Forward-planning researchers are scarcely renowned for their
unanimity on any issue, but on one point they are all in firm
agreement: the world is moving towards the mega-city. Even today,
there are more people living in large urban environments than in
rural areas, and in another 25 years no less than 70 percent of the
world's population will be living in mega-cities. Within that space
of time, it is estimated that the world's total building density
will have doubled.
This swift urbanisation means the world's urban and regional
planners are facing gigantic challenges. Not least on the issues of
the environment and climate since fast-growing cities impose
considerable burdens on both.
The UN's aim of limiting global warming to two degrees has been
adopted as the norm in this context. The EU has promised to reduce
emissions of greenhouse gases by 20 percent before 2020 -
increasing that figure to 30 percent if other countries also
toughen their eco-targets. The same trend can be seen elsewhere in
the world.
The question of how today's metropolitan centres can continue to
grow bearing in mind these increasingly tough targets is answered
by the experts with two words: increased density. After having
grown laterally for decades, tomorrow's major cities will now start
growing inwards, towards the centre.
"With a denser population structure, people have access to a wider
variety of services and facilities within a shorter range. This in
turn reduces travel requirements and increases the use of
sustainable transport methods such as walking and cycling," says
Sverker Hanson, civic engineer and transportation planner at
international consultancy Sweco. He continues:
"The same advantages of increased population density can be seen
with regard to logistics. There is already a trend towards a
greater number of distribution terminals in and around major
cities. With more densely populated cities, in the future it may be
possible to have one large reloading terminal per district, with
electrically powered distribution trucks providing just-in-time
delivery services to households and companies.
Other trends are the coordination of long-haul and distribution
transportation and the creation of public transport for goods.
However, increased population density and increasingly well
thought-out - and environmentally optimised - urban centres will
not solve the other major problem facing the planners: how
tomorrow's mega-cities will be kept supplied. The mathematics is
simple: more people means a growing need for consumer goods and
food - and a radical increase in the need for transport in to the
cities.
"We are moving towards a situation where many of our reserves of
fossil fuel, such as oil and natural gas, are beginning to dry up.
This together with increased demand for energy will lead to rising
energy prices. Linked to the climate issue, this means that the key
for tomorrow's transport will be energy efficiency," says Lars
Mårtensson, environmental affairs director at Volvo Trucks.
He feels that tomorrow's transport infrastructure must be based on
increased synchronisation of all existing transport methods. Ships,
railways and trucks will all need to work side by side.
"The future is with a wide variety of transport methods. What we
need to work on is improving the synergies between them. This is an
area in which we have considerable potential for improvement,"
explains Lars Mårtensson.
In the area of road transport, there is already a clear trend
towards increasingly large and heavy trucks for the longer routes.
And it is these energy-intensive transports that are in focus in
Volvo Trucks' most recent strategic environmental drive.
In a unique development project together with the EU, the Swedish
Energy Agency, Danish chemicals specialist Haldor Topsoe, fuel
giants Total and Preem and biofuel producer Chemrec, among others,
there is a project under way to develop an entirely new type of
biofuel: dimethyl ether or DME.
DME is a gas that is transformed into a liquid under low pressure,
which means it is relatively straightforward to handle. It is used
today for a variety of purposes, among others as a propellant in
spray-cans, as a fuel in cigarette lighters and as a base chemical
in the production of plastics.
DME can be produced both from natural gas and from a variety of
biomass sources, in which case it is known as Bio-DME.
As a fuel in a diesel engine, DME provides as high an efficiency
rating as a traditional diesel engine, but a lower noise level. The
combustion process produces no soot, so a far simpler method of
after-treating the exhaust gases can be used. What is more, the
engine can produce higher torque when starting off, thus improving
driveability.
All told, this makes Bio-DME an ideal fuel for diesel engines.
Volvos' project involves the development of DME fuel from black
liquor, a by-product of the forestry industry. Alongside the
Chemrec plant in Piteå in northern Sweden, construction has started
on a facility for extracting DME from black liquor obtained from
the nearby pulp plant. The cooking chemicals produced by
gasification of the black liquor are then sent back to the pulp
plant, thus creating a closed circuit characterised by unparalleled
energy-efficiency.
"From production of the fuel to its use in the engine, DME is the
most efficient biofuel in existence. Each hectare of land produces
five times the transport range with DME compared with biodiesel,"
says Per Salomonsson, DME project manager at Volvo Technology.
With a massive 95 percent lower climate impact than conventional
diesel oil, DME is particularly suitable for transports that
consume a lot of fuel - exactly the type of heavy long-haul
assignment that will supply tomorrow's growing mega-cities.
However, there is nothing to prevent DME, if it becomes successful,
from also being used for other purposes.
"Since DME can be produced from all types of biomass, it may become
viable even for countries without any significant forestry
industry. For instance, it could be used for other purposes than
just as a vehicle fuel. In China, for example, DME is used as an
additive in liquefied petroleum gas for household purposes,"
explains Per Salomonsson.
Within the framework of the project, which started in September
last year and will stretch over a total of four years, 14 test
trucks will be built for use in field tests throughout Sweden,
starting in summer 2010.
"From the holistic viewpoint, DME is one of the most promising
second-generation biofuels. The Bio-DME project creates exciting
new possibilities for testing DME in realistic conditions among our
regular customers," says Lars Mårtensson, environmental affairs
director at Volvo Trucks.
Facts DME
DME (di-methyl-ether) is a gas that transforms into a liquid under
low pressure. It can be handled more or less like liquefied
petroleum gas (LPG). Today DME is primarily used as a propellant in
spray-cans.
DME can be produced from natural gas and also from various forms of
biomass. According to EU estimates, by 2030 Bio-DME has the
potential for replacing more than 50% of the diesel oil currently
used for heavy road transport.
When Bio-DME is made from biomass via black liquor in a pulp plant,
the result is 95 percent lower carbon dioxide emissions compared
with fossil diesel. At the same time, it is five times more
efficient than biodiesel in terms of the transport kilometres
obtained from each hectare of land used for cultivation of the raw
material.
Together with the EU, the Swedish Energy Agency, Danish chemicals
specialist Haldor Topsoe, Total, Preem and biofuel producer
Chemrec, among others, Volvo Trucks is involved in a project to
examine the potential of Bio-DME as a future vehicle fuel.
The hub of the project is Chemrec's gasification plant in Piteå.
This will take in black liquor from a nearby pulp plant, extract
DME from the black liquor and then return some of the cooking
chemicals to the pulp plant. The energy content of the black
liquor, which today is used for heating and other purposes, will be
replaced by other biomass sources in the form of logging industry
waste that is not used in paper production. This biomass consists
of forestry residue such as branches, at present not a resource
that is fully exploited in the forest.
At present 14 test trucks are being built and from summer 2010 they
will be field-tested in regular day-to-day operations by customers
throughout Sweden. Preem will build fuel stations so the trucks can
be used under entirely normal operating conditions.