Electricity and Liquid Fuels from Natural Gas
Centralized power generation systems offer excellent economy of scale but often require long transmission distances between supply and distribution points, leading to efficiency losses throughout the grid. Additionally, it can be challenging to integrate energy from renewable energy sources into centralized systems. Fuel cells—or devices that convert the chemical energy of a fuel source into electrical energy—are optimal for distributed power generation systems, which generate power close to where it is used. Distributed generation systems offer an alternative to the large, centralized power generation facilities or power plants that are currently commonplace. There is also a need for small, modular technologies that convert natural gas to liquid fuels and other products for easier transport. Such processes are currently limited to very large installations with high capital expenses. Today’s fuel cell research generally focuses on technologies that either operate at high temperatures for grid-scale applications or at low temperatures for vehicle technologies. There is a critical need for intermediate-temperature fuel cells that offer low-cost, distributed generation both at the system and device levels.
Project Innovation + Advantages:
ANL is developing a new hybrid fuel cell technology that could generate both electricity and liquid fuels from natural gas. Existing fuel cell technologies typically convert chemical energy from hydrogen into electricity during a chemical reaction with oxygen or some other agent. In addition to generating electricity from hydrogen, ANL’s fuel cell would produce ethylene—a liquid fuel precursor—from natural gas. In this design, a methane-coupling catalyst is added to the anode side of a fuel cell that, when fed with natural gas, creates a chemical reaction that produces ethylene and utilizes leftover hydrogen, which is then passed through a proton-conducting membrane to generate electricity. Removing hydrogen from the reaction site leads to increased conversion of natural gas to ethylene.
If successful, ANL’s hybrid fuel cell will double the efficiency of the system relative to existing technologies, reduce the manufacturing cost from roughly $4000/kw to $1500-2000/kw, and create a small, modular way to produce ethylene.
Enabling more efficient use of natural gas for power generation provides a reliable alternative to other fuel sources—a broader fuel portfolio means more energy security.
Flaring and venting of natural gas results in significant greenhouse gas emissions. Converting stranded natural gas to a ethylene simultaneously reduces greenhouse gas emissions and produces valuable products.
Distributed generation technologies would reduce costs associated with power losses compared to centralized power stations and provide lower operating costs due to peak shaving.