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On April 16, 2015, the Hydrogen Energy Center held its annual meeting at the University of Southern Maine. The guest speaker was Dr. Glenn Eisman, an adjunct professor at both Rensselaer Polytechnic Institute (RPI) and Union Graduate College, who has spent his industrial career working on the cutting edge of fuel cell research and development and served on review committees supported by the US Department of Energy’s Fuel Cell and Hydrogen Fuel Initiative. Dr Eisman's talk was entitled, "Fuel Cells, Hydrogen and their Potential Impact on Emerging Energy Challenges". Green Energy Maine was there and brings you this report.
CHANGES IN ENERGY USE OVER TIME
Eisman began by taking a long look backward at what humans have used over the past 300+ years to supply energy. Before the 1700's, we used hydropower and wood. From the 1700's to the present, we have used coal. From the 1880's to the present, we added electrification and from the 1900's to the present, we have used oil, largely to power transportation. He pointed out that there has been an ongoing process of changes in energy supply.
Energy consumption in the US is 97 quads per year, one quad being equal to 1000 trillion BTUs. The residential, industrial and transportation sectors are each using about 1/3 of this energy. Approximately thirteen million of the 19 million barrels of oil we consume in the United States each day are used for transportation.
The supply of domestic oil is currently up due to hydraulic fracturing (or "fracking"), yet the auto industry is concerned about the long-term availability of fossil fuels. According to experts in the field, oil production would need to double by 2035-2050 if we continue to grow the population using fossil-fueled vehicles. The fracking wells may not produce long enough to meet this demand.
The US has 100 years' worth of coal reserves; natural gas is regarded as a transition fuel. There will be a natural progression towards a carbon-free society, tempered by the fact that the interest in renewables goes down as oil prices go down. The continuum of carbon-producing fuels begins with
wood being highest, followed by coal, then oil, then natural gas and hydrogen being lowest. Eisman (along with his colleagues) envisions a carbon-free renewable energy scenario using hydrogen and fuel cells.
WHAT ARE FUEL CELLS?
Fuel cells are a continuously-fed battery, a static electrochemical device. Interest in fuel cells began in the US when the Russians launched Sputnik and we had no power plant with which to compete. All of our space programs were powered by alkaline fuel cells mostly developed by United Technologies in Connecticut. A company named Ztech tested such fuel cells in taxicabs in the UK. General Electric is the parent of the [proton exchange] membrane technology in fuel cells. They were instrumental in developing nearly every aspect of the technology we know and use today.
In an integrated stationary fuel cell process, natural gas or propane is processed with air to reform the gas into hydrogen (H2). This is then run through a fuel cell stack, producing heat, water and DC power. The power is sent through a power conditioner to convert it to AC power. The heat can also be captured, as in the combined heat and power, or CHP process. The fuel cell electrochemical stack components have a targeted 5 year life span in stationary applications, and ~ 5000 hours in fuel cell vehicles: the anode, cathode and electrolyte are not consumed.
Each cell of the “stack” of the fuel cell device produces approximately 1 volt or less, so they are stacked in order to produce higher voltages. The stacks used in today's fuel cell electric vehicles (FCEV) are “works of art” compared to early models. Eisman listed the different types of fuel cells; their efficiencies ranged from 50-68%.
In solid oxide fuel cells, in the past there has been a thermal expansion issue, which Bloom Energy seems to have solved. The cells are stacked and the stacks are stacked into "hot boxes".
WHY USE FUEL CELLS IN VEHICLES?
The end game is the superior efficiency of the fuel cell power plant. Eisman listed the comparative efficiencies of power plants as follows:
Proton Exchange Membrane (PEM) fuel cells: 40-80%;
Internal Combustion Gasoline Engines (ICE): 20%;
Diesel Engines: 30% and
Combined Cycle Gas Turbine Power Plants: 20-30%.
Global motorization is a huge driver (pun intended!) for the implementation of fuel cells in vehicles. The number of vehicles per 1000 persons in US is the highest in the world. China and the Third World are trying to catch up, so demand is exploding; this will put pressure on fuel sources. With atmospheric CO2 levels ever increasing, we could be on a course toward an irreversible environmental catastrophe. The only emission from a fuel cell is water.
Fuel cell power plants will eventually be recycled by auto companies, so there will be less stress on platinum supplies than people fear there will be. There is already about 30 grams of platinum used in a typical ICE car, the goal being less that 10. Hybrid electric vehicles were developed to be a stepping stone on the way to a pure EV, fed by H2. Other "stops along the way" have included such vehicle fuel types as CNG, LNG and EV's.
There are many military applications for fuel cells; a main advantage is in the low thermal signatures for vehicles like tanks to prevent them being tracked. Fueling is a problem, however: armed forces don't want to carry two different logistic fuels into a battlefield.
WHY USE FUEL CELLS IN STATIONARY APPLICATIONS?
The running lifetime targets of a fuel cell are in the range of 5000-7000 hours in a FCEV and it is up to 40,000 hours for stationary fuel cell stacks. In GE's labs, they have been shown to run much longer.
