Why Geothermal?

What is Geothermal?

At its simplest, geothermal uses the earth’s subsurface to provide heating, cooling and, in the right conditions, energy generation.

Although the UK doesn’t generally have the high subsurface temperatures found in countries such as Iceland, to be used for energy generation, geothermal is still an abundant resource across the UK to provide heating and cooling for homes, businesses, industry and heat networks.

In almost any location, heat can be extracted from the ground (or from a water body, or from the air) and raised to the required temperature with a heat pump, providing a low-carbon, stable and local resource. When cooling is required, the waste heat can be stored in the ground for when it is needed, enhancing efficiency and cost savings.

Continuous, controllable, and secure
More affordable than air-source, water-source and all other low-carbon heat sources
Delivers water at stable temperatures year-round providing predictable and resilient price for the long term insulated from volatile energy prices
High generating efficiencies results in minimal grid electrical requirements
Underground thermal energy storage to store and recycle waste heat from cooling demands
Very low visual and noise impact
No local air pollution
Supports a localised circular energy market benefitting the local economy and creating jobs

Types of Geothermal

As an independent consultancy, TownRock consider all types of geothermal (and other low carbon) technologies to meet the needs of our clients. In brief, these fall into shallow ground-source systems, mine water systems, and deep geothermal. A low-carbon counterfactual, such as air-source, is always compared so the client knows they are choosing the best solution.

Closed-loop Ground Source

A closed-loop ground source system will typically consist of a collection (“array”) of vertical boreholes.

The number of boreholes, their depth and optimal arrangement will be informed by the rock properties and the heating (and cooling) demand.

The boreholes are installed with a plastic U-tube pipe through which a water-based working fluid is circulated, exchanging heat with the rocks via conduction. If needed, the temperature is upgraded with an efficient water-to-water heat pump, and the heat delivered to the users heating system.

Mine Water

Mine water source systems extract water from abandoned and flooded mine workings, making use of the naturally heated water stored in the mines.

The subsurface side of the system includes at least two boreholes into the mine workings, for abstraction and reinjection.

At surface, the mine water will be passed through a heat exchanger to transfer heat to a clean working fluid. The temperature is then efficiently boosted by a water-to-water heat pump to the users desired temperature.

Deep Geothermal

Deep geothermal systems utilise high temperature groundwater abstracted from water-bearing rocks (“aquifers”) at greater depths below the site.

A doublet comprising at least one abstraction and reinjection borehole circulate water from the rock to the surface and back into the rocks. Due to the higher subsurface temperatures at these depths, a water-to-water heat pump may not be required to reach the users desired temperatures.

Can Geothermal work for me?

We will be delighted to help you to answer that question. In order to do so we will consider your heating and/or cooling demands, understand the geology beneath your location, and understand your energy needs. We will advise which option(s) will best meet your needs and recommend the next steps to progress with your project.

If you’re interested in an initial discussion, please get in touch here