Mercury’s $1 Billion Geothermal Expansion Signals a New Era for New Zealand’s Renewable Energy Future By: Robert Buluma Mercury Doubles Down on Geothermal Power New Zealand’s renewable energy transition has entered a bold new chapter after Mercury announced plans to significantly scale its geothermal platform with a potential investment of up to $1 billion. The announcement marks one of the country’s most ambitious geothermal expansion strategies in recent years and reinforces geothermal energy’s growing role as a reliable, baseload renewable power source capable of supporting future electricity demand. Mercury revealed that it will immediately commit NZ$75 million toward geothermal appraisal drilling at two major projects located near Taupō — Ngā Tamariki and Rotokawa. These developments could collectively generate an additional 1 terawatt-hour (TWh) of electricity annually, enough to power approximately 125,000 more homes across New Zealand. The projects are expected to t...
Cornwall Awakens the Earth's Power: The UK's First Geothermal Plant Lights Up – And Starts Making Green Lithium
UK's Geothermal Dawn: Cornwall Lights Up the Future of Constant Clean Power and Green Lithium Too
On February 26, 2026, a quiet but historic moment unfolded in the granite heartland of Cornwall. After years of vision, engineering grit, and one of the deepest holes ever sunk into British rock, Geothermal Engineering Ltd (GEL) flipped the switch. The United Downs Deep Geothermal Power Plant came online – the first time the United Kingdom has ever generated grid electricity directly from the Earth’s natural heat.
This isn’t another wind farm that stops when the breeze dies, or a solar array that goes dark at dusk. This is baseload renewable power: steady, weather-independent, always available. Up to 3 MW of constant electricity is now flowing enough to supply roughly 10,000 British homes sold under a long-term agreement to Octopus Energy. At the same moment, the same geothermal brines began yielding the UK’s first demonstration-scale production of low-carbon lithium carbonate. A single site is delivering two critical pieces of the net-zero puzzle: reliable green electricity and ethically sourced battery-grade lithium.
From Ancient Tin Mines to Modern Geothermal Breakthrough
Cornwall’s geological story has always been one of hidden wealth. Lithium was actually first identified in hot spring waters here back in the 1860s during the heyday of tin mining. More than 160 years later, GEL – founded in 2008 by geologist Dr Ryan Law – has turned folklore into industrial reality.
The United Downs project sits on an unassuming former industrial site near Redruth. Beneath it lie two deep wells drilled into naturally fractured granite: a 5,275-metre production well (deeper than Mont Blanc is tall) and a 2,393-metre injection well. Cold water is sent down, absorbs intense heat (over 190 °C – among the hottest geothermal resources ever tapped in the UK), returns as superheated brine, spins turbines through an Organic Rankine Cycle (ORC) system, releases its lithium, and is reinjected in a fully closed loop.
No smokestacks. No sprawling panels or turbines. Minimal surface footprint. Near-zero operational emissions. The elegance lies in its invisibility: the Earth does most of the work.
The £50 million journey was far from smooth. Early funding came via EU grants, later support arrived through UK government lithium innovation programmes, and patient private capital was provided by energy-transition investors Kerogen Capital and Thrive Renewables. Exergy supplied the specialised ORC turbogenerator optimised for medium-enthalpy resources. Air-cooled condensers eliminate water consumption. Every technical and financial hurdle was cleared to reach this day.
Dr Ryan Law described the achievement simply: after fifteen years of persistence through every difficulty imaginable, “we’re finally there.”
Why This Matters Far Beyond Cornwall
Most renewables are variable. Geothermal is different. It provides firm, dispatchable power that can run flat-out 24 hours a day, 365 days a year. Octopus Energy’s Greg Jackson called it a genuine game-changer: Britain now has access to “always-on” green electricity at scale for the first time.
After generating power, the brine unusually rich at over 340 ppm lithium, among the highest concentrations found in geothermal systems globally moves to an on-site processing unit. Using selective adsorption and ion-exchange technologies, GEL extracts battery-grade lithium carbonate with virtually no carbon footprint compared with traditional hard-rock or brine evaporation methods. The fluid is then returned underground, leaving no waste ponds or mining scars.
The demonstration phase already proves technical feasibility. Commercial scaling at United Downs will begin modestly but grow rapidly. GEL’s longer-term ambition is to reach up to 10,000 tonnes of lithium carbonate production per year by 2030 enough raw material for around 250,000 electric vehicle batteries annually, equivalent to roughly 65% of the UK’s entire 2024 battery-electric vehicle registrations. That volume would dramatically reduce Britain’s dependence on overseas lithium supply chains.
Cornwall as the Geothermal Engine Room of Britain
The county’s famous granite batholith holds enormous untapped potential. GEL has already identified and is advancing at least two more deep geothermal sites in Cornwall, with a combined target of another 10 MW of baseload power within the decade. Clusters of such plants could quietly supply data centres, industrial parks, district heating networks, and communities while co-producing lithium and other critical minerals.
The environmental advantages compound quickly. Geothermal produces near-zero emissions during operation. It complements intermittent renewables rather than competing with them. It creates high-skill local jobs in drilling, reservoir engineering, chemistry, and maintenance. And it revives economically challenged post-mining regions with 21st-century green industry.
Overcoming Obstacles, Opening a New Era
Deep geothermal isn’t cheap or quick to develop. Drilling kilometres into hot, fractured rock carries risks. Regulatory pathways are still maturing. Public familiarity with the technology lags behind more visible renewables. Yet United Downs proves the concept is viable in the UK context.
The awarding of the country’s first-ever geothermal Contracts for Difference (CfD) in 2023 provided crucial revenue certainty. Government appointment of a dedicated geothermal lead and continued innovation funding show policy is finally catching up with geology. Globally, deep geothermal investment is surging; Britain is no longer watching from the sidelines.
The Bigger Promise
Right now, turbines at United Downs are turning, quietly converting heat that has existed since the planet formed into electricity for homes across the southwest. In the same facility, lithium ions future passengers in electric cars that will glide along Britain’s roads without tailpipe emissions are being separated from ancient brine.
This single site demonstrates what becomes possible when bold engineering meets favourable geology and long-term commitment. Geothermal doesn’t ask the weather for permission. It doesn’t cover fields in panels or dominate skylines with blades. It simply taps what the Earth has always offered and turns it into modern power and materials with extraordinary efficiency and low impact.
The revolution began today in Cornwall. A deep well, a turbine, a lithium extractor, and a vision that refused to quit have switched on not just a power plant, but a credible new pathway for Britain’s energy and industrial future one rooted in the rock beneath our feet.
The ground has kept its heat for billions of years. Now we are finally putting it to work.
Source: GEL
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