Last reviewed 3 January 2022

The Government announced plans at the end of 2021 to decarbonise the UK’s electricity system by building capacity in the renewables sector and other low carbon technologies that will eliminate reliance on fossil fuels by 2035. In part 1 of this two-part feature, John Barwise considers the pros and cons of achieving this ambition.

The Government’s Net Zero Strategy set out how it intended to halve UK emissions by 2035, and eliminate them altogether by 2050. Central to that commitment is the Prime Minister’s pledge to decarbonise the UK’s electricity system by expanding a “home-grown” renewables and nuclear sector that he says will help “unleash a green economic recovery” and support up to 220,000 jobs over the next decade.

There are various options for greening the electricity system and these are set out below, along with the benefits and limitations each option can deliver. But the general consensus is that whilst greening the electricity system will make a significant contribution to net zero ambitions, it will not be enough to fully decarbonise the UK power system.

Other options such as carbon capture and storage, and planting more trees to sequester carbon will need to be expanded. (Read more in our in-depth topic on Carbon Reduction, Footprinting and Reporting.) Banning petrol and diesel cars and promoting electric vehicles will also play a significant role. Equally important will be finding ways to improve energy efficiency in buildings which currently contributes around 19% of UK emissions, and which the Government has so far failed to tackle.

The benefits and limitations of delivering low carbon electricity

Nuclear power

Building nuclear power capacity is integral to government plans to achieve net zero by 2050. The UK generates about 20% of its electricity from nuclear, but its share of the mix is reducing and around half of current capacity is to be retired by 2025. A new large-scale plant at Hinckley Point in Somerset is expected to be commissioned by 2026, and work on other plants at Sizewell B in Suffolk and Wylfa on Anglesey are also expected to get the go ahead to boost nuclear capacity.

Nuclear power is a relatively stable low carbon source of power but there are concerns over the risks associated with the industry. Chernobyl in Ukraine, Three Mile Island in the US, Fukushima in Japan, together with the Windscale Fire at Sellafield in the UK, are prime examples of nuclear disasters that continue to have long-term global consequences. There have also been numerous incidents of radiation leakages at nuclear sites both in the UK and elsewhere.

Other issues relate to the reliability of Uranium (the primary source of nuclear power) both in terms of pollution from mining activities, long-term supply as the industry expands and on-going concerns over what to do about radioactive waste. Most of the UK’s untreated radioactive waste is stored in west Cumbria, but a permanent geological disposal facility (GDF) has not yet been allocated.

Future nuclear plans

The Government has also announced plans to support the building of up to 16 new small modular reactors (SMRs), as part of its “Green Industrial Revolution”. Backed by £210 million government funding for research, the programme is expected to generate private investment to take the project forward. More on government initiatives can be read here.

SMRs cost around £2 billion to build, which is about one tenth of the £20 billion one large scale reactors. Each SMR will have capacity to generate around 477MW of power, compared to the 3GW plant currently being built in Somerset.

Rolls Royce has embarked on the first phase of research and development to assess whether SMR power generation is suitable to be deployed in the UK. But concerns over safety, security and economies of scale remain, along with continuing problems over long-term waste storage. Critics argue the money would be better spent building more renewables and improving energy efficiency, than building more power plants.


Renewable energy is the big success story in the UK strategy to meet legally binding targets to achieve net zero emissions by 2050. On average, renewable energy provides nearly a third of power generation in the UK. This rose by almost 7% to over a 40% share in 2020, generating more electricity than fossil fuels in the year.

Energy from all renewable technologies increased in 2020. Statistics released by BEIS show that of the 24.3 million tonnes of oil equivalent of primary energy use was accounted for by renewables, 18.1 million tonnes were used to generate electricity, 4.5 million tonnes were used to generate heat, and 1.6 million tonnes was used for road transport.

Wind power

Electricity generation from wind power has increased by over 700% in the last 10 years which accounted for 24% of total electricity generation, with offshore wind accounting for 13% and onshore wind accounting for 11%.

Shallow seas and a windy coastline have led to a significant increase in offshore installations, with the UK now having more offshore capacity installed than any other country. The Government has ambitious plans to increase offshore capacity from the current 10GW of power to 40GW by 2030.

Onshore wind has also expanded with half the capacity in Scotland and the rest in other parts of the UK. But there is concern that planning authorities are approving fewer onshore applications than are needed to achieve net zero commitments. RenewableUK is calling on the Government to double the UK’s onshore capacity to 30GW by the end of the decade, which it says will generate £45 billion of economic activity and reduce consumer bills.

Solar power

Solar power increased significantly following the introduction of the Feed in Tariff (FiT) in 2010. Falling production costs and improved efficiency of solar power over the last decade has helped sustain some of that growth, despite the closure of the FiT scheme in 2019.

Annual electricity generation for 2020 stood at around 4% of UK electricity consumption, with installed capacity now around 14GW. According to Solar Energy UK, the rooftop solar sector is expanding with a further increase in large commercial rooftop projects. The industry body is predicting to reach 1GW of solar deployment every year to 2030, doubling current capacity, but adds that this needs to triple if the UK is to deliver net zero targets. The problem with solar is that it does not produce energy at night and capacity falls significantly in winter months when energy demand tends to rise.

Hydro power

The UK has been using water for electricity generation since the 18th century. Over the past 30 years, the proportion of electricity generated by hydropower has remained around 2% of total power generation. Capacity today is over 4,700 MW, with most large plants installed in the wet and mountainous regions of Wales and northwest Scotland. In the UK, future expansion is expected to be limited to small scale applications, including community-based projects, although larger pumped storage projects are also likely.

Hydropower it is the world’s largest source of renewable electricity and is projected to grow further in the coming decades, partly because there are no emissions linked to electricity generations and because stored capacity makes it more reliable than wind or solar. But building lakes to store potential energy requires a lot of land and there are concerns over the wider ecological impacts and displacement of local people.