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 Breakthrough Commercial-Scale Borehole Thermal Energy Storage

A Breakthrough in UK Geothermal: Pioneering Commercial-Scale Borehole Thermal Energy Storage


In a recent LinkedIn post, Simon Todd, Managing Director of Causeway Energies, shared exciting details about a groundbreaking geothermal project that's set to make history in the UK and Ireland. This initiative isn't just another feasibility study it's poised to deliver the region's first commercial-scale Borehole Thermal Energy Storage (BTES) system, with installation planned for 2026.

The Project: Smart Replacement for Aging Infrastructure

The story begins with a local authority council building that already had a ground source heat pump providing underfloor heating in winter. Unfortunately, the heat pump was damaged by water, and aging chillers were struggling to meet summer cooling demands.

Causeway Energies conducted a Phase 1 feasibility study and proposed a brilliant, efficient solution: replace both the old heat-only pump and the chillers with a single reversible dual-pack heat pump unit. This advanced system uses the existing boreholes to handle both heating and cooling loads.

Why is this a "no-brainer"? The capital costs are similar to replacing the systems separately, but the new setup delivers much higher efficiencies for both heating and cooling. The boreholes act as seasonal stores of heat rejecting excess heat in summer for recovery in winter leading to payback periods as short as three years. It also eliminates the thermal depletion risk associated with heat-only ground source systems.

Why This Matters: The Power of Circularity and Storage

Todd emphasizes the "circularity" of thermal energy supply and demand. By storing summer cooling waste heat in the boreholes (or aquifer), the system creates a highly efficient thermal battery. This approach, known as Borehole/Aquifer Thermal Energy Storage (B/TES or ATES), provides benefits to gross energy use and peak electricity demand that simply can't be replicated by air- or water-source heat pumps alone.

This project stands out because, despite being straightforward and supported by an informed client, it will be the first commercial-scale BTES in the region. Once operational in 2026, it will serve as a powerful demonstrator for clients across various sectors.

Geothermal's Optimal Fit: Buildings with Balanced Loads

As Todd notes, "Geothermal works best when buildings have both heat and cool demands." Modern offices, public buildings, and mixed-use developments often have significant year-round cooling needs (from IT equipment, lighting, and occupancy) alongside winter heating. Pairing these with reversible heat pumps and thermal storage maximizes efficiency and return on investment.

Causeway Energies, a renewable energy company focused on geothermal heating, cooling, and storage, is leading this charge. Founded by industry veterans with decades of experience, the company specializes in innovative solutions like GeoBattery (storing waste heat) and hybrid systems tailored for the UK and Ireland's geology.

The Bigger Picture for UK Decarbonisation

Heating and cooling account for a massive portion of the UK's energy use and emissions. With rising cooling demands due to climate change and denser urban living, technologies like BTES and ATES offer strategic opportunities for energy management. They reduce peak grid strain, lower bills, and cut carbon,often with rapid paybacks.

While the Netherlands and Scandinavia have deployed hundreds of such systems, the UK has lagged. This Causeway project could be the catalyst needed to accelerate adoption, proving that geothermal isn't just for volcanic regions,it's viable and valuable right here.

As Todd concludes, A/BTES represents a strategic opportunity for energy management in the UK and Ireland. With demonstrators like this coming online in 2026, the future for affordable, secure, and clean geothermal heat looks brighter than ever.


If you're involved in building decarbonisation, district heating, or public sector energy projects, this is one to watch. Geothermal is moving from niche to mainstream,one smart council building at a time.

Source: Alphaxioms

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