Just In Time Grid
'Just In Time' (JIT) is a manufacturing process which aims to minimise or eliminate inventory. Instead of warehousing components, the objective is to have them delivered continuously to the production line
Electricity generation is the ultimate JIT system; electrical supply has to be consumed within milliseconds of it being generated and demand has to match supply at all times. There is no practicable way to store more than an insignificantly small proportion of the total.
To illustrate the scale of the problem, consider a project to store 1% of UK electricity output over a four-hour period around midday and release it over four hours at night, such as might be used to 'time-shift' the output of solar PV. Taking a nominal electricity generating capacity of 40GW over four hours, this is 160 GW-h of power. 1% is 1.6 GW-h or 1,600 MW-h
E.ON's Blackburn Meadows 10MW battery[1] cost £3.89m[2]; it stores 5MW-h (fully charged - discharged in 1/2 hour)
Storing 1,600 MW-h would require 320 such installations at a cost of £1.2 billion