Alternative Energy - Frequently Asked Questions

What are fuel cells?

 
 

What are the Different Types of Fuel Cells?

 
There are six main types of fuel cells distinguished by the electrolyte used in the individual cells. The principal ones include the alkaline fuel cell (AFC), proton exchange membrane (PEM) fuel cell, direct methanol fuel cell (DMFC), molten carbonate fuel cell (MCFC), phosphoric acid fuel cell (PAFC), and solid oxide fuel cell (SOFC).

 
 

What is the history of fuel cells?

 
Sir William Grove first demonstrated the technology behind fuel cells in 1839. The gas battery, later named the fuel cell, reversed the well-understood principal of electrolysis to generate an electrical current. Grove's invention was largely a curiosity as the age was captivated by the horseless carriage and the large reserves of petroleum that were being discovered. Fuel cells remained in obscurity until 1960 when the upstart government agency, The National Aeronautic and Space Administration (NASA), began looking for a practical power source for extended missions to space. Through research and development sponsored by NASA and private industry, the fuel cell is poised to become a replacement for the internal combustion engine and redesign the utility industry by making energy cleaner, cheaper and portable.

 
 

How much does it cost to run a 1 kW Fuel Cell on hydrogen?

 
The cost of operating a 1kW fuel cell for 7.26 hours when only one cylinder is purchased per month is $134. This is equivalent to $18.40 per hour to operate at one kilowatt. When the number of hydrogen cylinders used is increased, then the cost is reduced. Assuming that 5 cylinders of hydrogen are consumed in one month, this gives 7.26 x 5 = 36.33 hours of operation. The cost of the cylinders is (5 x $100) + (5 x $14) + $20 = $590. This is equivalent to $16.24 per hour to operate at one kilowatt.


How do fuel cells work?

 
 

How does a Fuel Cell Generate Electricity?

 
Fuel cells generate electricity through an electrochemical reaction, known as reverse electrolysis. This reaction combines hydrogen and oxygen to form water vapor, heat and electricity. All three of the by-products of this reverse electrolysis reaction can be further utilized by the fuel cell system. Waste heat can be utilized for space heating and cooling. The water vapor can be captured and used as the feedstock for additional hydrogen and the electricity is channeled into an external circuit where it is used by any electric appliance.

 
 

What fuels do fuel cells use to produce electricity?

 
One advantage of fuel cells is their fuel flexibility. With the proper reforming technology, fuel cells can extract hydrogen from a wide variety of currently available fossil fuels (e.g. Natural gas, methanol, coal, etc.). From fossil fuels, fuel cells utilize one natural element as their fuel, hydrogen, the most abundant element on Earth. In addition to fossil fuels, hydrogen can be generated renewably from water and other photobiological means.

 
 

What are the Major Components for a Residential Fuel Cell System?

 
In a residential fuel cell system there are three main components. The source of hydrogen, the actual fuel cell stacks and the power condition unit. The hydrogen can either be reformed from fossil fuels (i.e. natural gas, propane, etc) or the unit can be coupled to a renewable energy source and generate hydrogen through electrolysis of water. The fuel cell stack is the part, which converts the hydrogen and oxygen into electricity, water vapor and heat. The last piece is the power conditioner. This inverts the DC current from the fuel cell into AC current that many household appliances operate on.


What are the effects and benefits of fuel cell utilization?

 
 

What are the Benefits of Fuel Cells?

 
What are the Benefits of Fuel Cells? Environmental - Fuel Cells achieve high fuel efficiency while emitting extremely low emissions. Engineering - Fuel cells operate on a wide variety of fuels, utilize electrochemical reactions and contain no moving parts. These features make them simple to operate, quiet and extremely reliable.

 
 

Is Hydrogen Safe?

 
Hydrogen is a medium for storing energy. To be useful as an energy carrier, all fuels, such as gasoline and natural gas, have a characteristic of being volatile. Hydrogen's benefits differ from the fossil fuels commonplace in an advanced energy utilizing society such as in the United States. Hydrogen is non-toxic. Gasoline and oil are extremely toxic and poisonous humans along with wildlife when unintentionally released into the environment. If a hydrogen spill occurred, the hydrogen would evaporate almost immediately leaving only water behind. Oil and gasoline, on the other hand, require immense cleanup efforts with the result being that most of the spilled toxic gasoline or oil seeps into the surrounding ecosystem wrecking irreparable harm. The hydrogen used in fuel cells is stored within a metal hydride, a solid crystalline-like molecule structure, the hydrogen is chemically bonded to the solid metal power and when released, returns to gas form. Due to this compact molecular structure, leaks in a tank containing metal hydride release hydrogen gas very slowly, allowing you more time to rectify and bypass an otherwise potentially dangerous scenario. Examples of metal hydrides are, lithium hydride, magnesium hydride, and calcium hydride.

 
 

If I install a residential fuel cell, what kind of reduction in my utility bill can I anticipate?

