India, Jan. 15 -- Sailing the Norwegian fjords aboard Havila Polaris ship in November, I gathered with fellow passengers in the Havblikk Bar to watch the vessel bunker. It's typically a mundane process-effectively, a stop to refuel-but for this voyage, it was the reason I was on board. A truck at the terminal pumped about 300 cubic meters of liquefied biogas (LBG), not fossil fuel, made from processed municipal waste (so, garbage) into the ship. Fish guts, food scraps, and agricultural waste from Norway's coastal communities would power this first-of-its-kind journey.

The next morning on the bridge, I asked the captain, Kurt Harald aerbo, if there was any difference running on biogas versus liquefied natural gas (LNG) or other fossil fue...