Solving the Persistent Issue of Renewable Energy Storage Reserves
In a bid to combat climate change and reduce reliance on fossil fuels, Germany and the United States have set ambitious goals to transition to 100% clean energy by 2035. However, the intermittent nature of solar and wind energy poses a significant challenge.
To address this variability problem, engineers worldwide are focusing on three main strategies. First, they are advancing technologies such as hybrid wind-solar systems, which complement each other's intermittency, ensuring a more continuous power supply. Second, they are developing advanced forecasting using AI and foundation models to predict solar and wind outputs more accurately. Third, they are innovating in solar technology, such as perovskite/silicon tandem cells for higher efficiency and bifacial panels to capture more sunlight.
In addition, efforts are being made to develop long-duration energy storage technologies. While specific technologies for mature, cost-effective solutions were not detailed, the broader context includes vigorous global efforts towards developing battery storage systems scaled to multi-hour or multi-day storage durations, exploring thermal energy storage, hydrogen, and other chemical storage methods, and integrating energy management schemes that combine forecasting, hybrid generation, and storage.
One such long-duration energy storage technology is the pumped thermal energy storage system, tested by Zhiwei Ma of Durham University. This system uses electricity to compress a gas, like argon, to a high pressure, heating it up; electricity is generated when the gas is allowed to expand through a turbine generator. Ma is optimistic that with more research, such thermal storage systems could help with daily storage needs.
For longer-duration storage - over weeks - many experts put their bets on hydrogen gas. Sodium-ion batteries are also being developed as a cheaper alternative to lithium-ion batteries, which remain costly due to their design and the price of mining and extracting lithium and other metals.
Compressed-air storage systems, such as those developed by Hydrostor, store electricity by compressing air and then stashing the air in caverns. Hydrostor plans several much larger facilities in California and is building a 200-megawatt facility in the Australian town Broken Hill.
Another long-duration storage technology is flywheel technology, which uses electricity to spin large steel discs and can store energy for weeks. However, they are most cost-effective when used at least daily.
In Germany, renewable energy generation fell to less than 30% of the nation's total in nearly a week in January 2023. To pick up the slack, gas-, oil-, and coal-powered plants were revved up. Solving this problem requires reimagining how to power our world, moving from a grid where fossil fuel plants are turned on and off in step with energy needs to one that converts fluctuating energy sources into a continuous power supply.
A carbon tax on fossil fuels, as suggested by Anne Liu of Aurora Energy Research, could make storage technologies more economical. However, the challenge is to avoid blackouts without turning to dependable but planet-warming fossil fuels.
In July 2023, Germany's solar and wind power plants produced more than 70% of the electricity generated in the country for nine days. Yet, wind turbines were turned off to avoid overloading the grid during this period.
Hydrogen and its derivatives are already being explored as fuel for ships, planes, and industrial processes. The first commercial compressed-air storage facility was launched by Hydrostor in 2019 in Goderich, Ontario.
In conclusion, the main strategies involve combining improved prediction and grid management via AI, deploying hybrid renewable setups, advancing more efficient solar and wind technologies, and actively developing diverse energy storage technologies to buffer and balance the intrinsic intermittency of solar and wind energy. These approaches together aim to create a reliable, cost-effective, and sustainable renewable energy infrastructure globally.
Investments in the renewable-energy industry, particularly finance for long-duration energy storage technologies like pumped thermal energy storage systems and hydrogen gas, are crucial to addressing the intermittent nature of solar and wind energy. Leveraging technology, such as AI for forecasting and hybrid wind-solar systems for continuous power supply, can help combat this variability in the renewable-energy sector.
