Fuel cell of pollution (other than ) for every 1,000 kW·h produced, compared to 25 pounds of pollutants generated by conventional combustion systems. Fuel Cells also produce 97% less nitrogen oxide emissions than conventional coal-fired power plants. One such pilot program is operating on Stuart Island in Washington State. There the Stuart Island Energy Initiative has built a complete, closed-loop system: Solar panels power an electrolyzer, which makes hydrogen. The hydrogen is stored in a tank at , and runs a ReliOn fuel cell to provide full electric back-up to the off-the-grid residence. Another closed system loop was unveiled in late 2011
Membraneless Fuel Cells valve at the supply end prevents any fuel entering while the bubbles are growing. The check valve is not mechanical but hydrophobic in nature. By creating micro structures which form specific contact angles with water, fuel cannot be drawn backwards. As the reaction continues, more CO is formed while fuel is consumed. The bubble begins to propagate towards the outlet of the cell. However, before the outlet, a hydrophobic vent allows the carbon dioxide to escape while simultaneously ensuring other byproducts (such as water) do not clog the vent. As the carbon dioxide is being vented, fresh fuel is also