At the moment, hydrogen seems to be the most practical way to power vehicles that do not emit carbon dioxide, the principal greenhouse gas. But despite considerable research, many hurdles remain. Here are some questions and answers:
Q: Where does hydrogen come from?
A: Hydrogen, an odorless, colorless gas, is the lightest and most plentiful element in the universe. It is found in water and in most organic matter, but it is usually bound with other elements. For that reason, it is called an energy carrier, meaning that energy has to be expended to extract it.
Q: But can't it be burned in an engine?
A: Fuels like coal, natural gas or oil can be taken from the ground and used with relatively little energy-intensive processing. But hydrogen must be turned into a fuel — and because it takes so much energy to produce, it should not be thought of as a direct replacement for fuels like gasoline. Rather, it is energy in a portable form, somewhat akin to electricity.
Q: Then why bother?
A: Because aside from being plentiful, it is very clean. Cars running on hydrogen produce very little tailpipe pollution and no greenhouse gases — they leave only a trail of water. In this way, cars running on fuel cells — which produce electricity by a chemical reaction of hydrogen and oxygen — would produce no tailpipe emissions.
Q: What is hydrogen used for today?
A: It has several uses. About 8.2 million tonnes of hydrogen are produced annually in the US, mostly for chemical production, petroleum refining and metal treatment.
Q: Can nuclear power be a source of inexpensive hydrogen?
A: Yes. Kenneth Schultz, operations director of the energy group at General Atomics, a research and development firm in San Diego, said that by 2025 the nuclear industry could be able to produce hydrogen for US$1.50 to US$2 a kilogram. But Amory Lovins, chairman and chief scientist at the Rocky Mountain Institute, a nonprofit energy research organization in Snowmass, Colorado, described both the process and the price as "aspirational."
Q: How will we use hydrogen in a motor vehicle?
A: There are several options. In the most common prediction, compressed hydrogen gas is stored in a reinforced tank aboard a car, then fed to a fuel cell. The cell is not an engine, but a small chemical factory that converts the pressurized gas to electricity, which runs an electric motor. The only emission is water.
Liquid hydrogen offers excellent energy density per volume, but it would have to be carried in cryogenic tanks because hydrogen doesn't liquefy until it reaches -97°C.
Metal hydrides offer an opportunity to store hydrogen in solid form, but such a system is heavy and therefore reduces the vehicle's travel range.
Hydrogen can also be burned in internal combustion engines. BMW and Ford, among others, have programs exploring hydrogen combustion, and BMW has a small fleet of bi-fuel 12-cylinder Hydrogen 7 vehicles on the road. No carbon dioxide is produced when hydrogen is burned.
Q: Is hydrogen safe? Isn't it very explosive?
A: That's the question on everybody's minds. Hydrogen definitely has safety challenges. It is extremely flammable (as the 1937 Hindenburg accident demonstrated), and burns without a visible flame while radiating very little heat. Because it is the lightest element, it can easily leak out of very small holes, pipe joints and even some metals. Once leaked, it can concentrate in a sealed space like a garage roof, presenting a fire hazard because hydrogen in a confined space can catch fire more easily than gasoline.
But hydrogen's lightness is also an advantage, because the gas dissipates in the air 12 times faster than gasoline vapor, making it harder for a fire to start. And automotive hydrogen fuel tanks, often made of composite materials, are designed to minimize leakage even in a severe impact. Quantum Fuel Systems of Irvine, California, says the hydrogen tanks that it makes go through two dozen tests and are shot with guns, suspended over fire, put through pressure cycles and subjected to temperatures ranging from -40° to 54°C.
Q: How will hydrogen be distributed to gas stations?
A: Very carefully, because hydrogen is such an escape artist that it is difficult and expensive to move. The hydrogen infrastructure is embryonic: There are about 1,130km of hydrogen pipelines in the country, compared with 1.6 million kilometers for natural gas. One challenge is that hydrogen pipelines have to be very tightly sealed and specially treated so that they do not become dangerously brittle. Trucking hydrogen not only burns fossil fuel, but requires energy-consuming compression, and even then a truck can carry far less energy than an equivalent gasoline tanker.
Q: How long before I can buy a hydrogen-powered car?
A: Honda says it will offer a limited number of its new-generation FCX fuel-cell vehicles for lease in 2008. Several companies, including BMW, General Motors and DaimlerChrysler, are building test fleets of as many as 100 hydrogen vehicles. Currently, the high cost of manufacturing the vehicles and setting up the hydrogen infrastructure mean it could be two decades before affordable hydrogen-powered cars and trucks are widely available. And it might never happen at all.
Growing up in a rural, religious community in western Canada, Kyle McCarthy loved hockey, but once he came out at 19, he quit, convinced being openly gay and an active player was untenable. So the 32-year-old says he is “very surprised” by the runaway success of Heated Rivalry, a Canadian-made series about the romance between two closeted gay players in a sport that has historically made gay men feel unwelcome. Ben Baby, the 43-year-old commissioner of the Toronto Gay Hockey Association (TGHA), calls the success of the show — which has catapulted its young lead actors to stardom -- “shocking,” and says
The 2018 nine-in-one local elections were a wild ride that no one saw coming. Entering that year, the Chinese Nationalist Party (KMT) was demoralized and in disarray — and fearing an existential crisis. By the end of the year, the party was riding high and swept most of the country in a landslide, including toppling the Democratic Progressive Party (DPP) in their Kaohsiung stronghold. Could something like that happen again on the DPP side in this year’s nine-in-one elections? The short answer is not exactly; the conditions were very specific. However, it does illustrate how swiftly every assumption early in an
Inside an ordinary-looking townhouse on a narrow road in central Kaohsiung, Tsai A-li (蔡阿李) raised her three children alone for 15 years. As far as the children knew, their father was away working in the US. They were kept in the dark for as long as possible by their mother, for the truth was perhaps too sad and unjust for their young minds to bear. The family home of White Terror victim Ko Chi-hua (柯旗化) is now open to the public. Admission is free and it is just a short walk from the Kaohsiung train station. Walk two blocks south along Jhongshan
Jan. 19 to Jan. 25 In 1933, an all-star team of musicians and lyricists began shaping a new sound. The person who brought them together was Chen Chun-yu (陳君玉), head of Columbia Records’ arts department. Tasked with creating Taiwanese “pop music,” they released hit after hit that year, with Chen contributing lyrics to several of the songs himself. Many figures from that group, including composer Teng Yu-hsien (鄧雨賢), vocalist Chun-chun (純純, Sun-sun in Taiwanese) and lyricist Lee Lin-chiu (李臨秋) remain well-known today, particularly for the famous classic Longing for the Spring Breeze (望春風). Chen, however, is not a name
RSS