That will be the problem in the long run, no doubt about it. In the short run, like NOW, for some folks, it is a viable alternative.
To really pull off a near self sustaining life style you need to also figure out how to preserve the food through the winter. Canning, drying, cold storage without electricity, etc. Your diet may be quite limited, lot's potatos if your Irish for instance. It's not a fun lifestyle, hard work, meager rations, long hours, but it is a survivable lifestyle.
I was surprised to see how many were living "off the grid" in Northern California while I was there recently. I was basically "holed up" in a small travel trailor and my 14' Box Van for a "shop". During that interesting time I learned a LOT about how to do it. I'm finding the same thing here in Oregon is pretty common as well, folks living "off the grid".
While it was educational, I was sure happy when my house closed and I got electric heat, internet, TV. Yeah, I'm pretty spoiled!
