Decarbonising the grid means reducing the grid's carbon intensity, in other words reducing carbon dioxide emissions per unit of electricity generated. We usually state this as the number of grams of carbon dioxide per kilowatt-hour of electricity generated.

To achieve net-zero carbon by 2050 and achieve the aims of the Paris Agreement to reduce emissions by 45 per cent by 2030, as highlighted at COP26 in Glasgow, countries must decarbonise their power around the world sectors. To achieve the Paris Agreements target to cap global temperature rise at 1.5 °C or even meet the somewhat more relaxed target of 2.0 °C, we have no alternative but almost completely to decarbonise the grid within this timeframe.

Moving away from fossil fuels will create a rapidly increasing demand for electricity to power our transport and provide us with heat. The only way to rapidly decarbonise the power sector is to increase the availability of low-carbon energy sources, specifically renewables, while simultaneously reducing the use of fossil fuels. Although there is undeniably a long way to go, we can be encouraged that a third of the power capacity can be produced globally from renewables.

Another potentially significant contributor to grid decarbonisation involves carbon capture and storage technologies (CCS). Although such technologies are relatively immature, 27 fully operational CCS facilities are currently globally. There are also many more, either in construction or early or advanced development, making 135 facilities with a projected capacity to capture nearly 150 million tons of carbon dioxide a year.

As we have said, decarbonising the grid means an increasing contribution from renewables. However, while wind power provides a significant proportion of renewable energy, we mustn't forget potential contributions from ocean, solar, geothermal and hydroelectric power, biofuels, and microgeneration.

• Wind – Currently, over 10,500 wind turbines are installed in the UK, with a total capacity of around 22 gigawatts. This capacity includes about 13.6 gigawatts of onshore and 8.5 gigawatts offshore capacity. Globally, the UK is the sixth most significant producer of wind power. The sector will continue to grow in the foreseeable future.
• Ocean power – Wave and tidal power offer the UK considerable potential to generate electricity. While wind power can be unreliable, tidal power is far more predictable. According to the Government, harvesting ocean power could potentially meet 20% of the UK's electricity demand. While this has been the subject of debate for decades, progress has been frustratingly slow. There appears to be a general reluctance to invest in the sector. However, some initiatives have been and are being pursued. In Scotland, initiatives include a European Marine Energy Centre project that harnesses wave power outside Stromness and a project looking at harnessing tidal power in a channel between Westray Firth and Stronsay Firth. Other initiatives include a prototype tidal farm being developed in Cornwall.
• Solar power – Current capacity (June 2021 figures) of solar power in the UK is 13.5 gigawatts. Residential solar power accounts for 2.5 gigawatts of this, with most being generated by large scale solar parks, the largest of which is in Newport, Wales (75 megawatts) and the second-largest in Flintshire (72 megawatts). The sector is growing – in 2021, it grew by 12% - and is predicted to at least double by 2030.
• Geothermal power – While other countries exploit geothermal energy, few initiatives exist in the UK. However, four deep geothermal power plants are planned for Cornwall and are expected to be online by 2026. These plants should generate over 500 megawatts of electricity.
• Hydroelectric power – Currently, the UK has 1.67 gigawatts of installed hydroelectric power which is around 14 per cent of current renewable capacity. While the potential future capacity in England is 146 megawatts and for Wales 248 megawatts, Scotland can potentially generate up to 2.6 gigawatts. However, it is unlikely to realise this as much of the potential is in regions of outstanding beauty.
• Biofuels – Biomass accounts for a substantial quantity of UK power generation. For instance, the Drax biomass power station in North Yorkshire generates 7% of the UK's total energy, mostly from burning wood pellets. Other biomass fuels include biogenic wastes and residues, perennial energy crops, short-rotation forestry, and marine biomass. Currently, 12.6% of total electrical energy is derived from biomass.

• Microgeneration includes local electricity production by homes and businesses from such energy sources as small wind turbines, hydropower, anaerobic digestion, and solar electricity generation. In 2020 it accounted for 6.8 gigawatts of installed capacity from over a million installations. Most (5.5 gigawatts) is from solar photovoltaics.

The UK government has factored in nuclear power as essential in decarbonising the grid. Nuclear power supplies about 16% of the UK's total electricity. The Government has also agreed on contracts for a new nuclear power plant. Called Hinkley Point C, this new plant will provide 7& of the UK energy needs.

Scotland also has a strong position in the generation of nuclear energy. In 2016 nuclear accounted for over 40% of Scotland's electricity generation. However, while the Scottish Government supports extending the lifespan of two currently operational nuclear power plants, Torness and Hunterston B, it opposes building new plants based on existing technologies. The Scottish Government argues that doing so would offer poor value for consumers. For example, they cite the UK Government's investment in Hinkley Point, requiring energy consumers to subsidise it until 2060.

Public opinion on nuclear energy is also divided. For example, just 14% strongly agree that nuclear power will help combat climate change in the UK.