Swedish national airport operator Swedavia is proving a lesson for all in terms of minimising the harmful emissions created on and around its apron. David Smith examines how the state-owned owner/operator has set about the task
There are only 20 carbon-neutral airports in the world, according to Airports Council International (ACI), and all of them are in Europe. Remarkably, half of them are operated by just one concern, Swedavia, which is responsible for 10 of Sweden’s biggest and busiest airports.
Partly because it is a state-owned business in what is arguably the world’s most environmentally conscious industrial nation, Swedavia has made strenuous efforts to reduce emissions in its energy sources, GSE equipment and fuel supplies. The task is highly complex and Swedavia’s success provides salutary lessons for competitors. For GSE operations, it’s not simply a case of buying the ‘greenest’ engines. There are many vehicle options to consider, as well as the logistical difficulties of finding affordable and efficient sources of fuel.
Since Swedavia began closely monitoring its emissions a decade ago it has made a reduction of 74% in emissions, but it is still not satisfied. The next goal is to eliminate them altogether. It has the highest possible 3+ (‘carbon neutral’) Airport Carbon Accreditation rating (the ACA programme, designed to measure airports’ carbon footprint, is the work of ACI and consulting firm WSP Environment & Energy) – but Swedavia’s operations still emit 3,200 tonnes of carbon per year. Because it has reduced its emissions a great deal, Swedavia has the right to offset this carbon by investing in ‘gold standard’ projects under the UN-approved Clean Development Mechanism (CDM).
There will be no need for offsetting at all, however, if Swedavia achieves its new target of zero fossil fuel emissions by 2020. The key to attaining this goal is to significantly reduce emissions from its fleet of 1,000 GSE vehicles. “These vehicles account for more than 90% of our remaining fossil emissions,” observes Yvonne Björnström, director Swedavia vehicles. “Our priorities have changed. Some years ago heat was the biggest issue, but we have largely tackled this problem and all our energy is now green. One of the main things we do is to use wood pellets for our heating systems rather than oil-fuelled boilers.”
Swedavia is also fortunate in being able to exploit a gigantic aquifer housed in a boulder ridge near Stockholm-Arlanda airport, Sweden’s busiest air gateway. The aquifer acts as a thermos for water storage and has made energy supplies cheaper and more environmentally efficient since 2009. In summer, cold water is pumped up to cool the airport. Then the heated water is pumped back into the ground and stored until winter, when it is used to melt snow on aircraft parking stands and pre-heat ventilation air. Using the aquifer has reduced Stockholm-Arlanda’s annual electricity consumption by 4 gigawatt hours (GWh) and district heating use by about 15 GWh, or a total of 19 GWh, which is equivalent to the energy used each year at Malmö Airport.
Having addressed these energy issues, Swedavia’s focus now is squarely upon the more complex problem of reducing emissions in GSE vehicles. An ongoing programme replaces vehicles that use fossil fuels with ones running on green electricity, renewable biogas, or bio-based synthetic diesel vehicles. By 2020, Swedavia hopes to have invested SEK1.2 billion (US$140 million) in both snow removal equipment and lighter vehicles. But there are challenges to overcome.
“The best solution available is green diesel. It’s an easy way for GSE providers to reduce emissions without even buying new engines as the fuel can be used in normal diesel engines,” Björnström considers. “But when we started to replace our fleet a few years ago we didn’t have any of this green fuel, so we focused on buying vehicles to run on green electricity or biogas. Those are still important sources for us, but now we have greater access to HVO (hydrotreated vegetable oil), also known as green fuel, which functions exactly like normal diesel.”
The market for HVO has grown rapidly over the past five years. By far the largest producer is the Finnish company Neste, which has two renewable plants in Finland together producing half a million tonnes of the oil per year. Neste has also built two even larger renewable plants with capacities of 800,000 tonnes a year in Singapore and Rotterdam. The NEXBTL fuel is made from vegetable oil and waste animal fats, rather than whole plants. It can be blended into diesel fuel in any ratio.
“Because it’s the same as normal diesel we can use it in the arctic temperatures at Kiruna Airport in northern Sweden. All our GSE vehicles at Umeå Airport, also in the north, are being run on HVO. Our ultimate goal is to replace all our petrol diesel with HVO,” Björnström notes.
But the introduction of HVO poses logistical problems and Swedavia cannot buy it for all its airports right now. “Not all our airline partners trust in it yet and we sell diesel to them at our airports. We don’t have enough tanks and reservoirs to keep separate supplies of HVO everywhere. We’re still at the beginning of the process and carrying out tests. So we are gradually introducing it at some airports and building that up,” she says.
Some suppliers of GSE equipment engines, including the two German companies Mercedes and MAN, won’t even allow Swedavia to run their engines using HVO. “They are not convinced yet as they have not done the certification procedures. But Volvo has given official approval for us to work with green diesel. They have tested it with oil companies and say there are no problems using it in their engines.”
