It’s going to take reliable, durable, safe, and, most importantly, less expensive batteries before wind and solar power can be viable, according to report from researchers at the Energy Department’s Pacific Northwest National Laboratory. The researchers examined four stationary batteries considered the most promising and outline what technological advances are needed to make each economically feasible.
Vanadium redox flow: A rechargeable battery that stores electrical energy is two tanks of electrolytes. When energy is needed, liquid id pumped from one tank to another. When energy needs to be stored, this process is reversed. It could provide backup energy for up to 12 hr and would work with wind or solar power in neighborhoods or industrial sites. To be marketable, engineers must determine how to make the device in a variety of sizes, make it portable, and bring down the price.
Sodium-beta alumina membrane battery: A rechargeable tube-shaped battery with elements such as sulfur combined with sodium ions layered in aluminum oxide in the battery's core. It could store lots of energy in a small space, and its energy density and rapid rate of charge and discharge could let it power electric vehicles and other applications that require short, high bursts of energy. However, materials are expensive and there are safety concerns with the battery’s high operating temperature of the battery. Changing the shape of the battery could improve efficiency, lower the operating temperature, and reduce the cost.
Lithium-ion, or Li-ion batteries. They store electrical energy in various compounds comprised of layers of different elements, such as lithium, manganese and cobalt. In the battery, positively charged lithium ions move through a liquid electrolyte while electrons flow through an external circuit, both moving back and forth from one side to the other. This movement creates and stores energy. High energy and power capacity have made Li-ion batteries the most promising option for electric vehicles. But making them larger makes them too expensive and prone to overheating and electrical shorting. So bringing down materials cost and improving safety would vastly improve Li-ion batteries. In the future, they could serve as back-up storage on the grid.
Lead-carbon batteries: These evolved from traditional lead-acid battery. Engineers discovered that adding carbon increases battery’s lifespan. The cost of these batteries remains at $500 per-kwh, which must be reduced to between $150-$200 per-kWh to be viable. These batteries could serve back-ups for wind and solar power based on their concentrated power.
For more details, go to the Chemical Review. (Warning: They may want a fee or registration to enter site.).