Michigan’s system also has unlimited rollover, so you DO NOT lose any credit at the end of the year–i.e. you can “store” energy on the grid indefinitely and NEVER lose credit for energy you’ve sent to the grid.

The only better situation would be getting paid $ for the excess generation, but in many states where that is the law, you only get paid wholesale for excess generation at the end of the year, so its arguable that Michigan’s 100% “credit” with unlimited rollover is even better than that.

Thanks to energy efficiency measures, we generate almost a megawatthour more solar energy than we use annually at http://www.DreamFarm.org, so we are “storing” our excess generation on the grid to be used by an electric car in a few years. (“Storing” is in quotes, because the energy we send to the grid is instantaneously used by our neighbors, but the energy credit is recorded by our utility company, and kept on account indefinitely.)

It’s great to have all these options to sort out with one or two viable ones left. Propane bills get quite expensive trying to heat a 2700 sq ft (but well insulated) home. Also: I was already planning to replace the floors.

For renewable energy systems, solar thermal systems typically have the fastest payback. In a cold, cloudy climate like my state of Michigan, I recommend evacuated tube collectors for the best winter heat production, because the vacuum minimizes heat loss, and the low mass of water in the collectors compared to other types ensures that these collectors will get up to temperature and bring solar heat into your building faster than any other type of collector. I’ve been very pleased with the system we installed on our house, by a company with US HQ in Michigan, http://www.btfsolar.com. We will also use them on our new Passive House as well, for space heating as well as domestic hot water, with the goal of achieving Zero Energy by means of a seasonal heat storage tank.

People often ask why I don’t include geothermal in my designs for off-grid Zero Energy homes, and that is because in Michigan, our coldest and cloudiest times roughly coincide, such that when the geothermal system is incapable of meeting all the loads with geothermal heat alone and would normally switch to electric resistance heating, there is the least available solar electric energy available. Of course, if one has a rural site and gets zoning approval for a tall windmill tower, or has access to hydropower, you might not have a scarcity of winter RE electricity. And grid-connected homes can use power from the utility and pay it back in summer, though we don’t yet have an equitable net-metering arrangement with the utilities in Michigan.