Car manufacturers and governments have been eagerly seeking a replacement for the automobile's main source of power, the internal-combustion engine. By far the most promising alternative source of energy for cars is the hydrogen-based fuel-cell engine, which uses hydrogen to create electricity that, in turn, powers the car. Fuel-cell engines have several advantages over internal-combustion engines and will probably soon replace them.
One of the main problems with the internal-combustion engine is that it relies on petroleum, either in the form of gasoline or diesel fuel. Petroleum is a finite resource; someday, we will run out of oil. The hydrogen needed for fuel-cell engines cannot easily be depleted. Hydrogen can be derived from various plentiful sources, including natural gas and even water. The fact that fuel-cell engines utilize easily available, renewable resources makes them particularly attractive.
Second, hydrogen-based fuel cells are attractive because they will solve many of the world's pollution problems. An unavoidable by-product of burning oil is carbon dioxide, and carbon dioxide harms the environment. On the other hand, the only byproduct of fuel-cell engines is water.
Third, fuel-cell engines will soon be economically competitive because people will spend less money to operate a fuel-cell engine than they will to operate an internal-combustion engine. This is true for one simple reason: a fuel-cell automobile is nearly twice as efficient in using its fuel as an automobile powered by an internal-combustion engine is. In other words, the fuel-cell powered car requires only half the fuel energy that the internal-combustion powered car does to go the same distance.
The reading is correct in pointing out the problems associated with oil-powered cars. Yes, oil is a finite resource, and yes, burning oil harms the environment. However, the reading is way too optimistic in its assessment of hydrogen-based fuel-cell engines. Hydrogen is not the solution to these problems.
First, hydrogen is not as easily available as the passage indicates. Although it's present in common substances like water, it's not directly useable in that form. For using a fuel-cell engine, hydrogen must first be obtained in a pure liquid state. This pure liquid hydrogen is a highly artificial substance. It's technologically very difficult to produce and store liquid hydrogen. For example, it must be kept very very cold at minus 253 degrees Celsius. Imagine the elaborate cooling technology that's required for that! So hydrogen is not such a practical and easily available substance, is it?
Second, using hydrogen would not solve the pollution problems associated with cars. Why? Producing pure hydrogen creates a lot of pollution. To get pure hydrogen from water or natural gas, you have to use a purification process that requires lots of energy that's obtained by burning coal or oil. And burning coal and oil creates lots of pollution. So although the cars would not pollute, the factories that generated the hydrogen for the cars would pollute.
Third, there won't necessarily be any cost savings when you consider how expensive it is to manufacture the fuel-cell engine. That's because fuel-cell engines require components made of platinum, a very rare and expensive metal. Without the platinum components in the engine, the hydrogen doesn't undergo the chemical reaction that produces the electricity to power the automobile. All the efforts to replace platinum with a cheaper material have so far been unsuccessful.
Main points: Fuel-cell have several advantages over internal-combustion engines.
Sub point 1: Internal-combustion relies on petroleum and Hydrogen is clean and renewable.
Sub point 2: Full cells can solve pollution problems.
Sub point 3: Full-cell soon can be economically competitive.
Attitude: R is too optimistic. (Hydrogen-based full-cell is not the solution.)
Sub Point 1: Hydrogen not easily available. (Need in a pure liquid state, need very cold temperature.)
Sub Point 2: Hydrogen does not solve the pollution. ( Producing creates a lot of pollution, Burning coal or oil.)
Sub Point 3: No cost saving since expensive to manufacture. (Require platinum, expensive.)
The lecturer points out several problems with the use of hydrogen-based fuel-cell engines which support her claim that substituting them for internal-combustion engines is technologically unfeasible, environmentally unfriendly, and economically unviable.
First, the lecturer states that it is impractical to replace internal-combustion engines with fuel-cell engines because using the latter requires hydrogen in a pure liquid form, which is technologically challenging to both obtain and store. However, the reading passage argues that because hydrogen can be extracted from many sources including water, fuel-cell engines powered by this infinite source of energy are an extremely attractive alternative.
Second, the lecturer refutes the claim in the reading that hydrogen cells are environmentally friendly. She argues that although engines that use hydrogen cells produce less pollution, the manufacturing of hydrogen cells generates large amounts of harmful by-products due to the burning of fossil fuels in the purification process.
在第二点environmental unfriendly 辩论上，作者直接陈述L认为R所说的电池很环保是错误的。L解释虽然电池引擎不会产生太多污染，但是制造电池引擎的提纯过程消耗了大量的化石燃料也是不环保的。
Third, although the reading suggests that hydrogen-based engines are more fuel-efficient and thus economically competitive than internal-combustion engines, the lecturer argues that such an advantage is undermined by the fact that fuel-cell engines are extremely expensive to manufacture, requiring the addition of platinum, a very rare and expensive material.
1. The lecturer /points out several problems(表达反对关系)/ with /the use of hydrogen-based fuel-cell engines(论文主要事件)/ which support her claim that /substituting them for internal-combustion engines(B的意见)/ is /technologically unfeasible, environmentally unfriendly, and economically unviable.(三个分论点)/