Fuel oil pollution control and additional maintenance required after burning it often outweigh the low cost of the fuel. Burning fuel oil, particularly residual fuel oil, produces uniformly higher carbon dioxide emissions than natural gas. Heavy fuel oils continue to be used in the boiler "lighting up" facility in many coal-fired power plants. This use is approximately analogous to using kindling to start a fire. Without performing this act it is difficult to begin the large-scale combustion process. The chief drawback to residual fuel oil is its high initial viscosity, particularly in the case of No. 6 oil, which requires a correctly
Bitumen-based fuel associated with the phenol group of surfactants. The most well known bitumen-based fuel has been developed by Intevep, the Research and Development Affiliate of Petroleos de Venezuela SA (PDVSA), in a collaboration with BP, and is branded "Orimulsion." It is an emulsion of natural bitumen mined from the Orinoco Belt and fresh water. Bitumen-based fuel is currently used as a commercial boiler fuel in power plants in Canada, Japan, Lithuania, and China. Commonly available air pollutant control technology can limit emissions from Orimulsion to levels considered Best Available Control Technology, as defined by the United States Environmental Protection Agency. Bitumen-based