The green road ahead [ Outside the Box ]

Photograph: Philip Barker/123RF.com

Despite making earnest efforts to cut its carbon dioxide output in its fight against global warming, Europe has had surprisingly little impact on limiting its member nations’ emissions. In 1990, the Union’s output stood at 4,566 million tonnes of carbon dioxide. In 2006, it lay at 4,558 million tonnes: a drop of 0.17 percent.

It is a miniscule decrease. Yet over the same period, massive efforts have gone into cleaning up our factories and constructing renewable energy plants. Think of those great sweeping turbines that dominate the European landscape from southern Spain to northern Scotland, generating hundreds of millions of kilowatt hours of clean electricity. Why have they had such little effect on our emissions?

The answer is simple: blame your car. Swelling numbers of vehicles on our roads caused carbon emissions from transport to soar from 940 to 1270 million tonnes a year between 1990 and 2006, wiping out all the gains made by industry and power generation. Transport, mostly road vehicles, is now responsible for almost 28 percent of the EU’s carbon emissions, compared with 20 percent in 1990.

“There are some things even the most green-conscious European will not give up and the ability to move about where and whenever he or she wants is a major one,” says Greg Arrowsmith, of the European Renewable Energy Research Centres Agency (EUREC) in Brussels. “As a result, transport has become one of our trickiest problems in trying to cut our carbon emissions.”

The EU has aspirations to put that right, of course. It wants renewable energy to account for 10 percent of fuel used in road transport by 2020 and is relying on two key technologies: using biofuels instead of petrol or diesel in vehicle engines and becoming increasingly reliant on electric cars and lorries. Both approaches have potential – and drawbacks.

Consider biofuels. These are currently made either by fermenting crops – wheat, corn, sugar cane, and sugar beet, for example – to make ethanol which can be used as a substitute for petrol, or by using vegetable oils as a substitute for diesel. By exploiting these plant-derived products, instead of using fossil-derived fuel, a driver would no longer be adding to the atmosphere’s carbon content.

And until recently, biofuels were considered to have vast potential. Then economists pointed out that the impact of using farmland to grow fuel crops instead of food could be devastating. Indeed, according to a report from the European Commission’s Joint Research Centre, if Europe used vegetable oil as a substitute for 10 percent of its diesel, so much land would have to be taken out of food production that the prices of staples would rise by up to 25 percent.

Similarly, using cereals as a source of ethanol to make a petrol substitute would also trigger food price rises. In addition, growing more and more palm oil trees for bio-diesel could devastate the rainforests of south-east Asia, where most plantations are found, thus removing trees desperately needed to soak up industrial carbon dioxide.

As a result, scientists are now looking at the development of second-generation biofuels which would rely only on waste, not prime foodstuffs like cereals or vegetable oils, for their main ingredients. To create these, forestry residues, including pieces of softwood such as spruce, corn stover (the leaves and stalks of maize plants) and straw are treated with enzymes to break them down into chemical constituents. These can then be fermented into ethanol, an approach adopted by the NILE project (New Improvements in Lignocellulosic Ethanol) funded by the European Commission. Scheduled for completion this year, NILE scientists have produced dramatic yields of ethanol from wood and crop waste using such techniques.

Nevertheless, the arithmetic still looks tricky. Biofuels accounted for less than 2 percent of the fuel used in Europe at the turn of the century. Today, the figure is still less than 4 percent. It will therefore be a challenge for biofuels alone to account for the 10 percent reduction in fossil fuel use that the EU is seeking on roads.

Of course, there is the prospect of savings made through that other wonder of the low-carbon age: the electric car. Most major car manufacturers – including Volkswagen, BMW and Volvo in Europe – have recently revealed they have plans to build hybrid vehicles which would burn petrol or diesel on open roads, but use electric engines, whose batteries would be charged overnight in household garages, on city roads or when carrying out low-gear manoeuvres.

Again it sounds promising, though Arrowsmith sounds a note of caution. “It is hard to tell just how committed manufacturers are to the idea of hybrid cars at present. They also continue to believe that incremental improvements in conventional engines offer scope for reducing carbon emissions and have invested a great deal of money in equipment for making standard car models over the past few decades. They are not going to switch over to total production of hybrids just like that.”

