Global trends indicate that countries around the world are investing enormous efforts in making commercially available technologies to separate and store carbon dioxide (CO2) from fossil fuels, produce hydrogen from fossil, nuclear and renewable energy sources, and develop fuel cells for clean and efficient use of hydrogen.

Thirty-eight nationally recognized companies in the United States, including eleven Fortune 500 corporations, are collectively saving millions of dollars in electricity costs while reducing carbon emissions by tens of thousands of tons per year by using fuel cells, according to a new report by Fuel Cells 2000, a non-profit education and outreach organization.   “The Business Case for Fuel Cells: Why Top Companies Are Purchasing Fuel Cells Today”, profiles thirty-eight companies and corporations that are purchasing and deploying fuel cells in various capacities, highlighting the attractive benefits and savings of fuel cells over competing technologies. The companies profiled in the report, cumulatively, have ordered, installed or deployed:

• More than 1,000 fuel cell forklifts;
  
• 58 stationary fuel cell systems totalling almost 15 MW of power; and
  
• More than 600 fuel cell units at telecom sites.
  

Fuel cells are used in a wide range of products, ranging from very small fuel cells in portable devices, through mobile applications to heat and power generators in stationary applications in the domestic and industrial sector. Future energy systems will also include improved conventional energy converters running on hydrogen as well as other energy carriers.

Here is a graph, Figure 1, which illustrates an overview, highlighting the sources, converters, and applications for commercializing fuel cells:

Looking bottom up at the sources depicted on the graph presented above, Refinery/chemical off-gases, natural gas, coal, under conventional and electricity, and heat under nuclear energy linked directly to “Hydrogen”, indicating that those are the direct sources for generating hydrogen. As far as the renewables are concerned two out of five – Biomass and Solar Thermal – have the capability to help generate hydrogen directly. However, the remaining three renewables – Solar PV, Hydro, and Wind – used as a source for heating water to generate hydrogen through electrolysis.

1.    HYDROGEN ELECTROLYSIS:

Looking at the graph under Figure 1, which indicates that wind, hydro, or solar PV, is source of heat for heating the water, resulting in the production of oxygen and hydrogen.

As illustrated in Figure 2, electrolysis is the process of using any energy source capable of generating electricity including fossil fuels, nuclear, and renewable energies such as solar, wind, or hydro, to split water into hydrogen and oxygen. However, electrolysis requires substantial amounts of electricity, and once again, is ultimately only as carbon-free as the energy source used to generate the electricity.

In other words, hydrogen produced via electrolysis can result in zero greenhouse gas emissions, depending on the source of the electricity used. The source of the required electricity—including its cost and efficiency, as well as emissions resulting from electricity generation—must be a factor for evaluating the benefits of hydrogen production via electrolysis.

According to the report, Hydrogen and Fuel Cells – Review of National R&D Programs, produced by the International Energy Agency, industrial electrolysis systems currently have hydrogen production capacities of up to 5 tons per hour and net system efficiencies up to 70-75 percent. Such systems operate with a net power consumption of around 40-45 kWh per kg of hydrogen produced. The aim of the current R&D efforts is at improving net system efficiencies of commercial electrolysis toward 85 percent.

2.    FUEL CELLS:

Looking at the graph, Figure 1, which indicates that hydrogen, is fed into fuel cell, discharging oxygen and water and feeding electricity to applications through various types of fuel cells.

Sir William Grove developed the first fuel cell in England in 1839. His experiments during this time on electrolysis — the use of electricity to split water into hydrogen and oxygen — led to the first mention of a device that would later be termed as the fuel cell by scientists Ludwig Mond and Charles Langer while those scientists were attempting in 1889 to build a practical model to produce electricity.

A fuel cell is an electrochemical energy conversion device. A fuel cell converts the chemicals hydrogen and oxygen into water, and as a result, it produces electrical power efficiently, without producing any CO2. The by-products of an operating fuel cell are heat and water. In principle, a fuel cell operates like a battery. However, unlike a battery, a fuel cell does not run down or require recharging. With a fuel cell, chemicals constantly flow into the cell so it never goes dead – as long as there is a flow of chemicals into the cell, the electricity flows out of the cell. Most fuel cells in use today use hydrogen and oxygen as the chemicals.

The graph, Figure 3, demonstrates that a fuel cell consists of two electrodes – a negative electrode (or anode) and a positive electrode (or cathode) – sandwiched around an electrolyte. Hydrogen is fed to the anode, and oxygen is fed to the cathode. Activated by a catalyst, hydrogen atoms separate into protons and electrons, which take different paths to the cathode. The electrons go through an external circuit, creating a flow of electricity. The protons migrate through the electrolyte to the cathode, where they reunite with oxygen and the electrons to produce water and heat.