 
Many factors enter into what your actual savings will be. These factors include; individual electricity consumption, geographic location, the particular utility, if utilizing a reformer the price of natural gas or propane, the avoided costs of installing lines to your residence when located in an off-grid area, etc.

 
 

What if my residential unit has excess electricity? Can I sell it to the utility?

 
The ability to sell electricity back into the grid depends on the geographic location of the unit. Many states have net metering laws, which allow qualified customers to sell surplus electricity back to the grid. Individual states vary on the amount of electricity each individual is allowed to sell, consult your local laws and ordinances.

 
 

Isn't hydrogen flammable? What about the Hindenburg and the H-bomb?

 
Hydrogen is flammable, but it is less flammable than gasoline and requires a higher temperature for auto-ignition. Because of hydrogen's low density, it evaporates quickly, greatly reducing the risk of an explosion if released into the atmosphere. Depending on the type of metal hydride used for storing the hydrogen, different safety precautions must be taken. An ideal metal hydride would, along with its byproducts, be nontoxic, it would also need to have a high ignition temperature and be capable of being safely stored at room temperature and atmospheric pressure. The fear of hydrogen from the Hindenburg disaster and the H-bomb is completely baseless. The current school of thought on the Hindenburg is that electricity around the flimsy, aluminum flake containing casing of the hydrogen most likely ignited it. The design and size of the Hindenburg also needs to be kept in mind. A passenger car or fuel cell operating on hydrogen would never have such a large amount of hydrogen stored in a flimsy cloth bag covered with highly conductive metal. Today’s fuel cell systems and hydrogen storage techniques are engineered with safety being a paramount concern. The composite tanks of metal hydride used today to store liquid and gaseous hydrogen are required to undergo rigorous safety testing before they are certified for hydrogen storage. The H-bomb was a thermonuclear weapon containing radioactive hydrogen isotopes forced into nuclear fusion by heat obtained from the nuclear fission of uranium. Only with the presence of a radioactive substance such as uranium undergoing fission, will the hydrogen atoms even come close to being hot enough to even potentially undergo fusion. Even then, H2 and its isotope H3, or tritium, must both be present. Tritium is extremely rare and breaks up in one millionth of a second. The hydrogen used in fuel cell energy is strictly H2.


How do fuel cells fair when compared to other energy production methods?

 
 

I already have a renewable energy source for my house, why would I want a fuel cell?

 
When a solar or wind system is coupled with an electrolyzer, the fuel cell system provides a more efficient, economical and completely renewable source of electricity. By generating hydrogen with a renewable system, the hydrogen becomes a storage medium for the energy contained in the captured sunlight or wind. Hydrogen and the fuel cell are able to replace the toxic, heavy, limited-life batteries currently used as energy storage. Generating hydrogen is non-toxic method to remove the temporal nature of renewable energy systems.

 
 

Automotive Batteries vs. Fuel Cells for Transportation

 
Vehicles powered by fuel cells combine the attractive advantages of battery-powered cars and the convenience of an internal combustion engine. Fuel cells operate quietly and are zero to low emissions, comparable to a battery-powered vehicle. Fuel cell powered vehicles offer the range, power, responsiveness and rapid fueling that the internal combustion engine provides. Unlike battery-powered cars, fuel cells do not require lengthy recharge times and will not transfer the pollution from the tailpipe over the grid to a central generating facility. The batteries used in automobiles are extremely heavy which limits the vehicles range and capacity. The batteries are also composed of toxic materials and have a limited lifetime leading to disposal problems. Fuel cell vehicles operating on pure hydrogen produce only water vapor and heat as emissions while fuel cells reforming fossil fuels into hydrogen would be classified as ultra-low emission vehicles.

 
 

I have heard that hydrogen burns cleanly, why not replace fossil fuels with hydrogen gas?

 
Hydrogen, when burned in a combustion engine is a huge improvement in terms of emissions when compared to fossil fuels. Burning hydrogen does release low amounts of nitrous oxide, a component of smog, into the atmosphere. This occurs whenever high temperature combustion occurs in the presence of oxygen. Other pollutants are also released as trace amounts of lubricants are burned in the process. The main reason to employ fuel cells instead of combusting hydrogen has to do with efficiency. Anytime a fuel is ignited and burned the overall efficiency is limited by the laws of physics, especially Carnot's Law, to around 10%. This is due to efficiency losses associated with heat and the additional steps necessary before the fuel is transformed into usable energy. A fuel cell directly converts the hydrogen fuel into electricity, which is more efficient than hydrogen combustion by cutting out unnecessary steps.

 
 

What is the amount of hydrogen that is equivalent to a gallon of gasoline?

 
It would take about 10 Nm3 of hydrogen gas to equal the energy present in 1 gallon of gasoline or 8.3 pounds of coal.


Current research and the future of fuel cells.

 
 

Why aren't fuel cells everywhere?