Nor are our cars and lorries our only problem. Aviation also causes headaches. At present, the sector accounts for only 4 percent of Europe’s carbon emissions but as it expands – at an expected annual rate of 5 percent – this figure will soar. By 2020, twice as many passengers could be passing through European airports compared with today; three times by 2030; until, by 2040, the aviation industry could be swallowing most of Europe’s entire carbon emissions quota – unless action is taken.

And the EU certainly plans to take action. Alone among major world powers, it has decided to include aviation fuel in its future carbon emissions calculations. From 2012, any plane flying into or out of an EU state will be part of the European emissions trading scheme. “Effectively, this will put a tax on flights and will add €15 to €20 to the price of transatlantic flights,” says Tim Johnson, of the Aviation Environment Federation. This sum could rise significantly as the EU changes the pricing of carbon permits, however.

Airlines will therefore need to find ways to limit such increases. Using less fossil fuel is the obvious answer – with biofuels, in particular bio-kerosene made from vegetable oil, again offering hope, by halting the addition of fossil carbon to the atmosphere. But aviation biofuels would also take up land needed for food production. Developing second-generation biofuels will therefore be crucial for air as well as land transport – with research using algae and non-food plants which can be grown in marginal, semi-arid land, like the jatropha plant, producing recent promising results. Again these projects will require a great deal of lengthy development work.

There are other ways to cut aviation carbon emissions, however. One is to reduce an aircraft’s weight – by using strong, lightweight composites, made out of several components including carbon fibres, for its fuselage and wings – so it needs less fuel to stay aloft. A typical composite is half the weight of aluminium and a fifth that of steel, for example, and planes such as the European Airbus A340 are already making use of these, cutting weight, fuel use and carbon emissions.

“The next generation of aircraft will make even more use of composites,” adds Professor Bill Banks of Strathclyde University.

“The new double-decker European Airbus A380 – which came into service in 2007 – is 30 percent composite, while the wide-bodied Airbus A350, set for flights around 2013, will be more than 50 percent composite: a tremendous saving in weight, fuel and carbon.”

Then there is the simple matter of air traffic control. At present, individual countries have their own routes for aircraft crossing their airspaces. A plane – on course from Britain, via France and Switzerland, to Italy, for example – is switched through several different national routes dictated by each country’s air traffic controllers. “Essentially aircraft dog-leg across Europe, and that is very inefficient in terms of fuel use,” says Dr John Green of the Greener by Design engineering group.

“We need to rationalise air traffic control so that planes fly in straight, energy-efficient lines.” This idea now forms the kernel of SESAR – the Single European Sky ATM Research project – which has been set up to rationalise air traffic control within the EU by 2020 and hopefully find another way to cut fuel use and carbon emissions.

It remains to be seen if these measures will be able to limit the environmental impact of the swelling numbers of people likely to take to the air over Europe by 2030. However, Green remains confident. “Even if air travel expands fourfold in that time, the counter-measures we can take could reduce fuel consumption, and emissions also by a factor of four. So it would balance out.”

Balancing out is not the same as reduction, of course, and it is clear that finding ways to reduce carbon emissions from road and air transport is going to be a particularly stressful problem for Europe. While industry and power plants have succeeded in cutting back their output, transport – with the exception of rail – continues to rise.

First that steady increase must be halted. Then comes the fight to make real reductions – and to get carbon off our roads and out of our skies.

Carbon off the rails

Photograph: Reuters

In contrast to road and air transport, trains perform very well in terms of the carbon dioxide that they emit.

Consider the amount released on a Eurostar journey from London to Paris: for the two-and-a-quarter-hour journey around 20kg of carbon dioxide is released per passenger. By contrast, around 244kg is pumped into the atmosphere for each passenger that does the trip by plane.

In general, carbon emissions per passenger-kilometre on Europe’s high-speed trains are one-third of those on its cars and only one-fourth of those on its planes. And as more and more electricity – which provides the power for most trains in Europe – is generated by renewable sources, such journeys are destined to become even greener and less polluting.

Last year, the heads of Europe’s railway companies committed themselves to cut carbon emissions from their trains so that they will be 30 percent of their level in 1990. The date for this target is 2020 and it will be achieved by a range of measures including the regeneration of braking energy, fleet modernisation, and operational procedures such as energy-efficient driving.

“Rail transport is already the least polluting major mode of transport,” said Johannes Ludewig, executive director of the Community of European Railways and Rail Infrastructure. “But we wish to do even better, and use every possibility to reduce our greenhouse gas emissions further.”