David Smith looks at the latest developments in the ground power unit (GPU) world
Port Columbus Airport in Ohio has been one of the major beneficiaries of a remarkably generous US Federal Aviation Administration (FAA) programme. The FAA’s Voluntary Airport Low Emission (VALE) programme has given a total of US$24.5 million to 14 airports for the installation of greener GPUs and pre-conditioned air (PCA) units, or the introduction of other measures to reduce emissions.
It would be rude not to accept such a kind offer and David Whitaker, vice president of business development at Port Columbus, was delighted by the ‘free’ grant of $2.7 million to pay 90% of the costs of purchasing and installing 13 GPUs and 11 PCA units at airport passenger gates. The measures will reduce fuel consumption on the part of auxiliary power units (APU) as well as emissions of carbon monoxide, ozone precursors, particulate matter, sulphur dioxide and greenhouse gases.
“The support from the FAA is amazing. It’s spectacular that we get given this money,” says Whitaker. “The primary goal is to advance low-emission initiatives while aircraft are parked at the gate. If they run the APU, they are still pumping out emissions, but the grants have paid for ground power and conditioned air attached to the jet bridges so the aircraft can shut down power.”
Since some of the existing gates at Port Columbus already had this emission reduction technology, the grant paid for improvements only at gates without PCA or that required conversion of electrified GPU to dual power (400 Hz and 28.5 DC) to meet current demands. In addition, a new substation has had to be added to Terminal B to supply sufficient power to support the improvements. The power for the PCA and GPU is taken from this new substation.
In the past, Port Columbus has allowed airlines to take control of their own power. This situation led to a complicated scenario: some carriers relied on the airport’s bridge infrastructure, others brought a variety of equipment to get the job done and some relied on their own internal aircraft systems. “We made a decision a few years ago to be the owner of all the jet bridges and provide a consistent level of equipment on all the bridges. It takes a while to achieve that goal. Some of the GPUs are end of life so we are replacing them and others are not well adapted for smaller aircraft.
“The VALE grant has been a win-win situation,” enthuses Whitaker. “We have better control of an important asset – the jet bridge – and can reduce our emissions, while the carriers don’t spend money on fuel to power their systems. In taking more control, we are also doing all maintenance in-house now. Nothing is being outsourced to external companies. We used to use external providers for a lot of the work.”
The $2.7 million grant for Port Columbus was one of the largest sums offered to the 14 airport beneficiaries of the VALE programme. But the largest grant of all went to Indianapolis International Airport, which received $3.9 million towards the purchase and installation of 12 GPUs and 22 stationary pole lights.
The measures to reduce emissions at Indianapolis are a continuation of the airport’s long-standing commitment to reducing emissions, according to Mike Medvescek, director of operations and public safety. Medvescek notes: “Because of our commitment to the environment, we only purchase electric GPUs, as there are no emissions.”
One downside of being a state-owned airport, however, is that Indianapolis has restricted choice of which GPUs to select. This doesn’t mean Medvescek is unhappy with the INET ones selected. It’s just that he isn’t given any choice under government rules. “I’d much prefer to have the freedom to choose but the rules won’t allow it. We have to select the lowest, most responsible bid because we’re spending the Government’s money. That doesn’t mean we get cheap and poorly manufactured products, though. The rules require serviceability in the field for the GPUs for at least three years before they’re allowed to bid. We can’t risk purchasing from any manufacturer that builds something that’s not tried and tested.”
Indianapolis used to be owned by BAA and was one of the first privatised airports in the US. In those days, equipment could be purchased without the bidding process stipulated by government regulations. But after the terrible tragedies of 9/11, Indianapolis transferred back to state ownership.
Other airports to benefit from major VALE grants include Chicago O’Hare International, which received $2 million to purchase and install 15 GPUs and PCAs; Baltimore-Washington International Thurgood Marshall, which was granted $2.5 million for eight GPUs and eight PCAs; and Houston’s George Bush Intercontinental, which received $2.7 million for 11 GPUs and PCA units.
