By John Addison (9/20/07)
Electric light rail is a popular way to whisk millions through cities with speed, ease, and minimal emissions. Per passenger mile, source-to-wheels emissions are far less than people trying to navigate busy cities in their cars. Even if there is a coal power plant supplying the electricity, the efficiency of moving masses with efficient electric drive systems results in very clean transportation.
Unfortunately, the initial capital expense of light rail prevents many worthy projects. MTA New York City is spending over $7.5 billion to extend its sub-way. Most light-rail costs over $10 million per mile.
Buses can move millions for a fraction of the cost of light-rail. Bus routes can be easily changed as cities grow, change in shape, and alter in transportation demands. Light-rail tracks are likely to be fixed for over forty years; bus routes may change annually. For most major cities, the ideal is intermodal solutions that include both bus and light-rail.
Now AC Transit in Oakland, California, is making bus travel as appealing as light-rail. Each day, over one thousand people ride on three hydrogen fuel cell buses in Oakland and in environmentally conscious Berkeley. By 2012, five thousand people daily will be riding on twelve such buses. The only emission is water vapor.
At the heart of these electric buses are Siemens electric-motors, similar to the larger motors which power electric light-rail. The motors are powered by electricity generated from 120kW fuel cells and from 95kW of batteries. The batteries are also used to capture braking and downhill energy. The batteries are recharged nightly, making these buses plug-in hybrid hydrogen fuel cell buses.
The hydrogen is made by onsite reformation of natural gas. Basically CH4 is combined with steam (H2O) to produce hydrogen. The electricity to power the reformation and the compression of the hydrogen gas is from solar power. The 150 kg/day of hydrogen is used by the three buses and up to eleven Hyundai vehicles for supervisors.
The net result is electric buses that can run hundreds of miles up 18 percent grades, and then be cleanly refueled in minutes. By 2010, the buses are likely to run 16 hours daily, up from the current eight. In five years, AC Transit is likely to buy at least seven hydrogen buses annually, staying ahead of California’s zero-emission bus mandate.
These are the most advanced buses used in the world with 40-foot Van Hool A330 bus chassis modified to accommodate UTC’s PureMotion™ 120 kW fuel cell power system and ISE’s hybrid-electric drive system. Hydrogen tanks on the roof give the bus a range of 300 to 350 miles, and batteries recharged during braking can provide an extra 95kW of power for acceleration and climbing steep grades.
HyRoad, this exciting model of public transportation, was made possible by more than $21 million of funding from the Bay Area Air Quality Management District, California Air Resources Board, California Energy Commission, California Transportation Commission, CalStart, Chevron Corporation, Department of Energy, and the Federal Transit Administration.
The National Renewable Energy Laboratory released a preliminary report on its evaluation of AC Transit’s fleet of fuel cell buses. The report includes eight months of performance data on three fuel cell buses in service, as well as data from a fleet of diesel control buses.
AC Transit; SunPower (SPWR); MMA Renewable Ventures; and PG&E (PCG) dedicated the AC Transit’s state-of-the-art 621-kilowatt solar electric system. The system, located on AC Transit facilities in Hayward and Oakland, is expected to generate approximately 767,000 kilowatt hours of power each year.
Over the 30-year life of the system, AC Transit expects to save $5 million in utility costs as a result of the clean, renewable solar power that the system will generate. It will offset the production of more than 14.5 million pounds of carbon dioxide emissions – equivalent to planting 2,000 acres of trees or removing 1,400 cars from California’s highways.
“AC Transit is committed to reducing emissions of greenhouse gases and improving the quality of life for the entire region in which we operate,” said AC Transit General Manager Rick Fernandez. “While installing a solar system to power our facilities makes a great deal of financial sense, it will also provide more than enough power to offset the 189,000 kilowatt hours per year required to operate AC Transit’s hydrogen production facility, and help lower the overall amount of energy we use from conventional sources.”
Instead of spending millions to install the solar system, AC Transit arranged to pay 13.5 cents per kilowatt hour to MMA Renewable Ventures, which finances and owns AC Transit’s solar power systems under a SunPower Access™ program. “AC Transit selected an innovative financing structure to effectively meet its financial goals and environmental objectives,” said Matt Cheney, CEO of MMA Renewable Ventures. “With its forward-thinking approach and commitment to clean energy, AC Transit is demonstrating that solar power is an affordable option for public agencies concerned with reducing carbon emissions.”
“AC Transit is an environmental leader that is doing its part to address our ongoing energy challenges,” said Howard Wenger, SunPower vice president. “By generating solar power, AC Transit is reducing demand from the utility grid, reducing operating costs, and improving air quality for its community. This energy solution saves money while helping the environment.”
A large portion of the installation cost of these solar systems was covered by a $1.9 million incentive from PG&E, under California’s Self Generation Incentive Program. Through this program, PG&E can provide almost $950 million in incentives over the next 10 years to help customers buy their own solar systems.
In the past twenty years, solar power has dropped 90% in price due to technology breakthroughs and production volume. Over the next twenty years, we will see the same improvement with hydrogen transportation. Already, the hydrogen used cost AC Transit no more per mile than diesel fuel used in similar buses.
As fuel cells reach lives beyond 10,000 hours, and as costs are significantly reduced, advanced transportation like AC Transit’s HyRoad will become available worldwide. When it does, we can thank AC Transit and its partners for leading the way.
