Electric grid balancing
Electric utilities must perfectly balance electric supply and demand on a second-by-second basis at all times to keep the electric grid functioning and to prevent power blackouts. The intermittency of sunlight and wind energy sources greatly complicates the job of guaranteeing a reliable supply of electricity on-demand. At present, electricity generated from fossil fuel can be used to balance the electric supply. In the future other methods of balancing the electric supply and demand are needed in order to achieve the goal of eliminating dirty fossil fuels and generating 100% of our electricity from renewable energy sources. Increasing use of electric vehicles in the future will add a large electric demand for EV battery recharging, but EVs can also make major contributions toward electric grid balancing.
Grid-scale electricity storage batteries are being installed to help balance the electricity supply. Vehicle grid integration can also enable electric vehicle batteries to help balance the electric grid when the vehicles are parked and plugged in for recharging. EV batteries that are too worn out for mobile use in vehicles still have enough storage capacity to be used for a while as stationary batteries to help balance the electric grid ("second use" EV batteries).
The electric smart grid of the future will also enable additional methods of grid balancing via communication between electric producers and electric users. Time-of-use rate plans provide customer incentives to avoid electric use whenever possible at times of peak demand. Many electric appliances (EV charging, refrigerator/freezer, air conditioner, etc.) can be designed to turn off briefly (demand response) to help avoid brownouts and blackouts. Smart appliances (e.g. clothes washer & dryer, dishwasher, etc.) could enable batches loaded at any time to be processed at a later time to avoid high electricity costs at times of peak demand (load shifting).
Special water heaters can act as thermal batteries for load shifting and balancing intermittent renewable energy generation in a smart grid environment.
Building an HVDC electric super grid would enable intermittent electricity sources over a wider geographic area to connect with a greater number of electricity users. Even when the local conditions are nighttime, cloudy and/or calm the HVDC lines would enable clean electricity to be delivered from faraway sources where sunlight and wind energy are available for electricity generation.