Wind power

Evening on Mars: the solar panels deliver nothing any more, outside three wind turbines are turning. How much power is arriving right now – and can the base rely on it?

Two turbines, one LogicType#

Both reveal only one thing via logic: PowerGeneration, the output at this moment. No On, no Setting – a turbine cannot be switched off, only deconstructed.

The output depends on the pressure of the outside air and on the wind strength. The wind strength drifts slowly up and down, so the output fluctuates all the time. A turbine inside a closed room delivers 0 W, and so does one in a vacuum. On Mars with its thin air it stays far below its maximum.

Adding up with Sum#

Power really adds up. Sum is right here:

lbn now WIND HASH("Windpark") PowerGeneration Sum

If there is no turbine with that name on the network, Sum returns 0, not NaN. For a power display that is even the right answer: no wind, no power.

Smoothing instead of twitching#

If you switch directly on now, you switch on every gust. A smoothed value is better, as you know from smoothing: every tick only catches up part of the difference.

sub diff now smooth
mul diff diff FACTOR
add smooth smooth diff

With FACTOR 0.1 the average needs a good 20 ticks, about ten seconds, to follow a jump. A short lull hardly counts any more.

Batteries buffer#

Wind is moody. That is why loads never hang directly on the turbine output but on the battery: the turbines charge, the loads discharge, and your chip decides by the batteries' Ratio when a generator steps in. The wind display is information, not a switch.