ISIS Press Release 20/03/06
Organic Waste-Powered
Cars
Fuel-efficient super-clean cars are at our doorstep and they
run on methane produced by cleaning up wastes. Mae-Wan Ho
Last Chance to Sponsor
the ISIS Energy Report (see advertisement below)
|
Global warming is accelerating and energy prices
are soaring. We have to find the right survival
strategies, and we have to find them now. Time
and energy resources are both running out;
squander them on the wrong technologies and the
consequences will be catastrophic, invest in the
right options and we can mitigate climate change
and thrive in a post fossil fuel world.
This report will help you
make the right choices
among nuclear, biofuels, wind, solar, energy
from wastes, and more…
Send it to your policy-makers to input to the
global energy debate. Sponsor this report by
making a donation that will entitle you to
multiple copies at print price plus p&p. For
details please e-mail:
energy@i-sis.org.uk
Individual copies are available for pre-order
at the
ISIS online store |
|
|
Sources for this report are available in the ISIS
members site. Full details
here
Organic-powered CEO
Chris Maltin arrived with a sunny smile at the Dream Farm
workshop organised by ISIS on a bright, clear Saturday morning
in January 2006.
He has driven to the venue at Kindersley Centre in Sheepdrove
Organic Farm Berkshire in his Mercedes People Carrier, and was
eager to show it off to everybody. It is not just any Mercedes
People Carrier, but one specially built to run on methane gas;
and not just any methane gas, but methane obtained from treating
organic wastes in a special anaerobic digester that Maltin has
designed.
Maltin, founder and CEO of Organic Power Ltd., a company
based in Somerset, has been keen on anaerobic digestion for many
years. “Anaerobic digestion converts biomass directly to useful
fuel without any intermediate steps, the conversion efficiency
is very high compared to other alternatives such as bioethanol
or biodiesel.” He says. “It can handle a variety of wet
substrates ranging from green garden waste, septic tank wastes,
kitchen waste, energy crops and a variety of other organic
materials in industrial byproducts or wastes.” (See “Dream Farm”
SiS 27; and “Dream Farm II”, SiS 29.)
There is no loss of nitrogen into the atmosphere, so all the
nutrients can be returned to the soil as fertiliser. “And, as
the materials digested are organic matter, they can be
considered carbon neutral.” He adds.
Figure 1. Organic Power's methane driven
Mercedes people carrier
The Maltin System
Maltin's improved anaerobic digester is based on his original
design, patented as the Maltin System. It consists of eight
identical plug-flow units (tanks) horizontally-mounted in
series, the tank is shaped in such a way that it maximises
circulation within the tank with minimum energy, but there is
little or no mixing between the tanks, so that a high efficiency
of digestion is achieved (Fig. 2). The digester is maintained in
an external temperature controlled lagoon, so it can be made of
relatively thin plastic sheet material, and the hydrostatic
pressure exerted on the wall from inside the reactor is balanced
by the pressure from the outside by the water in the holding
lagoon. Heat can easily be supplied to the digester by heating
the water in the holding lagoon.
Figure 2. The Maltin System
Wastewater is routinely analysed for chemical oxygen demand
(COD) – the quantity of oxygen used in biological and
non-biological oxidation of materials as a measure of total
wastes or water quality - and Biological Oxygen Demand (BOD) -
the amount of oxygen taken up by aerobic microorganisms to
decompose the organic matter as a measure of water pollution.
The digest, when tested in Professor Charles Banks'
laboratory at Reading University, showed that about 50 percent
of the COD was removed by the time it reached the last of the
eight tanks in series. (This level of waste removal is not
exceptional for biogas digesters.) The BOD removal was more
impressive, at 99.93 percent. That means the wastewater has been
effectively purified from bacterial contamination.
The water is not the only thing that's clean, so is the
exhaust from his Mercedes People Carrier.
