Technological progress could multiply quinque geothermal production

Well under the surface of the earth is an energy source with enormous and perpetual potential: geothermal heat. But forces in its hot and inhospitable depths must be tamed. Now scientists know what it will take.

“Underground deep, we find temperatures of more than 1,000 ° C, which can be converted into renewable energy and almost Co₂-free. This geothermal heat is also independent, available and stable 24 hours a day. “

These are the words of Hieu Nguyen Hoang, a main researcher at Sintef. He is one of the technologists that have undertaken danger of the inhospitable conditions deep in the earth.

Geothermal energy could become an extremely important source of energy that the world desperately needs more, because we accelerate change towards greener and more renewable energies. However, it is currently producing numerous greenhouse gas emissions.

Until now, the potential of Geothermal energy has been relatively unexploited, with less than 3% of world energy currently from geothermal heat. High costs and high energy production associated with drilling are the main reasons for this.

We must be able to break into temperatures high enough for profitable electricity production, because the more we get the heart of the earth, the more hot it becomes.

At least an increase in five -year efficiency

New technological progress brings us closer and closer to the objective.

Iceland is already on track to take advantage of the country’s unique geological conditions. Today, 99% of Icelandic electricity comes from renewable sources and geothermal energy is an important part of the energy mixture.

The Iceep Drilling (IDDP) project is research and development project who studied how to create well who can resist both high temperatures And the porous geological training of Iceland for several years.

The objective is to pierce towards “supercritical water” – a state of water that occurs when the temperature exceeds 374 ° C and the pressure increases the air pressure on the surface to 218 times. These extreme conditions produce five to ten times more electricity than traditional geothermal energy.

“Supercritical water, with its higher energy density, offers a unique opportunity to produce electricity. Luter this resource could revolutionize geothermal power And make it one of the most effective renewable energy sources, “said Hoang to Sintef.

IDDP partners come from several countries, including Equinor, Norway International Energy Company. They worked to find solutions thanks to two previous projects. So far, they have not succeeded.

“The first conditions of overheating well affected, and the second has reached supercritical conditions at a depth of 4,650 meters. However, the two wells experienced failures due to inadequate housing systems in the external wall of the well,” explains Hoang.

New super well

Now, a new IDDP project is underway: the Compass project resumes where its predecessor, Hotcase, has stopped. The objective is to build a new well which can resist both high temperatures and porous geological formations. At the same time, costs must be maintained as low as possible, so that the project is profitable and more sustainable.

“Corrosive fluids, extreme pressures and geothermal constraints are difficult challenges for the design of wells. Innovative solutions are essential to ensure the integrity and longevity of geothermal wells”, explains Hoang.

Sintef is responsible for the development of the simulation tool for the well. Reykjavik Energi is responsible for drilling what will be the third well of the IDDP project. With its subsidiary on power, they prepared for the task thanks to several research projects. The objective is to set new standards for good design with the help of an international team of experts.

Must resist “everything”

The extraction of geothermal energy occurs by water in the tank which flows into the well and to the surface. Porous formations with their natural cracks allow water to move in training. The challenge is to ensure the integrity of the well over time and in the extreme temperature and pressure conditions that exist in these geothermal environments.

Researchers from the Compass project will develop technology to provide a stronger and more flexible well that can manage extreme conditions. This includes the development of stronger and more flexible outdoor walls, called coils, to reduce thermal constraint. The project will also focus on innovative conceptions of corrosion resistant wells.

“Using a laser, we will apply a protective layer on the hose that resists corrosion and can withstand high pressure and corrosive liquids,” explains Tèrence Coudert, researcher and colleague from Sintef.

A technological crystal ball

Sintef has developed an advance simulation tool Called Casinteg, and this technology could completely change the design of geothermal wells, according to the researchers behind.

By simulating and extracting well data, the tool makes it possible to identify which types of physical phenomena occur in the depths of the earth. Simulation also provides information on chemical reactions and what materials are necessary to create a flexible structure.

“The tool is absolutely essential and is an important result of the previous hotcase project and the current Compass project. It provides us with rapid forces in the well and what the structure can resist, so that we can continue to develop technology and reduce costs,” explains CoudeT.

In the previous project, the tubing system quickly suffered damage in super hot conditions. The result was that the researchers were unable to measure the conditions in the well or carry out the planned tests.

“Our experience of the first IDDP wells shows how important the housing system is, so that the outside wall can hold,” explains Hoang.

Possible reuse of previous wells

According to researchers, geothermal energy could play an important role in the global energy transition and become a reliable and versatile alternative to traditional renewable energies.

However, geothermal energy is more than a renewable energy source: it also has the potential to play a key role in a circular energy economy. By reusing wells for carbon capture, thermal energy storage or hydrogen production, geothermal projects can prolong their life cycle and minimize their environmental impact.

“Our objective is to create wells with a lifespan of more than 30 years which can be adapted to future applications and conditions,” explains Lilja Tryggvadóttir at Reykjavik Energy.

“We also explore the possibilities of reusing and renovating old wells and extracting the energy from deeper resources,” she says.