Tidal Power: What Are The River Severn Barrage Plans?

With its vast tidal range — the second highest in the world — the River Severn has long been seen as one of the UK’s most promising natural energy sources. And once again, it’s back in the spotlight. New proposals and renewed interest in tidal power are reigniting discussions about the Severn Barrage — a bold infrastructure idea that’s been floating around for over a century.

At Green Flare, we’ve always championed practical, sustainable solutions. We know renewable energy needs to be ambitious and locally relevant. So, what’s the story with the Severn Barrage? Could it really power millions of homes? And is it the kind of project that fits with Bristol and the South West’s net-zero ambitions?

How Tidal Power Works

Tidal energy is one of the most reliable forms of renewable energy. Unlike solar or wind, tides are entirely predictable, driven by the gravitational pull of the moon and the rotation of the Earth.

There are a few different ways to generate power from tides, but the general idea is this: as the tide rises and falls, large volumes of water move in and out of estuaries. By channelling this movement through turbines — usually via structures like barrages or lagoons — we can convert the kinetic energy of water into electricity.

It’s an elegant solution with minimal visual impact and a lot of potential, especially in places like the Severn Estuary.

The Severn Barrage Plan: Big, Bold and Controversial

The Severn Barrage is the biggest of big ideas. It’s a proposed 16-kilometre structure stretching across the estuary, from Lavernock Point near Cardiff to Brean Down, just south of Weston-super-Mare.

If built, it could generate around 15–16 terawatt hours of electricity annually, roughly 5% of the UK’s total electricity needs. That’s enough to power over 3 million homes.

The concept has been debated since the early 20th century, with serious investigations cropping up in the 1970s, again in the early 2000s and now once more in 2024, as the UK searches for large-scale solutions to meet its net-zero targets.

The renewed interest follows the recent formation of a commission tasked with exploring tidal energy opportunities in the Severn Estuary. But this isn’t just about reviving old plans — it’s also about weighing up new ideas and approaches, including tidal lagoons and more modular technologies.

What’s the Appeal?

Tidal energy — especially from a site as dynamic as the Severn — has several big advantages:

• Reliability: Tides don’t depend on the weather. They’re predictable and consistent, which makes tidal power a reliable base-load energy source.

• Massive Scale: The estuary has the potential to deliver gigawatts of clean energy.

• Carbon Savings: Tidal power could offset millions of tonnes of CO₂ emissions each year.

• Job Creation: A project of this size could create thousands of skilled jobs during construction and ongoing maintenance.

• Flood Management: With the right design, the barrage could also provide coastal flood protection for vulnerable communities.

In short, the Severn Barrage represents a rare opportunity to create large-scale, long-term, low-carbon energy infrastructure — right here in the South West.

But Not Without Challenges

It’s a compelling idea, but it’s not without controversy. There are serious challenges to getting the project off the ground.

Environmental Impact

The Severn Estuary is a unique and highly protected environment. It’s a haven for migratory birds, fish species and diverse marine life. Critics argue that a barrage could cause significant disruption to these ecosystems, particularly by altering sediment flows and tidal patterns.

Even with today’s advanced engineering, there’s still a question mark over how such a large structure would affect water quality, wildlife habitats and the broader ecological balance.

High Upfront Costs

Building the barrage could cost between £15 billion and £20 billion. That’s a huge investment, especially when other renewable sources like solar and offshore wind are becoming increasingly cost-effective.

Securing funding would likely require significant government backing or a bold public-private partnership — neither of which are guaranteed.

Community Buy-In

Local communities around the estuary have mixed feelings. While some welcome the potential for jobs and investment, others are concerned about the impact on coastal heritage, local fishing industries and the visual character of the landscape.

Tidal Lagoons: A Smarter Alternative?

Given the challenges, attention is turning to tidal lagoons — a more flexible, modular approach to tidal power. Rather than building a continuous barrage, lagoons create semi-enclosed areas of water where tidal movements can be harnessed with less disruption to natural tidal flow.

Earlier this year, the Severn Estuary Commission recommended exploring tidal lagoon projects as a lower-risk way to move forward. The idea is to start with a pilot-scale lagoon to demonstrate viability, before scaling up.

At Green Flare, we see a lot of value in this approach — smaller, smarter and potentially easier to integrate with other local infrastructure.

A Role for Everyone in Bristol’s Energy Future

Whether or not the Severn Barrage goes ahead, the renewed conversation about tidal power is a reminder that the South West has a vital role to play in the UK’s energy transition.

At Green Flare, we work every day to help people power their homes and businesses with clean, local energy. From rooftop solar to advanced energy storage systems, we design solutions that reduce emissions and energy bills — while supporting the region’s broader sustainability goals.

We also understand that the future of energy isn’t one-size-fits-all. It’s about finding the right mix — from large-scale tidal infrastructure to everyday installations that make a difference on the ground.

The Bigger Picture

There’s a clear link between local action and national ambition. As the UK races towards its 2050 net zero target, we’ll need a blend of technologies and partnerships to get there — including a serious look at how tidal energy can contribute.

That’s why we’re watching the developments on the Severn closely. If the project — or something like it — can be done in a way that respects the environment, delivers real value to local people and complements other renewables, it could be a powerful step forward.

Want to Be Part of the Solution?

You don’t have to wait for big infrastructure projects to make a change. With Green Flare, you can start reducing your carbon footprint today. Whether you’re retrofitting an old property or building from scratch, our expert team can guide you through renewable energy options that make sense for you — and for the planet.

Contact Green Flare today and join the South West’s journey to a cleaner, greener future.