What will it take to decarbonise electricity by 2050?

A general finding from our analysis is that electrification can always extend a bit further if other, more cost-effective, system-wide measures such as Carbon Capture and Storage (CCS) or biomass are prohibited. However, there comes a point in each sector where the marginal cost of electrification gets very steep, for example in hard-to-treat buildings or in heavy-duty vehicles.

Electrification of light vehicles occupies an interesting middle ground at present. Set in the context of a system-wide decarbonisation, there appear to be more cost-effective ways of reaching our targets than pushing for early and complete electrification of cars and vans. In modelling terms the partial electrification via plug-in hybrids tends to be the optimal response to any pressure for further decarbonisation.

In Clockwork, partial electrification of the transport and heat sectors leads to an annual electricity consumption in 2050 of 440TWh, up from ~300TWh today. Here, the majority share of electricity is delivered through a combination of wind and nuclear. This scenario shows a mix of fixed and floating offshore wind turbines providing 40GW of capacity and 40% of total electricity generation in 2050, while onshore wind contributes a further 14GW and 10% of generation. We also see a new fleet of large nuclear plants with a capacity of 16GW provide baseload generation, accounting for 30% of electricity in 2050.

Assuming commercial CCS deployment is delayed until post-2025, in Clockwork there is a limited window of opportunity for this technology to support early decarbonisation of the power sector. Here, fossil-fuel power stations with CCS only emerge later, to play a seasonal balancing role with a low annual capacity factor.

In Patchwork the electrification of heat and especially transport, means the annual electricity demand in 2050 rises to 520TWh. We see wind energy as the largest source of electricity by this point, providing 54% of annual generation. The lack of a national programme to bring forward investment in new nuclear plants in Patchwork means only two projects are completed. Combined with legacy capacity still operating in 2050, these provide 8GW capacity and 12% of total annual generation.

As a CCS infrastructure begins to emerge in this scenario, it is quickly adopted for new gas-fired generation capacity to provide much needed dispatchable low carbon generation. By 2050, Gas CCS capacity reaches 13GW. Since Patchwork is characterised by the high electrification of transport, demand for which is broadly the same across the year, these CCS plants enjoy an average capacity factor of 75% and provide 20% of total electricity generation.

Despite the high deployment of wind and solar, without substantial deployment of either nuclear or CCS, the Patchwork electricity system cannot be fully decarbonised until after 2040. Patchwork relies on historically unprecedented rates of annual capacity build. Here, aggregate build rates across this sector rise to 8GW/yr through the 2030s and 2040s.

High Electrification pathway

For a recent ‘high electrification’ pathway we took a lead from the Clean Growth Strategy electricity pathway where possible, ensuring that by 2050 all cars and vans on the road are battery electric, four out of five buildings use electric heat and one third of industry energy is electricity. In addition, this scenario does not permit CCS.

With 100% electric cars, and 80% of heat, total electricity generation in 2050 is over 630TWh, which is more than double from today. This would require around 35GW of new nuclear and 64GW of wind. Although these are significant levels of deployment, it is not uncommon to see such high capacity of one or the other technology in some modelled scenarios.

The lessons from this alternative pathway are as much about the prohibition on CCS as they are about the push for electrification. Without negative emissions being generated from biomass with CCS, more comprehensive decarbonisation measures must be deployed across all sectors of the energy system.