What is the Potential of Hydroelectric Power in the UK?

Are you looking to learn more about the potential of hydroelectric power in the UK? Join me as I uncover why hydropower isn’t as prevalent as wind or solar in the UK and whether it’s a hidden gem that landowners and developers should look at in more depth.

When most people think of renewable energy in the UK, wind turbines on rolling hills and solar panels on rooftops usually come to mind.

These technologies have made impressive gains in recent years, and rightly so. They’re fast to deploy, relatively inexpensive and are highly scalable depending on budget and land availability. But one often-overlooked renewable quietly continues to deliver reliable, low-carbon electricity: hydroelectric power.

Hydropower may not be as flashy as newer technologies, but it’s one of the oldest and most dependable forms of renewable energy around. It provides consistent energy generation, fast response times and long operational lifespans. These traits are becoming increasingly important as we transition to a grid that’s dominated by variable sources like wind and solar.

And while the UK isn’t known for its vast rivers or dramatic elevation changes, it still has untapped hydro potential waiting to be harnessed. So, why hasn’t the UK embraced hydropower more readily? Well, the reasons are slightly complex.

High upfront costs, long payback periods and planning challenges have all played a role. And in recent years, changes to government incentives have made it harder for new projects to get off the ground. This is especially true for smaller schemes that once benefitted from Feed-in Tariffs.

With this in mind, what exactly is the potential of hydroelectric power in the UK? Is it something that should have a far bigger role in the UK’s current energy mix?

Well, let’s find out.

What Is Hydroelectric Power?

Hydroelectric power converts the energy of flowing or falling water into electricity. It’s one of the oldest forms of renewable energy in the UK and remains a reliable, low-carbon option.

While there aren’t many hydroelectric installations in Britain (particularly on a large scale), there’s huge potential for hydroelectric power in the UK.

There are three main types of hydropower:

• Storage hydro: Uses dams to store water in a reservoir, which is released through turbines to generate power.
• Run-of-river: Diverts a portion of a river’s flow through a channel or pipe to a turbine without large-scale storage.
• Pumped storage: Moves water between two reservoirs at different elevations. This means that the system can store energy by pumping water uphill during low demand and releasing it to generate power during high demand. So, it’s one of the more adaptable hydroelectric structures.

On the whole, hydroelectric systems are valued for their consistency, quick response times and long operational lifespans.

But these systems also face significant challenges, like high upfront costs and potential ecological impacts that make planning permission tricky to get.

If you’re interested in learning more about the advantages and disadvantages of hydroelectric energy, I’ve written a detailed rundown on the topic right here.

Hydroelectric Power in the UK Today

Hydroelectricity only provides around 1.5 to 2 per cent of the UK’s total electricity generation.

Most of the country’s hydro capacity comes from Scotland, which hosts more than 80 per cent of the UK’s hydro infrastructure. This is largely down to its mountainous terrain and heavy rainfall, which makes the country perfect for hosting hydro projects.

Wales also contributes significantly with facilities like the Dinorwig Power Station. This 1.7 gigawatt (GW) pumped-storage plant is known for its rapid-response capabilities and is an excellent source of clean power.

The UK also has hundreds of small-scale hydro installations, particularly in rural and community-owned settings. These micro-hydro systems often use historic mill sites or river weirs to generate clean and local power that’s surprisingly reliable.

The picture is slightly complex for hydropower in the UK at the moment, as support for this energy type has generally waxed and waned. Earlier projects benefited from Feed-in-Tariffs (FITs), but these incentives have largely been phased out as the scheme winds down.

The importance of CfDs

Today, hydro needs to compete for Contracts for Difference (CfD) allocations. As this solution is better suited to larger, lower-cost technologies like offshore wind, it’s looking difficult for hydropower to find its feet in the UK’s new landscape.

Given this evolving policy landscape, it’s more important than ever to understand the support mechanisms currently available for renewable energy projects in the UK. As I just mentioned, one of the primary routes for securing support these days is through the Contracts for Difference (CfD) scheme.

The CfD scheme is designed to encourage investment in low-carbon electricity generation by providing long-term price certainty. However, navigating the application process and understanding the eligibility criteria can be complex – especially for hydropower projects.

To help you make sense of it all, we’ve created a detailed guide to the CfD scheme, including what it means for hydro developers, how the auctions work, and where new opportunities might be emerging.

The Future of Renewable Energy Payments

With ROCs ending and CfDs taking over, landowners could face big shifts in income and opportunity.

Our free report explains what’s changing, what it means for your site, and the steps you can take now to stay ahead.

Download Your Free Report

Physical and technological potential

The UK isn’t overflowing with large rivers like the Rhine or the Danube that could provide serious power. But the potential of hydroelectric power in the UK is promising, especially in regions like the Scottish Highlands, Snowdonia and the Lake District.

