Types of clean electricity generation

If we’re to switch to alternative forms of electricity generation, we need new technologies to replace coal and gas power stations (and more rarely, oil power stations). There are a number of technologies available, mostly renewable energy. These are so named because their supply is essentially infinite – the world is never going to ‘run out’ of wind. Non-renewable resources have a limited reserve.

Renewables

Onshore wind

Onshore wind uses large turbines (pictured) to turn an electric generator. Onshore wind costs have plummeted recently, making it the cheapest form of power. However, it attracts some criticism in densely populated countries like the UK as lots of turbines near human settlements lead to complaints of visual impact.

Offshore wind

Offshore wind operates in the same way as onshore, and largely removes the complaints against onshore, as they are often barely visible from the coastline. They are also much more efficient than their onshore counterparts, almost twice as much in some cases.

Solar PV

Solar panels are a common sight in the UK, and unlike many other options on this list, are often installed in small numbers for individual homes. Solar is the most publicly popular energy technology in the UK, has no major visual or pollution issues, and costs are also tumbling. However, solar is one of the least efficient technologies here, especially in the UK, which is one of the cloudiest countries in the world.

Solar thermal

Solar thermal power also uses the sun, but unlike PV (which uses it to generate electricity more directly) solar thermal is concentrated into a point to generate heat. While it has large scale application for electricity in desert complexes in hot countries, it is not really used for electricity in the UK, but can be a useful source of heating in rooftop units (see the Heat section).

Hydropower

An older technology compared to wind and solar, hydropower is clean, efficient and well proven, but the UK does not have much exploitable resource left, so the role of hydropower is limited.

Tidal

Tidal power is expensive and experimental, but could be more efficient than other forms of renewable energy. Underwater turbines and lagoons in estuaries are being trialled in the UK, which is a world leader for this technology.

Wave

Wave power is also experimental, but seems to have less potential than tidal due to lower efficiency. It also has to compete with the cheaper equivalent of offshore wind. Nonetheless, experiments on wave energy are ongoing.

Biomass

Biomass technology varies, but essentially is the use of organic matter to generate electricity. The most common form of biomass is the burning of wood pellets to drive turbines, which can be used as back-up when the wind isn’t blowing or the sun shining. However, the environmental costs are high, as not only does there have to be considerable deforestation, but much of the UK’s biomass fuel is imported from the USA, thus lowering the emissions saved by its use.

Geothermal

The ground beneath the earth is warmer than that at the surface, meaning that this heat can be exploited for power. In the UK geothermal power has mostly applications for heating, but it is still a cheap and relatively untapped resource.

Non-renewable

Nuclear

Nuclear power splits atoms to generate electricity. While nuclear power stations can run almost constantly, and provide a great deal of power per station, they are unpopular because of nuclear accidents, radiation contamination, and extremely high costs, which often spiral. Nuclear divides environmentalists and political figures alike, many strongly supportive or opposed. Additionally, current nuclear plans have run into multiple cost and construction problems.

CCS

Carbon capture and storage involves capturing carbon chemically at a gas or coal power station and pumping it back into the ground, removing the emissions from an existing plant. CCS has the potential to provide back-up power for wind and solar, but very few plants are up and running, as due to high capital costs and unforeseen problems development of CCS has been severely delayed. There are also major concerns that the carbon cannot be stored forever and will eventually escape, negating the benefits.

Non-generation

Energy storage

Storing energy could be extremely useful if it is intermittent like solar, wind, wave and tidal, capturing electricity when there is a surplus and releasing it back when there is high demand. Energy storage technologies are numerous, and many experimental. They include storing water, heat and air in reservoirs and releasing it through turbines in times of need, giant batteries, and other more experimental forms. Large scale battery storage in particular has been very popular in recent years. There is massive potential here, but a lot more needs to be done to ensure these technologies are developed on a large scale.

Interconnectors

Not all countries are windy or sunny at the same time. If the UK is having a high output from renewables and another country needs power, or vice versa, interconnectors are large subsea and occaisionally overland cables that connect up powergrids in and inbetween countries. The UK is planning to quadruple its stock of these in the next decade, connecting us better to Ireland, France, Belgium, the Netherlands, Germany, Denmark, Norway and Iceland. Interconnectors offer long term responses to renewable variability, and are relatively cheap to build. However, they are criticised for other countries having to rely on each other for power.

Demand Side Response (DSR)

The biggest user of electricity in the UK are homes, but commerical and industrial demand is also high. Incentivising the organisations responsible for this demand to shut down or start up their electricity demand to correlate with high renewable output can offer a fast and cheap way of reducing demand and balancing out renewables.

Energy efficiency/behavioural change

Reducing the amount of electricity we actually demand from its source can often be the cheapest and fastest way of reducing greenhouse gas emissions, and much progress has been made in this area in recent years. Switching to more efficient light bulbs, encouraging consumers to use less energy and remote conferencing are all common examples. However, there is an inherent limit to this approach, as it can only reduce electricity demand, it doesn’t get rid of demand altogether and it doesn’t actually make the electricity any cleaner directly. So there will always be a need to decarbonise the electricity sector even if the amount of electricity used is lower.