It may seem like a new renewable energy milestone is being reached in the UK every week. So where are we in terms of infrastructure, technology, and deployment? Here is your quick guide
Great Britain is the Saudi Arabia of the wind. Wherever they have oil, we have the breeze. After years of lukewarm political support (Margaret Thatcher’s press secretary Bernard Ingham famously derided wind turbines as “toilet brushes in the sky”), successive governments have begun to realize their potential.
Driven by rapidly improving technology, falling costs and government funding, there are now around 11,000 wind turbines in operation in the UK, enough to meet a quarter of our electricity needs.
It ranks second after natural gas. “It’s a phenomenal achievement,” said Matthew Clayton, executive director of renewable energy investment company Thrive Renewables.
Although onshore wind remains the cheapest option, expansion is currently limited by planning constraints, particularly in England. Offshore investments have now grown rapidly and this is where the UK has great potential thanks to its extensive coastline and shallow seabed.
Onshore wind is still the cheapest option, but its expansion is limited by planning constraints. Image: Karsten Würth
Falling costs – by up to 90 percent this century – have contributed to the rapid expansion of photovoltaics (PV). It may not be quite as sunny in the UK, but modern photovoltaics are increasingly able to harvest meaningful amounts of electricity even when it is cloudy.
A spectacularly generous subsidy program about a decade ago encouraged thousands of house owners to put solar panels on their roofs. What Clayton calls the “absolutely staggering” drop in costs now means that larger solar farms are economically viable without subsidies and fuel growth that even a pandemic couldn’t derail.
In 2020 alone, Great Britain added 545 MW, an increase of over a quarter compared to 2019. Solar now covers well over 4 percent of our electricity needs. For Clayton, the appeal of solar energy lies in its predictability – while solar radiation varies from day to day, it is fairly constant over a year.
Together with rapid advances in module efficiency and innovations such as tracking (where the module follows the sun all day), solar energy will “play a major role” in the future, predicts Clayton.
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But what about the times when the sun doesn’t shine, the wind doesn’t blow? Answer: storage. A tried and tested solution is what is known as pumped storage: Excess energy is used to pump water uphill into a reservoir, from where it can be released to drive turbines, as in a hydropower plant. This proven technology could “quadruple or quintuple” in the coming years, says Clayton. And since climate instability increases the need for reservoirs, these could play a dual role.
Batteries, on the other hand, are the newcomer when it comes to network balancing tasks. Here, too, economies of scale depress costs, so that some really bulky battery farms can arise, such as the new “Gigafactory” that is to be built in Coventry. But smaller modules are also feasible.
And as Clayton points out, the growing feet of electric vehicles contain a ready-made small storage network in the form of their batteries that can feed power into and out of the grid when needed.
The storage of solar and wind energy is the key to unlocking the potential of renewable energies. Image: Red Zeppelin
The industrial revolution in Great Britain was founded on hydropower and continues to play a small but significant role in our energy mix today, covering around 1.6 percent of our electricity needs (like coal) in 2020.
Interest in relatively small systems is growing again: “They can offer the flexibility that the network needs,” says Clayton. The growing demand for reservoirs to keep the water flowing through our faucets also provides the opportunity for greater hydropower.
Tidal power plants such as those proposed for Swansea Bay could be expensive, but could one day meet a significant portion of our electricity needs.
Burning wood instead of coal to generate electricity is the black sheep of the renewables family. On the positive side, the mass conversion of coal-fired power plants operated by power generation company Drax in Yorkshire has increased the share of biomass in UK electricity production to 6.5 percent.
Proponents argue that combining such facilities with BECCS (Biomass Energy with Carbon Capture and Storage) technology during Drax’s development could even achieve a “net positive” power plant – actually reducing the amount of CO2 in the atmosphere. However, the technology has yet to prove itself on a large scale and concerns about the future sustainability of bioenergy are growing.
Carbon capture technology could make burning wood “planet-positive,” proponents say. Image: Alexander Schimmeck
Geothermal energy uses the natural heat in rocks deep below the earth’s surface to generate steam that can power electricity turbines around the clock, as well as providing heat to nearby communities. While it’s currently insignificant, it has significant potential, Clayton says, especially in places like Cornwall.
Thrive is investing in a project at United Downs in Cornwall that also has the potential to use lithium for batteries. “Three sustainable products from one project,” says Clayton, “is really very positive.”
Thrive Renewables has built or financed 26 wind, solar, hydro and heating projects. Find out more here.
Illustration: Andrea Manzati