Hydrogen Bus Lets Lab Visitors Glimpse Future
Dec. 14, 2010
Imagine making fuel for your vehicle by simply using water and the wind or sun, filling your tank and driving to your favorite weekend vacation spot before looking for a fueling station. It is not a chapter out of a "green" science fiction novel, but technology being demonstrated in a "big" way on the campus of the U.S. Department (DOE) of Energy's National Renewable Energy Laboratory in Colorado.
DOE recently funded the leases for 12 hydrogen-powered internal combustion engine (H2ICE) shuttle buses, which are being placed at federal facilities across the country to demonstrate market-ready advanced technology vehicles. NREL was the first facility to receive one of the leased buses, which it currently uses for tours of its Golden, Colo., campus.
"NREL's unique twist to this demonstration is that we are fueling our shuttle bus with hydrogen made from wind energy up at our National Wind Technology Center near Boulder," Hydrogen Technologies & Systems Director Robert Remick said. "So, the hydrogen in our shuttle was literally wind energy blowing off the Rocky Mountains last week."
Tweak to an Old Engine
The H2ICE shuttle bus in use at NREL was manufactured by Ford, one of the first automakers to develop commercially available H2ICEs. The shuttle uses the same basic technology as a conventional gasoline-powered engine but runs on the hydrogen fuel created at NREL's Wind to Hydrogen (Wind2H2) Project. The Wind2H2 project links wind turbines to electrolyzers, which pass the wind-generated electricity through water to split it into hydrogen and oxygen. The hydrogen can then be stored and used later to generate electricity from an internal combustion engine or a fuel cell.
The bus has a 6.8-liter supercharged Triton V-10 engine. Only modest design adjustments were needed to switch the basic gasoline-powered engine to a hydrogen-powered engine. Those modifications included using specially designed spark plugs and alternate materials for valve seats and other parts that may become brittle when exposed to hydrogen.
NREL's shuttle is up to 25 percent more efficient than similar gasoline-fueled passenger vans and can run 175-250 miles (depending on usage) before staff refuels. The lab outfitted its "green" hydrogen dispensing station with cascading storage tanks, which decreases the time required for refueling. This is particularly beneficial for vehicles with large onboard storage systems like the H2ICE bus, which can take up to 30 kilograms of hydrogen in a single fueling. Because NREL's fueling station has a 130 kg storage capacity at 413 bar (6,000 psi), filling the bus takes 20-30 minutes; however, refueling time is lower at other commercial hydrogen stations.
NREL is studying hydrogen use at the Wind2H2 site to gain practical experience operating and maintaining complete systems and to understand hydrogen's interaction with the shuttle and the storage system. "In addition to the fueling station, we are storing more than 200 kg of hydrogen at the Wind2H2 site," Keith Wipke, NREL Senior Engineer and Group Manager for Hydrogen Analysis said. "It allows us to capture intermittent renewable energy and both fuel the vehicle and put energy back on the grid at times when there is high demand for electricity."
Although making hydrogen from renewable resources and using it in an H2ICE shuttle bus is a step in the right direction, it is an incremental step for the use of hydrogen in vehicles.
"Fuel Cells are the most efficient way to use hydrogen in vehicles," Wipke said. "So, this type of passenger bus utilizing an internal combustion engine is less efficient than a fuel cell, but is a good stepping stone to get the technology into the market and provide an alternative to fleets while the infrastructure for hydrogen fueling stations develops."
Industry Ramps Up for 2015
Hydrogen fueling station are springing up across the U.S., with approximately 60 locations already in operation and 20 more slated for construction. "Infrastructure for hydrogen fueling stations is starting to happen," Wipke noted. "The recession has caused a bit of a delay, but California recently awarded funding for 11 new fueling stations, and this is on top of seven new stations that are currently under construction."
Although a commercial sized passenger bus is the technology currently being demonstrated at NREL, Wipke expects hydrogen vehicles to claim a piece of the personal car market as well. DOE set a target goal for hydrogen fuel cell passenger vehicles to hit the market in 2015 and many of the major players — GM, Daimler, Honda, Toyota, Nissan, and Hyundai-Kia —are targeting a 2015 launch for their larger hydrogen fuel cell market entries. DOE recently announced that 70 Mercedes Benz B-Class fuel cell vehicles will be deployed in California by 2012.
"You look at the auto industry after this recession, and the pruning that you would have expected — the fact that hydrogen is still very strong is a huge vote of confidence for this technology," Wipke said.
There are many benefits keeping hydrogen vehicles in play for the auto industry including very low tailpipe emissions of criteria pollutants and greenhouse gases, and increased economic competiveness and jobs in the U.S.
Wipke also believes that although fuel cell cars may start out as a small part of the passenger vehicle market, they won't be relegated to niche-market status. Consumers will be able to purchase fuel cell vehicles that can go up to 300 miles on a single fill-up and refuel in three to five minutes. Drivers seeking larger multi-purpose vehicles, such as trucks and SUVs, will also be able to tow trailers and recreational equipment using fuel cell vehicles.
Hydrogen Has Potential
- Hydrogen can be made from a wide variety of domestic, renewable resources such as solar, wind, biomass, and geothermal energy.
- Enough hydrogen is produced in the U.S. every year to fuel 34 million fuel cell vehicles. Right now the hydrogen is used primarily for commercial purposes such as cleaning up gasoline and processing certain foods.
- Hydrogen is neither more nor less hazardous than more common fuels like natural gas, propane, or gasoline.
- Compared to conventional gasoline engines, hydrogen powered engines have very low criteria emissions and near-zero greenhouse gas emissions when the hydrogen is produced from low carbon or renewable resources.
- Hydrogen is up to 25 percent more efficient than gasoline in conventional spark ignition engines and around 100 percent more efficient in fuel cell power trains.
- Only modest design modifications to standard combustion engine technology are needed, so the engine technology is familiar to mechanics and fleet personnel.
- With very few cost and technical issues limiting commercialization and deployment, H2ICE vehicles can help create the demand needed to support the build out of a hydrogen infrastructure.
NREL analysts noted in a 2007 report, "Potential for Hydrogen Production from Key Renewable Resources in the United States," that approximately 1 billion metric tons of hydrogen could be produced annually from wind, solar, and biomass resources in the United States with the potential to displace gasoline consumption in most U.S. states.
NREL's research in hydrogen and fuel cells will get a boost in the coming years as a new laboratory — the Energy Systems Integration Facility (ESIF) comes online in 2012 and provides new lab space for hydrogen and fuel cell related research.
"We are also looking to do more research on fuel cell vehicles as manufacturers get ready to launch their next line of demonstration cars. We will be able to demonstrate the path of source renewable energy all the way through to the vehicle."