Hydride Hurdles on the Hydrogen Highway

MALIBU, CALIFORNIA—Howard Hughes may have ended up nuttier than a fruitcake (The Aviator spares us most of the gory details), but he certainly did a lot for science. In the 1940s, the still-dynamic Hughes wanted to keep up on the latest developments in radar for his aircraft business and so set up the Hughes Research Labs.

Larry Burns of GM (left) with Matthew Ganz, Ph.D., CEO of HRL, and HydroGen3.© Jim Motavalli

The state-of-the-art lab was originally in Culver City (close to the movie business!) but in 1960 moved to a hilltop location in the Santa Monica Mountains overlooking the Pacific Ocean. It remains there today, on a 72-acre campus that is anyone"s idea of a great place to work. Perhaps inspired by the setting, Hughes scientists demonstrated the first laser in 1960, and did pioneering work in holography, solar cells and artificial intelligence. In the 1990s, the lab innovated wireless networks, lithium-ion batteries and auto radars.

Now called HRL Laboratories and owned jointly by Boeing, Raytheon and General Motors, the lab is working on fuel cells and hydrogen storage. It"s not likely to get made into a movie by Martin Scorsese, but it"s vital work that will determine the transportation systems of the future. It can"t happen fast enough, because there"s no way our planet can sustain the current growth of internal-combustion automobiles.

Our host in California was General Motors Vice President Larry Burns, who"s in charge of fulfilling the company"s promise to deliver a market-ready fuel-cell vehicle by 2010. He"s something of a fuel-cell visionary, one of the few auto executives with a wide-angle vision of where the industry is heading (and why it has to go there). Here"s some of what he said: "We"re currently 98 percent petroleum dependent in the auto industry, which is not a robust position to be in. We will have 1.2 billion cars on the world"s roads by 2020, so we need a clean form of personal transportation people can buy in high quantities. Fuel cells and hydrogen hold that key. We think people will want fuel-cell vehicles not because we’re running out of oil or because of global climate challenges, but because they’re simply better cars. It"s a business-driven decision for us. We’re very excited. The industry has become very idea-rich."

Some of the ideas are coming out of HRL, some out of Sandia National Laboratories in Livermore (which we also visited). At both labs, the focus is on storing hydrogen in metal hydrides. On the surface, it"s a screwy idea. Storing a gas on a metal? Calling Buck Rogers. But there"s some method to all this. The more conventional way to store hydrogen onboard a car is as a gas (at 5,000 to 10,000 pounds of pressure) or in liquid form (hydrogen liquefies at -423 degrees Fahrenheit). It"s hard to get enough gaseous hydrogen on board the vehicle to give it decent range, and keeping liquid hydrogen that cold is a huge technical headache.

Hydride storage is not a new concept. I wrote about it in my 2000 book Forward Drive: "[Toyota]," I wrote, "has demonstrated interest in storing hydrogen in metal hydride, a technology most other companies have tried and rejected because the metals are too heavy. But Toyota says it can obtain a 155-mile range with metal hydride storage."

A typical bay inside HRL's class 10 "clean room."

I visited Energy Conversion Devices (ECD) in Michigan, which champions hydride storage and was once partnered with GM. ECD says its metal hydrides "work like a sponge by bonding hydrogen atoms to a metal alloy, forming a safe, compact, low-pressure storage medium. A tank with a metal hydride inside can hold three times more hydrogen than can be stored as a compressed gas in the same space." The company claims its systems "could provide enough fuel to power a laptop for a month or a vehicle for hundreds of miles on a single charge."

The basic aim of the work at Sandia and HRL is the same, and it"s daunting. As James Spearot, director of GM"s chemical and environmental sciences laboratory, points out, something has to give before fuel-cell cars can have the range of today"s vehicles. Carmakers can either change the vehicle architecture to allow more room for fuel storage (basically, having tanks everywhere) or improve the capacity of the storage system. GM is currently investigating five different storage options, involving 15 separate material systems. So it remains a long haul, but it"s a step that has to be taken before hydrogen storage can be standardized and a nationwide system of filling stations established.

Hydrogen is the most abundant element in the universe, and it"s all around us, but it"s difficult to isolate and it"s a devil of a material to work with, because it is so light and slippery. The goal of the research is to create a storage system built around a complex metal alloy that can hold five to six percent of its weight (doesn"t sound like a lot, does it?) in hydrogen. That means that the "gas tank" equivalent, if it weighed 100 pounds, would carry five to six pounds of hydrogen. The greater efficiencies of hydrogen mean that such a car would have acceptable range, and metal hydride storage (with lithium boro-hydride as the material) promises systems holding 13 percent of their weight in hydrogen.

Hydrides store hydrogen and release it when exposed to heat. So you not only have to get the hydrogen to bond to the metal, you have to find an energy-efficient way to release it, too. They"re working on that, using what are known as "destabilizing agents." My favorite presentation over two days of talks was one by Leslie Momoda, director of the sensors and materials lab at HRL. She also compared hydrides to a sponge taking up water. The problem, she said, is that the sponge doesn"t want to be squeezed; the hydrogen is tightly bound to it.

Momoda"s analogy was to a child holding a balloon. If you try to take the balloon away, the child resists and it takes a "high energy investment" in the form of heat to get her to let go. But if you hand her an ice-cream cone she"ll be distracted and will release the balloon with minor effort. So the ice cream is the destabilizing agent, and the agent (the cone) can be used over and over with successful results. GM"s work with magnesium hydride as a destabilizer shows promise in allowing the system to work with lower temperatures (435 degrees Fahrenheit instead of 750 degrees).

Another challenge is getting this all to happen quickly, so the hydride can be recharged with hydrogen in three to five minutes, approximately the same time it takes to fill your gas tank now.

We finished our HRL tour with a visit to the lab"s 10,000-square-foot "clean room," where people in white Gore-Tex lab suits worked on the next generation of 150-gigahertz extreme microchips (10 times faster than today"s silicon-based chips). We looked in through little windows at people working on such tools as the electron beam pattern generator, etching semiconductors and other high-tech work. The work was right out of a movie; I half expected Dustin Hoffman to rip off his face mask and start yelling about a virus that had gotten loose. Did it have anything to do with cars? Probably not, but you may see those chips in a future car that will do everything but drive itself.

Outside the labs was one of GM"s HydroGen3 fuel-cell vans, not the latest technology but close to it. HydroGen3 carries 3.1 kilograms of hydrogen at 10,000 pounds of pressure, enough to give it a range

of up to 180 miles. The current GM fuel-cell vehicle, the Sequel, will reportedly be able to carry eight kilograms of hydrogen and go 300 miles. Hydride storage offers the possibility of doubling that range, but it"s not there yet. In 2005, it remains a head-scratcher for those people in the Gore-Tex suits.

CONTACT:

General Motors Advanced Technology

Hydrogen Forecast

Hydrogen and Fuel Cell Letter

Forward Drive: The Race to Build “Clean” Cars for the Future

Animal Rights National Conference 2018