There is a high-stakes global race underway to unlock a long-term energy storage technology with the potential to corner what is sure to be one of the energy sector’s hottest new markets. Venture capital is catching on quickly to “clean energy’s next trillion-dollar business” and pouring billions into finding new and innovative energy storage solutions. 

Currently, the energy storage sector is dominated by lithium-ion batteries. Lithium is extremely energy-dense and performs exceptionally well in cold weather, making it “indispensable for high-performance applications” according to an August report from EV World. However, this technology also has some critical tradeoffs. Lithium production is associated with significant negative environmental externalities, and supply chains for this “white gold” are politically fraught thanks to China’s near-total dominance in the sector. Plus, critically, lithium-ion batteries can only store energy for about 4 hours in grid-scale applications.

Discovering a commercially viable long-term storage solution is therefore critical to maintain energy security in a rapidly changing energy landscape. Wind and solar power are the fastest growing energy sources globally, and even overtook coal in global energy mixes for the first time ever this year. This means that our grids are increasingly reliable on variable energies. 

Production levels of solar and wind power depend on the weather, the time of day, and the season, unlike the steady, market-directed production levels of energy from fossil fuels. Keeping grids stable with therefore require huge amounts of energy storage to balance out supply and demand. In other words, energy storage is the backbone of the renewable revolution.  

Balancing energy demand with renewable energy supply will require energy storage that is capable of storing energy for weeks, months, and even years. Excess solar energy captured in the summer, for example, could be fed into the grid in winter months when homes need heating but the sun is shining on solar panels for much shorter hours. Discovering a technology capable of such long-term storage while also delivering a profit is going to be a disruptor of gargantuan proportion. 

Potential solutions in current phases of research and development are extremely diverse in technology and scope. At present, pumped hydro represents more than 90% of the planet’s high-capacity energy storage, but building new pumped hydro facilities is extremely expensive and requires specific topographical conditions. It’s also a controversial approach, as the massive dams necessary for this technology can be ecologically devastating. 

Other innovators want to use pumped hydro systems, but channel them down into the ground at high pressures, to “use the Earth as a massive battery.” This approach could store energy for months at a time. Other underground methods include ??compressed-air energy storage, which could one day store energy in the approximately 3.9 million depleted oil and gas wells in the United States. 

A new long-term energy storage project is looking not under the ground or out in rural waterways for the next energy storage solution, but 40 stories up in urban centers. Researchers at Canada’s University of Waterloo are dreaming up new designs for high-rise buildings that include large photovoltaic installations and rooftop wind turbines as well as a complementary energy storage system including short-term lithium-ion battery storage and longer-term gravity storage.  

Gravity storage is gaining a lot of traction in energy storage research for its beautiful simplicity. Gravity storage systems could include anything from using excess energy to lift and then lower massive concrete blocks, to gathering the excess energy a vehicle generates when travelling downhill to help power it back up the hill. In the case of the University of Waterloo project, the gravity storage would be a rope-and-pulley system to lift a heavy mass such as a steel or concrete block. When energy is later needed, the weight is released to spin a turbine, creating electricity. 

The scientists behind this building model say that the mechanical principles are proven, and that modelling confirms its long-term financial viability. The only thing holding it back is capital and momentum. But they think that both are soon to come.

“Independent analyses suggest that commercial maturity in terms of bankable, mainstream deployment in developed markets outside China is likely around the late 2020s, pending a few years of operational data from current flagships,” the research’s lead author, Muhammed A. Hassan, recently told PV magazine. “At present, above-ground gravity storage is commercially proven at initial scale, but not yet at volume-discounted mass adoption. Sustained contracts and reliability performance over the next three years should move the status to full commercial maturity.”

By Haley Zaremba for Oilprice.com 

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