Concentrator electricity usage

We have 2 EverFlow stationary oxygen concentrators running 24/7 in our home. Electricity costs are $60-70 a month. That’s about 1/3 of our total electricity usage ! Seems like a lot ,just to breath. Solar is expensive..any ideas,suggestions?
I think the real answer is some sort of concession from the power company ..A break in usage rates for medical purposes Anyone know of such a program in other areas ?