A couple of months ago I built a solar grinder out of a standard grinder, a slot machine hopper motor, and a small 12V PV panel. Preliminary tests show this device will grind enough flour in an hour to make a full loaf of bread. This is somewhat slower than using it as a 120V plug in grinder, but here are a couple of things I've noticed about the flour. It seems to grind a bit finer flour. The higher speed 120V unit makes ok flour, but it is just a wee bit coarse. Still makes great bread of course. The solar unit, since it runs slower, seems to give a very cold flour. Normally, higher speed makes the flour warm, and some suggest that that heat ruins the oils in the wheat. If that is the case, then this solar unit will make superior bread. Here's the breakdown: if there are 10 good hours of direct sunlight a day, then one can grind enough flour for probably 10+ loafs of bread a day. 10 breads is enough for 20 people to have a daily half loaf, and with 20 people that's, uh, right at a $10 investment. This may be a good tool for a group of people and neighbors who want to get off the grid. Of course, at an allocation of half a loaf daily, the grinder in 2 days can provide enough flour to feed 40 people. Your initial investment thus will drop to about the price of one loaf of good bread from your local bakery. You might want to suggest this to your local NNEMA group after you organize it. Also, this could be an excellent lifeboat tool, as well as an urban-tool sharing plan. There is great economic power in tool sharing and bulk purchasing. Good for times of economic uncertainty Drawbacks to prototype grinder: as the unit is now portable, this involves placing the PV panel directly at the sun and re-positioning it every hour or so. Also, when the sun disappears behind a cloud you lose power. One solution is to hook the panel up to a 12V car battery. One could possibly thus mount the PV panel in a permanent south position, and while losing just a little energy efficiency, and flour output, there would be no need for tracking the sun. I would guess you might lose 1/2 to 1/3 of your daily grain grinding capacity. That's still a lot of bread available daily though.... If you have questions, ideas, please write, and perhaps you can help develop this further.