Björnström is convinced that Mercedes and MAN will change their minds and give permission in the near future. “This fuel is the future. If they don’t allow us to use it in their engines, it will put them at a commercial disadvantage when they are bidding for new GSE contracts. In recent years we have bought more Volvo Penta engines,” she remarks.
Swedavia would also like to persuade other suppliers of GSE equipment operating at its airports to use HVO, or at least purchase vehicles with lower emissions. But it can only attempt to influence them. “Under the terms of our 3+ ACI accreditation, we are obliged to encourage other parties at the airport to reduce their emissions. But ultimately they make their own decisions,” Björnström says.
SECOND BEST NOT GOOD ENOUGH
When purchasing GSE vehicles, Swedavia screens the market carefully. There are discussions with potential suppliers and visits to seminars about new innovations. But on occasion, the types of vehicles Swedavia wants to buy are simply not available. This was the case in 2010 when it wanted to replace all its towed jet sweepers. These are huge snow-clearing machines that are vitally important for keeping Swedish airports open in winter, but collectively emitted a third of the GSE fleet’s emissions.
At the time, Swedavia wanted to buy jet sweepers powered by biogas because of the ready availability of this renewable fuel from local suppliers, but no one made the vehicles. Rather than opting for second best, Swedavia teamed up with GSE manufacturer Aebi Schmidt and the engine developer Volvo to come up with the world’s first biogas Towed Jet Sweepers (the TJS-C). At the end of a five-year collaborative process involving the trial of prototypes, 29 of the vehicles were delivered to Swedavia in 2014.
The various parties involved had consulted closely over Swedavia’s precise requirements. Drivers and mechanics were invited to meetings to express their views. Aebi Schmidt and Volvo listened carefully and then worked together to build the new machines. The development process involved years of research and experimentation, and Aebi Schmidt and Volvo had to work closely on the interfaces between the vehicles, the front tractor unit supplied by Volvo Construction Equipment and the engine in the rear supplied by Volvo Penta.
“Because the volume of machines is quite low compared to other work, we had to build the units using a standard base Volvo engine; otherwise, it would not be cost-effective,” explains Ingvar Waldebrink, manager special application solutions at Volvo Construction Equipment. “But because of Swedavia’s demands, we equipped the engine with other components made by a third party so it could work on 90% biogas and 10% diesel. That enables it to inject gas and reduces the amount of diesel used proportionately.”
Rolf Westlund, advanced engineering coordinator with Volvo Penta engines, points out that the “knocking limit” had determined how much gas could be pumped into the engine. “Much of the development involved testing how far we could go before we reached the knocking limit and reducing slightly from that point. There was lots of work with Aebi Schmidt over many years to find the best interfaces between their vehicles and our engines.”
Now that Volvo has developed a bi-fuel process, it can be fitted to other Aebi Schmidt machines, or sold to rival manufacturers of GSE equipment. “The partnership with Swedavia and Aebi Schmidt has allowed us to develop a dual fuel process that we didn’t have before and that opens up commercial opportunities for Volvo, but it isn’t suitable for all machines. To work well, the machines need to have a high load over longer periods of time,” Westlund informs.
Running the machines on 90% biogas provides a reduction of 40 litres of diesel per hour compared with the older jet sweepers and Swedavia expects to reduce emissions by 60-80% for snow clearing over the winter period.
The TJS sweepers clear the snow in three stages. First, the plough shovels snow to the side, then the rotary brush sweeps the remaining snow away, and finally the blower generates an intensive air flow over the entire swept area. Aebi Schmidt says there is no loss of performance compared with the older diesel machines. “Nothing has changed for airport operators, or ground handlers. The Green TJS does not differ in power from other TJS machines operating with a conventional Volvo engine,” says Andreas Schwald, key account manager for airport equipment at Aebi Schmidt. “The blower unit can generate a lateral air flow of up to 145 metres per second which blows away the snow across the runway and the machines can go without refuelling for over six hours.”
The next stage in Swedavia’s gradual updating of its GSE fleet will be to purchase new de-icers. A request to the market will be made in March or April this year. “For the de-icers I want to make sure they can run on HVO diesel,” Björnström says. “It’s not possible to run de-icers on biogas, as there’s no place for the tanks and electricity would be too expensive. It’s a good example of how we have to study the options carefully every time we make a purchase.”
Björnström believes the future of GSE equipment lies with vehicles powered by fuel cells, or green electricity. “Fuel cells have been developed since the 1960s and they are close to a breakthrough, so I think it will be a major energy source within 10 years, and we are already talking with suppliers about the possibility of electric buses for the airports.”
Volvo’s Westlund adds that the bi-fuel snow sweepers conform to current level IV emissions standards. But when level V come into effect in a few years time, the machines may not pass those more stringent regulations. “We will probably need to go a stage further, although the dual fuel will still be relevant to the Far East and other global markets,” he says.
