Fuel cell fuel cells so efficiencies vary, but most are between 40% and 60% energy efficient. However, when the fuel cell's waste heat is used to heat a building in a cogeneration system this efficiency can increase to 85%. This is significantly more efficient than traditional coal power plants, which are only about one third energy efficient. Assuming production at scale, fuel cells could save 20–40% on energy costs when used in cogeneration systems. Fuel cells are also much cleaner than traditional power generation; a fuel cell power plant using natural gas as a hydrogen source would create less than one ounce
Oxy-fuel combustion process process. Oxy-fuel combustion may also be cost effective in the incineration of low BTU value hazardous waste fuels. It is often combined with staged combustion for nitrogen oxide reduction, since pure oxygen can stabilize combustion characteristics of a flame. There are pilot plants undergoing initial proof-of-concept testing to evaluate the technologies for scaling up to commercial plants, including One case study of oxy-fuel combustion is the attempted White Rose plant in North Yorkshire, United Kingdom. The planned project was an oxy-fuel power plant coupled with air separation to capture two million tons of carbon dioxide per year. The carbon dioxide