Tuesday, 28 April 2009

Reading Debate; Hydrogen Vs Electric Car




Top industry experts will converge in Reading on Wednesday to debate the future of alternative cars and ask if the Government’s drive for consumers to buy electric is 'pushing hydrogen vehicles off the road'. The event takes place on Wednesday (29 April), from 6pm – 9pm at Foster Wheeler House, Shinfield Park, Reading.

Gasoline cars will one day be phased out; perhaps the replacement will be hydrogen fuel cell powered vehicles or electric vehicles. Both have pros, as well as many cons, quite a few of which are simply due to the early stages they are in.

Let’s look at hydrogen fuel cells first. When burned in an engine, the only emissions giving off is water, so a hydrogen powered vehicle is a zero emission vehicle. Hydrogen is also a better fuel than gasoline, it actually has the highest energy content per unit of weight of any known fuel. Hydrogen is also a very abundant element, though currently made by using fossil fuels, such as natural gas, coal, and oil. Also, hydrogen can be extracted from water, and we all know there’s a lot of water on this planet. Also, the technology to store hydrogen efficiently is still not ready yet.

One of the biggest disadvantages to a hydrogen fuel cell powered vehicle is the difficulty in refilling the hydrogen. Were these cars to become extremely popular, it would be possible to replace modern gas stations with hydrogen stations, but this would cost billions to do. As it is right now, hydrogen refills would be almost impossible to find outside of a few major cities.

In recent years, electric cars have been coming back on the scene in force. There are many hybrid models that have been available for a few years, and this year the first fully electric cars were released to consumers. Modern fully electric vehicles have a lot going for them. They are considered Zero Emission Vehicles (ZEV), since when they are running they give off no emissions. However, they are powered from the modern power grid, most of which is fossil fuel and gives off emissions. Modern electric vehicles have a range of about 250 miles. They can also store power during the day when it can be less in demand.

The main disadvantage electric vehicles have is that we are used to filling up, a recharge is not as simple as stopping at a gas station. A full recharge can take anywhere from five to eight hours – that’s just fine if you are commuting, but not practical for a long road trip. GM has proposed an answer to the distance difficulty by introducing the Volt – an electric vehicle equipped with an auxiliary motor designed to recharge the battery and extend the potential driving distance to as far as 600 miles. The auxiliary motor could be powered by gasoline, diesel, ethanol, or hydrogen.

Ethanol from corn or sugar cane(or soy biodiesel) requires land that puts pressure on the food supply, and it also requires petroleum to be grown and harvested. Ethanol from biomass decreases the need for fossil fuels and can be made from waste agriculture, but it is still requires vast land to fuel even a small percentage of vehicles, the technology is still in the laboratory phase, and it requires building out a distribution infrastructure.

Hydrogen fuel cell technology currently requires three to four times more energy to produce than it later generates, while plug-in critics maintain that battery technology is not advanced enough for long distance driving, and that the electricity grid would be overstretched if an entire nation attempted to recharge its cars.

The technology for mainstream electric cars is also not quite ready for all the major manufacturers to stop making gasoline powered cars, but it’s much closer than hydrogen currently.


http://www.wired.com/autopia/2007/03/hydrogen_vs_bat
http://ezinearticles.com/?Hydrogen-Fuel-Cell-Cars-vs-Electric-Cars---Which-Is-Really-The-Car-Of-The-Future?&id=555594
http://www.mindsinmotion.net/index.php/mim/themes/hydrogen_for_mobility/opinion/hydrogen_vs_electric_the_battle_continues

Institution of Mechanical Engineers, 0207 304 6888 or email media@imeche.org.

5 comments:

Digital Streetfighter said...

If you want to save the planet hydrogen is the way forward. If you want to TRY and save the planet electricity is the way forward. Depends what your end goal is.

Physics Mike MSc MPhys said...

Digital Streetfighter I do not think you fully understand the hydrogen generation process. We cannot simply suck it up out of the air. We have to spend alot of energy converting it to usable liquid hydrogen which can be stored in a compressed format for transportation.

So we have a system where we use fossil fuel and nuclear power stations to generate electricity. This electricity is used to generate hydrogen. This hydrogen is then used to generate elecricity in a car. The middle section is completely pointless other than to avoid long recharges. This downside can easily be avoided by battery swap stations where we pay to swap our near empty battery pack with a full one.

This reduction in efficiency will cost the planet. Google Ulf Bossel hydrogen to see some real sums and some hard thinking from science and not the oil companies who want to retain control of our transportation energy supply.

From the sums I have seen a hydrogen car is 23% efficient compared to an electric car which is 69% efficient.

Efficiency is the name of the game and hydrogen cars just dont cut it. We will have to build 3 power stations for every one to replace the energy from oil for hydrogen vs electric cars.

Electric cars also make good capacitors to keep the grid topped up overnight when considering solar power generation.

Adrian Windisch said...

Well said Mike, Hydrogen seems a long way off. But because the right wing in the USA pushed it as the future; some people think its great.

I suggest Digital Streetfighter that you go to the debate tonight.

luxematic said...

Hydrogen seems to be the only solution right now. But there isn't a technology yet cheap enough to make this as a source of fuel for all of us. As for the electric vehicles, sure it is a great idea. But have you ever thought about what would happen if a certain number of people would charge their vehicles at the same time?

wildlifer said...

Mike, it seems that we can now simply suck hydrogen out of the air...

MIT recently developed solar technology that can split water into hydrogen and oxygen without using exotic, expensive materials.
http://web.mit.edu/newsoffice/2008/oxygen-0731.html

If everyone used this technology at home, you wouldn't need centralized production facilities nor a need to transport energy. This would bring the number of processes for using hydrogen down to 3... electrolysis, compression/storage and fuel cell conversion to electricity. With no need for heavy batteries that lose their capacity over time and require exotic, expensive materials to make.