How green is the electric car?

Last Updated 05 July 2010, 11:20 IST

Just when there is much optimism about saving the planet comes the news that this one green endeavour is simply ineffective. A recent study by Transport Watch UK, an independent organisation, dubs the hope of carbon-emissions reduction through battery-operated cars as mere ‘fantasy’! These energy-efficient cars are labelled as problem-ridden. The study has sparked off a heated debate.

Electric cars, usually powered by on-board battery packs, have for long been known to reduce pollution through zero tail-pipe emissions. The magnitude of vehicle greenhouse gas savings depends on the electricity-source. Electric car usage is considered to be capable of reducing CO2 emissions by 30 per cent in the U S, 19 per cent in China and just one per cent in Germany.

Power plants that pollute

True, electric cars (EVs) don’t spew toxic gases from the tailpipe. But in the West, most power plants pollute the atmosphere. For instance, fossil fuels provide nearly two-thirds of the electricity generated in the US. So, the study claims that ICEVs (Internal Combustion Engine vehicles) produce half the CO2 that EVs do when the fossil-fuel-burning for the electricity-generation is considered. It also puts the electrical energy leaked lost between the power-plant and the vehicle-charging-point at a whopping 76 per cent in contrast to diesels which achieved 45 per cent efficiency!

The research was carried out in the UK where 20 per cent of electricity is generated by renewable energy. Countries where coal is the major electricity-source would produce much higher energy-inefficiency figures. This implies that burning fuel inside the vehicle is more environment-friendly than generating electricity and transmitting it through the grid. However, it fails to observe that massive CO2 emissions during the refining/transportation of petroleum negate this advantage of diesel/petrol engines.
Plus, since most of the EV-charging will occur overnight when the UK’s current grid system has abundant unused capacity to spare, EVs optimise power-utilisation. The counter-argument is that nocturnal EV-charging could pressurise the grid at night too, leading to greater fossil-fuel exploitation with its attendant CO2 emissions.

Indeed, supplying sufficient low-carbon power at peak demand times is difficult. Not all homes have garages and domestic electricity points for recharging. So, large-scale EV-adoption necessitates provision of sufficient kerbside electricity-supply points. Besides, charging loads at malls, stadia, venues that host exhibition, cultural, entertainment events and multi-storeyed car-parks would escalate enormously during peak hours. Increased fossil fuel usage would only nullify the EV’s green advantage. The formidable challenge lies in building hundreds of offshore wind turbines every year, increasing solar power generation manifold, harnessing wave, tidal energy and installing nuclear power-stations. For EVs’ environmental benefits to be apparent, a large-scale use is essential. This requires a complete changeover from the current ICEV-compatible environment. Ownership, funding and taxation models may all need a total revamp.

Smart grid another pre-requisite

A ‘smart grid’ or an ‘intelligent’ electricity network enabling “more dynamic real-time flows of information on the network.... and helping deliver electricity more efficiently and durably” is another pre-requisite. However, the exact modalities haven’t been worked out as yet. In the absence of an optimised smart grid, a huge question-mark hangs over the EV’s environmental benefits.

Yet, it’s claimed that even with the current high-carbon power-generation infrastructure, EVs leave a smaller carbon footprint than ICEVs.

Successful power-generation from alternative energy sources could bring EV-car CO2 emissions down to zero. But because these natural energy sources aren’t totally under human control, the amount of power generated isn’t constant. Heavy cloud cover and anticyclones, for instance, are detrimental to solar and tidal energy generation respectively. Hence, PHEVs (Plug-in Hybrid Electric Vehicles) possessing both an electric and a back-up petrol engine and not demanding huge infrastructural investment are being viewed as a more viable alternative.

Technological advances have yielded the lithium-ion batteries for EVs, the same as used in mobile phones and laptops. Powerful, relatively light with a high energy-to-weight ratio, these batteries recharge quickly and retain their charge when idle. But, the study points out that EV battery lasts only 100 miles/160 kms. between charges.

Besides, it is said to require an hour to charge the battery, even in optimum conditions. Solutions being worked out are battery-exchange stations and recharging facility at destination, on-street parking and at the workplace. Some workplaces are already providing solar-panel-powered vehicle-charging facilities. In colder regions like Finland, some northern US states and Canada, public power outlets for charging through block heaters with circuit breakers are already in existence.  

Internal combustion electric vehicles also release most energy as waste heat that’s utilised for heating the vehicle interior. But, the energy-efficient EV releases minimal waste-heat. So, the interiors have to be warmed by resistance electric heat. Plus, EVs consume more energy and yield lower range on a single charge in cold weather. In spite of these shortcomings, EVs remain suitable for short-distance, everyday transportation.

(Published 05 July 2010, 11:20 IST)

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