For questions 1-7, mark Y (for YES) if the statement agrees with the
information given in the passage; N (for NO) if the statement contradicts the
information given in the passage; NG (for NOT GIVEN) if the information is
not given in the passage. For questions 8-10, complete the sentences with the
information given in the passage. THE HYDROGEN ECONOMY It
seems-like every day there is a new announcement in the news about automobiles
powered by fuel cells. The promises are great, since fuel cells have the
potential to very quickly double the efficiency of cars while significantly
reducing air pollution. At the same time, there have been news
stories for decades about the problems associated with petroleum. Everything
from oil spills to ozone(臭氧) alerts to global warming gets blamed on our
dependence on fossil(化石) fuels. These two forces are leading the
world toward what is broadly known as the hydrogen economy. If the predictions
are true, over the next several decades we will all begin to see an amazing
shift away from the fossil fuel economy we have today toward a much cleaner
hydrogen future. Problems with the fossil fuel economy
While fossil fuels have played an important role in getting society to the
point it is at today, there are four big problems that fossil fuels
create: Air pollution—When cars burn gasoline, the internal
combustion engine also produces: Carbon monoxide, a poisonous
gas Nitrogen oxides, the main source of urban smog
Unburned hydrocarbons, the main source of urban ozone
Environmental pollution—The process of transporting and storing oil has a
big impact on the environment whenever something goes wrong. An oil spill,
pipeline explosion or well fire can create a huge mess. Global
warming—The carbon dioxide coming out of every car’s tailpipe is a greenhouse
gas that is slowly raising the temperature of the planet. The ultimate effects
are unknown, but it is a strong possibility that, eventually, there will be
dramatic climate changes that affect everyone on the planet.
Dependence—The United States, and most other countries, cannot produce
enough oil to meet demand, so they import it from oil-rich countries. That
creates an economic dependence. When Middle East oil producers decide to raise
the price of oil, the rest of the world has little choice but to pay the higher
price. Advantages of the hydrogen economy The hydrogen
economy promises to eliminate all of the problems that the fossil fuel economy
creates. Therefore, the advantages of the hydrogen economy include:
The elimination of pollution caused by fossil fuels—When hydrogen is used
in a fuel cell to create power, it is a completely clean technology. The only
byproduct is water. There are also no environmental dangers like oil spills to
worry about with hydrogen. The elimination of greenhouse
gases—If the hydrogen comes from the electrolysis of water, then hydrogen adds
no greenhouse gases to the environment. There is a perfect cycle—electrolysis
produces hydrogen from water, and the hydrogen recombines with oxygen to create
water and power in a fuel ceil. The elimination of economic
dependence—The elimination of oil means no dependence on the Middle East and its
oil reserves. Distributed production—Hydrogen can be produced
anywhere that you have electricity and water. People can even produce it in
their homes with relatively simple technology. The problems with
the fossil fuel economy are so great, and the environmental advantages of the
hydrogen economy so significant, that the push toward the hydrogen economy is
very strong. Technological Hurdles(障碍) The big
question with the hydrogen economy is, "Where does the hydrogen come from"
After that comes the question of transporting, distributing and storing
hydrogen. Hydrogen tends to be large and tricky in its natural gaseous
form. Once both of these questions are answered in an economical
way, the hydrogen economy will be in place. Where does the hydrogen come
from There are two possible sources for the
hydrogen: Electrolysis of water—Using electricity, it is easy to
split water molecules to create pure hydrogen and oxygen. One big advantage of
this process is that you can do it anywhere. For example, you could have a box
in your garage producing hydrogen from tap water, and you could fuel your car
with that hydrogen. Reforming fossil fuels—Oil and natural gas
contain hydrocarbons—molecules consisting of hydrogen and carbon. Using a device
called a fuel processor or a reformer, you can split the hydrogen off the carbon
in a hydrocarbon relatively easily and then use the hydrogen. You discard the
leftover carbon to the atmosphere as carbon dioxide. The second
option is, of course, slightly perverse(不正当的). You are using fossil fuel as the
source of hydrogen for the hydrogen economy. This approach reduces air
pollution, but it doesn’t solve either the greenhouse gas problem or the
dependence problem. However, it may be a good temporary step to take during the
transition(转变) to tile hydrogen economy. The interesting thing
about the first option is that it is the core of the real hydrogen economy. To
have a pure hydrogen economy, the hydrogen must be derived from renewable
sources rather than fossil fuels so that we stop releasing carbon into the
atmosphere. Having enough electricity to separate hydrogen from water, and
generating that electricity without using fossil fuels, will be the biggest
change that we see in creating the hydrogen economy. Where will
the electricity for the electrolysis of water come from Currently, about 68
percent of the electricity produced in the United States comes from coal or
natural gas. All of that genera ting capacity will have to be replaced by
renewable sources in the hydrogen economy. Right now there are
several different ways to create electricity that do not use fossil
fuels: Nuclear power
Hydroelectric dams Solar cells
Wind
turbines Geothermal power
Wave and tidal power
Co-generation How do you store and transport the
hydrogen Hydrogen is a large gas of its kind, and it is not
nearly as easy to work with as gasoline. Compressing the gas requires energy,
and compressed hydrogen contains far less energy than the same volume of
gasoline. However, solutions to the hydrogen storage problem are
surfacing. For example, hydrogen can be stored in a solid form
in a chemical called sodium borohydride. Once the storage problem is solved and
standardized, then a network of hydrogen stations and the transportation
infrastructure will have to develop around it. The main barrier to this might be
the technological sorting-out process. Stations will not develop quickly until
there is a storage technology that clearly dominates the marketplace. For
instance, if all hydrogen-powered cars from all manufacturers used sodium
borohydride, then a station network could develop quickly; that sort of
standardization is unlikely to happen rapidly, if history is any
guide. Prospects for the future You will hear more and
more about the hydrogen economy in the news in the coming months, because the
drumbeat is growing louder. The environmental problems of the fossil fuel
economy are combining With breakthroughs(突破) in fuel-cell technology, and the
pairing will allow us to take the first steps. The most obvious
step we will see is the marketing of fuel-cell-powered vehicles. Although they
will be powered initially by gasoline and reformers, fuel cells represent two
major improvements over the internal combustion engine: They are
about twice as efficient. They can significantly reduce air
pollution in cities. Possible sources for the hydrogen are both electrolysis of water and ______.