Toyota has long been a strong advocate for hydrogen fuel cells. Beyond producing the Mirai fuel cell car, the automaker is developing fuel cell buses for Japan and exploring the possibility of a fuel cell semi-truck. However, Toyota acknowledges that hydrogen power still faces significant challenges, particularly regarding hydrogen production and distribution infrastructure, which are major obstacles for fuel-cell vehicles. As a solution, Toyota is researching an alternative fuel source: natural gas.
Recently, the company installed a prototype hybrid fuel-cell system at its Motomachi Plant in Japan, where the Mirai is manufactured, along with the former production of the Lexus LFA supercar. This innovative system works by breaking down natural gas into hydrogen and carbon monoxide, subsequently utilizing these elements to generate electrical power.
This hybrid system combines both fuel cells and a micro gas turbine for power generation. The turbine supplies oxygen to the fuel cell using compressed air, which then reacts with the hydrogen and carbon monoxide to produce electricity. Additionally, the waste heat generated by the system is harnessed to yield more power, with the turbine operating on byproducts from the natural gas breakdown process.
According to Toyota, this system can generate up to 250 kilowatts of power, boasting an efficiency rate of 53 percent when relying solely on the fuel cell. When considering the use of waste heat to enhance power output, the overall efficiency rises to 65 percent, which Toyota claims is more efficient than conventional fuel cells. Notably, the fuel cell features an innovative solid-oxide design that eliminates the need for a platinum catalyst and operates at lower temperatures than traditional fuel cells.
Last year, Nissan introduced a prototype vehicle that utilized solid-oxide fuel cells. This converted e-NV200 van employed the fuel cell stack to charge an onboard battery pack. In contrast to Toyota’s approach, Nissan’s system used ethanol as the primary fuel to generate hydrogen. However, both initiatives aim to find alternatives to pure hydrogen, enhancing the practicality of fuel-cell vehicles.
Natural gas is more readily available than hydrogen, particularly in the United States, where it is extracted in large quantities via the controversial process of “fracking.” While natural gas emits fewer pollutants than gasoline or diesel, it still contributes to climate change. Additionally, despite its ease of production, natural gas encounters similar infrastructural challenges as hydrogen regarding fueling options, which has hindered the adoption of natural gas-powered passenger vehicles.
Currently, Toyota has not revealed any strategy for implementing its hybrid fuel-cell system in vehicles; its focus is on stationary electricity generation. This approach may be more viable considering that the necessary infrastructure for utilizing natural gas as fuel for power plants or heating systems is already established.
.
