Electric Vehicles
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Nissan LEAF ©
ecodrive |
There are now around a dozen EV scooters,
cars and vans.
The handful of electric cars now available span from 2-seater
urban compact vehicles to 5-seat family cars & MPVs
and high performance sports cars! Practical driving ranges over 100 miles mean that they
can meet the daily needs of many drivers, especially as
one of two or more vehicles in a household or
business. The Plug-In
Car Grant scheme offers up to £5,000 off the cost
of qualifying cars making them much more equitable with
Internal Combustion Engined vehicles, especially when reduced running costs are
factored in.
Whilst many households (or businesses) considering EVs
will have access to other vehicles for longer journeys,
manufacturers and dealers are aware of the limitations
of EVs and are working to provide alternative solutions
such as the use of conventional vehicles from
dealerships for occasional use. Often the
perception of limitation of vehicles is not borne out in
practice.
Commercial vehicles have, until
recently, generally been conversions of existing
vehicles. Since the start of 2012, factory
produced EV versions of smaller, well-known models are
available to complement the larger vehicles from
specialist converters. Many vans now qualify for
the Plug-In Van Grant
giving up to £8,000 towards the purchase cost.
Vehicles such as the Toyota Prius and Honda Civic
hybrids have long claimed environmental kudos by supplementing their
small petrol engines with an electric motor
to boost acceleration using energy recovered when going
downhill and during deceleration (called Regenerative
Braking) as most EVs do anyway. Some vehicles
be driven in 'EV mode' for a few miles at low speed, but
the current failure of these vehicles is that they still
take all of their energy from fossil fuels: there is no
way to recharge the battery from renewable energy.
Ultimately, the electric drive simply exists to improve
on the inherent inefficiency of a combustion engine.
Many smaller conventional vehicles, such as Citroen's
C1, achieve better fuel economy and similar CO2
emissions than a hybrid for much lower cost - and if
only half the difference was spent on energy efficiency
measures and renewable energy technologies for the
home/business, such as solar hot water or Photo-Voltaic
panels, it would more than make up for the difference.
In early 2012 the first examples of the evolution of the
Hybrid 'got a plug' allowing the vehicle
battery to be recharged from the mains to gain many of the
advantages an
EV where the vehicle is used for short journeys.
Vehicles such as Toyota's Prius Plug-in generally have larger batteries than 'normal' hybrids
to offer a better electric-only range than the existing
versions, but will only be suitable for short electric
journeys of around 10 miles at low speeds (not trunk
roads since at higher speeds the engine will
automatically engage too)
Volvo's V60 will be available as a diesel PHEV and
Peugeot will extend their diesel Hybrid4 range to PHEV
in 2013.
PHEVs should not regularly be recharged during the day
(unless from micro-generation such as Photo-Voltaic solar panels) since this is when there is already a lot of demand on
the grid - and the CO2 impact of the electricity is
higher. But if most days' driving is relatively few
miles at modest speeds and you desire the flexibility of
unlimited range, a PHEV might be a practical
solution.
Vauxhall-Opel Ampera © ecodrive |
Another solution is the "series hybrid" where the
vehicle is primarily an Electric Vehicle which is
recharged from the mains.
The principal means of driving the wheels is the
electric motor but there is also a small combustion
engine 'Range Extender', optimised to run very
efficiently at a fairly constant revolution rate.
Attached to the engine are generators which provide
electricity to drive the electric motor, recharge the
battery, or both. There is usually no mechanical
connection from the engine to the wheels since it is
more efficient (less energy is lost) to provide that
connection electrically. Depending on the journey
patterns and driving habits of the driver(s) the Range
Extender might rarely be used: only on longer journeys
beyond the range of the vehicle on battery power alone
or at high motorway speeds.
With a larger battery than a PHEV, range on battery alone is better but only
around half that of a similar 'pure' EV, although it may
be a more practical solution for a household (or
business user) that wants just one general purpose
vehicle without limitations.
So-called Extended-Range EVs (E-REVs) offer a practical
solution for the motorist who occasionally needs longer
range from their vehicle, particularly outside of areas
with suitable recharging infrastructure. The first
examples on the market are the Chevrolet Volt and Vauxhall (Opel)
Ampera (similar cars, both built by GM) which have
around a 40-mile electric-only range and around 300
miles from a full tank.