Plug-in electric vehicles and the electrification of road transport
Tuesday, 18 November 2008
By Richard Hunwick
Concerns over ‘peak oil’, increasing greenhouse gas emissions, and the likelihood that by the middle of this century there could be five times as many motor vehicles registered world-wide as there are currently, mean that the world’s almost total dependence on petroleum-based fuels for transport is in every sense of the word, unsustainable.
New, safer designs of lithium batteries, along with better power management systems originally developed for laptop computers and mobile phones, have meanwhile been developed just as these concerns have come to dominate energy policy formulation everywhere. A new consensus is emerging with remarkable speed: that road transport will be increasingly powered by electricity.
Hybrid electric vehicles (HEVs) such as Toyota’s Prius represent a first, tentative step. The much larger battery packs hosted by their vehicle descendants will allow them to plug into the grid, and draw and store sufficient electricity for most trips to be completed using electricity alone. Their fossil fuel-powered internal combustion engines will be relegated to the status of auxiliary power units, just driving a generator whose sole purpose is to recharge the battery packs as and when required.
Vehicle design will change, and simplify: gearboxes and transmissions will disappear as the electric motors that ultimately drive the wheels are built into the wheels themselves. There need be no separate disk brakes, as touching the brake pedal switches these motors into generator mode, allowing the energy of the vehicle’s motion as it slows to be converted back into electricity to be stored in the batteries rather than being wasted as heat, and to lock the wheels when it is stopped.
As batteries continue to fall in price, purchasers will increasingly elect to do without the APU, making their vehicles all-electric. Their concerns over flat batteries leaving them stranded on the motorway may be alleviated by, for example, being able to access a fast battery-pack exchange offered at service stations—whose roles will also change.
Significantly, as such plug-in electric vehicles (PEVs) proliferate, their on-board battery packs will collectively represent a very large and growing electricity storage capacity. When these vehicles are plugged in, electricity flows need not be just one way, from the grid to the vehicles (G2V) as in charging; it can also flow in the opposite direction: PEVs when plugged in, can support the grid (V2G). The consequences of this for the electricity supply system will be profound, and disruptive—but if handled correctly, quite benign. By drawing on the electricity collectively stored in those PEVs plugged in while parked in office garages, electricity suppliers can avoid having to purchase expensive electricity from dedicated peaking power stations. Meanwhile, overnight charging will represent an attractive market for off-peak and renewable power generators. An obvious consequence will be a shift by electricity retailers in favour of purchases of electricity from base-load and renewables-based power stations rather than from peaking plants.
Modelling by the author of a number of scenarios for electricity’s penetration into transport suggests that expected impacts tend mostly to be benign, certainly for the electricity supply industry, which should (so long as care is taken) enjoy better utilisation of existing base-load generation capacity, and of the transmission and distribution grids, as well as fewer problems accommodating renewable energy. The increase in electrical energy consumed even with very high PEV use turns out to be moderate, and PEVs should not of themselves, require that new base-load generation capacity be constructed.
Within a couple of decades most motor vehicles registered could be PEVs. While this would represent a profound change, it needs to be borne in mind that Australia’s motor vehicle fleets turn over essentially completely in a decade.
In the United States and many European Union countries PEVs are receiving broad support from an unlikely coalition of national security, utility, and environmental interests. Japanese corporations are as ever, at the technological forefront of the trend, while many in China and India realise that through electricity alone, can they hope to realize their vast populations’ aspirations for private motor vehicles.
In Australia awareness of these developments and their implications is just dawning. But the consequences of what is increasingly looking like a disruptive technology, must be considered and embraced here, actively and positively.
Richard Hunwick has worked in the electricity and broader energy sectors for more than a quarter of a century, both as a consultant and developer. He is a recognized expert on power generation technologies of all types, from the most distributed to the largest central, including nuclear and coal fired power stations. His recent focus has been on the identification, assessment, development and design of power generation project opportunities embracing all feasible technologies. He has long been interested in electricity storage and the benefits it promises, which has led to his recent focus on plug-in electric vehicles. A chemical engineer, he also has an MBA majoring in economics. He chaired the Sydney Branch of the Australian Institute of Energy for four years earlier this decade, has presented many papers focusing on power generation technologies and energy policy issues that stem from technological change, and authored more than 60 reports and submissions for electricity industry clients.
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