Energy generation in the UK will have to look dramatically different if we are to meet our promised carbon targets by 2030. Laurence Weir, technology lead at Plextek, suggests ways to meet our net-zero goals well ahead of schedule.
Taking a snapshot of the grid in the middle of winter clearly does not provide a representative sample of the UK’s energy mix. Solar power can dominate our energy production on a warm sunny day, even in the UK. Wind energy changes day-to-day, but stormy weather is usually a good sign for energy production. We do not have the space or geology to implement large-scale hydroelectric plants unless Scotland is willing to flood large parts of the Highlands. Nuclear plants are currently going offline as they age and drop out of use, and the goal is for Hinkley Point C to take up 3.2GW of this downfall. Recent press releases on mini-nuclear reactors delivering in the order of 100MW need to be fully developed and deployed before they can be relied upon.
While tidal has often been touted as a hugely reliable energy source, just waiting to be harvested, we are only now seeing the advent of tidal energy technology being commercially viable. I suspect it will play a much greater role in diversifying the energy portfolio in the 2030s, rather than being rolled out on a large scale this decade.
Supply and Demand
The current wind turbine generation capacity of the UK is 24.3GW and in 2030, this is expected to rise to 40GW. Solar has a capacity of 13.5GW and is likewise expected to rise to 40GW by 2030, although it could be much more if solar panels keep dropping in price, and there is government support for their installation and servicing on domestic properties. Therefore, on a windy, sunny day in 2030, we could be producing close to 100GW from our renewable sources alone. Demand on the electricity grid is currently around 40GW during the day and drops to around 20GW at night.
When it comes to demand, there are two big differences that will occur in the next ten years that will have a major impact. The first will be the dramatic rise in the usage of electric vehicles. The second is the conversion of domestic and commercial boilers to electric heat pumps or hydrogen burners. Given our need to create hydrogen through electricity, rather than methane, these two factors alone will easily double our electricity usage.
However, these two changes also indicate how we could phase out fossil fuel energy generation much quicker than predicted. The main issue with solar and wind generation is that they create insufficient energy when it is required and over-produce energy when it is not. There is therefore a vital need to store the excess wind energy created during the night, such that it can be used during the day, and excess solar energy on long summer days, such that it can be used in the winter.
Currently, there are close to 40 million vehicles on the road. Even if we estimate that by 2030, half will have made the electric transition, which means 20 million vehicles with batteries. My own Nissan Leaf has a 30kWh battery. In ten years, many will have dramatically larger capacities, with 60, 90, or 120kWh as standard. That does not even take into account the larger vehicles like buses and haulage.
A 60kWh average battery means 1.2TWh of storage countrywide, close to several days’ worth of total usage in the UK. If these batteries are charged through the grid whenever an excess is being generated – on windy nights or long sunny days, for example – vehicles could make up the shortfall in generation during the high-demand, low-generation time. Each would only have to give up a relatively small fraction of their total charge to power the grid while they are not in use, and top priority usage vehicles could be opted out of this scheme on the charger, at a cost to the user.
With so much energy generation, it is feasible that at some point all available vehicle batteries will be fully charged. Rather than waste the possible energy, hydrogen could be used as the mechanism of storage. The losses involved with the creation and use of hydrogen, around 50 per cent right now, are a lot worse than current batteries. However, the much greater energy density means it will provide an easy resource to convert back to electricity as required. The emergence of hydrogen hydride storage ’batteries’ being commercialised by companies like LAVO is envisioning a future where households can store the equivalent of a few kilograms of hydrogen.
Distributed across the UK, this could provide a storage capacity of several TeraWatt Hours, enough to power the grid for many days.
Between household and commercial hydrogen hydride batteries, vehicle batteries, home solar installations, and countrywide wind, solar and nuclear plants, the usage of the UK energy grid will look very different in 2030. Burning fossil fuels will become increasingly unnecessary, and we could meet our net-zero goals decades ahead of schedule.
