Following the UK's recent commitment to bring greenhouse gas emissions to net zero by 2050, the low-carbon energy from our onshore windfarms is more important than ever before. Onshore wind energy is now the cheapest form of new generation and its popularity is growing. This helps to explain why it supplied as much as 9.1% of UK electricity in 2018. BEIS data indicates that 76% of the public support the technology and a June 2019 poll suggests that Conservative voters prefer onshore wind to fracking by a majority of two to one.

Despite such evidence an expanded fleet of onshore wind projects probably remains a distant prospect in England and Wales for the moment. New technology may make 'repowering' attractive for existing wind power sites however. Repowering schemes can include extending the lifetime of current projects, as in the recent Kirkby Moor Windfarm appeal , or applying for a new project on an existing site. These schemes do not contravene the National Planning Policy Framework (NPPF), and enjoy support within BEIS.

It is not just central government that supports onshore wind. The National Infrastructure Commission (NIC) would like this technology to be supported by the 'Contracts for Difference' market mechanism to enable the lowest cost renewable generation mix to be brought forward in the in the near future. If such recommendations are followed onshore wind may be about to take off again.

Lifetime conditions

Planning permissions for existing onshore windfarms are typically subject to conditions requiring the site to be decommissioned after a set period of often 25 years. As the first large-scale commercial windfarms were built in the 1990s a number of these schemes are now approaching their decommissioning phase. By 2040 almost two-thirds of the UK’s current onshore capacity will be older than its expected 25 year lifetime. Repowering may well prove to be the answer.

Why is repowering required?

It would represent a loss of circa 8GW in capacity (equivalent to powering over 5 million UK homes per year) if every windfarm reaching the end of its life is decommissioned by 2040. BEIS' projections for decarbonisation assume that most of the existing fleet will be retained. So there is work to be done, even to 'stand still' on baseline power.

Amendment of the NPPF in July so that the 'repowering of existing wind turbines' would not be subject to the (otherwise very significant) planning hurdles that apply to new sites in England and Wales may be a sign that things are moving in the right direction.

What do windfarm owners need to do?

A 'sliding scale' of three main options for repowering exists, with increasing risk and reward along the progression:

  • A simple extension of a lifetime planning condition may be relatively easy. It may require only a limited update to existing environmental information, but the longer the extension the more fully its planning and environmental impacts will need to be reviewed. Certain environmental effects, especially any that engage the Habitats Regulations, may cause greater problems today than the 1990s and 2000s due to a tougher regulatory landscape and developments in case law. Of course, despite being potentially the simplest repowering method, a lifetime extension still leaves the project facing an eventual 'dead stop'.
  • Lifetime conditions can be removed entirely, although this approach may be more challenging to justify, and could invite a review likely to include a full Environmental Statement. The local planning authority (LPA) may wish to attach more substantial conditions, for example requiring the project to be physically and technically assessed after a further time period, and/or by tying its ongoing consent to the physical condition of the turbine towers and bases. Any major maintenance operation may require a separate planning application, depending on the LPA's desired approach and whether a full replacement has been environmentally assessed. Such instances would offer further opportunities for LPAs to exercise control over a project.
  • 'Full' repowering with a new planning application for a new project on the same site would incur the most risk but also the greatest potential rewards. An entirely new project could use higher capacity turbines and improved technology to comply with noise and wildlife conditions. It may also be able to incorporate battery storage and may improve visual design. It may be possible to implement some or all of these strategies within the same visual envelope as the existing project.

Success stories

Nineteen off-shore wind power sites had been successfully repowered by April 2019. Repowering work has increased the collective capacity of these schemes by 160% (compared to their original outage capacity), whilst using only 60% of the number of turbines.

Originally built in 1992 ScottishPower's onshore site at Carland Cross was repowered in 2013. The site's 15 original turbines were replaced with 10 new turbines five times more powerful than the original ones. This repowering increased site capacity by 233%.

Sancton Hill in East Riding has been subject to a successful lifetime condition amendment which has extended the project's lifetime from 25 to 30 years. This was approved in January 2018.

The Platina Energy Partners site at Slieve Rushen was repowered in 2008. Its capacity was increased by 500% from 9MW to 54MW and became the largest windfarm in Northern Ireland.

Analysis of eight projects in Scotland has shown that onshore wind brought more than £297 million in local value added to communities.

Numbers such as those described above should prove very attractive for operational portfolio owners in future.

Prospects for renewal?

The National Grid's Future Energy Scenarios (FES) (July 2019) sets out a range of credible futures for the whole energy system, based also on feedback received from stakeholders. Notably, each of the FES scenarios assumes that most onshore wind projects will survive due to repowering.

Rapid technological progress and market forces, together with policy changes, have created a swiftly changing landscape where it is difficult to accurately forecast a single energy future to 2050. Several major utility companies , investors and developers joined forces in August 2019 to write to BEIS to request that the government establish a more supportive strategy as a matter of urgency. Clearly, there is appetite among market players, especially those who already own and operate onshore wind projects, to improve the value of those assets in whatever way can be legally supported.

It remains to be seen how government policy may support a transition to clean energy incorporating onshore wind and for repowering the question is a case of 'watch this space'.