 
In the near future, fuel cells will play an increasing role in everyday life. Soon fuel cell powered cars and trucks will be cruising the streets of your town emitting nothing more than harmless water vapor. Fuel cells will find their way into cell phones and laptop computers whose battery life is measured in days instead of hours. Your house or office will have a fuel cell that replaces a conventional furnace, providing heat and electricity free from the disruptions associated with the utility's electric grid. Most of the companies planning to manufacture fuel cells are still in the research and development stage of production. Once their systems satisfy the manufacturers' stringent requirements for performance and safety, the fuel cell systems will be available to the general public.

 
 

Once transformed into a hydrogen-powered society, will the combined amount of water vapor from fuel cells cause environmental or climate problems?

 
The Union of Concerned Scientists have issued a report stating that, "If the entire U.S. passenger vehicle fleet were powered by hydrogen FCVs (fuel cell vehicles), the amount of water emitted annually (assuming no losses) would be 0.005% the rate of natural evapotranspiration, water that is released by plants during photosynthesis, in the continental U.S."

 
 

Does the United States Government Support Fuel Cell Development?

 
By supporting the research and development of fuel cells, the United States Government is developing clean energy sources for our future while strengthening the United States' competitiveness on the world energy market. Many governmental departments, including the Defense Department, the Department of Energy, and the Department of Transportation have fuel cell programs in their respective areas. All of these programs are leading towards the commercialization of fuel cell technology through partnering with private industry. The Federal Government supports research and development through monetary contributions towards research that is considered risky by industry and by creating the initial markets for expensive new technology. For example, the Climate Change Fuel Cell program provides cost sharing regarding the purchase of a fuel cell system.

 
 

What are the Benefits of the Federal Government Supporting Fuel Cell Development?

 
By supporting fuel cell development, the United States Government will achieve the goals of strengthening our national energy security, improving environmental conditions and developing an industry. The United States is dependent on politically unstable and unfriendly regions of the globe for its supply of oil. Currently, the United States imports 50% of its oil. According to the Department of Energy this number is expected to grow to 65% by 2020. Fuel cells, with their characteristic fuel flexibility, allow the United States to dramatically reduce its dependence on foreign energy sources and reduce its unbalanced foreign trade debt. By eliminating or greatly reducing the emissions associated with fossil fuels, a noticeable improvement in the environmental conditions in many major metropolitan areas will occur. This results in a reduction of pollution-related medical conditions and a dramatic increase in the quality of life for residents of these areas.


What is solar power?

 
 

What is solar energy and how is it utilized?

 
Surprisingly, solar power is actually a utilization of a form of nuclear energy. Our Sun is a main sequence star which creates thermal energy essential to life on Earth. This thermal energy comes from the nuclear fusion of hydrogen in the Sun's core. When two hydrogen isotopes combine, they release a helium atom, a freed neutron, and a substantial amount of radiant energy or light. While these rays of light may take anywhere from 10,000 to 170,000 years to reach the Sun's surface from its core, once at the surface, they take roughly 8.3 minutes to reach Earth, where they then provide us with light and warmth, as well as energy for your solar panel to capture and utilize. Solar panels contain crystalline silicon cells or some other semi-conducting agent to convert light energy into electrical energy.

 
 

What are the strengths and weaknesses of solar power?

 
While solar energy is essentially free, solar panels are rather large (for home sized energy collection) and very expensive. Solar energy collection is 100% environmentally friendly but this is not always the case in regards to the production of solar panels.


What is hydro power?

 
 

How does hydro power work?

 
Hydro power is electricity produced from the movement of water. Decent-sized bodies of water, such as streams or rivers with high elevation drops and high currents are the best candidates for hydro power. The current provides substantial energy, which is utilized when water pushes through the paddles of an installed turbine, creating mechanical energy. If hooked up to an electrical generator, the water-powered turbine will spin the generator, converting mechanical energy to electrical energy. Niagra Falls and the Hoover Dam are two examples of electricity produced in this fashion.


What is wind power?

 
 

How do we utilize wind power?

 
Wind power is the conversion of wind energy into mechanical and/or electrical energy. Wind turbines can produce electrical power from mechanical energy, windpumps are used for pumping water or for drainage, and windsails are used to propel and steer sailboats. The most notable and widely used application for collecting and converting wind energy is the wind turbine. China, the U.S., Germany, Spain and India and several other countries now implement groups of wind turbines, called wind farms, either offshore or onshore to convert wind energy into mechanical and eventually electrical energy.

 
 

How efficient is wind power?

 
Wind energy accounted for 2.5% of the world's energy in 2010. As of 2011, Denmark generates approximately one quarter of their electricity from wind energy.


What is bioenergy power?

 
 

How are biofuels produced?

 
Biofuels are fuels in solid, liquid or gas form created from biomass, an organic material acquired from either recently deceased or live organisms.

 
 

How is bioenergy different from fossil fuels?

 
Direct biomass combustion actually produces roughly the same amount of carbon dioxide as fossil fuels, but when converted to biofuels such as ethanol and biodiesel, their combustion does not produce substantial numbers of carbon emissions in comparison to that of fossil fuels. Biofuels are now being used as fuel additives to reduce carbon emissions and to help lower gasoline prices. Some alternative fuel vehicles will run on predominantly biofuel concentrated blends.