New project to explore whether Taranaki's old petroleum wells could heat its energy future
Ara Ake is leading and funding a project exploring whether hundreds of suspended and shut-in petroleum wells in the Taranaki region could be repurposed as practical, cost-effective and low-emission heat sources for industry, buildings and communities, before they are permanently abandoned.
“Industrial heat users need reliable, affordable alternatives to oil, gas and coal, and geoheat is uniquely placed to help deliver that. We don't yet know if developing geoheat using Taranaki's petroleum wells, rather than drilling new ones is commercially viable, but finding that out is exactly what Ara Ake exists to do, for Taranaki and for New Zealand,” says Sophie Braggins, Ara Ake Chief Executive.
The geothermal resource being explored is called geoheat, and is less than 120°C. This type of heat is best suited for direct heating (or less commonly, cooling) uses such as industrial process heat, space heating for factories and buildings, district heating schemes, horticulture and swimming pools.
Project lead Evelien Wallace says six decades of petroleum development is beneficial to the project.
“Drilling a new geothermal well is typically the largest single cost in any geoheat project, and the biggest technical risk is being unsure of the heat and water flow underground. Repurposing wells that are already in the ground, and drawing on data that has already been collected, significantly reduces both the cost and risk of development,” says Evelien Wallace, Ara Ake Senior Energy Innovation Manager.
“The real innovation here is in how we think about legacy assets. Just as bioenergy has reframed waste as are source, we need to reframe legacy infrastructure the same way, and ask if it can contribute to a greener, more sustainable energy future.”
Other countries such as the United States, India and across Europe are also grappling with the future of their petroleum structure, and this project is working alongside a growing international body of work.
Ara Ake commissioned a scoping study and baseline review of relevant literature and international projects, which were recently completed by Earth Science NZ and GeoExchange and technical expert GLS Consulting.
“We are working with key stakeholders and experts to decide which opportunities we want to progress further. Developing bespoke work programmes for these opportunities will help us unpack the value they may provide, as well as what roadblocks there may be, and if these can and should be overcome,” says Evelien. “No matter what we find with this project, we believe Taranaki will be better placed to develop geoheat regionally, based on the legacy of our petroleum past.”
Find out more about the Taranaki Geoheat Discovery Challenge here.
The image above is from the scoping study and shows the modelled depth to a defined temperature for the Taranaki region.
Left, modelled subsurface depth at which 30ºC is reached and the image on the right shows the modelled subsurface depths at which 80 ºC is reached, both show the locations of key Taranaki heat users.