The philosophical basis strikes me as being a case of plain old tax evasion - Offgrid technologies can often reach parity with the enduser price of power, because the bulk of that price is in fact taxes, and while getting offgrid gets you out of paying them legally, it doesnt actually reduce the amount of revenue the state needs to collect at all, so all you are doing is freeloading. Further, it is also likely to have highly undesirable psycological and political consequences. If you are living off grid thanks to a set of sophisticated production and storage technologies, you are, in the end, every bit as dependant on the rest of society for power as you are when living hooked up to the grid, because you can neither manufacture nor repair any of it. But it becomes much easier to ignore that dependancy, and the very last thing the world needs is more libertarians who belive they can do without society.