100kWh of electricity used to drive a vehicle via fuel cell compared with chemical battery. Fuel cell delivers only one third of the energy to the wheels.
Credit: Ulf Bossel/phys.org/Electrek
Many people find the idea of a hydrogen fuel cell vehicle (HFCV) very attractive. And there is no denying the attraction of a simple replacement of the rapid fueling of an internal combustion engine vehicle for the similar fueling time of a HFCV.
Unfortunately, outside of fast refueling, compared to battery electric vehicles (BEVs) it’s all disadvantages:
● There is almost no hydrogen fueling infrastructure.
● Over 95% of hydrogen is obtained by splitting from fossil fuel – so it is neither no-carbon, nor sustainable.
● Hydrogen can be produced from water using electricity – sustainably if sustainable electricity (hydro, solar, wind etc.) is used.
● Electricity used to drive a vehicle via a hydrogen fuel cell will provide one third of the energy to the wheels compared to the same amount of electricity powering a vehicle via a lithium ion battery. See the diagram at the top of this post.
● Hydrogen fuel cells produce electricity only slowly, so a fuel-cell-only vehicle would have unacceptably poor acceleration. Also, an HFC can’t be recharged using electricity, so regenerative braking doesn’t work, substantially reducing the efficiency of a fuel-cell-only vehicle. To overcome these problems, a conventional, rechargeable battery is fitted. The fuel cell charges the battery & the stored electricity is used to drive the vehicle. The battery also provides storage for regenerative braking. As a price control measure, plus all the space taken up by the fuel cell, hydrogen tank etc., the battery has to be small. A small battery can only release electricity relatively slowly. Faster than a fuel cell, but still slowly. As a result, performance is poor. E.g. the Toyota Mirai has been described as, “rather like a Prius, only quieter,” with “0-to-60-mph time of just under 10 seconds”. At $57,500 in USA, how big is the market for a car, which drives like a Prius, is responsible for almost as much CO2 & has almost no refueling infrastructure?
What about BEVs? Are they a viable solution to personal transport?
● While there is almost no hydrogen fueling infrastructure, electricity is available everywhere.
● All commercial BEVs are able to charge overnight on a domestic power point for a normal commute – other options include at work, while shopping for groceries etc.1
● Fast charging & range greater than 160 km (100 miles) are only necessary for long trips.
● Tesla’s luxury Model S combined with their Supercharger network for long trips (the other half of a BEV-based sustainable personal transport system) has shown how a sustainable personal transport system can work – leaving only the question of cost.
● A question which will be answered by GM’s Bolt 200 mile (320km) BEV which is expected to go on sale for between $30,000–$40,000 USD later this year. Although, without access to a fast-charging network necessary for long distance travel.
● Tesla has promised to show its similarly priced 200 mile BEV, the Model 3, in prototype form, in March 2016 – with access to Tesla’s fast-charging network.
Update – Tesla announced its Model 3, as promised, in March 2016.
Update – Chevrolet's Bolt went on sale in some states of USA in late 2016.
http://cleantechnica.com/2014/12/01/fuel-cell-economics-vs-batteries/
http://tonyseba.com/toyota-vs-tesla-can-hydrogen-fuel-cell-vehicles-compete-with-electric-vehicles/
http://evobsession.com/hydrogen-cars-vs-electric-cars-detailed-comparison-efficiency/
http://www.autoblog.com/2014/08/05/why-battery-electric-vehicles-will-beat-fuel-cells/
http://phys.org/news/2006-12-hydrogen-economy-doesnt.html
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1 An episode of Fully Charged included a Nissan Leaf owner who was not able to charge at home, but paid her employer for the electricity to charge at work – at a considerable saving compared to the petrol vehicle she previously owned – starts at the 4:20 mark:
/ BEV EV lithium ion LiIon battery charge recharge Supercharger Tesla Nissan Leaf range charge recharge fool cells /