3.    FUEL CELL TYPES:

Looking at the graph, Figure 1, it indicates there are six types of fuel cells, connected to two different types of applications – Stationary and Transport. Here is a brief description of each type of fuel cell:

3.1    Proton Exchange Membrane Fuel Cells (PEMFC):

This type also known as Poly Electrolyte Membrane. These fuel cells deliver high power density and offer the advantages of low weight and volume compared to other fuel cells. PEMFC are particularly suited to powering passenger cars and buses due to their fast start-up time, favourable power density, and power-to-weight ratio.

3.2    Phosphoric Acid Fuel Cells (PAFC):

Phosphoric acid fuel cells (PAFC) use phosphoric acid as an electrolyte and porous carbon electrodes containing a platinum catalyst. They were the first fuel cells ever used commercially and over 200 units are currently in use. Primarily used in stationary power applications, as well as for powering buses.

3.3    Direct Methanol Fuel Cells (DMFC):

Most fuel cells are powered by hydrogen, which can be fed to the fuel cell system directly or can be generated within the fuel cell system by reforming hydrogen-rich fuels such as methanol, ethanol, and hydrocarbon fuels. DMFC, however, are powered by pure methanol. DMFC fuel cell technology is relatively new, compared to that of fuel cells powered by pure hydrogen, and research and development are roughly 3-4 years behind that of other fuel cell types.

3.4    Alkaline Fuel Cells (AFC):

Alkaline fuel cells (AFC) were the first fuel cell technology ever developed and used in the United States’ space programme. They use a potassium hydroxide solution as the electrolyte and a variety of non-precious metals as a catalyst at the anode and cathode. AFC typically operate at between 100-250 °C, but recent versions operate at between 23-70 °C. AFC are high-performance devices that achieve an efficiency of 60 percent, but they are vulnerable to poisoning by even small amounts of carbon dioxide.

3.5    Molten Carbonate Fuel Cells (MCFC):

Molten Carbonate Fuel Cells (MCFC), are being developed to be fuelled by natural gas. These fuel cells cannot be fuelled by pure hydrogen. MCFC use a molten-carbonate-salt electrolyte suspended in a porous, inert ceramic matrix. They do not need an external reformer, because they operate at high temperatures (>650 °C). In addition, they do not use precious-metal catalysts, further reducing their cost

3.6    Solid Oxide (SOFC):

Solid Oxide Fuel Cells (SOFC) used a non-porous ceramic electrolyte and appeared to be the most promising technology for electricity generation. When combined with a gas turbine, SOFC, expected to achieve an electrical efficiency of 70 percent and up to 80-85 percent efficiency in cogeneration. High operating temperatures of 800-1000 °C mean precious-metal catalysts and external reformers are unnecessary, helping to reduce the cost of SOFC.

4.    APPLICATIONS:

Looking at the graph, Figure 1 that indicates the two categories of applications and here is a brief description of each category:

4.1    Stationary:

4.1.1    Buildings:

Thousand of fuel cell systems installed all over the world. Companies are happy with the performance of the installed fuel cell power generation systems as they achieve 40 percent fuel-to-electricity efficiency utilizing hydrocarbon fuels. In addition to zero noise and no air pollution, when the fuel cell is sited near the point of use, waste heat can be captured for cogeneration, where it can be used to provide hot water, space heating, or cooling. This combined heat and power (CHP) installation can deliver 80 percent to 90 percent overall fuel efficiency. Heat can also be used for refrigeration using absorption chillers, as supermarkets installing fuel cells are opting to do. In large-scale building systems, these fuel cell cogeneration systems can reduce facility-energy service costs by 20 percent to 40 percent over conventional energy service.

The applications for the buildings: Power Generation Systems; Backup Power Systems; Combined Heat & Power System with sub-systems for water heating, space heating, air conditioning systems, refrigeration systems; Materials Handling Systems (Forklifts). The types of building: Manufacturing Facilities; Distribution Centres; Office Buildings; Data Centres; Nursing Homes; Hotels; Schools; Utility Power Plants; Etc.

4.1.2    Telecommunications:

Fuel cell systems are currently being used by major telecommunicating companies to support cellular phones, wireless laptops, Blackberrys, and other 3G devices by supporting primary or backup power for telecom switch nodes, cell towers, and other electronic system that require reliable, onsite, direct DC power supply. Fuel cells can replace batteries to provide power for 1kW to 5kW telecom sites without noise or emissions, and are durable, providing power in sites that are either hard to access or are subject to inclement weather. 

According to various reports, companies have already demonstrated fuel cells that can power cell phones for 30 days with out recharging and laptops for 20 hours. Other applications for micro fuel cells include pagers, video recorders, portable power tools, and low power remote devices such as hearing aids, smoke detectors, burglar alarms, hotel locks and meter readers. These miniature fuel cells generally run on methanol, an inexpensive wood alcohol also used in windshield wiper fluid.

