Electricity Supply

The debate

After the formal presentations, the speakers came together in a panel to discuss relevant topics with members of audience, including: demand flexibility; intermittency; hydrogen and tidal power.

Although electricity demand is projected to triple over the coming years, demand flexibility will be very important for minimising supply requirements on the grid: the flatter the load curve, the better. Decades ago, Economy 7 helped to do that with domestic demand. This led to storage heaters as standard items in houses. There are lots of technologies that can help move demand and so remove some of the peaks in demand. Today, heat batteries, which use phase change materials, along with heat pumps, can perform a similar role in shifting the heat load.

Another issue, given current grid constraints, is the matter of siting demand and supply closer. Is localised generation going to be better overall than large plants that cost less to generate per megawatt but which are not accessible? Another option would be to move industry closer to generation centres.

One of the biggest problems that has still not been solved and needs to be tackled in order to optimise the future grid is that, looking at the amount of renewables that will be installed on the system, a great deal of extra capacity is needed to compensate for intermittency. In summer, weather conditions usually result in an excess of wind and solar generation. The challenge is how to store that so that it can be used in winter. Is seasonal storage at scale even possible? Storage will be critical to the energy future because it is replacing the inherent storage of fossil fuels.

Hydrogen storage is likely to be extremely economic in some applications, particularly industrial complexes, trains and heavy goods vehicles. Green hydrogen could also be used in many industrial processes like steel production, which are currently dependent on fossil fuels. So it may be more important for industrial applications than for home heating.

For reliable, predictable, persistent, renewable energy, tidal power is a strong candidate. It is predictable rather than intermittent. With generating stations distributed around the country, there could be a constant feed into the grid.

However, while there was a definite, clear strategy for promoting offshore wind, with a Contract for Difference model, there has been no similar attempt to take tidal through the period when its costs are relatively high, to a point when it becomes usable and cost-effective.