Accommodating high levels of variable generation
As reinforced throughout a recent report supported by Sandia National Laboratories on behalf of the U. Department of Energy’s (DOE) Office of Electricity Delivery and Energy Reliability and the Office of Energy Efficiency and Renewable Energy Solar Technologies Program, energy storage is a viable solution to our renewable energy needs. There is general agreement that at low levels of variable generation, there will be minimal disruption to utility operations and negligible curtailment of the renewable resource.“Investment in energy storage is essential for keeping pace with the increasing demands for electricity arising from continued growth in U. productivity, shifts and continued expansion of national cultural imperatives (e.g., the distributed grid and electric vehicles), and the projected increase in renewable energy sources……”“One of the most promising approaches to addressing the growing limitations of the electric grid and the increasing demand for renewable energy is to incorporate stationary energy storage technologies into the U. As the renewable contribution increases, the number of variables – and goals - that must be considered expands, and the predictions become less consistent.Presidio, Texas has installed a 4 MW sodium-sulphur battery for emergency backup, claimed to be the largest battery of this type in the US.They have a high energy density and charge/discharge efficiencies in the range of 90%.The first is response time – how quickly the storage device can respond to a grid disturbance.
This effectively stores electricity with high round-trip efficiency.” Thermal energy storage for cooling is currently being applied on a broad scale with commercial success based solely on its own economic benefits.Some utilities offer rebates but generally, the time-of-day dependent charges (demand and energy) incorporated into virtually all commercial electrical rate structures provide the energy cost savings that justify thermal storage for cooling applications.These are installations that building owners request and pay for now – at costs far below typical battery or utility side technologies.Climate change, national security, energy independence, jobs and energy cost are some of the factors that are merging to reinvigorate efforts in energy storage development.
And predictably, much of the effort is related to the ability of storage to support renewable energy sources, such as wind and solar, that possess some level of uncertainty or variability, or where the availability may be temporally out of phase with demand.
Additionally, there are potential benefits from energy storage other than operational stability or maximizing the k Wh of renewable resources.