H for Hybrid or Hydrogen?

Since the environmentalists and green hippies have raised the issue of global warming, every single car manufacturers are looking for new and clean way to power cars and reduce green house gas emission, and they basically went to two main directions, Hybrid and Hydrogen. So here is my brief analysis of them.

Hybrid

A hybrid vehicle uses a combination of two or more than two different energy source; they can be any two, for instance, petrol and electric, hydrogen and petrol, etc. But most commonly, hybrid car nowadays refers to hybrid electric vehicles, which is the combination of an internal combustion engine and an electric motor; those vehicles are designed and developed by car manufactures in response to air pollution, greenhouse gas emissions and global warming issues.

There are two different types of hybrid electric car; the difference is where the electricity comes from. One is normal hybrid, which uses the onboard gasoline engine to generate and charge the batteries. The other is plug-in hybrid, which uses a plug to connect to the electric grid to charge the batteries. However, those hybrid cars also uses regenerative braking technology to capture the kinetic energy produced by braking and convert to electricity. No matter what kind of hybrid it is, a hybrid car usually consumes less fuel and produce less greenhouse gas to cover a certain distance than a normal petrol car of the same size. And as more people are concerning the global warming issues and fuel prices, hybrid cars are in high demand in the recent years.

However, there are a lot of debate and argument about hybrid electric vehicles. First of all is the cost of owning one. Although a hybrid car uses less gas and can save a few dollars in the fuel bill, it is more expensive to buy than the same size non hybrid car in the first place. And then there is service cost, because the life of the batteries in the car does not last as long as the car itself and will become less efficiency throughout the years, the batteries have to be changed once a few years. Secondly is the energy used and the environmental damage caused during the production of the hybrid cars, which is usually the aspect largely ignored by most hybrid car buyers. Take the top seller Toyota Prius for example; the manufacture has literally destroyed the planet in order to make the car eco friendly. The nickel that used to make the batteries to power the electric motor comes from a mine in Canada, and then shipped to Europe to be refined and then sent to China to be turned into foam to send to Japan to be put into the batteries in the car. In fact, it uses more energy to produce a Toyota Prius than a Hummer and in the long term does more environmental damage than a Land Rover Discovery. Apart from that, the real efficiency and economy of a hybrid car has been doubted as well. Because a hybrid car carries two different type of motor and a pack of batteries onboard, it is heavier than a single motor car of the same size, so the question will be is it worth it to carry the extra weight to be able to produce another type of energy to then be used to transport these extra weight around. One extreme example will be in the Formula 1, some of the F1 teams use a KERS (Kinetic Energy Recovery Systems) in 2009 season which uses heat from the brakes to charge a battery up to a point so the driver can use that extra energy as a boost when overtaking. But the KERS added an extra 50kg to the car which makes the car slower than other cars at the first place. Even on a normal everyday car, some diesel models can manage to use less fuel than hybrid cars in the same distance and driving patterns. More than that, part of the electricity in the battery is produced by the petrol motor, so the so called clean energy is actually from dirty fuel, and quite a few of the energy will be lost when convert to electricity due to the efficiency of the battery and mechanical friction, and more will be lost when using those electricity. This problem seems to be solved when plug-in hybrid was introduced, but let us not forget where the electricity of the electric grid comes from, usually from coal burning, greenhouse gas emission power stations. The economy of a hybrid car also heavily depends on the way it is driven. Due to the different performance of the car, the 1.5L Toyota Prius been driven aggressively uses more fuel than a 4L BMW M3 doing the same maneuver. Last but not least is the styling of the hybrid, the looks of most current hybrid cars are considered as ugly, not sexy and uncool by any normal human beings.

Hydrogen

Hydrogen itself is regarded by almost everyone as clean energy, because the only thing produced by burning it is water. There are two way of using hydrogen as power source in cars at the moment, one is directly burn hydrogen in an internal combustion engine, the other is hydrogen fuel cell.

The hydrogen internal combustion engine is basically the same as a petrol internal combustion engine, only slightly modified to run on hydrogen, and it burns the hydrogen in the same method as petrol. However, for the same engine, when using hydrogen the power output is up by 20% more than using petrol. In theory, any type of existing internal combustion engine, V6, V8, wankel rotary, etc, can be converted to run on hydrogen, which can be a significant saving for automotive industry in retooling, and it can be serviced by the same technician who is used to service traditional cars. Most people knows that the product of burning hydrogen is water, but when combustion hydrogen with air, it also produce oxides of nitrogen just like the petrol engine does, due to there is 78% of nitrogen in the air, and oxides of nitrogen, apart from it is a greenhouse gas, can also cause lung damage and heart disease.

Hydrogen fuel cell combines hydrogen with oxygen from the air to produce water and electricity, the electricity then be used to power electric motors which drives the car. Currently, many car manufacturers are researching and developing hydrogen fuel cell power unit, and there are already many experimental vehicles in operation, however, the cost of producing hydrogen fuel cell is still very high and the power output is low. There are more issues, hydrogen fuel cell is fragile and can not withstand bumps and vibrations. More than that, because it produce water when it is working, and water freezes below 0°C, which means, the fuel cell will not start to work in freezing temperature, in other words, the user can not start his hydrogen fuel cell car to go to work in the morning in winter. Above all that, a hydrogen fuel cell car is much heavier than a hydrogen internal combustion engine car due to the weight of the fuel cell and battery pack carried on board, it will affect the performance of the car and the power used to move the package around may not worth it to have it in the first place.

One common problem for all hydrogen vehicles is, of course, the hydrogen itself. Although the element hydrogen is everywhere in nature, it is always stuck to something, not in its pure form, which means hydrogen has to be produced, not like oil, which can be just dug out and refined. And currently hydrogen is produced by using fossil fuel to separate carbon and hydrogen from methane, the process produces huge amount of greenhouse gas, so big that in the overall cycle, a hydrogen vehicle is more polluting than any modern petrol or diesel cars. A cleaner way will be to electrolyze water, but only when the electricity is coming from renewable energy power plants like windmills, solar panels or at least nuclear, not from burning coal. Since it takes energy to produce hydrogen, why not to use the energy to charge batteries in the first place? Another problem comes after hydrogen is produced, transport and store it. Due to the nature of hydrogen, it can either be stored as liquid in cryogenic tank which keeps the temperature at 252.87°C, or compressed to 5000 psi to 10,000 psi, to achieve any of the methods is hard and dangerous. Even though, it still takes considerably larger amount of space than petrol, in a car or a service station. Then is the hydrogen infrastructure, it takes way to much to build that it will remain largely unavailable to most countries and people.

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