PROJECTS
Project: Langford Solar Farm
Location: Langford, Mid Devon
Client: JBM Solar
Services: Flood planning
Value: £40m
We became involved in creating a solar farm on 150 acres of agricultural land in Mid Devon, capable of generating 49.9MW of renewable energy (enough to power approximately 10,000 local households) to help fulfil the UK’s binding commitment to reduce CO2 emissions and counter climate change.
The proposed site – in fields either side of the River Weaver in Devon – is designated Flood Zone 3 by the Flood Map for Planning, on the basis of nationally generated flood models. However, Mid Devon Council’s policy is that all areas defined as Flood Zone 3 should be categorised as Flood Zone 3b, ‘the functional floodplain’, unless proven otherwise, which severely restricts the appropriate development types.
‘Appropriate development’ is defined within the government’s National Planning Policy Framework and includes critical evacuation roads, power stations, sewage works and even wind turbines – but not solar farms (although this was due to change) – but any development in FZ3b has to pass an exception test, including ‘providing sustainability benefits to the community that outweigh flood risk’, and without increasing flood risk elsewhere.
As the Environment Agency (EA) had objected to the proposal, and the Mid Devon Council case officer had advised that the application would be refused on this basis, it was critical that these objections were overcome.
Thanks to our modelling work, the Environment Agency withdrew its objection to the Langford proposals in December 2020. In January 2021, the Environment Agency announced that solar farms should be included on the essential infrastructure list; and in the same month, the government released a consultation document to make it national policy.
The spirit of government policy is to protect the function of FZ3b (‘the functional floodplain’) to store and convey flood water. Our challenge was to convince the EA that neither would be impaired by the construction of a solar farm on the site, or at least over the majority of the site; and negotiate where panels should be excluded as there was no policy or guidance to draw from.
We argued that wind turbines should be treated as a proxy for solar panels: an argument attempted elsewhere, but not yet successful in FZ3b. Our hydraulic modelling work not only defined the extent of FZ3b, but also provided flood depth, velocity and hazard data to allow a better understanding of the risks across the site. The results demonstrated that flooding in all events would, in fact, be quite shallow (less than 0.3m, not deep enough to reach the bottom of the panels), and slow flowing across most of the site.
Knowing the risk that the EA would cite concerns about the possibility of tree branches and other debris catching in the legs of the solar panels, we met the EA officer on site to show the lie of the land. Although the ground upstream was steep, there were not many trees to be swept down, and the land itself was relatively flat with small drainage channels.
The original proposals were to cover the majority of the site with solar panels. In the end, the EA agreed to mitigation measures. A particularly vulnerable area would be excluded: about 3% of the total site area. In part of that section, the ground would be lowered by 0.1m to collect water, more than offsetting the potential loss of storage capacity due to access roads and the slender legs of the thousands of panels.
Calibro has not only been able to identify and present clear and compelling strategies for large and complex site promotions – ones that don’t just rely on costly infrastructure improvements – but they also take a very proactive and innovative approach in the way they engage with key stakeholders.
