Getty geothermal pool

Professor Iain Stewart
Professor of Geoscience Communication
Jordan-UK El Hassan Research Chair in Sustainability

South West England. A sprawling patchwork of forest and farmland hugging a heartland of granite moor and fringed by dramatic coastal cliffs and bay beaches. There is a sense of crossing time zones into a slower pace of life. A rural idyll perhaps. But certainly not a technological frontierland. And yet, beyond and below the wonderful ‘natural capital’ of Devon and Cornwall, a renewable energy revolution is brewing – the sleepy South West is emerging as the UK’s Natural Powerhouse.

Along its shores, the power of wave and wind are all too obvious. The nearshore waters have long been a testing ground for the deployment of new technologies such as wave and tidal energy, but now on the horizon is the exciting prospect of offshore wind. Wind farms are an integral (and contested) part of the region’s onshore landscape but that potential does not stop at the beach.

For the last decade, the UK’s renewable energy development target – now 40GW by 2030 – has focused on the North Sea. But now, as a marine energy infrastructure of interconnectors, oil and gas platforms and pipelines jostles with communications cables, mineral dredging, navigation and fisheries, seaspace in the UK’s eastern seaboard is at a premium. To satisfy the ambitions of our soaring appetite for clean wind power, we need to look to our less congested offshore areas.

The marine extent of Devon and Cornwall measures over 88,000 square kilometres – almost 10 times larger than the land area. The deeper seas of these Western Approaches do not allow for towering turbines to be anchored to the seabed, but instead require the deployment of new floating wind technologies. Deeper seas allow floating turbines to be sited nearer to shore (as close as 20km) and extend far offshore, accessing wind regimes capable of generating energy capacities of least 15GW and perhaps more than 50GW.

It may be that distant offshore Devon and Cornwall wind fields will find more acceptance among residents and visitors than equivalent developments on land. But, as in the North Sea, exploiting the physical power of offshore wind will potentially bring renewable energy development into conflict with the biological ecosystems that sustain fisheries and aquaculture and underpin marine conservation as well as other maritime activities and coastal communities. 

To grasp this challenge we need to reframe natural asset leadership and bring together sectors that don’t normally interact as a partnership, to deliver mutual benefit through sustainable development.

Map of the South West Regional Seas

Map of the South West Regional Seas

Onshore, the remnants of the region’s last great technological leap forward litter the land. Derelict engine houses and foundries are the visible signs of a vast underground network – adits, tunnels, drives and shafts – that delve deep into the metal-rich roots of the peninsula’s famous granite basement.

In the late 18th and 19th century these long-abandoned metal mines (copper, zinc, lead) fed Britain’s industrial revolution. That revolution ultimately ushered in the high-carbon fossil-fuel world of 19th and 20th century economic growth and led to the current climate crisis, but the same rocks may offer solutions for a transition to a decarbonized future.

Although Devon and Cornwall’s once molten Cornubian granite is several hundred million years old, it’s still hot down there. In fact, a few kilometres down are some of the hottest rocks in the UK, and the most promising geological conditions for generating a very different kind of renewable energy. Geothermal energy. Heat from the Earth.

Stoked by natural radioactive heat from the granite, scalding waters circulate through natural fractures. Deep boreholes can tap into these superheated groundwaters, bringing them to the surface to generate electricity and liberate their heat. Last year, the UK’s deepest onshore borehole was drilled near Redruth as part of the £30M United Downs Deep Geothermal Power project. At the bottom of the 5km deep well, the waters were at 188ºC – hot enough to drive a turbine and generate electricity. The UK’s first commercial geothermal power project has an agreement to offload around 4 MWe to the local grid. But this is just a start. Within the last month or so, deep drilling for geothermal energy has started at the Eden Project in Cornwall, with much of Cornwall and west Devon sharing that same geology.

The ancient granite powerhouse offers the promise of a new energy renaissance. But there is another, more direct, way in which deep geothermal waters can aid the ‘energy transition’ that is central to the UK’s ‘green recovery’.

Those subterranean thermal waters also carry a dissolved cargo of minerals, including the much valued lithium. The lightest known metal and lightest solid element, lithium is a critical component of the batteries used in electric vehicles. It is currently mined in only a handful of countries around the world but UK carmakers have three years to source local electric car batteries, following the Brexit free trade deal inked last year. So the hunt for lithium is on.

Sampled deep geothermal waters from United Downs indicate lithium grades described as “globally significant’. A local mining company, Cornish Lithium, plans to extract the battery metal from the thermal brines, as well as from more conventional rock drilling project near St Austell. Given this potential, it is possible that the UK could produce a significant percentage of its lithium demand domestically.

In a region in which mining is largely confined to the visitor attractions of UNESCO’s Cornwall and West Devon Mining Landscape World Heritage Site, this will have to be mining fit for the 21st century. And the reality is that our exploitation of the South West’s ‘hidden commons’ – whether far offshore or deep below ground – will be won or lost through public consent.

Learning from all that’s gone in the past, it will require the integrated, holistic management of competing – and, at times, conflicting – economic and environmental interests. It offers a unique opportunity to design and futureproof a new energy landscape, onshore and offshore, blending world-class research and jobs in science, technology and engineering with community-centred environmental and social governance. A Natural Powerhouse that is a genuine partnership of people and planet.

The Natural Powerhouse

Utilising natural resources to deliver clean growth and wellbeing, The South West Natural Powerhouse is an independent consortium formed from industry, academia and local government who work in collaboration to facilitate net zero in South West England.

Find out more about the consortium
Wheal Coates abandoned tin mine on Cornish coast at sunset. St Agnes. Getty

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The UN Climate Change Convention in 2021 – also known as COP26 – represented the largest coming together of world leaders to address climate change, and find real solutions. The race is truly on to slow climate change and protect our planet, improve global health and re-build post-pandemic economies through a green recovery.

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