BiogasPermaculture Design Magazine: Unfulfilled Promise: Biogas Systems December 1, 2017 Bob Hamburg Leave a commentPlease click the link below to read my article published in the Permaculture Design Magazine November 2016 issue.PERMACULTURE DESIGN #102 NOVEMBER 2016Share this:Click to share on Facebook (Opens in new window)Click to share on LinkedIn (Opens in new window)Click to share on Twitter (Opens in new window)Click to share on Pinterest (Opens in new window)Click to email this to a friend (Opens in new window)