Sphagnum a sustainable substitute in growing media. Coir has also been touted as a sustainable alternative to peat moss in growing media. Another peat moss alternative is manufactured in California from sustainably harvested redwood fiber. Semi-open cell polyurethane materials available in flaked and sheet stock are also finding application as sphagnum replacements with typical usage in green wall and roof garden substrates. Europe has a long history of the exploitation of peatlands. The Netherlands, for example, once had large areas of peatland, both fen and bog. Between 100 AD and the present, they were drained and converted to agricultural land. The
Alternative fuel vehicle cells and electric motors instead of a traditional engine. Hydrogen reacts with oxygen inside the fuel cells, which produces electricity to power the motors. One primary area of research is hydrogen storage, to try to increase the range of hydrogen vehicles while reducing the weight, energy consumption, and complexity of the storage systems. Two primary methods of storage are metal hydrides and compression. Some believe that hydrogen cars will never be economically viable and that the emphasis on this technology is a diversion from the development and popularization of more efficient hybrid cars and other alternative technologies. A study by