FAQs

Get in touch for more information.

How much can I make from selling the electricity I generate?

The Smart Export Guarantee (SEG) launched on 1 January 2020 and requires some electricity suppliers to pay small-scale generators for low-carbon electricity they export back to the National Grid, providing certain criteria are met. Currently this is very low at ~ 4p/kWh for every unit of power you export.

If your scheme is generating electricity that will be consumed on-site, and therefore displacing imported electricity, this can offer the best value.

A Power Purchase Agreement can be arranged with an energy supplier. Contact the BHA if you would like us to put you in touch.

A private wire is a cable that runs directly from the hydro generator to an off-taker to someone who can consume the electricity. This is a private arrangement that can benefit both parties.

Grid constraints

A grid connection must be arranged with your local Distribution Network Operator (DNO). Alternatively, some large schemes may connect directly to the Transmission Network. Network capacity is scarce in certain parts of the country and should be assessed and reserved as early as possible to prevent delays to any project.

The costs of grid connection are site-specific, but the main variables influencing cost are: connection voltage; physical location and access to the network; network capacity and availability; upgrade requirement, if any; and generation technology.

The costs vary between DNOs and also depend on the connection voltage. Design fees vary between a few hundred pounds for small low-voltage connections and several thousands for connections to the 33 kV network.

The DNO has a three-month period to design and cost an appropriate connection. It will also identify the contestable and non-contestable works.

Once the design is complete, contracts are signed. In addition, Use of System Agreements will have to be signed for the export of electricity to the network.

What is the cost of hydropower?

This is very site-dependant, but the cost is very rarely less than £35,000. As a very rough rule of thumb, it may be useful to think of £8,000 per kW capacity for smaller sites or £4,000 per kW capacity for a larger system, but there is huge variation from one site to another.

Business rates

Unless the scheme is classed as a domestic installation where the energy generated is consumed on-site, the scheme will be liable for business rates. This can be a considerable tax burden on schemes and the BHA is calling for a reset of this charge to recognise the value of hydropower within the net zero transition.

Can I generate electricity from a fast-flowing river without a fall?

In theory, this is possible but the amount of power available is very small in comparison to sites where the water drops. See our ‘I Want to Install Hydropower’ page, which explains how much power can be generated from water.

Are there grants available for hydro schemes?

There are no UK-wide grant schemes or generation tariffs for hydropower. There may be local grants available to community groups.

Can I generate using my old water mill?

This is dependent on the site. Things to consider include:

Is your building listed?
Is there space for a turbine and generator?
Is there water flow and head (drop)?

The power generation from historic mills was very low compared to our power needs today.

Will my scheme need a licence or planning permission?

Typically, one or more licences will be required from the Environment Agency (EA) in England, the Scottish Environment Protection Agency (SEPA) or National Resources Wales (NRW). Planning permission is also often required as well. We would recommend consulting the local authority and EA, SEPA or NRW as soon as the technical viability of a project has been established.

How do I know who to go to for advice?

With hydropower there is no standard solution. The best design for a site is often not obvious. It is important to take advice at an early stage from someone with experience and a good track record. Ask for references or information on working installations – hydropower schemes should last for a long time. Look at our list of consultants and advisers and get in touch if you need more information.

Information on large dams and methane

Recent scientific studies have shown that previously ignored carbon and methane emissions from reservoirs are a significant source of greenhouse gases, and these emissions are not just limited to the first few years of vegetation potentially drowning after a new reservoir is formed. Emissions can be significant for periods of 20 years and beyond.

The BHA recognises the essential role that the science must play in the feasibility and carbon analysis of projects involving the formation of new reservoirs. It is important that projects that do not significantly contribute to the overall lowering of greenhouse gas emissions are not incorrectly considered as viable. Too often a lack of knowledge and understanding of the positives and negatives of large dam projects has led to polarised debate, with individuals either for hydropower or against it. The reality is that the difference between the positives and negatives of large dam hydropower is so vast that both camps can be right and wrong.

For example, a new dam of say 150 metres in height in the fjords of Norway might have a reservoir capacity that is very large from a relatively small surface area and be on a site with a large river flow. Calculations on drowned area and methane emissions show that – taking into consideration the very high global warming potential of methane (25 times that of CO2) – the emissions are a very tiny fraction compared with the carbon savings from replacing fossil fuel power generation. However, take the same set of calculations, for example, with the 128-metre-high Kariba Dam on the Zambezi River at the Zimbabwe–Zambia border. With its large, shallow tropical reservoir, the yearly methane CO2 equivalent emissions come out significantly higher than the carbon savings from the yearly electricity generation.

When it comes to reservoir surface evaporation – another significant issue in some parts of the world – the difference from one project to another can be significant and dependent on surface area and climate/location.

The BHA supports projects that provide overall significant benefits, and we support every effort in the work that is undertaken to ensure that only environmentally beneficial hydropower projects are built with care for the natural environment through planning and construction as well as throughout their operation.

Mailing List


Sign up and stay informed with the latest updates in the hydropower sector.

This field is for validation purposes and should be left unchanged.