Hydropower is one of the oldest power sources on the planet. The concept of harnessing energy from flowing water as it spins through a wheel or turbine has been used for farming as far back as ancient Greece. Why? Because, it’s a highly efficient, readily available and reliable source of energy.
Large vs small-scale projects
Today, we often associate “hydropower” with large dams with enormous reservoirs; the Hoover Dam or Aswan Dam come to mind. These massive engineering feats have been an important part of our global electricity supply, with hydro as a whole producing around 16% of the world’s electricity, and contributing 60% of all renewable electricity. However, creating such large scale projects requires enormous amounts of resources, and they inevitably impact on the built environment, local communities, and wildlife.
Small-scale hydro ‘run-of-river’ is a very different picture. Instead of holding back the river flow, water is simply diverted at the weir and returned immediately downstream, which results in an ultra-low impact development. Where appropriate, rivers and streams are an untapped resource, often running through towns and cities where there is high demand for electricity.
A community hydro scheme in Bristol, UK
Our project at Netham Weir is a brilliant example of harnessing water energy right on our doorstep. The project is still in development, but we’re super excited about sharing the benefits of the scheme and maybe even seeing it replicate in other UK cities.
Here are 7 reasons why local level hydro can be brilliant in a city:
- Minimal impact on the local environment. The Netham Weir hydro scheme will be constructed in the riverbank and will be mostly hidden below ground. A hydropower station will sit in a carpark, having limited impacts on the existing businesses there.
- It’s reliable, especially at peak demand. Typically there are 20 tonnes of water/second passing through Netham Weir on the River Avon in Bristol. During winter months the flow of the river is higher, meaning it will work at optimum supply.
- It’s long lasting. The two Archimedes screw turbines we are using at Netham Weir are projected to last 40 years or more. This is longer than most renewable technologies, and helps justify the upfront work involved.
- Keep it local…and cheap. The electricity generated from Netham Weir will stay local, on what is called a “private wire”. This means it helps to avoid some of the high distribution costs associated with selling electricity to the grid. At Netham Weir the electricity will supply a business locally, who’ll benefit from low electricity prices.
- An improvement for fish migration. At the moment, Netham Weir is the first barrier to fish migration on the River Avon. Our project developers are working on improvements to enable salmon, sea trout, eel, lamprey and other fish to move upstream and allow their young better chances of survival
- Avoid wasting the energy. In a town or city, electricity demand is 24/7. Standing by Netham Weir, and listening to the noise of the water, you quickly get a feel for all the potential that’s there. We have a choice to either make use of up to 300 kW of renewable power or let it go to waste. We opt for action!
- Energy can be energising – seeing new renewable energy projects in our city is an inspiration for the next generation. The better we understand where energy comes from, the more we will see it as a precious resource to be used carefully. Already, the Netham Weir project has been a real talking point in Bristol and could become an educational attraction. Perhaps it will even be the trigger that inspires someone to study engineering.
Interested in developing more local level hydropower? Why not get in touch with your local community energy organisation to chat a bit more to them about their projects. There are hundreds of community energy providers around the UK working to accelerate our move away from fossil fuels in a way that benefits us all on a local level.
 Estimated renewable energy share of global electricity production in 2019 (Source: REN21 2020)