Frequently asked questions

How proven is geothermal energy?

It is already highly successful, especially in countries like Iceland where it heats 85% of all homes and provides virtually all of the country’s electricity. However, the ready availability of very hot water in many parts of Iceland makes it relatively easy to exploit at a level not possible here. The potential of geothermal energy is still largely untapped in the UK, although it is already in use in Cornwall. Plans are in place to sell power from it to the National Grid, and there are geothermally heated community swimming pools in Hayle (www.hayletowncouncil.net/your-council/outdoor-swimming-pool/) and Penzance (https://jubileepool.co.uk/). If successful, this project will be a first for Ryedale. It would also be the very first example in the UK of oil and gas wells being repurposed for the community use of renewable energy.

How could geothermal energy work locally?

Nine of the 12 wells in Ryedale are already linked by a pipe network, which means that hot water from some or all of them could be used for a district heating system for houses which are near enough. There would be three aspects to this:

• A micro energy centre (2m by 2m) at each well, with heat exchangers and pumps to ensure a steady flow at the right temperature.

• A heat network from wellhead to kerbside throughout the villages involved, supported by distribution pumps.

• Heat pumps at each property to bring the heat up to the required temperature, connected to the kerbside network.

The Committee on Climate Change estimates that around 18% of UK heat will need to come from heat networks by 2050 if the UK is to meet its carbon targets cost effectively. To make the geothermal heating easy to provide for commercial users, another option would be to construct buildings or facilities next to or on top of wells – such as greenhouses, holiday accommodation or swimming pools.

What is the engineering involved?

There are three possible ways of managing water-based geothermal energy:

• Open loop transfers heat from abstracted groundwater via a heat exchanger. A heat pump may also be used, depending on the temperature and flow of water. The used water is then disposed of back underground. PK1 and PK2 are the most suitable for this option ; taking water from one well and returning it via the other.

• Deep coaxial wells take warm water from depth through an insulated pipe, pass it through a heat exchanger and return it to the well after the heat has been used aboveground. A heat pump is normally needed to deliver a constant temperature. KM8 is predicted to have the highest output of wells using this method, as it has a base temperature of approximately 90 degrees Celsius.

• Closed loop can be an option for shallower systems, but there are practical and efficiency issues associated with circulating the water within a continuous pipe at depths over 300 metres. The depth of Ryedale's wells mean that this option has been ruled out.

Does this mean the end of any idea of fracking?

Fracking is already off the agenda in Ryedale and won’t be happening. The local wells are operated by Third Energy. The company has new owners and has committed to moving away from fossil fuels to renewable energy. This is reflected in the feasibility work now underway.

How realistic is this in Ryedale?

The feasibility studies currently underway have been commissioned specifically to answer this question. Early indications are encouraging, but more detailed work needs to be done to identify how many of the local wells could realistically be used, and how. This includes assessing:

• Water temperatures underground at the well bases (in some cases, more than 3km deep)

• The technical challenges of getting it to the surface

• How best to capture, distribute and use the heat provided

• Methods for returning the water to the ground afterwards

• Financial aspects, including developing a business model for the wells

What would the benefits be?

Geothermal energy provides a long lasting, low carbon solution to commercial and domestic heating. No emissions are emitted from geothermal heat and the distribution process uses low amounts of electricity which can be generated by renewables. Geothermal has the potential to bring a cheaper and more efficient alternative to fossil fuels. The scheme also has the potential to support both the local economy – increasing visitors to the area in a green and renewable way, and offering new opportunities for farmers.

Is it safe?

Yes. The process of extracting water and then returning it to the ground rock in a controlled way is well proven.

If I sign up for this geothermal energy, what would it cost?

At this early stage, it’s not possible to give precise figures. The current volatility in gas and oil prices also makes it difficult to make accurate comparisons. There would be some costs for the installation of new systems, but the potential savings for households in a heat network could be hundreds of pounds a year.

The Council is keen to hear from anyone interested in finding out more.

When could this happen and how long will it take?

The intention is for the feasibility studies to finish before the end of 2022. However, further modelling will then be needed, and it is likely to be some time before a geothermal energy system is up and running in Ryedale. If the idea does proves viable, the wells could provide clean green energy for at least 30 years.

What will be the impact on our countryside/neighbourhood?

The feasibility work does not require any major engineering or heavy equipment, so the impact will be minimal. If shown to be viable, a geothermal energy system would require a two-metre by two-metre micro energy centre at each active well, to house heat exchangers and pumps. Should a local heating network prove feasible, underground pipework would also need to be installed, to carry hot water to the communities involved.

Would I need to install anything in my home or business, to make geothermal energy work?

Geothermal energy would be provided by pipes to homes, where it could be used to heat rooms (by radiators or underfloor heating) and water. Depending on the existing systems in each property, new system may need to be fitted. Government funding towards low carbon heat networks is currently available and would be applicable for this type of installation.

Have there been any wells repurposed in other countries?

Yes, the USA currently have projects where they have been repurposing oil and gas wells for geothermal heat. In France, there are examples of oil wells that produce a lot of heated fluids being used for community heating and in the Netherlands, there are a few examples of redundant gas wells being used for greenhouse heating.

Are there any downsides or risks in the technology for neighbours to the wells?

As we are currently in the feasibility stage, it is too early to give a definitive answer. However, with the information we currently have, if the project proceeds there would be a period of works which would increase footfall in the area during the construction of the heat network and retrofit of the wells. Similar to any infrastructure project, this would cause minor disruptions in the flow of traffic and there may be some construction noise during this period.

The geothermal system will need minimal maintenance. The building which contains the system will be small and screened from view and noise levels in the area will not be impacted. Depending on the off-taker of the heat source, local residents may not notice any changes, other than being able to opt into a green heat network to heat their homes.

What is the impact on the current infrastructure and the cost benefits?

Geothermal is a long-lasting renewable heat source which will not be impacted by international fossil fuel markets, making it sustainable economically as well as environmentally. By introducing geothermal heat to the area, it has the potential to bring in investment to local infrastructure and supply a reliable cost-effective renewable heat source for the long term.

How many properties do you need to make it profitable?

This is yet to be determined, feasibility studies will give us more insight to be able to answer this question in the future.

Can you generate power from the wells as they do in Iceland?

No, our wells are between 50-90°c, this is sufficient to create heat networks, but not sufficient enough to create electrical power.
The minimum heat required to generate power is c.100°c however, most geothermal power stations are 250°c and above.

Would there be incentives to convert to geothermal energy?

It is too early to give a definite answer but, it is expected that schemes such as the Green Homes Grant would be used, or depending on government funding, project specific incentives may be a possibility.