Page last updated on 19th August 2026

Turbines in a tidal barrage working to generate electricity from moving water.

How does tidal energy work and how could it impact your energy use?

Tidal energy is a form of renewable energy that uses the natural rise and fall of the tides to generate electricity. Although tidal power currently makes up less than 0.01% of energy generation in the UK, it has the potential to play a larger role in the country’s low-carbon energy mix.

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In this guide, we’ll explain how tidal power works, how tides can be used to generate electricity, and the main benefits and challenges for homes, businesses, and the wider energy system.

What is tidal energy?

Tidal energy, also known as tidal power, is a form of renewable energy that uses the natural movement of ocean tides to generate electricity. It captures energy from the rise and fall of sea levels or the flow of tidal currents.

Tidal energy is often described as a form of hydropower because it uses moving water to turn turbines. However, while traditional hydropower usually relies on rivers, dams and reservoirs, tidal energy uses the predictable movement of the sea. This means electricity from tides can be generated in coastal regions where tidal streams are strong enough.

How does tidal energy work?

Tidal energy works by using the natural movement of the sea as tides rise and fall. In coastal areas, the movement of water between high and low tides creates powerful flows that can be captured and converted into renewable energy.

One common method is a tidal barrage, which is a structure built across a river estuary or bay where tidal flow is strong. The barrage contains turbines that are turned by moving water.

To understand how electricity is generated from tidal energy, here is a simple breakdown of the process:

Tidal barrage

A tidal barrage is built in an area with a strong tidal range, such as across a river estuary or between two sections of land. As the tide moves in and out, water passes through the barrage.
Water flow turns the turbines

As the tidal flow increases, water moves through the barrage and spins the turbines. The stronger and faster the water flow, the more energy can be captured.
Movement is converted into energy

The spinning turbines drive generators, converting the kinetic energy from moving water into electricity. This electricity can then be transported back to land, often through undersea cables, and fed into the electricity network.

Tidal projects depend heavily on the strength and speed of the water flow. That is why they are usually located in coastal areas with large tidal ranges. In simple terms, faster-moving water can drive turbines more effectively and generate more electricity.

Advantages and disadvantages of tidal energy

Understanding the advantages and disadvantages of tidal energy can help explain why tidal power has strong potential, but is not yet widely used. Like any renewable technology, there are clear benefits as well as practical challenges to consider.

Below, we look at the main pros and cons of tidal energy.

What are the advantages of tidal energy?

Reliability

Tidal energy is highly predictable. Because tides follow regular patterns, tidal electricity generation can produce a relatively consistent amount of electricity compared with some other renewables. For example, solar energy can vary depending on the weather.

Low operating costs

Although setting up a tidal power production plant can be expensive, the ongoing maintenance and operation costs are often relatively low once the system is in place. This can make tidal electricity generation more cost-effective over the long-term.

Clean and renewable

Tidal energy is renewable because it uses the natural movement of the sea. It does not rely on burning fossil fuels, so these systems do not produce greenhouse gas emissions during operation.

What are the disadvantages of tidal energy?

Geographic limits

Tidal energy systems depend on location and can only be built in areas with strong, consistent tides. This limits where projects can be developed and is one of the key challenges of using tidal power at scale.

Environmental impact

Tidal barrages can affect local marine ecosystems. For example, they may disrupt fish migration, change water flow, or affect habitats for aquatic life. That is why environmental assessments are important before large projects are built.

High initial costs

Building tidal electricity generation systems requires major infrastructure and specialist engineering.

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How do renewable energy and smart meters work together?

If you’re interested in Great Britain’s energy infrastructure, why not learn more about smart meters?

Smart meters help to make the energy system smarter by allowing energy suppliers to offer incentives for households who can reduce their energy use during peak hours. This can help to balance supply and demand, reduce pressure on the grid, and support the national transition to low-carbon energy.

For most households, tidal energy would not directly change how you use electricity day to day. Instead, it could affect consumers indirectly by helping to support a more diverse low-carbon grid over time, alongside other renewable sources and smarter energy management.

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Tidal energy FAQs

Is tidal energy renewable or non-renewable?

Tidal energy is renewable because it comes from the natural rise and fall of ocean tides. These tides are caused by the gravitational pull of the moon and the sun, meaning the energy source is naturally replenished.

Why is tidal energy a renewable resource?

Tidal energy is a renewable resource because tides happen every day and do not run out when used to generate electricity. Unlike fossil fuels, tidal power does not rely on a limited fuel source that needs to be extracted or burned.

How does tidal energy affect the environment?

Tidal energy can have both positive and negative environmental effects. It generates clean and reliable low-carbon electricity, but tidal barrages and other infrastructure can affect marine habitats and fish migration. Careful site selection and environmental assessments are important before tidal electricity projects are developed.