The VALE programme has been running since 2005, although the focus on GPUs is a recent development. The FAA says it has reduced ozone emissions by about 801 tonnes a year, which is the equivalent of removing more than 44,735 cars and trucks from the road annually. The focus on GPUs is a recent development and one of a number of strategies that also include providing funding for clean fuel-burning vehicles, refuelling stations, electric heaters and electric buses.
Mixed picture
The trend towards buying green GPUs has forced manufacturers to design products that reduce emissions. But the market has not always made it easy to sell them to smaller, regional airports, according to Kevin Smith, sales manager for the UK and Ireland for AXA Power, one of the brands within the ITW GSE combine (ITW GSE, part of the Illinois Tool Works Company, incorporates the AXA Power, Hobart, Houchin, ITW GSE Military and J&B Aviation brands, which together offers a wide range of GPU and APU systems).
Smith says that the Airport Operators Association (AOA) was pushing the green agenda for some time, but then the industry took two steps backwards. “Some countries in the developing world as well as southern European countries were kicking their heels and not responding to the drive for greener products, and the smaller airports in the UK responded to that and said perhaps we’re going too fast.
“They’re not under the same pressure as newer airport developments that have all kinds of caveats inserted about emissions and pollution and noise when they make planning applications. So some of the regionals carry on with business as usual, which can be frustrating when we are selling innovative new products and they’ve backed off from environmental issues.”
Aside from the environmental issues, the market picture in general for GPU products has been mixed in the UK in recent times, Smith comments. “We’ve had the upheaval from the Brexit decision and before that there was the fallout from a general election so it’s been anything but a normal period. There have been real peaks and troughs in the British market, so it’s hard to predict what will happen next.”
Smith says that one discernible trend, however, is towards mounting equipment on bridges, such as at Heathrow Terminals 2 and 3. “Airports are starting to move equipment away from the ground wherever possible. If we look at greenfield sites in the Middle East, architects like the idea of making the area around the aircraft as clutter-free as possible as there’s so much going on there. So Middle Eastern airports are starting to look cleaner.
“Older airports like Gatwick and Heathrow and Manchester haven’t had the luxury of so many air bridges but they’re getting more now.”
At the same time there’s been a move away from engine drive to fixed ground power that is electrically driven and supplied by airports. All that extra electrical infrastructure means additional power supplies are needed, and substation upgrades must be built to provide it. But airports will recoup some of the money quickly from the revenue streams. “Airports don’t get their revenue from engine-driven units which are brought in by ground handlers, but from fixed ground power. Lots are realising that offering these services provides a reliable source of long-term income,” Smith reveals.
The multitude of GPU products on the market these days can confuse operators. However, ITW GSE is taking steps to simplify its various offerings by providing a common design platform across all product lines, says Poul Elvstrøm, vice president sales & marketing at ITW GSE. “Whether the GPUs are line-powered, diesel-driven or we are talking PCA, they have all had the same design platform for the past two years – a strategy that continues and which we will further develop.
“Neither voltage nor whether it’s bridge-mounted or mobile units matters. All products use the same interface. It therefore becomes easier to do staff training and it minimises human errors. Plus, the common ITW GSE interface is very intuitive and logical for operators – it’s just like a smart phone.”
ITW GSE is also trying to work towards parts commonality in its products. “The idea is to use as many common parts through the complete product range as possible and to reduce the number of parts in general. That provides savings to airports and handlers and reduces complexity,” Elvstrøm advises.
Changing needs
Elvstrøm continues: “As most people know, the B787 ‘Dreamliner’ is an all-electric aircraft, which makes the world a greener place to live. Like the A350 and the A380, the Dreamliner requires power factor 1 rather than the usual 0.8. This was an issue some years ago. But recently another issue came up.
