With about 600 million passenger vehicles around the globe today – and currently with a worldwide production of approximately 55 million units per year – the automobile powered by fossil oil-based fuels is a major
source of environmental pollution. Efforts to market hydrogen-powered cars, which started in the early 2000s, have generally failed. In 2010, The Economist concluded that:
Having soared on the promise of carbon-free motoring, the idea of the ‘hydrogen economy’ crashed and burned when it collided with reality.
Hundreds of experimental hydrogen-powered cars – once hailed as the best solution for reducing America’s dependence on foreign oil for over half its consumption – are now gathering dust in manufacturers’ parking lots.11
In 2009, the US Government cancelled funding for research into hydrogen-powered vehicles. In the same country, General Motors ditched its fleet of 100 Chevrolet Equinox fuel-cell cars after a two-year trial. Likewise, in mid 2009 BMW withdrew its own test fleet of 100 7-Series limousines equipped with hydrogen internal combustion engines, tested since 2000.12
However, believing that the combination of a fuel cell electric vehicle and the solar hydrogen station could help lead to the establishment of a hydrogen society based on renewable energy, the Japanese car maker Honda is continuing to build a network of refueling stations to accommodate a growing customer base both in Europe (Figure 4.10)
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Figure 4.10 The first hydrogen station in the UK, at the Honda factory at South Marston, located near the car maker’s plant in Swindon, Wiltshire, has been operated by industrial gas company BOC since September 2011. (Reproduced from Ref. 11, with kind permission.) |
and in the USA (see discussion of the new generation of solar hydrogen stations for home use, based on the high differential pressure electrolyzer, Chapter 2).13
Similarly, Daimler’s Mercedes-Benz also recently unveiled that they would launch a mass-produced fuel cell car in 2014, based on the next- generation B-Class model. In 2010, Toyota expanded its hydrogen car program, aiming to come to market in 2015 or earlier with a vehicle that will be reliable and durable, with excellent fuel economy and zero emissions at an affordable price The carmaker has cut the cost to make hydrogen models for less than $100 000 and aims to halve that price by the time sales begin.14
A simple look at the comprehensive and continuously updated overview of all types of hydrogen vehicles (since, astonishingly enough, 1807) offered by the H2mobility. org15 website clearly shows that hydrogen motoring is far from being a doomed reality, as the author of the cited article in The Economist seems to believe.
In North America, Japan and Europe, demonstration fleets of hydrogen-fueled fuel cell or ICE buses are on the road, operated by municipal transport professionals and run under conventional conditions with passenger loads, and these maintain the usual time schedules.
The experience is positive. For example, 36 Mercedes-Benz Citaros, fitted with hybrid fuel cell and battery technology and deployed on the streets on three continents from 2003 to 2009 have logged more than 2.2 million kilometers by late August 2011. No hazard has been reported, and no major repairs were necessary (Figure 4.11).
Given that most city transit buses run on the same routes, only a small number (possibly as low as one) of hydrogen fueling stations are needed to supply the fuel. As the hydrogen fueling infrastructure continues to expand so will bus routes, including for buses that travel to cities farther away and need to refuel at a second station.
Clearly, the development of a public hydrogen supply infrastructure is essential for the successful marketing of both hydrogen fuel cell and ICE vehicles. What remains to be done, therefore, is to build a nationwide infrastructure of hydrogen refueling stations, such as in Germany, where the first filling stations have already become established in metropolitan areas such as Berlin und Hamburg. The more a station is used the lower the cost of the hydrogen supplied, with an almost hyperbolic cost trend (Figure 4.12).
Currently, 7 of the 30 hydrogen filling stations in Germany are integrated into a public filling station operation, whereas Daimler and the Linde agreed in 2009 to build 20 additional hydrogen filling stations.
Eventually, the whole structure of the automobile and trucking industry, with the ICE at its core, will be replaced by an industrial structure built around an electrochemical motor requiring the production of membranes and stacks, heat exchangers, hydrogen tanks and delivery systems, electrical and electronic equipment.
Electric cars that use either H2 fuel or electricity from batteries will certainly be competitive because battery electric vehicles (BEVs) are typically 3 to 4 times as efficient as hydrogen powered vehicles (Figure 4.13), and BEVs can be recharged easily at home every two or
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Chapter 4 |
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Figure 4.13 The infrastructure for the electric car exists already everywhere: the electric grid. Therefore the high investment costs of a hydrogen station need not be incurred. (Reproduced from Ref. 14, with kind permission.) |
three days (with no need for an extensive infrastructure) using the existing grid and plugs.
The well-to-wheels efficiency of hydrogen FCVs tends to be about one-third that of electric vehicles (EVs) when electrolysis is used.16 In contrast, BEVs, which are already commercially available from several manufacturers, do not require expansion of the existing infrastructure for electricity transmission and distribution, and ideally can be recharged at night with idle off-peak power plant capacity that currently goes unused.17
However, compared with BEVs, automobiles equipped with hydrogen fuel cells generate electricity onboard and have a far longer autonomy. Compressed hydrogen powering a fuel cell can provide electricity to a vehicle traction motor with 5 times more energy per unit mass than the current NiMH batteries used in most gasoline hydrogen electric vehicles, and 2 times more than advanced lithium-ion batteries.18
The fuel cell EV has many superior attributes over EVs with only 320 km ranges, but the advantages of the fuel cell EV are dominant if the BEV must have 480 km range to serve as a fully functional all-purpose passenger vehicle. This is plotted in Figure 4.14 as the ratio of the battery EV value to the fuel cell EV value for each attribute.
