The day is crystal blue as you pull into a refueling station in your sleek silver SUV. Despite being an advocate for a green Earth, the demands of your life—three kids, a German shepherd, and a work-at-home husband—were greater than your compact car could handle. So a year ago, in 2009, you made your first payment on a brand new vehicle. It has a tremendous amount of cargo space, a comfy interior, and—surprisingly — no steering wheel. Instead, a cockpit-style stick gives you precision control as you maneuver up to the pump. But what is most shocking of all is that the $1.50-per-pound fuel that powers your car is not gasoline, but the emission-free fuel that has been all the rage since its introduction in 2004: hydrogen.
You pop open the fuel cap and slide the nozzle end of the hose securely onto a shiny silver receptacle. A “ding” from the pump reassures you that the seal is tight and you turn to watch the fuel meter as hydrogen quickly fills the compressed gas tank located in the back of the car. When the car is running, the hydrogen powers a fuel cell that generates electricity via a low-temperature chemical reaction. In the fuel cell, hydrogen combines with oxygen, producing electricity to power electric motors that move the car and emit only water vapor as exhaust. Additional efficiency is gained by recovering energy produced during braking and storing it for the next acceleration.
Half of the car's hydrogen tank was filled yesterday by solar cells covering the roof of your home. As the noonday sun baked the solar cells, a small electrolyzer separated the H2O from a container of filtered wastewater into hydrogen and oxygen and stored the hydrogen until you returned home. Then, the car's tank was filled partway with this homemade hydrogen. The trip to the pump today was for the five pounds of additional hydrogen needed for a full tank. This hydrogen comes from a wind farm in a mountain pass that you can see in the distance. As you slide your credit card to pay your $7.50 fuel bill, you gloat a little, knowing that you'll not need to refill the tank of your fuel cell-powered SUV Hypercar for another 500 miles.
The need for hydrogen
In 2001, we are in the endgame of the Fossil Economy. Nobody doubts this. The only question is whether the end will come sooner or later. Energy analysts know what comes next: the Solar Hydrogen Economy. The US Department of Energy confirms that hydrogen technologies “will provide America with near-, mid-, and long-term strategies for a clean, sustainable, domestic energy supply.” The Fossil Economy is coming to an end because the supply of petroleum is dwindling—with less oil discovered every day than is being burned. But much more seriously, the release of additional fossil carbon into the Earth's atmospheric carbon cycle has the potential of tipping that cycle into an accelerated feedback loop of self-reinforced heating, called a “runaway” greenhouse effect.
According to the United Nations Intergovernmental Panel on Climate Change, the world needs to reduce greenhouse gas emissions by 60–70 percent to effectively prevent increased global warming. A reduction as dramatic as that entails abandoning fossil fuels as the central energy source for the world's societies. Switching to renewable hydrogen can do the trick— without radical economic dislocations. The Solar Hydrogen Economy is inevitable. The only issue is whether we can bring it about quickly, or whether the transition will be stalled by vested interests until it is too late to prevent the runaway greenhouse effect.
The solar hydrogen economy
What is a Solar Hydrogen Economy? It is any economy (it could be either high tech or low tech) in which the fuel for cooking, home heating, transportation, electricity, and production of goods and services comes directly or indirectly from the sun, the wind, renewable biomass, or ocean energies. All of these energy sources derive from the sun. All can generate electricity to convert water to hydrogen. Either electricity or hydrogen fuel can be used for nearly any energy application.
Hydrogen can be made from wind-generated and solar-generated electricity by electrolysis, a process of running electricity through water that separates the H2O molecules into hydrogen and oxygen gases. Only two gallons of water are necessary to make one gallon of gasoline equivalent hydrogen.
Hydrogen burns like natural gas, but it is completely clean. When it burns it releases only water vapor. It is as safe or safer than any common fuel in use today. It can fuel your cook stove, warm your house, power internal combustion cars, as well as buses, trains, and aircraft. In addition, it is the most direct source of fuel for fuel cells, which are highly efficient electric power plants that can be used to power cars or to provide electricity and heat in buildings.
Producing affordable hydrogen
Today's state-of-the-art wind turbines are producing electricity for 4 cents a kilowatt hour before any subsidies. (For comparison, the average wholesale electricity price in California eighteen months ago was three cents; a year ago 10 cents; six months ago 31 cents.) Wind power is immune to erratic fuel prices and is fully competitive today with electricity from fossil fuels.
Electrolyzed hydrogen from wind power would cost somewhat more than its per-energy equivalent in gasoline sold at the pump today, but hydrogen's greater efficiency in vehicles would help narrow the difference on a per-mile basis. For example, if in an adapted combustion engine, hydrogen could provide 50 percent more mileage per equivalent unit of energy than gasoline provides, then, even if hydrogen were to cost twice as much gasoline, the cost-per-mile for hydrogen would be only a little more than gasoline. Fuel cells are expected to be more than twice as efficient as current gasoline engines, which means that even if hydrogen costs twice as much at the pump, the per mile cost for hydrogen will be less than for gasoline.
