As the world becomes more reliant on variable renewable energies, energy storage is becoming an increasingly essential pillar of energy security. Currently, energy storage is dominated by lithium-ion batteries, but these hold energy for a matter of hours, when maintaining grid stability in a 100% renewable scenario will require energy storage technologies that can hold onto energy for a matter of months, if not longer.
Wind and solar energy, which are the fastest-growing energy sources in the world, are both variable forms of energy – meaning that their levels of production vary according to the weather, the time of day, and the seasons. To keep a steady flow of energy to and from our power grids, energy storage is necessary to capture excess energy when the sun is shining and the wind is blowing, and feed that energy back into the grid when demand outpaces supply. While short-term energy storage is highly useful in this capacity on a day-to-day basis, it can’t address deeper issues of seasonality and long-term weather patterns. In the words of PV Magazine, “low-cost long-duration energy storage has been the holy grail in making intermittent solar act like baseload thermal generation.”
Because of this, energy storage – and especially long-term energy storage – is becoming an increasingly critical market and exciting sector for innovative research and development. As of 2022, the energy storage system market size was valued at $198.8 billion. In the near term, Allied Market Research estimates that it will reach $329.1 billion by 2032, with a compound annual growth rate of 5.2% from 2023 to 2032. Indeed, energy storage is heating up to be “clean energy’s next trillion-dollar business,” and the competition to find a long-term storage solution is fierce.
There are a lot of different technologies vying to find the perfect recipe for affordable and scalable energy storage. One of the main contenders for long-term energy storage is pumped hydro storage, which uses pumps to transfer water uphill, where it is held until energy is needed. At this point, it’s released to flow downhill, rotating a turbine to create electricity. Pumped hydro is simple and already in use, but it has some serious downsides. Environmentalists in particular are divided on the issue, as energy storage is critical for 100% renewable grids, but massive dams associated with pumped hydro projects are their own form of environmental catastrophe.
Even hardcore fossil fuel backers are interested enough in long-term energy storage to pour some serious cash into potential unicorn startups – and one of those emerging darlings is Texan firm Quidnet Energy. Quidnet plans to “use the Earth as a massive battery” by pumping water at extremely high pressures into the ground, which it can hold onto for months at a time. This novel method is known as Geomechanical Energy Storage (GES) technology. They hope that this closed-loop twist on traditional pumped hydro storage will finally crack the code on cheap and reliable long-term energy storage.
And so far, the company’s testing is looking very, very promising. In fact, the Houston-based company says that its MWh-scale functional testing and accelerated lifetime testing indicate that GES can provide grid-scale energy storage over long timelines.
“Achieving this level of performance and scale marks a major milestone in our development of the GES technology,” said Joe Zhou, Chief Executive Officer of Quidnet Energy, in an interview with Power. “These tests confirm that our storage technology is ready for commercial deployments just as electrical grids grapple with the rapid rise in load growth from industrial electrification and AI data centers. With a mature, well-established supply chain and proven technology, we look forward to delivering GES at scale at a critical time for the energy industry.”