Hydrogen fuel cell power is cleaner and more efficient than fossil fuel combustion, and it has better reliability and lower maintenance requirements than battery power. The technology has particular merit for materials-handling equipment, which is pervasive in indoor industrial environments.
"Concerns about oil supply, climate change and the environment make hydrogen-powered fuel cell technology a logical addition to the portfolio of alternative energy sources,” says Gunnar Walmet, program director at the New York State Energy and Resource Development Authority (NYSERDA).
Fuel cell forklift developments: In 2007, a public-private partnership with The Raymond Corp., NYSERDA and the New York State Power Authority (NYPA) was established to research hydrogen fuel cell applications in electric lift trucks. Solutions from Nuvera Fuel Cells, Plug Power and Hydrogenics were incorporated into four reach and pallet trucks. The trucks are currently undergoing a 24-month trial at Raymond’s Greene, N.Y., manufacturing facility, performing work in the “living lab” while being monitored for reliability, consumption and safety under real-world conditions.
"The current fuel cell systems are hybrids running on hydrogen and utilizing a battery or supercapacitors,” explains Steve Medwin, Raymond’s manager of advanced research. “This first step is a battery emulator, allowing batteries to be replaced with fuel cells in current trucks. In the future, we foresee a clean-sheet lift truck design that runs only on hydrogen, with the fuel cell permanently mounted in the truck.”
The hybrid trucks draw on proton exchange membrane (PEM)-based fuel cells, which use an electrochemical reaction between hydrogen and oxygen to generate electricity. Individual fuel cells are combined into a fuel cell stack, the size of which determines the amount of power it can supply. The hydrogen stored in a tank on-board the vehicle is converted to electricity as needed, and water and heat are the only byproducts.
The test trial established a permanent indoor hydrogen refueling station. The indoor fast-fill hydrogen refueling infrastructure from Nuvera is a new technology. Normally, refueling systems are installed outdoors. The refueling station is in an explosion-proof area with sensors for hydrogen leaks, and the gas is drawn in during the refueling process from tube trailers located outside the facility.
Trial results: Early results are promising. Raymond has found its fuel cell-powered systems have equivalent performance in terms of top speed, acceleration, braking distance and lift speed. And, the trucks stay in operation longer than those operating with battery packs.
"Companies can offset the cost of fuel cell lift trucks with increased productivity,” Medwin says. “Our fuel cell tanks are sized to run 1.5 shifts on average, whereas a battery typically lasts one shift (five to six hours) before needing to be swapped. It takes less time to reload a fuel cell than to change a battery; the operators can do their own refueling within one or two minutes. In addition, fuel cell lift trucks provide constant performance, while battery voltage drops."
Lower life cycle costs are another benefit. The life span of the fuel cell stack is estimated to be about 7,500 hours to 10,000 hours, depending on how hard the truck is used and how well it's maintained and serviced. In contrast, lead-acid batteries have an average life expectancy of five years. Fuel cell lift trucks require significantly less maintenance than their conventional electric counterparts because there are no batteries or battery rooms to maintain.
From a local-environment perspective, clean fuel cell technologies have a distinct advantage over fuel-burning equipment that emits carbon monoxide, DC motors that generate carbon dust and lead-acid battery-powered equipment.
Logistical and safety considerations: The biggest cost associated with fuel cell lift trucks is hydrogen transportation. If large quantities are to be consumed, it might be worth generating hydrogen on site, preferably from a clean, renewable source such as wind, solar or hydro power. Biomass and coal have obvious environmental costs.
Another consideration is the number and location of hydrogen dispensers. To avoid excessive travel time to refuel, companies may want to install more than one dispenser at the site.
As with any other industrial gas – and there are many used in plant environments – hydrogen needs to be treated with respect. Comprehensive hydrogen awareness education is mandatory to ensure the safe maintenance and operation of fuel cell equipment and hydrogen storage and refueling facilities, as well as to convey emergency response procedures.
E-mail Contributing Editor Sheila Kennedy, managing director of Additive Communications, at [email protected].
Reference Web sites:
www.nyserda.org
www.raymondcorp.com
www.nuvera.com
www.plugpower.com
www.hydrogenics.com
www.plantservices.com/articles/2002/137.html