Countries around the world are actively promoting green energy and Israel is no exception. The barren southern Negev Desert is a good place to develop solar energy. However, there is no sun at night, so a return to fossil fuel burning is necessary to generate electricity. If you want to use solar energy at night, you have to have a way to store energy.
Global energy storage technology start-up companies are like mushrooms after rain. As a country of start-ups, Israel is not lagging behind. Augwind Energy, an Israeli energy storage company listed on the Tel Aviv Stock Exchange with a market value of 1.2 billion shekels (approximately US$386 million), has launched a water-pump-type indirect compressed air energy storage system which is comparable with traditional wind cave compressed air energy storage that relies on natural or previously excavated mine pits and other geographically restricted spaces or man-made compressed air energy storage spaces that require expensive special above-ground structures. Augwind Energy uses steel channels laminated with a polymer interior buried in the ground, which can be scaled up according to planning and design.
Augwind Energy's technology uses indirect compressed air. When storing energy, electricity drives a water pump which injects water into a tank originally filled with air. The water pressure I used to slowly squeeze the air into a compressed air storage tank. Thus, pressure rises relatively smoothly. After the compression tank is filled with water, the water is emptied and air introduced. Then the process of compressing the air into the compression tank with water is repeated. When electricity is needed, the compressed air is used to drive water flow over water turbines to generate electricity. This can achieve more ideal storage and discharge efficiency than general compressed air energy storage, which is approximately 80%.
At present, mainstream energy storage is still performed with lithium batteries. Although lithium batteries have the advantage of quick uptake, it is not suitable for long-term transfer of large power currents because, as charge and discharge cycles increase, performance will gradually decrease. Therefore, numerous start-up companies have developed various physical energy storage technologies mainly for long-term large-scale energy storage requirements. For example, solar energy resources in southern Israel have the potential to supply all-weather electricity but electricity used at night must be stored during the day.
The small town of Kibbutz Yehel in the Negev Desert uses Augwind Energy’s compressed air energy storage to store solar energy during the day and use it at night as a test of its efficacy on the ground.
The energy storage cost of Augwind Energy is currently US$250 per kilowatt-hour of energy storage capacity and it is expected to fall to less than US$200 in 2022 as scale expands. Although competing with lithium batteries in terms of price is still quite difficult, the advantage of physical energy storage is that it can be used for a longer period of time without performance degradation or the need to replace a battery. Augwind Energy has raised a total of US$60 million from institutional investors so far and plans to install millions of units in the next five years.
（Image：TPG Images）