“Normally, GPUs are used to start an aircraft’s onboard APU, which then starts the aircraft’s main engines,” he explains. “If the APU fails, an air start unit (ASU), which is basically a large engine that can create high-pressure air, is used to start the main engines – a so-called ‘dry start’. However, as the Dreamliner is an all-electric aircraft, it can’t be started by an ASU in the case of an APU failure. It requires a GPU instead.”
Over the past six to eight months, many line-powered (also known as solid-state) GPUs had problems starting the Dreamliner, Elvstrøm suggests. Therefore, Boeing advised using mobile, engine-driven GPUs instead. However, this is not an optimal solution since many airports have fixed solid-state power units under the passenger boarding bridges or at the gate, he continues.
“Since ITW GSE always monitors the market closely and quickly adapts its products to the requirements, we have found a solution for the issue,” Elvstrøm says. The ITW GSE 2400 solid-state range can reliably start the B787 when the APU is out of action. “We demonstrated it on a Norwegian aircraft in Copenhagen, then on an Atlantic aircraft in Heathrow and we did a dry engine start with United in Houston,” he recalls.
Another exciting project for ITW GSE is the contract to provide GPUs for the world’s largest new airport project, the Istanbul New Airport, which is currently under construction in the Arnavutkoy district of Turkey’s largest city and which will be able to handle 150 million passenger a year. “We have been awarded the contract for all the gates, meaning 114 point-of-use PCA systems and 147 GPUs. It’s a huge project and we’re proud to be involved,” Elvstrøm says.
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Battery-powered GPUs
Where it is impossible to deliver mains ground power to aircraft on the stands, the classic alternative has usually been a diesel-powered generator. But these emit pollutants (especially carbon dioxide), and can be noisy and expensive.
However, there is an alternative, says James Ackland, sales director of UK-headquartered Powervamp – battery-powered GPUs such as Powervamp’s Coolspool range. Each cart is configured to deliver clean, pure wave-form DC current at 28 volts. Output can range from 130 and 410 amp hours.
Such units are compact, silent and pollution-free at point of use, require little maintenance, and cost only a third as much as a diesel unit (and as little as a sixth to run), Ackland explains. They can be pulled manually or towed, and recharged from a single phase electrical supply. The batteries suffer no ‘memory effect’ problems, so can be top-up charged at any time.
Typically, a single cart can handle at least three aircraft turnrounds on a single charge, running on-board electrics and avionics and also dealing with engine starting.
Though small, they can serve quite large aircraft. The Coolspool, for instance, easily handles the power requirements of large DC aircraft such as the ATR72-600, Saab 340 or Jetstream.
Recently signed up customers for Coolspool include Azul, Hawaiian Airlines and Terberg DTS, which has taken over 100 units.
In operation with one of these customers, it was found that the Coolspool 410 has sufficient amp/hour capacity to handle a typical ATR-600/72 turnaround of between 30-45 minutes, followed by a turbine start. This process was repeated a second and third time. This means that a fully charged Coolspool 410 can handle the arrival/departure of up to three ATR-600/72 aircraft on a typical turnaround without having to be re-charged between arrivals. In practice, however, it would be prudent, Powervamp suggests, to recharge the Coolspool 410 between aircraft turnarounds in order to avoid excess of discharge of the battery cart.
Other options
Static mains-powered 400Hz AC converters suitable for narrowbody passenger airliners such as the B737 are also becoming more popular. Powervamp’s PV90-3, for instance, has recently been introduced at the UK’s Heathrow and Birmingham airports, as well as in Switzerland, Poland, Gibraltar and New Zealand.
Meanwhile, Ackland adds, the perennial challenge of delivering power safely to an aircraft is being solved with snaking extendible wheeled cable carriers such as Powervamp’s Sidewinder.
Finally, Powervamp has developed a self-contained AC unit for cleaning aircraft in remote hangar locations, the mobile Powerbank, which combines lead acid batteries with a frequency converter and delivers 115 volt, 400Hz AC power.
