The transport sector accounts for 13 percent of the global emissions of greenhouse gases. In Sweden, domestic transport accounts for more than 30 percent of the country’s emissions. This makes the search for environmentally friendly fuels a priority.
Fuel from atmospheric carbon dioxide
There are a number of research projects seeking to exploit man-made and carbon-neutral fuels from the carbon dioxide in the atmosphere. There are different solutions, but the principles are similar.
The idea is that water and carbon dioxide, using electricity, can be converted into carbon monoxide and hydrogen, which through a catalyst can be converted into a variety of hydrocarbon fuels.
With electrolysis, a water molecule can be split into hydrogen and oxygen. Turning carbon dioxide into carbon monoxide requires a gas temperature 2400 degrees.
Researchers at the Sandia National Laboratories in New Mexico, USA, have developed a method to do this at lower temperatures. By using concentrated sunlight to heat rotating ceramic rings, the material Fe3O4 is heated up to 1500 degrees. At such temperatures, oxygen disappears and the material in the rings is reduced to FeO.
The ceramic rings are then moved into a room with lower temperatures and higher concentrations of CO2. As the rings cool, they take the oxygen from the ambient CO2 and turn it into carbon monoxide. The process can be repeated with the same rings over and over again creating a continuous conversion of carbon dioxide to carbon monoxide.
To get access to a continuous flow of CO2 to use in the reaction, the most economical process would be to place the conversion facility adjacent to power plants that emit carbon dioxide. In this way, plant emissions are purified while giving birth to a new product.
This technology has the potential to reduce and delay the emissions of CO2. Combined with technology to capture carbon dioxide already in the atmosphere this would be a completely carbon neutral system.
The infrastructure already exists
One advantage of this technology is that gasoline can be transported with existing infrastructure. Many other potential solutions to pollution problems in the automotive sector include the requirement for huge infrastructure investments in order to be financially sustainable.
Systems for the transportation and sale of gasoline exist already. So solar energy and carbon-based fuel could easily be converted into existing logistics systems without any additional investments.
Environmentally friendly, yet expensive
The use of renewable energy to make gasoline carbon neutral is an attractive feature in times when the search for emission reductions is intense.
For the fuel to be economically sustainable, the world needs sky rocketing oil prices. Calculations indicate that the renewable fuel would be profitable if crude oil prices rise above €80 per barrel, a level reached several times already in 2011.
One potential drawback is that it requires more renewable energy to produce the fuel in question. Making renewable energy in adequate volumes is difficult in an environment of ever-increasing demand for energy. Another challenge is also to minimize energy losses in the process, in order to get as much fuel as possible for as little input energy as possible.
The vision of carbon neutral gasoline, however, is so attractive that development projects are likely to continue. If they succeed to reduce costs and increase efficiencies, cars in the future might run on completely environmentally friendly gasoline.
The article was published in November 2011