 4.2    Transport:    

Fuel cell vehicles have already proven much more efficient than similar internal combustion vehicles. Toyota has published their efficiency results showing their conventional gasoline vehicle having a tank-to-wheel efficiency of only 16 percent, while their FCVH-4 running on hydrogen shows a 48 percent tank-to-wheel efficiency – an amazing three times more efficient. GM has also announced that their fuel cell prototypes running on hydrogen have twice the efficiency of their conventional gasoline vehicles.

As fuel cell vehicles begin to operate on fuels like natural gas or gasoline, greenhouse gas emissions will be reduced by 50 percent. In the future, the combination of high efficiency fuel cells and fuels from renewable energy sources (Figure 1) will eliminate greenhouse gas emissions. Because fuel cell vehicles operate with electric motors which have very few moving parts (only those pumps and blowers needed to provide fuel and coolant), vehicle vibrations and noise will be vastly reduced and routine maintenance (oil changes, spark plug replacement) will be eliminated. Fuel cells also have a great advantage over battery powered electric vehicles because they eliminate charging time, allow a wide range of speeds, and operate as long as fuel is supplied.

The applications for transport fuel cells included: Cars, Buses, Scooters, Forklifts, Auxiliary Power Units, Trains, Planes, and Boats.

5.    CONCLUSION:

While the promising technology of fuel cells came a long way since 1839 when Sir William Grove developed the first fuel cell in England, it has a long way to go to realize fully the associated mammoth benefits and this is not going to happen until fuel cells are in widespread use for power generation and transport. Unfortunately, most of the current global production of hydrogen, around 65 millions tons per year, is for captive use in chemical and refinery industries. The configuration of global production of hydrogen represents 48 percent natural gas, 30 percent refinery/chemical off-gases, 18 percent coal, and 4 percent electrolysis. The popularity of the fuel cell applications in the future will have a direct positive impact on these logistics.

Here are some realities:

• If hydrogen is produced by water electrolysis, using conventional electricity as a source of heat, emissions are created. In other words, the operation of cars powered by hydrogen fuel cells may be carbon free but the production of hydrogen is not. However, if hydrogen is produce by electrolysis as shown in the graph, Figure 1, using renewable – either wind, hydro, or solar PV – it will be a total carbon free operation;
  
• If hydrogen is produced from renewables, nuclear energy – nuclear electricity and nuclear heat – as demonstrated on the graph, Figure 1, it can be carbon free, supporting the idea of reducing emissions and diversifying the energy supply. However, the energy produced by nuclear reactors may come in the form of heat or electricity and it would be cheaper to use nuclear heat instead of nuclear electricity to separate hydrogen from either water or natural gas. But, given the fact that current reactors put out only about 3000 megawatt thermal (MWt) and the use of heat from nuclear reactors requires 1600 MWt for efficient hydrogen production, therefore, it is suggested that the removal of such a huge chunk of heat from nuclear reactors would lessen the efficiency of electricity production.
  

Recognizing the potential for hydrogen to be a dominant energy carrier of the future sustainable energy supply system, the nuclear countries around the world are concentrating on building advanced nuclear reactors with huge capacity, focusing on sustainability, economics, safety and reliability, and proliferation resistance and physical protection and this will be the ultimate solution to producing cheap, clean, and efficient hydrogen for fuel cells.

Nonetheless, fuel cells are extremely clean. Since there are typically no combustion related emissions from the fuel cell itself, emissions depend on the choice of fuel. When using pure hydrogen, the emissions are zero. When using natural gas, the emissions are still very low, much lower than fuel combustion. Based on measured data, a fuel cell power plant may create less than one ounce of pollution per 1,000 kilowatt-hours of electricity produced – compared to the 25 pounds of pollutants for conventional combustion generating systems.

While allowing countries to build advanced nuclear reactors that will provide adequate heat to produce cheap and carbon-free hydrogen, a combination of thirty-eight companies including Walmart, Whole Foods, Coca-Cola, Staples, Sysco, and Fed Ex, decided to capitalize on the current efficiencies offered by the fuel cell technologies, resulting in huge savings of:

• More than $2 million a year in electricity costs from 4.2 MW of fuel cell power (6 companies aggregate);
  
• $700,000 a year in labour and insurance costs (3 companies aggregate);
  
• 43,122 tons of carbon emissions per year, roughly the same as removing 8,983 passengers vehicles from the road each year (20 companies aggregate); and
  
• 35 staff hours/day previously spent on recharging forklift batteries allowing reassignment of 6-7 employees to other work (Nisan North America).
  

The statistics presented above reflect the buildings, vehicles, and forklifts, powered by various types of hydrogen fuel cells.

mirali@aimamc.com