Putting Plants to Work

Using the power of the sun is nothing new. People have had solar-powered calculators and buildings with solar panels for decades. But plants are the real experts: They’ve been using sunlight as an energy source for billions of years.

Ceils in the green leaves of plants work like tiny factories to convert sunlight, carbon dioxide, and water into¹ sugars and starches, stored energy that the plants can use. This conversion process is called photosynthesis. Unfortunately, unless you’re a plant, it’s difficult and expensive to convert sunlight into storable energy. That’s why scientists are taking a closer look at exactly how plants do it.

Some scientists are trying to get plants, or biological cells that act like plants, to work as miniature photosynthetic power stations. For example, Mafia Ghirardi of the National Renewable Energy Laboratory in Golden, Colo.², is working with green algae³. She’s trying to trick them into producing hydrogen⁴ instead of sugars when they perform photosynthesis. Once the researchers can get the algae working efficiently, the hydrogen that they produce could be used to power fuel cells in cars or to generate electricity.

The algae are grown in narrow-necked glass bottles to produce hydrogen in the lab. During photosynthesis, plants normally make sugars or starches. “But under certain conditions, a lot of algae are able to use the sunlight energy not to store starch, but to make hydrogen,” Ghirardi says. For example, algae will produce hydrogen in an air free environment. It’s the oxygen in the air that prevents algae from making hydrogen most of the time.

Working in an air free environment, however, is difficult. It’s not a practical way to produce cheap energy. But Ghirardi and her colleagues have discovered that by removing a chemical called sulfate from the environment that the algae grow in, they will make hydrogen instead of sugars, even when air is present.

Unfortunately, removing the sulfate also makes the algae’s cells work very slowly, and not much hydrogen is produced. Still, the researchers see this as a first step in their goal to produce hydrogen efficiently from algae. With more work, they may be able to speed the cells" activity and produce larger quantities of hydrogen.

The researchers hope that algae will one day be an easy-to-use fuel source. The organisms are cheap to get and to feed, Ghirardi says, and they can grow almost anywhere: “You can grow them in a reactor, in a pond. You can grow them in the ocean. There’s a lot of flexibility in how you can use these organisms.”

词汇:

panel /5pAnl/ n.嵌板，发热板，仪器板  

starch /stB:tF/ n. 淀粉

miniature /5minjEtFE/ adj.口巧．微型的

sulfate /5sQlfeit/ n. 硫酸盐，硫酸酯

carbon dioxide 二氧化碳  

photosynthesis /7fEutEu5sinWEsis/ n. 光合作用

algae /5AldVi:/ n. 水藻，海藻  

注释:    

1. convert … into…：将……转换为 ……     

2. Colo.：Colorado，（美国科罗拉多州）的缩写形式  

3. Green algae: 绿藻       

What does the writer say about plants concerning solar energy?

A:Plants are "the real experts in producing solar energy. B:Plants have been used to produce solar energy. C:Plants have been using solar energy for billions of years. D:Plants have been a source of solar energy.

The population of the United States is only 6% the world’s population, but Americans (1) one third of all the energy (2) in the world. This fact alone says that Americans need to use less energy. And because the price of energy had been rising very rapidly (3) the limited supplies of oil in particular, Americans are becoming aware to the need to (4) energy. In California we have a California Energy Commission which has set up in the past five years to (5) plan for our future energy rise. We have (6) laws in California to help us conserve energy. First of all, our houses in California have been very (7) of energy in the past. They were not (8) very carefully and so the heat would go out of the house very rapidly. Now we require that the homes have a (9) level of insulation, and so the homes built now are much more (10)
(11) , in transportation (12) a large percentage of oil energy is used, we need to develop more public transportation. In China, of course, you have a very good public-transportation system. And it is a (n) (13) for the kind of thing we need to develop more in the United States. Automobiles are also becoming more (14) The smaller automobile with efficient engine can help to conserve a large amount of energy along with planning our (15) more carefully.
Many different studies have shown that we could (16) our energy consumption by (17) half or two thirds and still have the (18) quality of life. And many different types of technologies are currently being researched as to (19) they can be built to use 20 energy and still supply the same service.

A:transportation B:travel C:energy D:automobiles

The population of the United States is only 6% the world’s population, but Americans (1) one third of all the energy (2) in the world. This fact alone says that Americans need to use less energy. And because the price of energy had been rising very rapidly (3) the limited supplies of oil in particular, Americans are becoming aware to the need to (4) energy. In California we have a California Energy Commission which has set up in the past five years to (5) plan for our future energy rise. We have (6) laws in California to help us conserve energy. First of all, our houses in California have been very (7) of energy in the past. They were not (8) very carefully and so the heat would go out of the house very rapidly. Now we require that the homes have a (9) level of insulation, and so the homes built now are much more (10)
(11) , in transportation (12) a large percentage of oil energy is used, we need to develop more public transportation. In China, of course, you have a very good public-transportation system. And it is a (n) (13) for the kind of thing we need to develop more in the United States. Automobiles are also becoming more (14) The smaller automobile with efficient engine can help to conserve a large amount of energy along with planning our (15) more carefully.
Many different studies have shown that we could (16) our energy consumption by (17) half or two thirds and still have the (18) quality of life. And many different types of technologies are currently being researched as to (19) they can be built to use 20 energy and still supply the same service.

