewable energy generation we currently have and put in place a lot of energy storage.
There are really four main methods of doing this; onshore wind turbines, offshore wind turbines, solar photovoltaic and the three forms of marine energy. These are wave (where the rising and falling of waves caused by wind generate electricity), tidal (where the currents caused by the tide coming in and out generate electricity) and sub-sea currents (where the permanent and very powerful arctic underwater currents which come down past Scotland’s east coast power underwater turbines). Scotland has enormous marine energy potential – but it is important to be clear that this technology is still developing and is not yet ready for large-scale deployment. So we have to work with the other three technologies for meeting domestic demand. Ultimately, Scotland’s marine energy can be a valuable export for Scotland when the technologies mature, generating a further return on this investment.
Solar energy should be used mainly to generate heat rather than electricity because solar thermal is much more efficient than solar PV – but there are places without local heating demand where there is potential for big solar farms, so it will be part of the picture. However wind will be the primary generator of Scotland’s electricity. Onshore wind is much cheaper than offshore wind and so should be prioritised.
It is important that energy is part of a coordinated national strategy, and so should be publicly owned and its profits should benefit the public. A Scottish Energy Development Agency should be set up to plan the new generation capacity and a National Energy Company should be set up to install and operate it. It should also buy existing privately-owned wind farms and bring the electricity grid into public ownership so the whole system can be fully integrated for maximum efficiency and performance.
The National Energy Company must also create a lot of energy storage. There are a number of ways to do this. First, at the local grid level (for each town and city) there needs to be local storage to ensure ‘energy smoothing’ (which just means dealing with all the little rises and falls in electricity usage over the course of the day). This is best met by installing large-capacity batteries as part of a complete upgrade of the National Grid, moving Scotland to a ‘smart grid’ system which uses technology to learn and manage the patterns of demand and so continually improve grid stability. This investment can help overcome energy wastage and reduce costs for the consumer.
But there also needs to be larger national-level storage to smooth periods when the direct supply of renewable energy is lower. There are a number of ways of doing this (Scotland already has a lot of ‘pump store’ where excess electricity is used to pump water up into reservoirs, which can then run back down through turbines which generate electricity when needed), but one is likely to dominate: hydrogen. At the moment using hydrogen to store energy is comparatively expensive because the technology is still developing and the market is currently small. But this will change; hydrogen is going to be crucial to decarbonising transport (it powers the fuel cells which will replace fossil fuels in large vehicles, ships and probably airplanes) and will increasingly become a highly sought-after resource. If Scotland moves quickly to develop this technology, we could have a valuable export commodity.
Hydrogen is produced from electricity through electrolysis – an electric current is run through water and it breaks the water into hydrogen and oxygen. The hydrogen can be stored and then, when needed, can be used to power existing gas turbine generators. There is probably no nation in Europe with more potential for clean hydrogen and Scotland should seek to specialise in this. Although early electrolysis plants will be less efficient, as we build and operate them, Scotland will become one of the leading centres for hydrogen technology. As production becomes increasingly efficient, Scotland could gain a firm foothold in the global hydrogen market. Based on the world's current largest non-fossil fuel derived hydrogen plant, we need to build approximately 650 electrolysis plants to meet demand - though this number will reduce as technology improves the size and efficiciency of the plants. As marine energy develops, we can explore ‘at sea electrolysers’ to produce hydrogen for export.
By the end of the 25 years of the Common Home Plan, Scotland must have stopped extracting oil and gas from its North Sea. To enable this transition the National Energy Company should do everything possible to build up domestic supply chains to create industries and jobs to replace those already being lost in the oil and gas sectors. Many of the supply chains for the oil industry can be redirected to provide the materials required for the roll-out of district heating. A National Diversification Agency should be set up to help establish new supply chains for the manufacture of the equipment needed for the electricity system