Adam Weber, photo from http://eetd.lbl.gov/people/adam-weber

Hydrogen fuel cells power city buses all over Oakland, CA, surrounding the Chabot Space and Science Center and transporting visitors around town. Guest speaker Adam Weber, staff scientist at Lawrence Berkeley National Laboratory’s fuel cell program manager, spoke at Chabot on future prospects of this technology during February’s enrichment lecture.

According to Weber, hydrogen fuel as a workable, commercial scale technology in the U.S. is at least 10-20 years in the future, as a minimum. However, he supports continued research and development into the area as the technology represents the promise of a 45 percent reduction in our country’s carbon emissions by 2050.

Hydrogen differs from other fuels as it cannot be mined or harvested directly, but must be produced on a large scale, usually by splitting water molecules through electrolysis. The energy to power the electrolysis can come from natural gas, coal, nuclear energy, or, as he hopes, ultimately from renewable sources.

Hydrogen batteries are more easily scalable for use in industry and transportation because the amount of power can be increased by adding more hydrogen fuel rather than having to add more batteries. However, with our existing technology, storing hydrogen in batteries, even over a few days, gets very expensive very quickly. Weber and other researchers are investigating better storage options, including geological storage.

Invented in 1839 by Sir William Grove, the hydrogen fuel cell can be even more efficient than a traditional engine. NASA uses fuel cell technology to power some of its spacecraft and many cities use fuel cells for buses. Hydrogen fuel cells are also used for some specialty applications where an engine would not be practical, such as forklifts, and these applications do not require special subsidies to promote the development of the technology.

Fuel cells convert chemical to electrical energy, oxidizing (burning) a fuel in the process. A fuel can be anything easily combined with oxygen and supplied to the cell. Fuel cells are classified by their electrolytes, the substances they contain which contain free electrical ions and are thus able to conduct electricity. Hydrogen fuel cells promise more horsepower over a longer range than either lead acid or lithium ion batteries and much lower pollutant or greenhouse gas emissions.

Technical challenges along the road to improving the commercial viability of hydrogen fuel cells include the risk of a ‘thermal event’ – or an explosion. This can be lessened by carefully separating the compartments within the cell. Also there is a risk of ‘flooding’ or the cell filling with liquid water and losing the ability to function well.

Dr. Weber outlined the process by which a hydrogen fuel cell produces electrical energy. Hydrogen gets fed to the cell and diffuses across it while the electrons combine with and ‘reduce’ the oxygen which diffuses to the positively charged cathode layer of the cell. This atom-splitting reaction results in the loss of energy as heat and the reduction reaction (where negatively charged electrons bond with oxygen, ‘reducing’ its charge) requires catalysis from expensive metals.

Lawrence Berkeley Labs’ researchers are attempting to improve the efficiency of this process by increasing the battery voltage to speed up this reaction and by using porous electrodes to increase the surface area available for the reaction. Their goal is to put these cells on par with other batteries. Researchers are also using gas diffusion layers to spread out the flow of gases within the cell and help remove excess liquid to minimize the problem of flooding.

Currently the cost of energy produced in this way averages $40/kilowatt hour. Researchers speculate that the cost could be brought down in the future through using thinner/nanoparticle size frames as surfaces on which the oxygen can be reduced through combination with electrons. The company 3M has already invented a thin film structure that could be useful in this capacity. However, tensile stresses could prove a challenge at such a small film width.

Researchers also consider using solar powered photoelectrochemical devices to produce energy from hydrogen. Weber suggested that this could become commercially efficient with improvements in the effectiveness and lifespan of the photoelectrochemical (PEC) cell.

Weber showed diagrams evaluating the systemic costs of producing hydrogen and then harnessing it as a fuel for use in transportation. He said that currently the cost of hydrogen fuel comes to about $4 per gallon when compared to gasoline. With thought and continued investment in research, he expects that figure could be brought down to $2 over the next few decades. And he encouraged us to think like Japanese automakers, whom he praised for having a longer term vision when it comes to developing sustainable and effective technologies.

Read more about Dr. Adam Weber and research into renewable energy at Lawrence Berkeley Labs here.