The British Hydropower Association estimates that the UK could develop up to 2.5 to 3 GW of additional hydro capacity, including both traditional and pumped-storage systems. This is in addition to its current total installed capacity of 2 GWs and storage capacity of 900 gigawatt hours (GWh).

There are also thousands of disused water mills and river sites that could host small-scale, low-impact hydro schemes. These projects typically range from 5 kilowatts (kW) to 100 kW and are ideal for powering remote homes, farms or community buildings.

Pumped-storage is where much of the untapped potential in the UK lies. Projects like Coire Glas in Scotland (which is currently under development) could double the UK’s existing pumped-storage capacity. It would also play a vital role in balancing intermittent renewables like wind and solar.

Technological advances are also helping to overcome some of the environmental issues that come with hydro (more on that below). New modular turbines can operate in low-head environments, and fish-friendly designs are improving the environmental profile of run-of-river systems and making a hydro-powered future more likely.

Environmental considerations

Like any type of large infrastructure, hydro has environmental trade-offs that can make its benefits feel less worthwhile. Large dams can flood habitats, alter ecosystems and disrupt fish migration. Run-of-river systems, while less intrusive, still change river flow patterns and can impact aquatic life.

But mitigation strategies are improving in a major way. Modern hydro installations often include fish ladders, bypass channels and variable flow releases to better mimic natural river conditions and impact wildlife less.

Environmental regulations from agencies like the Environment Agency (EA) and the Scottish Environment Protection Agency (SEPA) can also help ensure that new projects meet strict ecological standards. While this can make planning permission more difficult, it also reduces community resistance to new projects.

Storage and stability

While wind and solar grab headlines for record-breaking generation in the UK, hydro brings something equally valuable. And that’s reliability.

Hydro has the ability to provide consistent baseload power and rapid response. So, it’s essential for a grid that increasingly relies on variable renewables. Pumped-storage systems act like giant batteries by absorbing excess energy when supply is high and releasing it when demand spikes. This helps prevent blackouts and smooth out fluctuations in generation from other energy sources.

Hydro also complements other renewables. It often performs best in wetter, windier months when solar production is low. And unlike wind or solar, some hydro systems can restart the grid after a blackout, offering what’s known as ‘black-start’ capability.

Economically, hydro offers great long-term returns. Though initial construction is expensive, operating costs are low and systems can run efficiently for 50 years or more, which may appeal to developers and landowners seeking a long-term project.

Barriers and policy challenges

While I’ve run through several factors that make hydro look like a strong part of the UK’s energy mix, it does face some challenges.

The biggest of these is regulatory complexities that make it difficult to get projects off the ground. Hydro projects must navigate multiple agencies and obtain permits related to water use, ecology and land access before developers can get started.

And even if these planning difficulties weren’t there, hydro projects (especially small-scale ones) often struggle to attract funding. This is largely down to long payback periods and lack of government incentives.

As I mentioned earlier, hydro projects struggle to compete for CfD allocations, which makes them far less viable than other renewables options at present. As it stands, the current CfD system doesn’t favour hydro, especially community-scale projects that can’t compete with offshore wind on price.

The Future Potential of Hydroelectric Power in the UK

The future potential of hydroelectric power in the UK is difficult to place. But the unique services it provides may make it a far more popular renewables option down the line.

As the National Grid and local grids become more reliant on intermittent renewables, the value of flexibility and energy storage will only grow.

New projects like Coire Glas could transform the energy storage landscape and help decrease the UK’s reliance on foreign oil and gas that are sending energy prices sky-rocketing. Meanwhile, revitalising disused mill sites for micro-hydro could bring low-carbon power to rural communities and support local economies.

But in order to boost the UK’s hydroelectric capacity, government support will be key. Updated incentive schemes, streamlined planning processes and inclusion in net-zero roadmaps could all unlock significant hydro capacity.

But this requires ongoing and genuine support to build out the sector. Only then will these projects feel financially viable to both developers and landowners.

So, while hydroelectric power may not dominate the UK’s energy mix, its value goes far beyond raw generation. It offers reliability, responsiveness and storage capacity that are essential in a renewable-heavy National Grid. And with net-zero limits looming, these are all critical things that the UK government will want to consider.

With strategic investment and policy reform, hydro could quietly but powerfully support the UK’s transition to net-zero. It’s time we put more energy into water.

At Lumify Energy, we work closely with landowners, developers and communities to ensure hydro opportunities are financially viable, long-term energy projects. If you would like to optimise an existing hydro project, our team can guide you through contracts, planning and revenue strategies to help you get the most out of your project.