Comment: I remember the brown cloud from back in the 60's.  Some days you couldn't see the mountains from Aurora.  We fixed that with catalytic convertors, not solar.  I was in the solar business in the early 80's, and sold a ton of domestic water heating systems to reduce the use of natural gas, or in a few cases, electricity or propane.  We used charts showing how much the price of nat gas had risen since the early 70's and projected that 30 years into the future to justify the cost.  But in 1983, the deregulated price of nat gas led production to meet demand, and the price has been coming down as fast as those solar panels came off the rooftops.  There aren't any tax credits for parts and repairs on those damned things, so it wasn't worth it to fix them for the small amount it was saving on the utility bill.