During the start-up period, we can expect some portion of hydrogen to come from natural gas (CH4). To prevent the release of CO2 in the steam created by hydrogen production, Robert Williams of Princeton has suggested that the CO2 be pumped back down the gas well to re-pressurize it and extend its useful life. The capture and disposal of CO2 adds 25–30 percent to the cost of hydrogen produced by the steam reforming of natural gas. A new process called thermocatalytic decomposition is being developed that would produce hydrogen from natural gas without carbon dioxide emissions, thus not require sequestration. Carbon is extracted during the process as carbon black, a valuable material that could be sold for $100 or more per ton.
Eventually, with high demand and mass production, electricity from solar thermal electric power plants and photovoltaic cells will become competitive with gasoline.
Making the transition
Originally, it was thought that fuel cells would initiate the hydrogen economy. They are efficient, clean and have no moving parts. But they are still in the development stage and the costs are still high. At present the cost of fuel cells is hovering at $1,500–$2,000/kW, more than 10 times what would be a competitive cost for transportation. Although most people in the industry expect the price to come down as the volume of units purchased increases, it is unclear how long it will take before fuel cells become competitive for the transportation market. It could be 8–10 years.
Fortunately, initiating the hydrogen economy may not depend entirely on cheap fuel cells. There are other uses of hydrogen that can serve as a bridge to fuel cells over the next 5–10 years. Larger hybrid cars with internal combustion engines are expected soon. If their engines are adapted to use hydrogen, the combined efficiencies will be high and the cost per mile of hydrogen reasonable.
In addition, there are no overwhelming technological barriers to converting most of the 200 million vehicles on the highways in America today (and the 800 million worldwide) to use hydrogen fuel. Engineers estimate a company that converted 100,000 cars a year could convert an individual car to hydrogen fuel for less that $2,500. Although there are no conversion kits available today, a well-coordinated local or regional political initiative might initiate this process.
The construction of the first hydrogen refueling stations strategically placed in regional corridors could begin at the same time as the introduction of these hydrogen vehicles. Neither would have to come first. This would solve the so-called “chicken and egg problem.”
Municipal buses and city government vehicle fleets can also be hydrogen fueled without waiting for a refueling infrastructure, since they return to the same fueling station at night. Local and regional initiatives will be what provide us with a smooth and steady pathway to the hydrogen economy.
While hydrogen will be somewhat more expensive than gasoline in the early years of its introduction, this could easily be offset by collecting a portion of its extra cost from the price of gasoline. This mechanism is termed a “feebate”: the cost of hydrogen and gasoline at the pump are kept the same by collecting the extra cost of hydrogen from a slightly increased gasoline price. Because the cost of the feebate on the relatively small volumes of hydrogen fuel would be spread over the
infinitely larger volumes of gasoline, the impact of the feebate would not become noticeable to the consumer until hydrogen comprised roughly 10 percent of the total market. By then, the costs of producing hydrogen are likely to have dropped substantially.
Because hydrogen is the least dense substance in the universe, it must be compressed significantly to be able to supply energy equivalent to a comparable volume of gasoline. Compression tanks have been designed and crash-tested to address this issue. An average internal combustion engine in today's cars gets only 27 miles to a gallon of gasoline. A tank of hydrogen, compressed at 5,000 psi, would give the car a range of 190 miles. This tank will be larger, but lighter, than a tank of gasoline. Hydrogen is three times lighter than gasoline per Btu. (Tanks that carry compressed gases for industrial purposes are commonly at 3,500 psi. Pressures between 4,000 and 5,000 psi will soon be common.) According to the Electric Power Research Institute, 40 percent of all personal cars in the US are driven no more than 20 miles a day, and many millions more are driven less than 40 miles a day. Thus, a moderate-sized, 5,000 psi compressed hydrogen tank would get the range necessary to make many hydrogen vehicles viable.
Local politics can do it
The conversion to a hydrogen economy is not a problem of limited technologies but of political priorities. Citizens can influence the leadership at the state and regional levels even without federal cooperation. Visionary mayors can create the first “Hydrogen Cities.” Local citizens can join in regional task forces for finding the green energy sources appropriate for their geographic area. Cities can join with neighboring municipalities to create Regional Hydrogen Utility Districts, planning and implementing hydrogen refueling corridors, converting municipal fleets or bus services to run on hydrogen, and accessing potential sites for the introduction of
stationary fuel cells, such as schools, police head-quarters, or local airports.
Years ago, Buckminster Fuller saw fossil fuels as the “starter motor” for the industrial-technological society. He said it is time to move from the starter motor to the main engines, which are solar, wind, and ocean energies. By moving to the hydrogen economy, we will return to making our living within the steady income energies of nature. If we can shift from the starter motor to the main engines in time to prevent global warming, we may yet acquire the wisdom to direct the rest of our technologies towards a more positive effect on the living world.