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7. Replacing Diesel-powered Technology with Electric-powered Technology

Replacing Diesel-powered Technology with Electric-powered Technology

The analysis and conclusions contained in this case study are those of the authors alone and do not necessarily represent the point of view of the Government of Canada.

Organization
Winnipeg Airports Authority

Major Findings

• Replacing diesel portable units with on-gate electric units at the Winnipeg Airport can, on average, reduce CO, NO_x and PM emissions by about 88% and CO₂ by 45% to 68%.
• Removing portable diesel units from the apron can also reduce clutter and increase safety and efficiency.

Project Timeline
January to December 2006

Please note that some figures such as fuel costs are based on data from the period that this project took place.

Introduction
An aircraft auxiliary power unit (APU) provides electricity and compressed air to operate an aircraft's lights, instruments, ventilation (heating and air conditioning) and other equipment when its main engines are turned off. It also provides power for starting up the main engines. When the aircraft is at a gate, the APU remains in use unless other sources of power are available. These can include diesel portable Ground Power Units (GPU) and Preconditioned Air (PCAir) units or electrically powered GPU and PCAir units.

The Winnipeg James Armstrong Richardson International Airport does not have electrically powered GPUs and APUs directly attached to the gates. It uses 16 to 20 portable diesel units to provide heat, cooling and power to parked aircraft when pilots shut down the APU. These diesel units have no emission controls and release greenhouse gases. Many units are 15 to 30 years of age.

Installing on-gate electric airport service equipment at new gates and retrofitting existing gates for point-of-use electric systems has proven to reduce GHG emissions at airports across North America. This is why the Winnipeg Airports Authority (WAA) submitted a project proposal to Transport Canada under the Freight Incentives Program, for funding to switch from diesel to cleaner electric power sources. Electricity in Manitoba is generated mainly from hydro and wind-powered sources.

Project Description
The WAA project proposal detailed a plan to replace portable diesel GPUs and PCAir units with electric on-gate systems - and to monitor and report on GHG emission reductions. Transport Canada provided funding for the purchase and installation of one on-gate electrical unit.

Project Goals and Objectives
The WAA wanted an on-gate electrical power unit to reduce emissions from idling aircraft engines and from portable diesel units during passenger boarding and overnight stops. Removing portable diesel units from the apron would also reduce clutter and increase safety and efficiency.

Project Methodology
WAA installed meters on the new electric GPU and PCAir units to track their hourly usage. Weekly or bi-weekly meter readings were recorded from June 23, 2006 until December 23, 2006. Emissions reduction calculations were based on electric unit use. They assumed that when the electric units were in use, diesel and on-board APU units would not be required.

The first step was to conduct an airlines survey to learn which airlines used the electric GPU and PCAir units.

The ICAO Engine Exhaust Emissions Data Bank provided WAA with hydrocarbons (HC), carbon monoxide (CO) and oxides of nitrogen (NO_x) emission data for select engine models at idling power levels.

Fuel flow (kg/second) was obtained for each aircraft engine and multiplied by meter readings (in seconds) for both the electric GPU and PCAir systems to obtain the total fuel usage (kg). The total fuel usage was then compared to the emissions that are released from the aircraft engines at idle power to obtain a total value of emissions released. This valuerepresents the total emissions reduced from using the electric units compared to the aircraft APU.

The U.S. Environmental Protection Agency (EPA) provided data from a study of carbon dioxide (CO₂), Nitrogen Oxides (NO_x), particulate matter (PM) and CO emission rates (May 1999) from diesel units. To determine emission savings, data was compared to the meter readings for the electric units.

The emissions for the diesel portable units (in grams/hr) were multiplied by the total meter readings (in hours) for the electric GPU and PCAir units and divided by 1 000 to obtain the value for the total amount of emissions (kg) reduced.

WAA obtained baseline data for expected usage of diesel portable units from the U.S. EPA. This was compared with the usage of the electric units.

Results
The study confirmed that GHG emissions from idling aircraft engines and portable diesel units were higher than those produced by the new electric equipment.

The WAA survey showed that when aircraft arrive at a bridge pilots either idle their engines or use APUs to supply power and conditioned air to the aircraft. Some pilots would shut down their engines and hook up to both electric PCAir and GPUs. Others continued to keep their APU on for power only, but would also hook up to electric PCAir units. Since specific data for time-of-use for the APUs and/or the electrical systems was not tracked, and not all flights were observed, the WAA could not accurately calculate emissions reductions resulting from using the electric units.

A more accurate calculation of emission reductions was based on the non-use of diesel units. Based on similar aircraft and traffic volumes, the use of portable diesel GPUs at the bridge over a six-month period was estimated to be 1 095 hours. The project showed electrical GPU use was 1 001.8 hours. Therefore by using electric instead of diesel GPUs, emissions were reduced by about 91% (1001.8 hours/1095 hours). These results were compared with the results of the U.S. EPA study that found that replacing diesel portable units with on-gate electric units reduced CO, NO_x and PM by an average of 97%, and CO₂ by an average of 50% to 75%.

The WAA concluded that on average, this technology would reduce Winnipeg Airport CO, NO_x and PM emissions by 88.3% and CO₂ emissions by 45.5-68.3%. The WAA predicted that increased use of these units would bring emission reductions closer the U.S. EPA values.

Using electric units reduces noise, saves time, and removes clutter on the apron, which improves safety and efficiency.

Conclusion
WAA is building a new sustainable air terminal in which five electric GPU and PCAir units will be installed. These electric units will reduce noise, GHG emissions, safety concerns and the need for portable units on the apron.

To obtain the full benefit of these electric systems and increase their use over time, the WAA will promote their use among airlines, pilots and ground handlers. WAA will stress the financial savings to the airlines for using electricity versus petroleum-fuelled power sources.

Additional Information

• Winnipeg Airports Authority

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Date modified:

2012-02-07

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