There are some super interesting things that can be done with that, both for heating AND cooling. Combining some of the solarium/hot wall ideas with Solar Chimney's could make some SUPER interesting building designs (there are some really cool existing installations that have been around for centuries..
https://en.wikipedia.org/wiki/Solar_chimney).
I think that it could be especially relevant for a 3.5 or 4 season greenhouse installation.. as well..
You could have helped the summer issue with appropriately angled overhangs (assuming you were far enough north that sun angle matters..). My last house had sort of half done that and it made a pretty big difference (they had big east/west windows as well which, while awesome for the view, kind of put a bit of a hit on the passive solar efficiency come summer time).
That's a lot of the difference.. We're at just under 0.06 which is harder to make up the difference for (at 8900kw we'd be $534.0/yr in usage - the base rate adds some on top.. this is actually dang close to my yearly as well.. mostly because I have a lot of fridges and freezers ... and we don't always remember to turn off the laser printer when it's not in use.
). You're usage is at or below national avg so pretty decent.