What if you could pump almost endless electricity from the ground with only an investment of twenty million euros?
In Iceland, this can be realized if Krafla Magma Testbed organization plans are advancing from the magma power plant. It would utilize supercritical water heated in molten rock.
Last In recent years, there has been a lot of news from Iceland about threatening volcanic magma eruptions. This is not a surprise. Iceland is located on the mid-Atlantic ridge.
At the back, the continental plates of Europe and North America are moving apart at a rate of about 2.5 centimeters per year. From the resulting crack, hot magma from the Earth's mantle flows into the upper layers, sometimes up to the surface.
Fiery soil also has its advantages. More than 90 percent of Iceland's homes are heated from the ground with geothermal energy. About the electricity used in the country with geothermal about 30 percent is produced with energy.
Now there are plans for a new supercritical water power plant. It would take the utilization of soil heat to a new level. The most enthusiastic even talk about an “unlimited” source of energy.
Project started in 2009, when an Icelandic geological team did test drilling in the Krafla caldera in North Iceland. Caldera means a crater left by an extinct volcano.
The caldera is on top of the Mid-Atlantic ridge just mentioned. Geologists tried to find supercritical water there.
Supercritical water is the extreme state of water that only occurs when the water pressure is over 220 bar i.e. more than 200 times atmospheric pressure and temperature more than 373 degrees.
Supercritical water is not ice, liquid or steam, but the fourth state of matter between gas and water.
It is denser than steam but lighter than ordinary liquid water. Supercritical water even dissolves diamond. In a supercritical state, water can bind up to five times as much energy as ordinary water.
Water can reach such a state in the heat and compression of the deep earth's crust. Geologists assumed that they would find it at a depth of about 4.5 kilometers.
Drilling however, stopped after just over two kilometers. The hole did not stay closed and the drill bits started to melt at a temperature of more than 800 degrees.
Geologists soon realized that they had found a magma chamber full of molten rock at a depth of just over two kilometers.
Finding a magma chamber so close to the surface is a matter of quite a bit of luck. There is no reliable way to find magma chambers.
The exact temperature of the chamber could not be measured, but it is estimated to be over a thousand degrees. The chamber was also stable. Drilling did not lead to an eruption or earthquakes.
Although two kilometers may sound like a lot, when drilling into the ground it is by no means an exceptional depth. For comparison, for example, the test hole drilled in Otaniemi, Espoo, is more than six kilometers deep.
The magma chamber near the surface enables a completely new type of geothermal power plant. In that, the water would be heated above the magma chamber to supercritical.
Supercritical water could run turbines much more efficiently than current steam-based power plants.
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“Usually the holes are reinforced with steel pipes, but near the magma the pipes simply melted.”
At issue it would be the first time that an underground magma chamber would be used as an energy source for a power plant.
The purpose would be to start drilling the holes in 2026. Since the holes do not need to be drilled deep, the cost would also remain at a fairly moderate 25 million euros.
Geology leading expert of the research center Teppo Arola knows the Icelanders' plans and considers them feasible.
“Of course, there are plenty of challenges in the plans. For example, during test drilling in 2009, keeping the hole open proved difficult. Usually the holes are reinforced with steel pipes, but near the magma the pipes simply melted.”
Another question is whether the magma remains stable despite the holes. Pipelines suitable for treating supercritical water still need to be developed. However, Arola says the challenges are technical.
“From a natural science point of view, there would be nothing special about the power plant. That's why I believe in its realization, but it's hard to say anything about the schedule.”
A power plant utilizing supercritical water could produce electricity in principle indefinitely. There is no fear of hot magma cooling down even over hundreds of years. Electricity could even become an export product for Iceland, Arola thinks.
Already during Iceland's financial crisis fifteen years ago, it was considered running a power line from Iceland to Britain. Even if a loss occurs on a journey of more than a thousand kilometers, Arola does not consider it a problem.
“If you could get unlimited and practically free renewable electricity, waste wouldn't matter so much in the end.”
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