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Rocks of the North Sea could be used to store renewable energy

Posted January 25, 2019

Renewable power is great. Wind, tide and river energy can be harnessed quite effectively these days, but there is a problem. Wind doesn’t always blow when we consume the most energy. Sun is also gone at night, when we turn on the lights. So the periods of peak energy consumption of peak renewable energy production do not always overlap. That is why scientists are looking for green energy storage solutions and North Sea rocks could be one of them.

There are several big wind farms in the North Sea – energy from them could be stored in the seabed rocks for months. Image credit: Phil Hollman via Wikimedia (CC BY 2.0)

Engineers and geoscientists from the Universities of Edinburgh and Strathclyde conducted a research, which revealed that rock formations found in the North Sea off the UK coast are porous enough to be used for energy storage. Of course, using rocks to store energy sounds quite difficult to believe, but scientists have an idea. They used mathematical models to assess the potential of the process, called compressed air energy storage (CAES). Essentially, porous rocks would be pumped with compressed air, which could later be released to drive a turbine to generate large amounts of electricity.

Scientists estimated that the process could be scaled up quite a bit, aiding to meet the UK’s electricity needs during winter, when demand is highest. Of course, air would be compressed into the seabed rock using the renewable energy that is not needed at that specific moment due to low consumption. In this way rocks could be storing energy for months. Scientists estimate that these porous rocks in the North Sea could store about one and a half times the UK’s typical electricity demand for January and February. Of course, this technology doesn’t even exist yet, but something similar has been used in deep salt caverns in Germany and the US.

The basic principle is actually quite simple. They would have to drill a deep well into the sandstone of the North Sea. At this place they would a specialized plant, which would be powered by renewable energy and would pump air into the well. This compressed air could be stored for months and could be released to power a turbine in order to produce energy when demand is higher. Dr Julien Mouli-Castillo, one of the geoscientists behind this study, said: “This method could make it possible to store renewable energy produced in the summer for those chilly winter nights. It can provide a viable, though expensive, option to ensure the UK’s renewable electricity supply is resilient between seasons. More research could help to refine the process and bring costs down”.

Essentially, this would make renewable energy a bit more practical and, potentially, cheaper. However, we will have to wait and see how expensive such project would be. Also, only experiments can truly reveal if it is possible at all to reliably store compressed air in the rocks of the North Sea.

Source: University of Edinburgh


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