Solar power will become a bigger part of the world’s electric supply, particularly as the world works to stem climate change. While it’s an inexhaustible, clean and renewable energy source, it will still pose challenges to the world’s electric grids. New research from MIT and the Institute for Research and Technology (ITT) at Comillas University in Spain looked into what that will transition will require—it won’t be simple or straightforward.
The study, part of the MIT’s “Future of Solar Energy” research, found that the transition will require strengthening existing equipment, modifying regulations and pricing, and developing critical technologies. “One of the big messages of the solar study is that the power system has to get ready for very high levels of solar PV generation,” Ignacio Pérez-Arriaga, a MIT visiting from IIT explained. One of the keys will be developing low-cost energy storage technologies at large scale.
“Without the ability to store energy, all solar (and wind) power devices are intermittent sources of electricity,” MIT said. The institute said the intermittent nature of the resources—particularly from distributed generation delivers energy to a system designed to deliver but not receive electricity. It also requires other power plants to operate in ways they weren’t built for. New equipment will be needed, adding costs to the grid in some situations.
“In some situations, the addition of dispersed PV systems reduces the distance electricity must travel along power lines, so less is lost in transit and costs go down,” MIT said. “But as the PV energy share grows, that benefit is eclipsed by the need to invest in reinforcing or modifying the existing network to handle two-way power flows. Changes could include installing larger transformers, thicker wires, and new voltage regulators or even reconfiguring the network, but the net result is added cost to protect both equipment and quality of service.”
Energy storage will help reduce some of those costs, according to MIT. When solar energy reaches 30 percent of the grid’s energy supply, storage could reduce added costs by one-third in Europe and half them in the U.S.
“That doesn’t mean that deployment of storage is economically viable now,” Pérez-Arriaga cautioned. “Current storage technology is expensive, but one of the services with economic value that it can provide is to bring down the cost of deploying solar PV.”
The study outlines other issues that will face the world as more solar energy comes online. Net-metering policy in the U.S., for instance, can force non-solar customers to pay for solar customers. In addition, higher amounts of solar energy on the grid will require power plants to ramp up production quickly as the sun goes down, which means gas-fired power plants will be key while energy storage is added. The study said gas-fired plants are more expensive than coal or nuclear but in the U.S. gas is now cheaper—and cleaner—than coal.Tweet