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Grid energy storage (also called large-scale energy storage) is a collection of methods used to store electrical energy on a large scale within an electrical power grid. Electrical energy is stored during times when production (especially from intermittent power plants such as renewable electricity sources such as wind power, tidal power, solar power) exceeds consumption, and returned to the grid when production falls below consumption. == Benefits of storage and managing peak load == The stores are used - feeding power to the grid - at times when consumption that cannot be deferred or delayed exceeds production. In this way, electricity production need not be drastically scaled up and down to meet momentary consumption – instead, transmission from the combination of generators plus storage facilities is maintained at a more constant level. An alternate and complementary approach to achieve the same effect as grid energy storage is to use a smart grid communication infrastructure to enable Demand response (DR). Both of these technologies shift energy usage and transmission of power on the grid from one time (when it's not useful) to another (when it's desperately immediately needed). Any electrical power grid must adapt energy production to energy consumption, both of which vary drastically over time. Any combination of energy storage and demand response has these advantages: *fuel-based power plants (i.e. coal, oil, gas, nuclear) can be more efficiently and easily operated at constant production levels *electricity generated by (or with the potential to be generated by) intermittent sources can be stored and used later, whereas it would otherwise have to be transmitted for sale elsewhere, or simply wasted *peak generating or transmission capacity can be reduced by the total potential of all storage plus deferrable loads (see demand side management), saving expense of this capacity *more stable pricing: the cost of the storage and/or demand management is included in pricing so there is less variance in power rates charged to customers or alternatively (if rates are kept stable by law) less loss to the utility from expensive on-peak wholesale power rates when peak demand must be met by imported wholesale power *emergency preparedness—vital needs can be met reliably even with no transmission or generation going on while non-essential needs are deferred Energy derived from photovoltaic and wind sources inherently varies – the amount of electrical energy produced varies with time, day of the week, season, and random factors such as the weather. Thus, renewables present special challenges to electric utilities. While hooking up many wind sources can reduce the variability, solar is reliably not available at night except when stored in molten salt, and tidal power shifts with the moon so is never reliably available on peak demand. How much this affects any given utility varies significantly. In a summer peak utility, more solar can generally be absorbed and matched to demand. In winter peak utilities, to a lesser degree, wind correlates to heating demand and can be used to meet that demand. Depending on these factors, beyond about 20-40% of total generation, grid-connected intermittent energy sources such as photovoltaics and wind turbines tend to require investment in either grid energy storage or demand side management or both. In an electrical power grid without energy storage, energy sources that rely on energy stored within fuels (coal, oil, gas, nuclear) must be scaled up and down to match the rise and fall of energy production from intermittent energy sources (see load following power plant). While oil and gas plants can be scaled up when wind dies down quickly, coal and nuclear plants take considerable time to respond to load. Utilities with less gas or oil power generation are thus more reliant on demand management and grid storage. The French consulting firm Yole Développement figures this “stationary storage” market could be a $13.5 billion opportunity by 2023, compared with less than $1 billion in 2015. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Grid energy storage」の詳細全文を読む スポンサード リンク
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