What About Batteries?
Improving battery technology can help solve the energy storage question.
One of the main obstacles to widespread use of wind and solar power production is nature itself: The wind doesn't always blow, and the sun doesn't always shine. But work is under way to develop technology aimed at storing excess energy for when it's needed most, including when the wind isn't blowing nor the sun shining.
The U.S. Department of Energy forecasts that energy storage will significantly change the electric grid. With it, the nation could possibly create an electricity "stockpile." Until then, improving energy storage systems will help make renewable generation sources more reliable and operationally feasible — a critical step as the U.S. develops ways to create a more diverse energy production portfolio.
Another advantage of battery storage systems: They improve power quality and can cut down on blinks — those momentary service interruptions that force you to reset your digital clocks. If enough energy is stored, power could continue to flow to homes and businesses during such an event.
The state of storage today
Battery storage systems, first developed in the 1970s, have become more viable on a large scale thanks to recent chemistry breakthroughs that increase the longevity while lowering the cost of batteries. If battery energy storage at the utility level can be made commercially and economically viable, it could address issues related to America's aging electric grid.
Although they would be a big investment for any electric cooperative, benefits of battery storage exist beyond leveling out renewable energy supply.
"Well positioned and properly managed battery storage systems can delay the need for building expensive transmission lines that are difficult to site and get permits for in the first place," says Dale Bradshaw, a senior program manager with the Cooperative Research Network, the research and development arm of the National Rural Electric Cooperative Association.
At present, the largest-capacity form of energy storage is pumped-storage hydro — a hydroelectric plant that generates power by using water previously pumped to an elevated reservoir during off-peak hours, when electricity is less expensive. Another option, compressed-air energy storage — power plants "fueled" by air pushed into an underground cavern during times of low electricity consumption — has received more attention because it can be expanded relatively cheaply.
Pumped-storage hydro and compressed-air energy storage facilities generally operate when electricity use soars. But geography and environmental concerns limit where they can be located.
That means development of better batteries could be the key to wide use of energy storage technologies.
Before central station electric service came to rural America via the electric cooperative movement in the 1930s, farmers used "battery sets" that were recharged with windmills and ram pumps. Like conventional sealed lead-acid car batteries, those batteries could go through only a limited number of discharge-charge cycles before they were exhausted.
Today, developers are aiming for batteries that can function through 80 percent discharge for 10,000 cycles — allowing for longevity of three decades or more.
"If you're supplementing wind or solar, you're going through a complete cycle on a daily basis," Bradshaw says. "In other words, a long cycle life remains key."
While we still have significant work to do, electric cooperatives continue to invest in research to make battery technology work for our needs today and in the future.