The World in 2050_ Four Forces Shaping Civilization's Northern Future - Laurence C. Smith [32]
Let’s start with the last. First, it is important to remember hydrogen is not truly an energy source but, like electricity, an energy carrier. Pure hydrogen makes a wonderful fuel but isn’t just lying around for the taking.117 Instead, just like making electricity, it must be generated using energy from some other source.118 A feedstock material is also needed from which to strip hydrogen atoms. The most common feedstocks in use today are natural gas or water, but others, like coal or biomass, are also feasible sources of hydrogen. Energy is used to crack the hydrogen from the feedstock—for example through electrolysis of water119—yielding a portable fuel in gas or liquid form. One kilogram is packed with about the same energy as a gallon of gasoline.
But unlike gasoline, the hydrogen is not then burned in a combustion engine. It is instead converted to electricity on-site, by feeding it into a fuel cell. Fuel cells essentially reverse the hydrolysis reaction, combining hydrogen with oxygen to create electricity and water. The newly made electricity is then used to power the car, appliance, furnace, or whatever, with the water by-product either released as vapor or recycled. Like plug-in electrics, fuel-cell cars release no tailpipe pollution or greenhouse gases (besides water vapor120). However, they are released at the hydrogen plant, unless fossil fuels or biomass can be avoided as sources of energy or feedstocks. In principle, solar, wind, or hydroelectric power could be used to split hydrogen from a water feedstock, making the entire process quite pollution-free from beginning to end.
Sounds wonderful, and many energy experts and futurists believe that one day we will have a full-blown hydrogen economy. The ultimate dream is to use solar energy to split hydrogen from seawater, thus providing the world with an infinite supply of clean hydrogen fuel—and even some freshwater as a bonus—with no air pollution or greenhouse gases. But nothing like that will be in place by 2050.
Years of research are needed to resolve a rat’s nest of challenges concealed within the previous two paragraphs, with major technology advances and cost reductions necessary in all areas.121 Basic research in hydrogen manufacture, transport, and fuel cells is still lacking. The cost of making a fuel-cell vehicle is extremely high. A completely new physical infrastructure is required, including manufacturing plants, pipelines, distribution and bottling centers, and filling stations. Hydrogen is explosive, so there are many safety issues to be resolved, like how to safely pack enough of it into a vehicle to drive three hundred miles, comparable to vehicles today. One way is to use highly pressurized hydrogen, but the collision safety of ten-thousand-psi tanks remains unproven. Early hydrogen supplies are all but certain to be made from fossil fuels, and thus will help little with reducing carbon emissions.
In light of these challenges, most experts agree that a hydrogen economy lies at least thirty to forty years in the future, at which point hydrogen fuel-cell cars might possibly be the new “next-generation” technology that plug-in hybrids are today. Under the conservative ground rules of our thought experiment, we will assume the world will not convert to a hydrogen economy by the year 2050.
Running on Moonshine and Wood
Unlike hydrogen, biofuels offer a quicker solution to the liquid-fuels problem. Like gasoline, they are refined hydrocarbons that are burned in an internal combustion engine. They use the same filling stations and, with only slight modifications, the same car and truck engines of today.122 The only real difference between biofuels and current fuels is that they are made from contemporary organic matter rather than ancient organic matter, and are somewhat cleaner. They emit similar levels