Niall Caldwell: Why diesel is here to stay for years to come

The Scottish Government is to be lauded for its fantastic ambition in decarbonising our energy use '“ and transport has a very big part to play.

Moving from A to B accounts for around 25 per cent of Scotland’s emissions, and we all need to think hard on how we can radically reduce this impact in the decades ahead.

The family car of the future will no doubt be electric, but this will take time – a recent forecast predicts that plug-in models will only be ten per cent of global car sales by 2030.

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More challenging are big, heavy vehicles, which account for around 30 per cent of transport emissions. Buses, trucks, trains and off-road vehicles all have daily energy requirements far in excess of what the batteries of today can provide.

Off-road vehicles like excavators, forestry equipment and farm vehicles are power-hungry and often operate in remote locations without easy access to the electricity grid. The average excavator, for example, would burn through five Tesla batteries a day – even if there was somewhere to charge it. Although some of Scotland’s railway lines have been electrified, the majority have not, and the high capital costs means we will be with diesel trains for years to come.

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In an ideal world we would have new low-carbon fuel sources or could rely on, for example, hydrogen made from renewable energy. But so far hydrogen remains prohibitively expensive (demonstrator buses cost more than €1 million) and will rely on significant public subsidy in the years ahead.

It is not all gloom, however. There are opportunities to take a more cost-effective route by radically improving the efficiency of existing diesel vehicles. Here in Scotland companies like Artemis Intelligent Power are coming up with novel solutions to do just that. In 2010 we did a study with ScotRail which showed that, on the standard Fife commuter route, between 65 and 73 per cent of a train’s energy is lost through braking and transmission inefficiencies. Working with Lothian buses, we’ve found around half of a bus’s energy is wasted through cooling fans and as heat in the brakes. While with excavators, 70 per cent of the engine’s power is lost as heat in the hydraulics.

What if we could reduce these losses through a proven home-grown technology and find a low-cost path to a greener future? Well, the good news is we can. At Artemis we are working with a number of multinationals to rethink the way diesel vehicles work – and to replace outdated transmissions and hydraulics with new, computer-controlled digital hydraulic pumps and motors.

We are currently piloting a project with ScotRail, and are already seeing significant fuel savings. We believe future versions will deliver 30 to 50 per cent energy savings in some cases and position Scotland in the vanguard of a new technology. This new class of digital hydraulics will be subsidy-free and offer customers a payback in two to three years.

We are now in talks with manufacturers in several sectors to bring this technology to market. The idea of improving diesel efficiency through digital hydraulics does not sound as snappy as what Elon Musk might have to say. But if it reduces Scotland’s 2030 emissions in the lowest cost way, and gives Scotland another feather in its low-carbon cap, then it surely is an idea worth exploring.

Niall Caldwell is managing director of Artemis Intelligent Power