Over the next few months, we'll be joining the BBC World Service Click radio team as they ride a Route 66 of the future, learning how life on the road is set to change as technology makes its own in-roads into our transport networks and daily commuting lives. In the first episode of this special series, presenter Gareth Mitchell trials a new fuel cell-powered car, leading us to ask: Is the future of the car electric?
There's no doubt that the number of gadgets in our cars is increasing, from GPS to digital dashboards; and when we're away from home for a day or two, I know that our family car often doubles up as a handy recharging point for phones and tablet computers. The power source we rely on to power all these devices is the humble car battery. In most cars, the battery is recharged from the engine using an alternator. The alternator is essentially a generator - a motor in reverse - that takes in rotational energy from the engine and converts it to electricity; this electrical energy is then stored by the battery.
If you want to make your own generator, it's not too hard, as this OpenLearn DIY Recipe on how to generate your own electricity describes. And if you want to know how a battery works, the Rough Science team covered that too: Challenge: recharge a battery.
Most road vehicles today still use petrol- or diesel-powered internal combustion engines to generate the mechanical energy used to turn the vehicle's wheels. Hybrid vehicles supplement the use of power plant such as a petrol engine with a battery powered electrical motor. Hybrid vehicles can then work in a couple of ways: in the first "parallel hybrid" case, both the engine and the electrical motor may be mechanically connected to the wheels; in the second "series hybrid" case, (familiar to railway enthusiasts who know their diesel-electric from an overhead-powered electric train), the engine is used to charge the battery and the battery then powers electrical motors that turn the wheels.
In a fully electric vehicle, a battery is used to power the motors, raising the question of how we generate the electricity that the battery then stores, as well as how we practically recharge the battery. For the data sleuths amont you, local councils are starting to publish details about where to find electrical vehicle charging points in their council area, as for example Lambeth and Newcastle do; several websites, such as next greencar, are also starting to publish national location maps.
An alternative way of charging a car might be to do it wirelessly. As described in the other report on the first of our Click Route 66 specials, Lighting up the roads of the future, there are several new approaches being explored around how to illuminate highways through the use of solar powered cats-eyes and fluorescent road markings, as well as different methods for harvesting energy from traffic passing over roadways. But what if we could make use of Wireless Electric Vehicle Charging, using inductive coils in the roadway to charge cars passing over them, in much the same way that inductive mats can be used to wirelessly charge the latest lines of mobile phone or laptop computer or as several key players in the Formula E electric motor racing series would like to see (Starting grid: Formula E set to bring electric racing to the streets).
In a fuel cell car, the aim is to provide a refuellable fuel cell that can directly power the motors. According to an OU PhD thesis from 1998, Victor Adams' The potential of fuel cells to reduce energy demands and pollution from the UK transport sector, fuel cells date back to 1839, and Sir William Grove’s gaseous voltaic cell (p.55). But while the principles may well have been understood over a century and a half ago, it took over a century more before the first practical fuel cells were developed, finding their first notable use in the Apollo space programme. Although developments have continued since then, the technology does not yet directly serve a mass market, not least because the infrastructure required support, a hydrogen economy is still lacking as this list of hydrogen refuelling stations in the UK demonstrates.
As Gareth described while he was trying out the fuel cell powered car, fuel cells operate by combining hydrogen gas with oxygen from the air to generate electricity, along with water as a waste product. Chapter three of Victor Adam's thesis has a rather more complete description of the whole process, but if you've only got a few minutes to spare, here's a simpler description of how fuel cells work from the Naked Scientists...
With hydrogen fuel cell cars going into production over the next few years, it will be interesting to see how they compete against electric vehicles with different refuelling approaches (plug-in electrical recharging, inductive charging, or even diesel electric). While battery recharging and the preparation of hydrogen for fuel cells both require the generation of electricity elsewhere, the relative costs of production, transportation to the refuelling point of the fuel itself (electricity or hydrogen respectively), and the installation of the physical infrastructure required to support the act of refuelling itself are also likely to have an important role to play.
The free OpenLearn course Why sustainable energy matters also reviews how we need to account for demand side energy requirements when planning how we meet our energy needs - Demand-side efficiency improvements. Because to get the hydrogen for our fuel cells, we need to generate electricity to obtain it...