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Electric Cars
Electric vehicle have been around for a
number of years now and a number of new
technical innovations and tax advantages
mean they are increasing with
popularity. They are powered
by an electric motor (DC or AC) which
draws its power from an on-board battery
packs which act as an energy store.
Batteries, usually Nickel metal-hydride
or Lithium-ion are charged by simply
connecting the vehicle to a mains power
supply, and is usually charged overnight
for a full charge. A feature of
most modern electric cars is the
regenerative braking system which allows
the battery to be topped up when the
brakes are applied.
Current
electric vehicles available in the UK
tend to be smaller 2 seater cars which
are smaller and therefore lighter.
A range of 40 to 100 miles is achievable
with top speeds from 25 to 45 mph.
This makes them favoured by city
drivers, especially where a congestion
charge is in force such as London where
huge savings can be made and traffic is
generally low speed. Because they
are zero-emission vehicles, they
generally have many tax advantages
including the fact they don't run on
petrol. Emissions are however
produced during the generation of
electricity unless a renewable energy
supplier is used.
Hybrid
Hybrid cars generally use a combination
of two power sources. The most common
hybrids currently available on the
market use both electric motors and the
petrol combustion engines. Batteries
charge and act as a storage device to
power an electric motor, usually working
when the vehicle is travelling at low
speed or in traffic, therefore ideal for
city driving. The petrol engine,
usually a small efficient unit then
powers the car when more power is needed
such as at higher speeds allowing the
combustion engine to only operate at its
more optimum efficient speeds. A number
of manufactures have announced plans for
diesel-electric hybrids which could be
available a soon as 2008.
The combustion engine is used to
recharge the battery cells along with
regenerative braking, therefore hybrid
cars do not need to be plugged into an
external power supply. This
combination of battery power and
internal combustion engine produces less
pollution and CO2 as no gases are
released when the electric motor is
running.
BioDiesel
Biodiesel is produced from renewable
energy sources such as rapeseed,
sunflower or soybean oil.
Biodiesel is green as it has the
potential to be carbon-neutral, that is
to say all the carbon dioxide emitted
during use of the fuel when emitted from
the vehicle is balanced by the
absorption from the atmosphere during
the fuel crop’s growth.
Biodiesel
in some instances can be a direct
replacement for diesel, however most
manufacturers remain cautious about
engine wear and recommend a blend of
between 5% to 30% biodiesel although
some modern engines are capable of
running on 100% biodiesel.
Ethanol
Ethanol,
also known as grain alcohol is produced
from plants, usually sugar cane.
The fuel has a high octane rating which
in turn means increased engine
efficiency. Ethanol is widely used
globally as a fuel and is increasing in
popularity in Europe. A number of
manufactures have developed flexi-fuel
vehicles (FFVs) currently available on
from Ford, Saab and shortly Volvo cars.
Flexi-Fuel
vehicles can run on a blend of ethanol
and petrol, usually up to E85 (85%
Ethanol, 15% Petrol) which is the most
common blend in the UK or just petrol.
This gives drivers flexibility as the
current ethanol filling station in the
UK is limited.
Bioethanol
is green as it has the potential to be
carbon-neutral, that is to say all the
carbon dioxide emitted during use of the
fuel when emitted from the vehicle is
balanced by the absorption from the
atmosphere during the fuel crop’s
growth.
LPG
Liquefied Petroleum Gas (LPG) is a
natural hydrocarbon fuel made up of
propane and butane. LPG produces
far less carbon dioxide than petrol and
fewer particulates and nitrogen oxides
than diesel. It can be used within
a modified internal combustion engine
after conversions which cost around
£1,500-£2,000. A conversion
includes the installation of a second
fuel tank for the LPG which means the
vehicle can switch between petrol or
LPG.
LPG has
the special property of becoming liquid
when under pressure, and reverting to
gases at atmospheric pressure. This
means it can be easily and conveniently
stored as a liquid. About 60% of
the world supply of LPG comes from the
separation of natural gas products, and
40% is a by-product from the refining of
crude oil. In the past, LPG has been
considered as waste and flared off; now
it is recognised as a major energy
source and currently offered by about
10% of refuelling stations.
Fuel Cell
Fuel cells are electrochemical energy
conversion devices which produce energy
from an electro-chemical reaction.
Electricity can constantly be produce as
long as the flow of reactants is
available. The technology is still
being developed and is current
expensive. One problem is that
hydrogen can still not be produced
efficiently to make viable as an
alternative fuel just yet.
Many
manufacturers have already demonstrated
fuel cell vehicles and there are a
handful currently in use providing
important information and feedback for
the future development of fuel cell
cars.
Compressed Natural Gas
Compressed
Natural Gas is a fossil fuel sourced
from reserves deep under the Earth's
surface. It has lower CO2 emissions
compared to petrol/diesel but is still a
greenhouse gas.
Similarly
to LPG it requires a conversion so that
the car can be switched between gas and
petrol. The gas is compressed in a
cylinder rather than being stored as a
liquid form. The gas mixes well
with air prior to combustion and has a
high octane rating and therefore is fuel
efficient.
CNG is
popular worldwide and increasing in
popularity in the UK. There are a
number of aftermarket conversions
available and options also available
from the factory from manufacturers such
as Volvo.
Petrol
Petrol engine cars are the most common car
available. They are generally cheaper than their diesel counterparts
to buy. Petrol powered cars release carbon dioxide into the atmosphere
and burn non-renewable energy sources. We all know this is bad for the
environment but there are obviously some petrol cars which are less harmful
(greener) than others.
The most efficient petrol cars return the best
miles per gallon (mpg) of fuel and produce the lowest CO2 emissions.
These are usually the smaller super mini's as they are lighter and therefore
have smaller engines. These cars are usually the cheapest Green Cars to
buy and running cost are low. Concessions are made with lower road tax
rates for producing less harmful emissions and they are usually cheaper to
insure and you will notice savings on fuel because of their efficiency.
Diesel
Diesel cars sales are on the rise in the
UK as consumers are more cost conscious and demand more efficient
vehicles. Across Europe, diesel sale amount to nearly half of all new
vehicle sold. Diesels operate on average 30% more fuel efficiently
than petrol powered vehicles by using higher compression ratios and
higher combustion temperatures.
Diesel still release carbon dioxide into
the atmosphere and is a non-renewable energy sources but this is usually
less so than in petrol cars. However other compounds such as nitrous
oxides and particulate matter is released which have harmful effects to
the ozone and humans.
You you may think then diesel cars are not
so green then but they certainly can be greener and by buying the most
efficient in terms of good miles per gallon (mpg) of fuel and the lowest
CO2 emissions will help the environment.
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