Using running water to generate power is hardly a new concept — hydroelectricity has a long history
And smaller scale hydroelectricity, or hydropower, can be used on a domestic scale to heat your home or run your appliances.
But how does hydropower work? Is a domestic system feasible? How much does it cost, and what are the main benefits of hydropower? We’ve got the answers here.
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How does hydropower work?
Hydroelectricity is based on the power of gravity, plain and simple. Water in rivers and streams flows downwards towards the sea; as the water passes through a hydropower system, the energy in the water drives a turbine which turns a generator and energy is produced.
The power of the system will depend on the strength of the water passing through, as well as the efficiency of the system.
There are three standard types of hydropower systems. The first is a standard ‘run of river’ system, which uses the existing flow of the river. Water is typically redirected to pass through the turbine and the water is passed back into the river or stream.
While this system is the most straightforward, it also has the disadvantage of being entirely dependent on the river strength. If your river goes dry due to drought, your system will not run.
However, due to its simplicity it is also the most typical to use for domestic of community systems.
The second type is a storage system, or dam, which is the most common form. Dams are used for large-scale hydroelectricity projects around the world, but can also be used for smaller systems.
A reservoir stores the water from the river and lets it through gradually. This offers a greater degree of control because the system can still work if the river runs dry.
The final type is a pumped system, which uses cheaper off-peak energy to pump stored water back up to a higher point to generate energy at peak times.
Is domestic hydropower feasible?
Hydropower’s practicality depends entirely on your access to running water. But, even if you have a river or stream nearby, it doesn’t mean you can automatically consider hydropower.
If you think you may be eligible, you should contact a certified hydropower installer who can take a look at your site. Whether it is suitable or not will depend not only on your location and access, but also how steeply the river flows and how much water passes through.
You should also consider the seasons. Your river’s lowest level will determine how feasible your site is more than your river’s highest level.This in turn will vary year by year depending on rainfall levels.
The Energy Saving Trust recommend that hydropower can be an excellent community development project. This will lower installation costs and give you greater flexibility around installation.
How much does it cost?
The cost of a hydroelectricity system depends almost entirely on its size and where you put it.
The costs are likely to be significant either way. A typical 5kW system to power one home will cost around £25,000, but it could be more or less. The good news is that once the system is installed it requires very little upkeep.
How much energy the system will generate, and hence what your savings will be, is even harder to estimate as it will depend not only on the system, but also how long it is able to operate at full efficiency, which in turn depends on the water levels in your area.
Crucially, as hydroelectricity is a renewable resource, you will also be eligible for the Feed-in Tariff scheme, meaning you can get paid for every kWh of energy generated, and receive further payments for any unused energy you export back to the national grid.
To make sure you are eligible for the Feed-in Tariff you must fulfil certain criteria, so take a look at our dedicated Feed-in Tariff page.
Remember, you will only receive payments if your property has an Energy Performance Certificate rating of Grade D or below. And the rate you receive will depend on the actual grade, as well as when you apply.
What are the main advantages and disadvantages?
As with most renewable energy systems, hydroelectric comes with both pros and cons.
The pros include:
- A clean, renewable resource perfect for a wet climate like the UK
- Almost maintenance free, hydropower systems have a life expectancy of up to 50 years
- You may be eligible for Feed-in Tariff payments
The cons include:
- Installation costs can be high, so you may be better off developing a hydropower system together with your local community
- Suitability depends entirely on location, and even if you have access to a river or stream the location may not be suitable
- The amount of energy you receive will be very easy to predict, but will also be highly seasonal
- Ground Source Heat Pumps Heat pumps are a heating alternative worth looking into
- Energy Performance Certificates You need an energy performance certificate if you sell, rent or build a property
- Carbon Footprint What is a carbon footprint, how can it be measured, and what can you do to reduce your carbon footprint?