Houston biotech startup Cemvita Factory is partnering with US gas-equipment manufacturer Chart Industries Inc. to produce gold hydrogen by injecting oil-eating microbes into depleted crude oil reservoirs that might otherwise be plugged and abandoned. If successful, what Cemvita calls its "Gold Hydrogen Project" could open a new, ecofriendly revenue stream for the fossil fuel industry, according to a news release issued by the company on 17 February at the 2nd American Hydrogen Forum held in Houston. The US- and Canada-based engineering consultancy, EXP, as well as the nonprofit Center for Houston's Future, are also involved in the project which aims to produce low-to-no-carbon gold hydrogen at a cost Cemvita claims would be 4 to 6 times lower than the cost of producing low-carbon green hydrogen from renewable energy. Gold hydrogen exists underground in nature and is thus carbon free because it is not subject to any manufacturing process as compared to other fuels on the hydrogen color spectrum: gray (produced from coal or natural gas); blue (coal or natural gas with carbon capture); and green (derived from water electrolysis). Companies in Spain and South Australia are currently exploring for gold hydrogen using traditional mining and gas production techniques.