LATHAM, N.Y., April 30, 2003 — Plug Power Inc. and partner Vaillant GmbH have installed 13 proton exchange membrane fuel cell heating appliances during the past three months in multi-family homes and ...

The boxy machines look and function like large air-conditioners on reverse, but Germans hope they hold the key to Europe’s push for fossil-free heating. By Melissa Eddy and Patrick Junker Photographs ...