Fuel cells offer greater efficiency in conventional power generation, distributed generation, micro-grids, combined heat & power, reduced transmission costs and losses (often 8% or more) and the co-generation of hydrogen.
Many companies such as Apple and eBAY are using Bloom Energy fuel cells to generate power for their facilities. Other fuel cell companies like Fuel Cell Energy in Connecticut are in the process of developing a tri-generation technology: Combined Heat and Power and hydrogen for possible use in localized fueling stations. H2Pump developed a technology that can recycle industrial hydrogen waste. During blackouts, buildings equipped with stationary hydrogen fuel cells can remain powered when the rest of the lines are dark. This has big implications for emergency preparedness.
One might ask whether the electric utilities are opposed to this and no, they are on board. [An audience member mentioned that there is a problem in deregulated markets (such as Maine and Connecticut), where CHP is regarded as being a type of power generation and so the transmission and delivery companies are prohibited from owning it.]
After having many companies working on them in past years, residential fuel cells in the US have been taking a back seat to vehicle applications. Fuel cells can provide power supplies for portable electronic devices, as well. Fuel cell vehicles have also been considered power sources for the home.
OPPORTUNITES AND CHALLENGES IN COMMERCIALIZATION OF HYDROGEN
There are many initiatives underway globally. This is forcing the US to do more and to set the standards to be followed. We know how to make and handle hydrogen. Worldwide production is about 40 million tons per year. Of that total, 37.5 million TPY is "captive" (used in place) and 2.5 million TPY is "merchant", that is, sold and moved. Businesses do not like to transport H2, as it is lightweight and costly to transport.
Most hydrogen in the US is produced by steam reformation of natural gas (80-85%) or purification of chemical byproducts. Coal gasification to syngas, or nuclear thermal cycles may be used in the future.
Renewable hydrogen production is done by electrolysis (if the electricity comes from a hydro plant or solar farm), photo-electrochemical processes, photo-biological systems, thermal degradation or biomass gasification. Methane from biomass can be gasified and converted to H2, then run through fuel cells. While electrolysis is expensive, it works well as a means to generate and store H2.
Eisman compared the energy content of fuels: hydrogen provides 33 kWh per kg, while gasoline has only 12 kWh/kg.
The biggest challenge for FCEV is storage; hydrogen is currently stored under pressure to reduce volume as other technologies have not yet yielded. Other challenges are generation, distribution of supply (as in home refueling stations) and carbon sequestration. When it comes to hydrogen vehicle fueling, one asks, "which comes first, the cars or the fueling infrastructure?". No one wants to go in solo, as investments can become stranded assets, so the two must go hand-in-hand. That said, the auto makers are working full-tilt on FCEV's.
COMMERCIALIZATION OF FUEL CELLS
Commercialization got started in the 1980's. Since then, widespread adoption has been consistently seen to be just 5 years out. Today, we see that fuel cells are increasingly making news headlines and they may be truly part of the energy solution sooner, rather than later.
The issues to be surmounted are: the cost of development, the lifetime of the power plant stack and reliability. The lifetime and reliability issues affect cost; this applies to all fuel cells. The other big issue is the availability of H2 fuel infrastructure. Regulatory and insurance standards will all take time to work out.
The auto industry is now closer to viability than is the residential sector. Residential hydrogen was earlier thought to precede motive applications but the reverse has occurred, at least In US. Home refueling concepts have been proposed whereby the residential fuel cell can both power a home and charge the auto.
All car companies were advancing technology for onboard gasoline reformers (gas to H2). It took too long to heat up the reformer before it would work; this complicated matters for our daily vehicle use expectations. The DOE significantly reduced funding this research around 2008. For the near term and until further advancements are made, it became easier to store hydrogen under pressure in vehicles.
For widespread adoption in decades to come, Eisman felt that fuel cell stacks will have to become a commodity that are low cost and are easily exchanged. The costly platinum catalyst can be recycled and advancements in non-precious metal catalysts have been made. Component costs are coming down and will come down faster as volume manufacturing is ramped up.
THE PERSPECTIVE FROM 30,000 FEET
Commercialization dates have been slipping forward. There are both auto and stationary barriers: materials, reliability and costs. The first commercially viable applications may be in materials handling.
Stationary fuel cell technology for residential, portable and backup power is still in development. Large-scale stationary fuel cell development is promising.
Motive fuel cells will be intimately tied to the evolving hydrogen store. As investment initiatives go, development is taking too long for investors to have patience. The investment community is cautious after 15 years of consolidation. Many players have sold out or gone bankrupt. Now that we are nearing commercialization, new companies are entering the space, however.
The supply chain continues to evolve. Codes & standards are being addressed. In summary, says Eisman, “We are closer now than ever before.”
ABOUT THE HYDROGEN ENERGY CENTER
The Hydrogen Energy Center is a non-profit organization run by visionary volunteers who are acting on their commitment to a better energy future. Membership fees fund these operations. The knowledge and energy of HEC's members fuel everything they do. Its members share the desire to see hydrogen energy help correct the problems of dirty air, climate disruption, world conflicts and poverty which have been caused by our fossil fuel economy.