(1/n) Thread on 9 PM lights-out & candles-on plan by @narendramodi

TL/DR – it should *likely* not be a problem because (1) we can plan; (2) the lighting load is modest (maybe 10% of total grid at most. (3) We have enough fast acting supply options that can manage.

(2/n) SCIENCE: 3 factors that matter; 1) how much switches off/on? 2) How fast does this happen? 3) What does the grid look like to be able to cope? Oversimiplification – we’ll only look macro level (means frequency, not voltage), and ignore transients.

(3/n) Earth day is usually not as high participation in India – but it also involves switching off more loads than just lights. We handle that easily. (NOTE in graph (from http://carbontracker.in ), as I predicted before, after stabilizing, daily high is trending up – summer/ACs!)

(4/n) @PosocoIndia (grid operator) estimates swing about 11.3-12.9 GW (grid-based & bottom-up estimates). I think that’s high; all the daily swing 6-9PM isn’t just lighting. People watch TV, cook, etc. Even this is just ~10% of grid load (119 GW yesterday). (LEDs are efficient!)

(6/n) To work, grid operators need to plan and coordinate. May need nationalized thinking for how to handle hydro resources. Hydro-rich states may need to think regional and share UP/DOWN capabilities outside state borders.

(7/n) What can a citizen do?
(action 1/3) Don’t panic. Good that we’ll have candles ready just in case!
(action 2/3) It probably WON’T help to switch on ACs/loads since it is the FALL in demand (+rise 9 min later) that matters. The % change for 130->120 GW vs 120->110 is small.

(8/n) (action 3/3) SUGGESTION: Try and stagger some switching off lights maybe half an hour in advance. Don’t switch off the whole house in 3 seconds. Switch off “unneeded” rooms gradually. Come into one room as a family. Then switch off the last lights at about 9 PM.

(n/n) We have surplus supply in the grid for sure. I have faith in the grid operators and other heroes working on so many essential services during this time. Bless them all.