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Hydroelectric Systems

Hydroelectricity systems use flowing water to generate electricity. They are only suitable for specific sites , therefore not everyone can install one. 

How does hydroelectricity work? 

1. Water from streams and rivers flow downhill. The higher the water source, the more potential energy it has and the more electricity the system can generate. 
2. Flowing water passes through a narrow tunnel called a penstock. This turns the water’s potential energy into kinetic energy. 
3. Water rushes through a turbine, causing it to spin. 
4. The turbine powers a generator to produce electricity. 
5. Electricity runs through a transformer to turn it from direct current (DC) to alternating current (AC). 
6. The electricity generated is then used to power homes or can be sold to the grid. 

Benefits to hydroelectricity systems

• 24/7 operation – as water is continually flowing through the system, you will be generating electricity.
• Lower electricity bills – Since you don’t rely on electricity from the grid, you save money, and you can sell any excess electricity back to the grid.
• Ideal for off-grid homes – A hydroelectricity scheme provides one of the most reliable alternatives to mains electricity for isolated properties. Installing a hydro system can be expensive, but it may cost less than connecting to the grid.
• Reduces your carbon footprint – hydroelectricity is a green renewable energy and doesn’t realise harmful carbon emissions. 

Is a hydroelectric system suitable for me? 

Whether you can install one or not depends on the site itself. If you think you have a suitable site, consult with the local environment agency SEPA.

Hydropower systems

Hydropower systems are also regulated in Scotland therefore planning permission is required and you may be required to apply for a water abstraction licence. 

A suitable site needs a combination of: 

• Flow – how much water is flowing through the system 
• Head – the difference in height between the water at the top of the system and the bottom. 

You should also consider what happens to the watercourse in the summer, as the minimum flow is what accessors will consider.

How much does it cost? 

As sites vary so much, and planning is very site specific depending on where you want to install and what equipment you need, as well as any surveys, and planning permission you need to submit, therefore it’s difficult to estimate a cost. 

The Centre for Alternative Technology estimates that it may be possible to DIY a micro-hydro turbine for under £10,000. You can read more about that here. 

How long do hydroelectricity generators last? 

Most systems can last for 40-50 years, with low running and maintenance costs. Debris carried downstream during flooding can cause damage, but you can add a screen to the system to minimize this risk.

Hydro Schemes on Arran 

There are several hydro-electric schemes in Arran. Most of these were installed recently, but one is much older.  Arran Eco Savvy organised a trip to one of these to enable members to see how they work.

Claddoch

This scheme was installed in 1909 by the then owners of Brodick Castle. This is now an SSE site. 

Glenkiln

Located near Lamlash, utilises water from the Benlister Burn. It’s a 500 kW scheme that aims to generate power for 400 local homes. At full power it generates approximately 15% of the electricity used by Arran’s domestic customers. The project was a collaboration between J K and C Bone, a long established farming business who owns Glenkiln Farm and MEG Renewables, who are a renewable developer.

The hydro-scheme took two years to build, and since the area was a Special Protection Area, work could only take place outside the nesting season in the winter months. This was particularly challenging due to appalling weather conditions and record levels of rainfall over the winter of 2015/16.  Shortly after its completion the Scottish Parliament massed a motion to congratulate Kenneth Bone for steering the scheme through to completion. In April 2022 members of Eco Savvy were able to visit the hydro scheme in Glenkiln and to see it working first hand. The Bones are also currently working on the pre-development of a four megawatt solar farm in conjunction with Arran Community Renewables. 

Eas Mor

Located on the Allt Mor, a small river near Kildonan. The scheme is operated by the Eas Mor Ecology Centre. The intake is located just above the Eas Mor waterfall. Most of the pipeline is buried beneath existing pathways to the east of the river. The turbine house is situated downstream in Auchenhew Wood and is visitable by foot. 

Dougarie

Located near Pirnmill, it is a run of the river scheme where it utilises the waters of Allt Gobhlach.  The scheme is built on land owned by the Dougarie Estate, and the scheme can generate a maximum of 500 kW.

Kilmory

Located next to Kilmory Primary School is a small hydro scheme which helps power the school. In recent years this was broken however it is now fixed and operational again.

This page is part of our Sustainable Directory

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