June 25, 2009

A recipe for clean, green hydrogen power
New ideas, old technology may offer the key to storing renewable energy

By Kathy Gray
of The Chronicle

     Water containing enough potential hydrogen energy to equal all of Saudi Arabia’s remaining oil reserves flows down the Columbia River every 67 days.
     “It’s one of our great, undervalued resources,” Jack Robertson told the Northern Wasco County PUD board of directors during their meeting on Tuesday.
     For 15 years, Robertson watched that untapped resource flow to the sea as a deputy and occasionally acting director at Bonneville Power Administration. He longed for a way to tap that hydrogen energy potential. When he left Bonneville a few years ago, he helped form the Northwest Hydrogen Alliance, nonprofit group whose focus is to tap that elusive resource.
     Now, with the PUD’s financial help, Robertson believes the alliance has cracked the code to produce a clean, renewable energy source that doesn’t take miles of new power transmission lines costing millions upon millions of dollars to get where it’s needed most.
     Robertson reported Tuesday, letting the PUD know about the potential development that may come from a $50,000 conservation funds donation made early this year.
     “Can we capture the hydrogen that’s in water, make it practical, make it real and really compete against the carbon atom?” was the question the alliance posed. And the answer appears to be “yes.”
     The alliance came up with the concept of hydrogen hubs that would produce what Robertson describes as the most hydrogen-rich liquid around — twice as dense in hydrogen as liquid hydrogen itself, and much less volatile.
     “It has the highest likelihood of any renewable resource you can imagine to compete against the carbon atom,” Robertson said.
     The key to affordably producing this safer, nonpolluting energy source is to use inexpensive surplus hydro, wind and solar power generated in excess of seasonal demands. During the springtime, for example, the Columbia River hydropower system produces surplus power that is sold on the market for pennies on the dollar.      Likewise, high wind periods at times generate more wind power than the region can use. The surplus power is often sold for almost nothing or even given away, because it can’t be effectively stored over long periods of time.
     Robertson hopes to change that through this new method. At present, the alliance is working with Dr. John Holbrook, a former employee of the Pacific Northwest National Laboratory in Richland, Wash., to obtain independent confirmation that the process will work as planned.
     “Once it’s proven, we think the hydrogen hubs’ unique technology will qualify for green funds,” Robertson said. He hopes the lab’s confirmation will come in September, before the start of the next federal fiscal year in October.
     The process involves what Robertson describes as three simple steps.
     “What we’re going to do is take three renewable
resources and combine them into ‘green” ammonia fuel,” Robertson said.
The process captures nitrogen from the air, which is 70 percent nitrogen, hydrogen from a commercial water source using an off-the-shelf electrolyzer. The two elements are then combined through the early 20th century Haber-Bosch process, which fixes one atom of nitrogen with three atoms of hydrogen to produce anhydrous ammonia.
     “The ammonia is simply a liquid to carry the densest amount of hydrogen to one place or another,” Robertson explained, that’s half again as dense as liquid hydrogen and, while liquid hydrogen is highly volatile, anhydrous ammonia is much more stable at ambient temperatures.
     Anhydrous ammonia is nothing new. It’s shipped all around the world by ship, train, truck and barge for use as agricultural fertilizer, Robertson added, so shipping mechanisms are already in place to get the liquid from its production site to market.
     “It’s the third biggest chemical product in the world,” Robertson said.
     Once the ammonia is manufactured, it can be shipped through normal channels to reach the point of demand — a large city for example — where it can be burned cleanly in a modified diesel generator. The only byproduct of the combustion process is water vapor, Robertson said, which can be captured and, in some cases, recycled.
     Northwest farmers are also interested in this “green” anhydrous ammonia because conventional methods of the fertilizer production have a “huge carbon footprint,” Robertson said. Often produced in developing or less developed nations using coal or natural gas fuels, then shipped around the world, the ammonia contributes a large amount of carbon to the atmosphere.
     PUD directors had many questions about the process, including how much water is used in the process.
     “It takes 420 gallons of water to create a ton of ammonia,” Robertson explained, but if the production plant and power generating site are near one another, the water vapor released in the generation process can be recaptured and used again and again. They hydrogen atoms aren’t lost in the generator’s ignition process. Instead, they combine with oxygen in the air to become water vapor.
     Likewise, the nitrogen captured from the air and fixed with hydrogen in the production process is returned to the air during the generation process.
     “If you capture the water vapor and recycle it, you lose almost none of the water vapor,” Robertson said.
     Other than shipping, the ammonia has virtually no carbon footprint, Robertson suggests.
     “It’s as close as I’ve ever seen to a perfect environmental closed loop,” Robertson said.
     Most of the equipment needed for the production process is available off the shelf, including a surplus of diesel generators mothballed after the 1970s energy crisis. The generators need to be stripped of their copper components because of ammonia’s corrosive effect, Robertson said.
     He expects the cost of the hydrogen hubs to be around $1.5 million for megawatt, less than the $1.75 million per megawatt average for wind turbines. The retrofitted diesel generators would be between $600,000 and $1 million he estimates.
     Robertson hopes to have prototype systems under way next year.
     After probing the production methods and equipment, PUD board members were most interested in investment opportunities and potential for local power production.
Robertson said organizations like the PUD, which contributed to the research process, will have first opportunities for investment. He also suggested the technology has potential for local use.
     “We’ve been saying for a long time that if the country is going to solve its energy challenges, it’s got to use innovation,” said PUD Manager Dwight Langer.

A recipe for clean, green hydrogen power:

     1. Extract hydrogen from tap water using an electrolyzer and low-cost, off-peak renewable energy.

     2. Extract nitrogen from air.

     3. Combine the two using century-old Haber-Bosch Process to produce anhydrous ammonia (NH3).

     Anhydrous ammonia is the
densest carrier of hydrogen fuel, 50 percent more dense than liquid hydrogen, and more stable.