- A source of power
- User of the power and/or access to the grid
- Willingness of those involved to support the project
Generation
There are a number of different ways of generating renewable power. There follows a list of the more common ways.
Solar
Solar panels can be mounted on roofs or on the ground. They should be oriented towards the south as far as possible with minimal shading from adjacent buildings and trees. The ideal elevation for panels in the UK is around 40 degrees.
Many buildings have multiple roof orientations and a combination ranging from east to west offers the opportunity for good generation throughout the day. Naturally, solar panels generate best in the summer, with comparatively little generated on a short, overcast winter's day.
Currently Stour Power is looking for sites that can accommodate upwards of 40 panels. If you have a site that you would like us to consider, get in touch and we can estimate its generation potential.
Nayland, Bures and Hartest are among the many village halls benefiting from the installation of solar panels on their roofs.
Wind
To be economically viable wind turbines need to be quite large. Typical sizes for community energy would be 50m high, or more. Although they will not turn on still days, unlike PV they can generate well throughout the day and throughout the year.
For a site to be technically viable it needs an average wind speed of 5.5 to 7m/s. There are a considerable number of other factors to take into consideration including: potential interruption of airport radar and telecommunication services; bird flightpaths; sensitive areas such as AONBs; distance from residential properties; and visual impacts.
Taking account of such factors Friends of the Earth and researchers at Exeter University have published a useful map showing potential sites at https://mapst.ac/foe/onshore-renewables-england
Hydro
For centuries the river Stour provided water power for flour mills. With the latest, low flow water turbines there's the opportunity to generate electricity.
Old mills and weirs provide potential sites. Key to a viable project will be a good flow and reasonable drop in river height (the head). Typical, absolute minimum figures would be around 1m³/s flow and a head of 1m, ideally more.
To calculate potential hydropower, multiply the water's flow rate by the head and a gravity factor adjusted for system losses:
Approximate generation (kW) = Head (m) × Flow (m³/s) × 5
Consumption
For optimum economic viability of a project any electricity generated will be used on the same site as it is generated. In some cases neighbouring properties might be able to be connected by private wire.
Any excess electricity can be sold into the grid, either at a standard export tariff or through special contractual arrangements known as Power Purchase Agreements (PPAs). When there are no on-site or neighbouring consumers connected by private wire, all the electricity will need to be exported onto the grid.
Stour Power can evaluate potential grid connectivity requirements and liaise with UK Power Networks to explore options and constraints for grid connectivity.
Where electricity is being exported we can also investigate options to sell it to local customers, thereby keeping it in the community.
Supporting the project
Local engagement and support will help steer a project to a successful conclusion.
This might include gaining community support by organising consultation events, running local communications etc.
It might also involve working with Stour Power on applications for funding and/or promoting community investment.