Will transport ever be truly green?


With global infrastructure leaders meeting later this week, we look at how transport infrastructure can become more sustainable despite severe legacy challenges.

Transport infrastructure has a remarkably durable impact. It is even said that the width of a roman horse determined the size of the space shuttle’s booster rockets. But that doesn’t mean change isn’t possible.

Legacy is about more than old roads
To understand the scale of the legacy challenge in infrastructure, the Roman shuttle story goes as follows:

Romans built the first highways across much of the ancient world and, by the time the English started building tramways and then railways, they did so based on the size of carts that were built to fit ancient ruts created in ancient roads by Roman chariots. The world, including the USA, converged upon the new normal for railways and so, by the time of the space programme, components had to be built at a size that could be transported by rail through bridges and tunnels that had been shaped, long ago, by the size of roman horses.

In truth, the roads on which English carts once passed had long since been rebuilt, railway gauges differ from place to place, and modern manufacturing methods meant any component could be assembled on site in order that smaller parts could be transported before becoming much larger when the final shuttle was complete. Still, a rational tendency to converge on the path of least resistance is real.

So, with millions of miles of roads and rail now in place, along with ports and airports, how do we ensure a path of least resistance doesn’t keep this infrastructure unsustainable?

Making transport infrastructure truly sustainable
One of the big issues with transport sustainability is how we think about it. For many, the vehicles are the main source of carbon in the atmosphere, not the infrastructure. But the two are not disconnected, so let’s start with vehicles before dealing with the infrastructure.

More than a billion passenger cars now travel on roads around the world. Electrification of vehicles is one solution to the carbon these vehicles emit, but that is not a realistic aspiration with existing infrastructure. Almost all refuelling infrastructure is designed to put gasoline or petrol into those cars. So without an overhaul of the infrastructure to provide electric refuelling, cars will continue to pollute.

With rail, that challenge is even more acute even though railways tend to pollute less than roads. Electrification of diesel railways is a huge infrastructure undertaking – which means delivering electrification would involve huge expense and, importantly, carbon emissions. Perhaps just in time, we are now seeing the emergence of hydrogen as a possible alternative thanks to companies like AECOM and Iberdrola. But even that involves investment in the required hydrogen infrastructure, which needs to be done sustainably too.

Hydrogen may yet prove invaluable for shipping and aviation too, which are far less able to convert to electricity at present. That is one of the reasons why it is seen as a significant industry for the future, with the Middle East investing in green hydrogen already, while Ramboll’s chief executive has called to create a Danish-German green hydrogen hub.

We should not forget short journeys though. The low-pollution alternatives in urban environments are also infrastructure dependent. The humble bicycle is heavily affected by the way every junction works, the way lanes are laid out and the facilities available at destinations. Busses are similarly dependent on protected space that keeps these vehicles moving.

And all of that just addresses the carbon emitted by vehicles.

Planning strategic infrastructure sustainably
In the development of HS2 in the UK, huge sums have been invested in effectively minimising the lasting impact on the communities it passes. Even more is being spent on the concrete and steel from which a rail network is made. That generates carbon and the same is true for roads, airports and ports.

Sometimes that infrastructure represents a good opportunity to reduce carbon from other sources. That is certainly the ambition with the proposed Houston-Dallas line being prepared for construction in Texas. It is also the case with the new renewables hub at Port of Leith. But again, that notion of net benefit isn’t the same as being truly net zero – which has to be the ambition for engineers and contractors now.

That is at least partly possible already. The construction of a road can be undertaken with zero or low emission vehicles and machinery. Roads can can also be designed with efficient lighting and signage and, for what carbon cannot yet be prevented, offsetting should now always be put in place with projects like tree-planting along routes.

Paying for strategic infrastructure sustainably
One solution to all of this is of course to stop building. That would entrench the grotesque inequality of the world as it stands today but as governments and multilateral development banks put more and more requirements on projects to meet green standards before they agree to fund them, there is a real risk of projects failing to go ahead. And this is not only a developing world problem.

Germany has a highly developed highways network and Japan’s bullet trains are globally renowned. In some regards, however, they face a similar challenge to places like Pakistan, which is seeking to improve social and economic conditions by building new roads, and Nigeria, which is investing heavily in new railways for similar reasons.

In all four cases, the process of building and maintaining this infrastructure is carbon intensive, which may in future have implications for funding streams. So infrastructure leaders need to examine how to turn construction and maintenance into a process that can still benefit from the ever-growing requirements of green investors.

This means innovative options need to be considered. Relatively new practices that might reduce carbon, like the innovative use of recycled materials in aggregates or even tarmac, may prove invaluable to that. And then there is the question of user-pricing.

Energy bills create a valuable impetus to be efficient and reduce use. Most of the world’s roads, however, have no pay-per-mile mechanism at all. While that option may be unpopular in many places, genuine alternatives will be needed if it is to be largely avoided.

The Global Infrastructure Conference brings together global infrastructure leaders each year to discuss the world’s biggest challenges and how they might be addressed. Taking place on Friday 10th and Monday 13th of September, IG will be there to report on all the news that emerges.