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리딩지문
As fossil fuels rapidly dwindle, people are starting to explore alternative energy sources for the 21th centruy and beyound. Hydrogen energy is increasingly viewed as an attractive new source with many fuel and energy applications including poweing vehicles, running turbines or fuel cells to produce electricity, and generating heat and electricity for buildings.
One major reason for hydrogen's potential is that it is the third most abundant element on the earth's surface, where it is found primarily in water. That is, hydrogen is produced by using electricity or sunlight to split water into hydrogen and oxygen. Thus, its widespread avaliability means hydrogen energy would be a much cheaper alternative energy source to nonrenewable fossil fuels, which are projected to be depleted as early as forty years from now.
In addition, hydrogen energy is very environmentally friendly, barely producing any emissions or by-products. It can also be isolated by using renewable sources of energy such as the wind and the sun to split water, a method that is eco-friendly as well.
Another benefit of hydrogen is that it is easy to store and transport. Hydrogen can be compressed into a liquid or gas and then transported in a tank. In addition, with the advent of new technology to store hydrogen in the form of a solid using a hydrogen storage alloy, transport concerns of thi volatile resource disppear. In this way, we can simply combine metal and hydroge, transport the alloy in a stable condition, and then heat up the alloy to get the hydrogen back for use.
리스닝 지문 :
Ok, let's take a look at hydrogen energy today. While it may look like a promising source of energy, on closer inspection, it doesn't pass the test. First of all, although water is widely available, the cost of electricity required to obtain hydrogen from water is one huge barrier... in fact did you know that the per-kilogram cost of renewable hydrogen is much higher than the per-gallon cost of gasoline?
Hmmm, what else?... Well, when we look at splitting water to obtain hydrogen, we have to take into account that we'll still be relying on electricity, which isn't really environmentally friendly. In other words, the harm to our planet doesn't disappear, but it simply moves somewhere else in the process of producing the energy. On top of that, when we look at using renewable energy sources to split water, it's not always feasible because, well... we can't control the weather! The wind won't blow and the sun won't shine when we need it to.
Another drawback to hydrogen energy is that it's not as easy to store and transport as you might have believed. Not only is transforming hydrogen into a liquid or a gas a difficult task, but hydrogen in these forms is very volatile and dangerous because it ignites fast. When it comes to a hydrogen storage alloy, its extraordinary weight makes it an unfeasible choice. For instance, if you're going to build a hydrogen-fueled car storing the energy in the alloy, the fuel tank alone would weigh more than 300kg! |