Squeaking clean car
Maltin is actively involved in the development and supply of
gas-fuelled vehicles. The advantage of natural gas is that it
has a very much higher octane rating than petrol. The octane
rating of a fuel tells you how much it can be compressed before
it spontaneously ignites. One way to increase the power of the
engine is to increase its compression ratio, so a high
performance engine has a higher compression ratio and requires
higher-octane fuel.
Hence, a dedicated natural gas engine can incorporate higher
compression ratio with higher power output, which also means
higher fuel efficiency.
Instead of natural gas, Maltin runs his Mercedes on what he
calls “renewable natural gas”, which is almost pure methane from
biogas after removing carbon dioxide and hydrogen sulphide.
Compared with petrol or diesel, renewable natural gas
considerably reduces exhaust noise levels, lowers emissions of
nitrogen oxides, and has almost zero emissions of particles or
dust. The car has a range of 350 miles.
The exhaust in a gas engine runs hotter and the catalytic
converter (device that removers pollutants from motor vehicle
exhaust) needs to be a dedicated unit to cope with this and to
trap any unburnt methane in the exhaust. Organic Power is
working closely with Lubrizol to develop this catalytic
converter.
At a sustainable technology fair in Glasgow, Scotland in May
2004, West Lothian Council provided their latest exhaust
emissions testing vehicle to test Maltin's Mercedes. Even
without a catalytic converter, it had 0.02 percent carbon
monoxide (3.5 percent allowed), and 123 ppm particulates ( 1 200
ppm allowed). 1
Organic Power has been lobbying for fuel duty to reflect
environmental impact in order to encourage renewable fuels.
Sweden, Switzerland and Germany have no fuel duty on renewable
natural gas, and Sweden is world leader in gas-powered vehicles
(see Box).
|
The case of Sweden
2
Sweden leads the world in using natural
gas as a vehicle fuel and in particular biogas. The
population is sparce, so it is difficult to invest in
large infrastructure. In the western part of the
country, a gas distribution system exists which imports
mainly from Denmark. In the rest of the country, methane
gas is distributed from a number of biogas plants where
methane is produced locally, typically owned and
operated by the municipalities. Much growth in the use
of natural gas vehicles was achieved through joint
ventures between carmakers and bus and taxi companies.
There are now around 4 500 natural gas vehicles in
Sweden, 40 percent run on biogas. The Swedish Natural
Energy Administration have allocated 1.5 m euros for the
national organisation and co-ordination of clean biogas
or clean natural gas infrastructure development, and the
Swedish government has proposed a 20 percent lower
taxation on company cars when choosing clean fuel
vehicles, and support of 30 percent of the investment in
plants upgrading biogas to vehicle fuel. There is
permanent tax relief on biogas and a moderate tax level
on natural gas. There are more than 230 biogas plants in
Sweden and about 130 of these are located at sewage
water treatment plants. Sixty percent of the total
Swedish biogas production comes from these plants. The
other main source (30 percent) is from landfills. |
Best environmental car for 2005
The Swedish Association of Green Motorists has ranked
renewable natural gas driven cars the best environmental car for
2005,3 they occupied the first 8 positions of 52 cars
tested. The CO2 emission in gram/km ranged from 9 to
14, about one-tenth that of petrol and diesel driven cars. For
comparison, two ethanol (E85, 85 percent ethanol blended with
petrol) driven cars had emissions of 54 and 69 gram/km.
Wasted opportunities
Some 200 m tonnes of municipal solid wastes are generated
each year in the European Community, 4 60 to 70
percent of which is probably organic. In addition, hundreds of
tonnes of livestock manure and crop wastes are produced on
European farms. Much of this organic waste is going to waste in
landfills or incinerators. The UK topped the league of EU
nations by sending more than 70 percent of its municipal wastes
to landfills in 2003,5 releasing methane into the
atmosphere and poisoning land and water.
Instead of which, the organic wastes could be treated in
anaerobic digesters to provide methane for fuel, rich
fertilisers for crops, and much cleaner land, water and air.
“Using biogas produced from organic materials in the UK and
uprating this to renewable natural gas could provide 20 percent
UK's vehicle fuel.” Says Chris Maltin.
|
Website/Mailing List
