Tuesday, October 9, 2012

2012 Transportation Cleantech - Locomotives

2012 Transportation Cleantech – Part 2, Locomotives

Railroads are one of the most efficient means for transporting freight and passengers over relatively long distances. In the US, two major forms of railroad locomotive are currently in use, as pointed out by the inventors of our next patent:
Diesel-electric locomotives employ a diesel engine to drive an electric power generator, which in turn drives a set of traction motors that rotate the locomotive wheels. Diesel-electric locomotives have the advantage of requiring a minimal amount of support infrastructure and thus are particularly suited for providing transport across remote geographical regions. On the other hand, because diesel-electric locomotives consume diesel, they contribute to urban air pollution and are subject to operating costs tied directly to the cost of oil.
Catenary-electric locomotives run directly from an electricity source, typically electric lines running above the railroad tracks. Catenary-electric locomotives are cleaner-operating on a locomotive-by-locomotive basis than diesel-electric locomotives; however, catenary-electric locomotives must be viewed as small parts of a much larger distributed power system, which includes an electricity generation plant, transformers, and a system of transmission lines required to bring electricity to the locomotives as they run down the tracks. This large distributed power system is typically unsuitable for remove geographic regions and overall is less efficient than a system utilizing diesel locomotives.
Back to the 2010 USDOE EERE statistics. Railroad locomotives consumed a daily average of 240,000 barrels of petroleum (10.1 million gallons). Electric locomotives (whether the catenary type, or the electrified third-rail type – think Washington DC’s Metro subway system) used about 20,870 million kW-hrs of electricity in 2010, roughly the equivalent used by 1.82 million average US homes.

It’s An Engine, Or a Mobile Electricity Source

Arnold R. Miller of Lakewood, CO and three co-inventors were granted patent 8,117,969 in February, 2012 for “Hydrogen fuel cell hybrid locomotives,” their patent is assigned to the BNSF Railway Company. The invention provides a set of batteries for driving multiple electric traction motors (as are currently used in diesel-electric locomotives) for moving the locomotive “and a fuel cell power plant for charging the set of batteries and driving the electric traction motors. The fuel cell power plant includes at least one fuel cell power module for generating electrical current by reacting hydrogen fuel and oxygen from intake air, the amount of electrical current being proportional to an air mass flow of the intake air. An air system selectively provides an air mass flow to the fuel cell module to generate an amount of electrical current required for corresponding operating conditions of the locomotive. A cooling system cools the at least one fuel cell power module in response to the amount of current being generated.”

Advantages of a hydrogen fuel cell locomotive include
[a]mong other things, such hydrogen hybrid fuel cell locomotives help reduce particulate air pollution in urban rail yards, as well as reduce the amount of greenhouse gases expelled into the atmosphere. Furthermore, the use of hydrogen as a fuel reduces the dependency of the railroads on imported oil and decouples locomotive operating costs from the volatile fossil fuel markets. Moreover, hydrogen hybrid fuel cell locomotives can act as mobile electricity sources, for example in disaster recovery scenarios.