Keeping geothermal operations sustainable and safe
While Earth has been cooling down since its formation, the intense temperatures at the centre of our planet continue to heat the inner crust. When this heat comes up to the surface carried by water or steam, it can be harnessed and used for heating, or to generate clean electricity. “There is so much energy under the ground,” says EASYGO project coordinator Maren Brehme from ETH Zurich in Switzerland. “The deeper you go, the hotter it gets. You also don’t need a lot of space on the surface for a geothermal plant compared to solar or wind energy.”
Challenges to exploiting geothermal energy
Nonetheless, geothermal power is not as advanced as other forms of renewable energy. This is something that the EASYGO project, supported by the Marie Skłodowska-Curie Actions programme, sought to address. “There are three basic challenges to exploiting geothermal energy,” explains Brehme. “The first is knowing where these geothermal resources are, and whether there are water channels to transport the heat.” The second challenge is accessing and extracting this energy. Two boreholes are always needed to create the geothermal energy cycle – one to extract water and take off the heat at the surface, and the second to reinject the cooled water into the Earth for reheating. This can be very expensive. The EASYGO project focused on the third key challenge – keeping geothermal operations sustainable and safe. Injecting water into the Earth can change pressure and temperature, sometimes leading to seismic events. Geothermal fluids can also be affected by these changes, causing geochemical reactions within the subsurface and surface infrastructure. Clogged pipelines, heat loss and other operational disruptions can lead to the closure of plants.
Safety and efficiency of geothermal systems
EASYGO brought together 13 PhD students to propose new system components, monitoring concepts and operational techniques to enhance the safety and efficiency of geothermal systems. “Our approach was to try and find preventive solutions to potential problems,” adds Brehme. “Each of the students worked with two universities and an industry partner.” Students worked on developing measuring techniques to detect cold waterfronts, as well as methods for removing heat at the surface more efficiently. New ways of monitoring seismic events were also developed and predicting the risk of clogging. “This work is important because we need geothermal plants to be close to people and cities,” explains Brehme. “Transporting heat over long distances is not possible, so we need to build plants where the demand is.” Detecting problems early means that plants can operate safely, and better control their operations. Action can be taken in time to avoid major disruptions. “Taken together, these innovations represent a major advancement,” says Brehme.
Holistic view of geothermal energy
Education has been another significant legacy of the project. A training week was held every year at one of the participating universities, with industry partners also involved. The goal of these weeks was to provide students with a holistic view of geothermal energy. “You need to know about chemistry, physics, geology and mathematics to understand geothermal energy,” notes Brehme. “These training weeks have become a permanent feature and have continued since project completion.” Many participating students have since been hired by industry and are currently working on putting their ideas into practice. “Industry knows that these graduates come with knowledge and training,” adds Brehme.
Keywords
EASYGO, geothermal, energy, sustainable, electricity, Earth, solar
