Saving energy

This post is not about drafting in a pace line where a cyclist can save 20 to 30 percent of his or her energy expenditure by letting a group of riders take turns breaking the wind at the front of the pace line.

We have had solar thermal panels on our home for our hot water needs since 1985.  They have paid for themselves many times over since then.  They were trouble-free until earlier this year when one developed a leak.  We replaced them and hope to have another 20 plus years of service from them.

This year we invested in photovoltaic panels as well.  They cover most of the remaining portion of our south-facing roof.  They are generating an average of 200 kilowatt hours per week thus far.  The daily high production was 38 kwh while the low was only 4 kwh on a cloudy, rainy day earlier this week.  The supplier estimates that they should supply 90 percent of our annual electricity needs (we have an all-electric home).  They generate twice our current needs with the surplus rolling over to the winter months when our electric demand is higher to heat our home.  The payback on these panels is longer than for solar thermal, but in an age of global warming it seemed the right thing to do.  After six weeks, the panels have offset an estimated 1,364 pounds of carbon dioxide going into the atmosphere.