Currently there is about 210 MW of operating onshore wind capacity that is older than 15 years, but by 2020 this figure will grow to nearly 1,000 MW. As onshore wind farms reach the end of their design life, there are a range of options which will be available to the operator. These range from seeking to extend the life of the existing turbines – ‘life extension’ – or alternatively redevelopment on the existing site, but with new generating assets usually described as ‘repowering’. The extent to which there will be opportunities within the UK for either will depend on the development of a regulatory framework which allows a route to market for onshore wind beyond the currently announced levels of support.
There is the real prospect of extending the design life of turbines from 20 to 30 years. Manufacturers are already well advanced in looking at life extension issues. They are studying the performance of turbines and evaluating what interventions may be required to safely extend the life to 30 years. Manufacturers are likely to be able to provide operators with some certainty as to availability and potential output. It will be important to understand and evaluate the existing land rights to consider what changes may be required to facilitate the extension. Most planning permissions/consents granted in the UK have a time limit of 25 years. If the time restrictions are only contained in conditions then an application to vary the condition may be appropriate, but in other circumstances a more substantive application to vary the permission may be required. Furthermore, in the event that the original application was subject to environmental impact assessment, it is very likely that an environmental statement may be required. The key issue in reducing cost and time will be to ensure that that statement is proportionate to what is being proposed and that proper consideration has been given to the scope of the requirement. This will require regulators to consider the issue and respond proportionately. A further consideration will be the extent to which there is appropriate energy and planning policy in respect of life extension. The nature of policy support is likely to vary throughout the UK depending on the different jurisdictions.
Existing sites are also likely to provide new opportunities. They often have the best wind resource and are well located with regard to infrastructure. The future of commercial onshore wind in the UK is likely to be linked to the deployment of larger and more efficient equipment. This has a significant bearing on generation costs and its competitiveness. The larger turbines and blades will require larger separation distances. It is unlikely that existing turbine foundations would be either appropriate or located in the right places for a repowering project. There will also be ongoing obligations in respect of the existing projects and the crossover between the two will have to be managed. This is likely to focus on restoration aftercare obligations which have been imposed on the earlier permission. There will be a need to re-evaluate land rights and potentially negotiate and renew these.
Life extension and repowering will play a critical role in the further development of the onshore wind sector in the UK. It would seem sensible to have a policy which ensured that existing developments continue for as long as they reasonably can and the history of the energy industry has been one of extending the life of generating plants. The ageing of equipment at existing sites may also afford an opportunity to start again and deploy the latest technologies with the resultant cost benefits.