Our Natural Powerhouse: the South West is the UK’s hub for clean green growth

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.