Renewable energy

Wind turbines are designed to last 20 to 25 years. With good maintenance and favourable conditions, some can continue operating for 30 years or more. The lifespan of a solar farm is similar, at 25 to 30 years. Towards the end of their lifespan solar panels become less effective and generate less electricity. In such cases it sometimes makes economic sense for a solar farm to replace old panels with new ones, though solar panels older than this are still in use.

A wind turbine or solar farm doesn’t have to be right next to a grid connection point, for example such as a substation. But the further away it is, the more expensive it can be to connect, because of the longer cables and any additional infrastructure that may be needed. Overhead lines are generally cheaper than underground cables. If cables need to cross particular land, permission will also be required by the landowner, which can add time and complexity. There can also be small energy losses when electricity travels longer distances.

Both wind turbines and solar panels have environmental impacts linked to the materials and energy, needed to build, transport and construct them. However, once installed, they generate low-carbon electricity for many years. One way of measuring their environmental impact is to consider their “carbon payback time”, that is the time it takes for a wind turbine or solar farm to offset the emissions from the manufacturing and installation phase by generating clean electricity.   Studies show that for solar this is 1-2 years, and for wind turbines 6-8 months. While exact figures vary depending on how and where equipment is made, and where they’re sited, but it’s safe to say that both technologies quickly repay their carbon impact and go on to produce low-carbon electricity for many years.

Mostly, but not completely.  Let’s take solar panels first. Most of the materials used in their manufacture - glass, aluminium, silicon - can be reused or recycled. But there is a cost to this, and this should be borne in mind by a community energy group looking to undertake a solar project. In the UK, solar panels fall under the Waste Electrical and Electronic Equipment regulations which require producers and importers to help ensure panels are properly collected and treated when they reach the end of their life. Organisations such as PV Cycle provide recycling services this purpose. Most parts of a wind turbine, including the steel tower, copper wiring and concrete foundations, can be recycled. It’s the blades, made from composite materials such as fibreglass and resin, that are most difficult to re-use. Alternative uses are being explored, including shredding old blades and using the material in construction products, or using them for playground equipment, bridges and storage sheds. Both solar panels and wind turbines rely on materials that are sourced through global supply chains. We would urge community energy organisations (and indeed private developers) to always chose manufacturers with strong environmental standards, responsible sourcing policies and transparent supply chains to help reduce environmental and social impacts associated with their manufacture.

Our main focus is supporting community energy groups who want to run renewable energy projects in areas where the community is supportive, and this is usually wind turbines or small-scale solar farms. But battery storage can be used alongside these technologies to store electricity and use it when needed and for the benefit of local people, for example, when the sun isn’t shining or the wind isn’t blowing. A battery system can reduce bills and help to balance local supply and demand. Some community energy projects do include battery storage, including Bristol Energy Cooperative, and Low Carbon Hub. In all these cases, the groups involved have had to weigh up whether battery storage is suitable, taking into account factors such as the pattern of local energy use and cost of installation.

Wind turbines do pose a small risk to birds and bats, but the level of this risk is very carefully assessed as part of the planning process that wind developments must go through. In fact, wind turbines are subjected to some of the most detailed environmental and planning assessments of any infrastructure project, particularly in relation to wildlife. It’s important to bear in mind that, compared to other causes of bird death, the impact from wind turbines is relatively low. Research (BBC Science Focus) has shown that cats kill around 100 times more birds than wind turbines in the UK, with some estimates suggesting up to 300 times more. The bird charity RSPB says climate change is the greatest long-term threat to birds. They support wind turbine development in the right area, that is where sensitive mapping and assessments have identified a site with lower ecological risk (RSPB Onshore Wind Power). Before a wind development is given permission to go ahead, environmental impact assessments and wildlife surveys are carried out to understand local species and minimise any potential impacts. Areas that are designated zones for protecting bats are typically avoided. Natural England has guidance to help inform this.

In many cases, yes. A development of several wind turbines can benefit from economy of scale, because the associated costs such as planning, access roads, grid connections and construction are shared across the whole project and are less per wind turbine. You get more electricity for your investment. And it’s not just about money. Adding more turbines can significantly increase the amount of electricity generated, helping to deliver greater energy security and environmental and community benefits. But there are cases where a single large wind turbine is better than a group of small ones. Large turbines usually generate much more electricity than several smaller ones. This is because wind speeds are generally stronger and more consistent higher above the ground, and longer blades can capture more energy from the wind. So, while several small turbines may be easier to fit into some landscapes, they are unlikely to be as beneficial as a single modern commercial-scale turbine in a good location.

Yes, there can be some temporary disruption during the construction phase, particularly from increased traffic and the use of local roads. It is impossible to say how long the disruption will last because it depends on the size of the development. Developers are generally acutely aware of the need to keep disruption to a minimum, and it is in their interest to do so. And they are required to work with the local authority where necessary on measures to manage site traffic, protect road conditions, and ensure safety. Community energy developments often have a working group with local residents who can help to design suitable measures to reduce this impact further, based on their knowledge of the area. Once construction is complete, traffic levels typically return to normal.

Yes, solar panels can be installed on canopies over car parks. There are examples of these in public carparks including at Stourton Park & Ride in Leeds; at Eastbourne District General Hospital; and at MidKent College, Maidstone. In many cases are combined with electric vehicle (EV) charging points, allowing the electricity generated on site to be used for vehicle charging. However, because the structure that supports the solar panels is more complex, the build is necessarily much more expensive and really only makes sense on newly developed car parks that are part of large infrastructure projects. The business case for adding a canopy to an existing car park is extremely unlikely to stack up.

To put it simply, it's because you can generate more power with ground mounted solar. Many community energy groups have undertaken successful projects that have installed solar panels on the roofs of schools, village halls and other buildings. See for example Bristol Energy Cooperative and Repowering London. But not all roofs are suitable for solar panels. Some roofs don't face south, or they're shaded by trees or other buildings. Structural limitations and ownership arrangements can all also affect whether you can put an array of solar panels on a roof. By contrast, ground-mounted solar schemes are larger and easier to access and maintain, and the panels can be pointed in the direction that will generate the most electricity. Because of this, ground-mounted systems can produce large amounts of electricity more cost-effectively than rooftop schemes. Westmill and Fairy Hill are good examples of community-owned solar farms. It is true that the impacts of a solar farm on the local landscape and community needs careful consideration. And part of the FEL approach is always making sure that the community is consulted, and people’s views are made known. Note that ground-mounted solar can work alongside some forms of agriculture. By combining solar arrays with sheep grazing, some farmers have found a higher and more stable income per acre than before.