A:transportation B:travel C:energy D:automobiles

According to the author energy security can only be achieved by ______.

A:using less oil in power generation B:replacing fossil fuels with more nuclear power C:seeking energy self - sufficiency D:expanding the sources of power supply

According to scientists, if the energy in the atmosphere were put under our control, what would happen

A:We have an inexhaustible supply of energy from it. B:This could bring the world to an energy crisis. C:The sources of energy on earth would become unreliable. D:We find ourselves in difficult position with environmental pollution.

The energy produced by the sun ______.

A:is easy to store B:poses similar problems to the other newer energy sources C:poses very few problems D:poses different problems from the other newer energy sources

第一篇Energy and Public Lands The United States boasts substantial energy resources. Federal lands provide a good deal of U.S. energy production; the U.S. Department of the Interior manages federal energy leasing, both on land and on the offshore Outer Continental Shelf. Production from these sources amounts to nearly 30 percent of total annual U.S. energy production. In 2000, 32 percent of U.S. oil, 35 percent of natural gas, and 37 percent of coal were produced from federal lands, representing 20,000 producing oil and gas leases and 135 producing coal leases. Federal lands are also estimated to contain approximately 68 percent of all undiscovered U.S. oil reserves and 74 percent of undiscovered natural gas. Revenues from federal oil, gas, and coal leasing provide significant returns to U.S. taxpayers as well as State governments. In 1999, for example, $553 million in oil and gas revenues were paid to the U.S. Treasury, and non-Indian coal leases accounted for over $304 million in revenues, of which 50 percent were paid to State governments. Public lands also play a critical role in energy delivery. Each year, federal land managers authorize rights of way for transmission lines, rail systems, pipelines, and other facilities related to energy production and use. Alternative energy production from federal lands lags behind conventional energy production, though the amount is still significant. For example, federal geothermal resources produce about 7.5 billion kilowatt-hours of electricity per year, 47 percent of all electricity generated from U.S. geothermal energy. There are 2,960 wind turbines on public lands in California alone, producing electricity for about 300,000 people. Federal hydropower facilities produce about 17 percent of all hydropower produced in the United States. Because of the growing U.S. thirst for energy and increasing public unease with dependence on foreign oil sources, pressure on the public lands to meet U.S. energy demands is intensifying. Public lands are available for energy development only after they have been evaluated through the land use planning process. If development of energy resources conflicts with management or use of other resources, development restrictions or impact mitigation measures may be imposed, or mineral production may be banned altogether.Geothermal resources, wind turbines, and hydropower facilities in Paragraph 4 are cited as examples to illustrate that

A:alternative energy production is no less than conventional energy production. B:they are the most typical conventional energy resources from public lands. C:geothermal resources are more important than the other two. D:the amount of alternative energy production from public lands is huge.

第一篇Energy and Public Lands The United States boasts substantial energy resources. Federal lands provide a good deal of U.S. energy production; the U.S. Department of the Interior manages federal energy leasing, both on land and on the offshore Outer Continental Shelf. Production from these sources amounts to nearly 30 percent of total annual U.S. energy production. In 2000, 32 percent of U.S. oil, 35 percent of natural gas, and 37 percent of coal were produced from federal lands, representing 20,000 producing oil and gas leases and 135 producing coal leases. Federal lands are also estimated to contain approximately 68 percent of all undiscovered U.S. oil reserves and 74 percent of undiscovered natural gas. Revenues from federal oil, gas, and coal leasing provide significant returns to U.S. taxpayers as well as State governments. In 1999, for example, $553 million in oil and gas revenues were paid to the U.S. Treasury, and non-Indian coal leases accounted for over $304 million in revenues, of which 50 percent were paid to State governments. Public lands also play a critical role in energy delivery. Each year, federal land managers authorize rights of way for transmission lines, rail systems, pipelines, and other facilities related to energy production and use. Alternative energy production from federal lands lags behind conventional energy production, though the amount is still significant. For example, federal geothermal resources produce about 7.5 billion kilowatt-hours of electricity per year, 47 percent of all electricity generated from U.S. geothermal energy. There are 2,960 wind turbines on public lands in California alone, producing electricity for about 300,000 people. Federal hydropower facilities produce about 17 percent of all hydropower produced in the United States. Because of the growing U.S. thirst for energy and increasing public unease with dependence on foreign oil sources, pressure on the public lands to meet U.S. energy demands is intensifying. Public lands are available for energy development only after they have been evaluated through the land use planning process. If development of energy resources conflicts with management or use of other resources, development restrictions or impact mitigation measures may be imposed, or mineral production may be banned altogether.Geothermal resources, wind turbines, and hydropower facilities in Paragraph 4 are cited as examples to illustrate that

A:the amount of alternative energy production from public lands is huge. B:alternative energy production is no less than conventional energy production. C:they are the most typical conventional energy resources from public lands. D:geothermal resources are more important than the other two.