Economics of Batteries for Stabilizing and Storage on Distribution Grids
In the future, there will be much less consumption of energy from fossil fuels, and increasing annual percentages of PV solar energy on distribution grids. Those percentages may become as high as 50%. Any rational planning and design of energy systems, and the systems of the users, should be based on the world’s fossil fuel bank account being depleted in not too distant future.
Technologies are evolving to enable more generation closer to the user. Future buildings must be much more energy efficient regarding heating, cooling and electricity, and be zero-energy and energy surplus, for self-use, and to power electric heat pumps and electric cars. That means the role of the distribution grid would increase, and of the high voltage grid decrease, but not eliminated.
There still would be significant energy generated and fed into the high voltage grid, such as from nuclear plants, large hydro plants, and large CSP plants, but eventually, the fossil plants would disappear.
Because of future increased energy efficiency, such as due to net-zero-energy and energy-surplus residential and other buildings, increased use of electric light vehicles (cars, minivans, SUVs and 1/4-ton pick-ups), and the ongoing trend of less Btu/$ of real GDP, and likely low, real GDP growth, that 50% may become less MWh than at present.
Additional generating capacity on a distribution grid should provide most of the other energy consumed within a distribution grid.
The distribution grid would be minimally dependent on the high voltage grid, which, as a side benefit, would significantly reduce energy losses on the high voltage grid. See The Need for Economically Viable Energy Storage Systems.
Example of Other Energy on an Industrial Distribution Grid: At 400 kWh/metric ton, a 300-metric ton, industrial, electric arc furnace requires about 120 MWh of energy to melt the steel, and a “power-on time” (the time steel is being melted with an arc) of about 37 minutes, and “power-off” time of about 20 minutes, for a total tap-to-tap time of about 57 minutes, to produce 300 metric ton of steel. The EAF steel production = 300 x 8760 x 0.55 = 1,445,400 metric ton/y. The EAF energy consumption = 120 x 8760 x 0.55 = 578,160 MWh/y.
Electric arc steelmaking is only economical where there is plentiful electricity, with a well-developed electrical grid. In many locations, EAF mills operate during off-peak hours, when utilities have surplus power generating capacity and the price of electricity is less.