What is clean energy (really), and how can the UK generate it at scale?

There’s a reason that you’re hearing about clean energy more often. A perfect storm of fast-approaching emissions targets and an aging electricity grid have turned clean energy into a hot topic.

With everyone from the government to businesses on the lookout for generators that fit the bill, it’s a good time to get specific about what “clean” really means.

What is clean energy?

To be transparent we don’t really use the term “clean energy” at tem. It’s not specific enough. To cut through the noise, we refer to clean energy as “low-carbon electrons”. That rules out sources like coal and natural gas, which deliver electricity with a hefty dose of CO2 emissions.

Clean energy refers to renewable energy sources that keep greenhouse gases to a minimum. In other words: power generated by sunlight, wind, water and waste.

Here’s a closer look at those renewable energy sources — and the hurdles we’ll need to overcome to build a lower-carbon grid.

Solar power

When it comes to renewable power, it’s hard to beat the biggest star in our solar system. According to NASA, you’d need 44 million large power plants to match the 44 quadrillion watts of energy the sun sends to Earth.

Thankfully, there’s a more cost-effective way to capture some of that power: photovoltaic (PV) panels turn sunlight into electricity, even in overcast conditions.

PV panels are low maintenance: they last from 25 to 30 years, and only need to be cleaned every six months. With PV costs dropping by 73% in the last decade, they’ll be even cheaper when the time comes for a replacement.

Wind power

In 2024, wind power was the UK’s largest single source of electricity.

The 11,500 turbines responsible are largely found in “wind farms”, but they’re cropping up on more traditional farms, too. Their small footprint has integrated land use: generating power and growing food on the same plot.

Turbines come in a huge variety, but most last as long as PV panels.

Hydroelectric power

Hydroelectric plants have been generating power in the UK since 1878, and are still behind about 2% of our electricity to this day.

That’s not a huge amount of energy. Hydropower does make it easier to adopt cheaper renewables, though. As the National Grid’s primary method for long-term energy storage, it helps balance things out when the sun isn’t shining, or the wind isn’t blowing.

Relying on reservoirs, rivers, and large-scale pumping stations, hydropower often involves major infrastructure projects. With that said, “micro-hydro turbines” are available for smaller sites. Steep upfront costs are offset by long lifespans: most are in action for 50 to 100 years.

Anaerobic digestion

Unlike the renewables we’ve covered so far, anaerobic digestion does involve emissions – but it’s still a “clean” energy source. That’s because it turns gases that would have been released from landfills into fuel for renewable generators.

Anaerobic digestion plants turn organic waste into biogas, which gets released as material breaks down. That biogas fuels turbines, producing electricity.

The process does result in some CO2 emissions, but they’re less impactful than the alternative: landfills emit 20% of human-related methane, which is far more potent than CO2.

What’s holding clean energy back?

With quadrillions of watts on offer, you’d be forgiven for asking why only 46.3% of the UK’s power came from renewables at the start of 2025.

100% clean energy is a vision for the future. There’s still a lot of work to be done by regulators, investors, and innovators (like us!) before we abandon fossil fuels altogether. Today, it’s about using as much clean energy as possible, and supporting the people that generate it.

Some persistent barriers stand in the way of a more renewable grid — but they’re not insurmountable.

Outdated grid infrastructure

The UK’s grid infrastructure wasn’t built with renewables in mind. It’s designed to distribute electricity from more consistent sources like coal-fired power plants. Power from solar and wind generators can vary with the weather. That presents a challenge when your grid isn’t designed to balance things out.

There’s also a huge backlog of energy waiting to connect to the National Grid. By recent estimates, there’s 700 gigawatts (GW) of potential capacity in the queue. That’s the same as seven hundred nuclear power plants.

The silver lining:

Those issues haven’t gone unnoticed at Ofgem, which announced an £80 billion investment plan to modernise the grid. Phase one will see an extra 126GW of clean energy added by 2030, and massive investments in battery technologies that offset renewables’ variability.

Net zero targets on the near horizon, so Ofgem have also addressed the connection challenge. Instead of working through the backlog one-by-one, they’ll prioritise connections for projects that are ready to start generating power.

Upfront costs

Renewables are often cheaper to operate than coal or gas plants… once they’re up and running. The up-front costs required for wind turbines, solar farms or anaerobic digestion plants can put potential generators off. The recent interest rate hike doesn’t make things any easier.

The silver lining:

Along with their investment in the grid, the UK government set a record for renewable energy spending in 2024. That’s vital for developing existing solar and wind farms, and encouraging investment in future projects.

Renewable infrastructure is also cheaper than ever, with the cost of PV panels and wind turbines dropping significantly over the last few years. Countries like the UK are modernising their grids to accommodate renewables, and meet the energy demands of data centres (and air conditioners!). That means cheaper energy infrastructure will become even more important.

Opaque energy markets

The wholesale energy market involves so many transaction fees and middlemen that revenue shrinks by the time it reaches renewable generators. Smaller profits make it harder to invest in more clean energy infrastructure.

Counterintuitively, the UK’s Renewable Energy Guarantees of Origin (REGO) certificates have made it more difficult to scale clean energy generation. Big Energy suppliers can buy REGOs to offset fossil fuel generation, and still tell consumers that they’re providing “clean energy”.

REGOs are so cheap that they don’t even support much investment in new renewable capacity for the generators that actually earn them.

The silver lining:

REGOs have been dwindling in popularity over the last few years. Some energy providers have even abandoned them to avoid accusations of greenwashing. REGO prices plunged in 2025, suggesting that even Big Energy is on the lookout for more transparent alternatives.

Ofgem-compliant platforms like RED™ are also eliminating wholesale market fees by connecting consumers directly to a network of renewable energy providers, balancing real-world demand with energy that’s as clean and transparent as possible.

Generate clean energy at scale

Conditions have never been better for the UK’s renewable generators to scale. Costs are falling, private businesses are demanding a more transparent supply of clean energy, and, now, generators no longer have to sacrifice those savings and gains to wholesale energy markets.

Platforms like RED™ ensure the people behind truly clean energy get paid fairly for what they produce — making renewables more accessible, more profitable, and more scalable. Find out more about how it works here.