Best way to reduce supplemental lighting this winter?

[camille1585]

This may seem like an odd question to many. Due to strong inflation, the situation with Russia and no emergency mitigation measures in place in the Netherlands, energy prices are through the roof. When multi-year fixed price energy contracts expire, the new prices are often 10-12 times higher for companies and at least 3-5 times higher for households. Our contract expired this summer and we too are slammed with a huge increase. We've been carefully looking at our lifestyle, trying to see where we can save on gas and electricity use. One potential place to make some savings is the LED lights for the orchids, but I'd like to find the best way to reduce their use rather than turn them off completely.

I run them as supplemental lighting 10 hours per day from late october to late march. My collection is 80% Phals and the rest a mix of Neofinetia, Dens, Phrags, and assorted minis. Despite being in a south window I noted a massive improvement in growth when I started using supplemental winter light, so I'd rather not turn them off entirely. Now my question : I want to reduce the total power used by about about 50% and see several scenarios :

* Reduce from 10 to 5 hours per day, primarily before/after daylight hours, as daylight extension.
* Turn off the lights on half the shelves, and rotate shelves on a weekly/biweekly basis
* Variation of above, with 1 shelf lit permanently, containing high light plants like Neos, mini vandas... and then do the weekly rotation for the Phals and other low light plants.
* Other option I haven't thought of yet.

As an additional measure, my long-ish term project is to buy an Arduino and light sensors, and program the lights to turn off on sunny days. Iff it's a cloudy winter that doesn't save much electricity, but I still see it as something useful to do.