<<On Tue, 3 Mar 2026 10:32:20 -0500, Brooks Harris via tz <tz@iana.org> said:
I find it curious how we all live by the clock on the wall rather than natural daylight. This of course makes sense since the whole point of civil time it to "coordinate activities", But DST basically makes no sense. Why do we need more sunlight in the afternoon in summer when we naturally have more sunlight in the afternoon in summer?
Historically, when a large amount of electric power demand was due to lighting (all those incandescent bulbs), it was highly desirable to align working hours with daylight, and DST moves solar noon to 1 p.m., the middle of the working day. Today, when a large amount of electric power *supply* comes from solar energy, having sunset *after* the end of the working day means that the evening peak can benefit from solar energy (particularly of the behind-the-meter variety) which reduces the slope of the ramp and thus the cost to the electric grid. Obviously it's not possible to have sunset after 6 p.m. all year, unless everyone gets up in the dark or we all move to the tropics. Both of these economic benefits only accrue with coordination, and it's much easier as a coordination problem to change clocks than it is to change employment contracts, operating hours, traffic regulations, and so on, all at once. -GAWollman