Of all the sources of renewable energy, one type invariably dredges up more debate than any other--biomass. Granted, the term biomass does cover a lot of topics and a lot of different controversies--from food versus fuel to the unintended consequences of anaerobic digestion. But perhaps the most enduring of all the biomass conundrums is this one--to burn wood or not to burn wood. Now Rob Hopkins, founder of the Transition Movement, is igniting the debate once more. And he's rethinking the installation of a stove at his house.