What the U.K.’s Target of Net Zero Emissions Would Really Entail

In 2019, Britain’s Conservative government toughened existing climate-change legislation by setting the country the target of net zero carbon emissions by 2050 (the previous target had been 80 percent). There are other yet more ambitious proposals, providing for full decarbonization at even earlier dates, such as Extinction Rebellion’s 2025 and the Green Party’s 2030. In addition, other policies such as banning the sale of new cars and vans with internal-combustion-engines from 2030 are under serious consideration by the government in order to decarbonize transport as part of the overall CO2 target. As discussed below, the challenges of the energy transition required are enormous enough to seem unsurmountable and don’t seem to be sufficiently appreciated by those who set the targets. The scale of the challenge is great. A schedule, a budget, and engineering targets need to be put in place, and the work needs to start immediately, if the government is serious about meeting the targets for zero carbon emissions. It won’t be easy.

Target: Zero Net Carbon Emissions by 2050Fossil fuels, coal (7.9 mtoe, million tonnes of oil equivalent), oil (68.5 mtoe) and gas (875.6 TWh, or 75.3 mtoe) supplied 151.7 mtoe, or 79.6 percent of the primary energy used in the U.K. in 2019, while wind and solar accounted for 3.47 percent of the total primary energy-use (BEIS).

How much additional CO2-free energy will the United Kingdom need to generate by 2050 to replace fossil fuels?
Let us assume that by 2050 the United Kingdom will need to replace only 60 percent of current fossil-fuel energy use (91 mtoe, or 1,058 terawatt hours (TWh) by CO2-free energy, thanks to greater overall energy efficiency. Even on this extremely optimistic assumption, the U.K. will need 121 gigawatts (GW) of new continuous CO2-free power generation, equivalent to 40 nuclear plants of 3 GW each or to 100,000 offshore wind turbines of 3 MW each, given a capacity factor of 0.4 — i.e., 10 MW installed capacity will deliver only 4 MW on average because it is not available all the time. The scope for large growth in the U.K. for inland wind or hydro power is limited. Solar, though coming down in cost, has a very low capacity factor of 0.1. Wind and solar will also require storage systems to cope with intermittency. Incidentally, 1,610 GW of new continuous CO2-free power generation will be needed for the U.S. to replace 60 percent of its current fossil-fuel use.