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7. The Use of Pre-Conditioned Air Units to Reduce Emissions at Aircraft Gates

The Use of Pre-Conditioned Air Units to Reduce Emissions at Aircraft Gates

Project Objective: Reduce greenhouse gas (GHG) emissions at aircraft gates by replacing onboard electricity and compressed air generators that operate using fuel with on-ground pre-conditioned air (PCA) units which operate using electricity.

Organization: Vancouver Airport Authority at Vancouver International Airport

Project Timeline: February 2010 to February 2011

Project Results: Based on a 6-month trial period, the PCA units averaged an annual reduction of 79,230 liters of fuel and 203,564 kg of greenhouse gases (GHG).

   Table 1 - Performance Results

Fuel Saving per hour of PCA unit operation (liters/hr)	Total Annual Use (hrs)	Total Annual Fuel Reduction (liters)	Total Annual GHG Reduction (kg)
96.09	824.54	79,230	203,564

           Table 2 - Financial Results

Total Annual Net Savings per Month1	Total Cost of Project	Payback Period
$ 65,940	$898,588	13.6 yrs

Project Description

With funding from Transport Canada’s Freight Technology Incentives Program, the Vancouver Airport Authority purchased and installed PCA units at the aircraft gates of the Vancouver International Airport (YVR) to reduce GHG emissions. The project also generated fuel and maintenance cost reductions. The Vancouver Airport Authority is the not-for-profit organization that manages Canada’s second busiest airport.

Auxiliary power units (APUs) generate electricity and compressed air for onboard functions while the main engines are turned off on the ground. Their use causes 5% of the airport’s total emissions of greenhouse gases (GHGs), and criteria air contaminants (CACs) which impair air quality.

The use of APUs can be significantly reduced if gate-mounted alternatives are available on ground, such as pre-conditioned air (PCA) units which run on electricity. The PCA units provide cooling or heating, as well as filtering the aircraft’s air while on the ground.

Methodology

The Airport Authority purchased and installed six PCA units at six gates used by narrow-body aircrafts at the YVR. The gates of US airlines were chosen because they have strong policies on turning off the APU, and thus, were more likely to use the PCA units.

Upgrades to the electrical and communication infrastructure at the six designated gates were completed. In addition to these upgrades, airport crews were trained on how to use the PCA units and how to analyze the use of the equipment. Electricity meters were installed on each of the PCA units to monitor use by recording electricity consumption (in 5 minutes increments). The data collected by the meters was then linked to aircraft gate records to identify specific events as to when the PCA was used, the duration of its use, the aircraft type and which APU model it replaced in order to calculate fuel savings. With this data, a weighted average of fuel consumption saving per PCA hour of operation was calculated. GHG emission reductions were calculated based on fuel savings and Environment Canada’s most recent equivalency factors at the time of this writing.

Detailed Performance Results

APUs in this project consumed between 64 to 157 liters of fuel per hour based on aircraft type and APU model. PCA units only use clean hydroelectricity from BC Hydro. Based on the collected data, which is representative of activity at the YVR, fuel consumption savings and GHG emission reductions were calculated. Tables 3 and 4 below show the results from the 6-month testing period (July to December, 2010) and the annual projection based on these results.

           Table 3 – Fuel Savings and GHG Redu

	Fuel Saving per hour of PCA unit operation (liters/hr)	Total Use (hrs)	Total Fuel Reduction (liters)	Total GHG Reduction (kg)
6-Month Period	96.09	412.27	39,615	101,782
Annual Projection	96.09	824.54	79,230	203,564

           Table 4 – Reduction of Criteria Air Contaminant Emissions

	NOx Reduced (kg)	CO Reduced (kg)	SO2 Reduced (kg)	HC Reduced (kg)
6-Month Period	237.4	200.4	17.4	19.2
Annual Projection	474.8	400.8	34.8	38.4

Detailed Financial Results

PCA Units generate monthly savings of $5,495. When taking into account the total project cost of $898,588 the payback period of less than 14 years can be achieved for this investment. Table 5 details the net savings and payback period.

           Table 5.1 - Savings

	6-month	Annual
Fuel Savings (APU)	$29,274	$58,548
Maintenance Savings (APU)	$8,610	$17,220
Total Savings	$37,884	$75,768

     Table 5.2 - Costs

	6-month	Coûts Annuel
Electricity Costs (PCA)	$3,834	$7,668
Maintenance Costs (PCA)	$1,435	$2,870
Total Costs	$5,269	$10,538

           Table 5.3 - Net Project Savings and Payback Period

	Annual
Net Savings (Total Savings – Total Costs)	$65,230
Total Project Costs	$898,588
Payback Period (Total Project Costs / Net Savings)	13,6 yrs

Conclusion

The technology was well received by the Airport Authority, and the emission reductions were significant thanks to clean electricity from BC Hydro. Despite a few minor technical issues that occurred, the PCA units have resulted in less maintenance issues, and a monthly average of approximately 6600 liters of fuel savings for airlines.

The PCA hoses chosen in this project were more durable than the hoses that are typically used to connect the PCA unit to the aircraft. They are also easier to use, and allow ground crew to connect aircrafts faster.

The biggest issue in this project was that use of PCA units is voluntary, and depends entirely on participation from airlines, flight crews, and ground crews. Because of this, it is recommended to use a phased-approach to implementing PCA units. This allows airports to make adjustments based on feedback and use by airlines and ground crew.

The overall use of the units was not as high as had been hoped, but the project did meet the expectations considering the time of year of the testing period (July to December). Until fuel prices increase further, airlines may continue to use APUs.

It was found that the demand for cooled air is significantly greater than the demand for heated air. Thus, this project might be more successful in warmer climates (i.e. temperatures above 18°C), as well as in extreme cold.

The project is recommended for airports wishing to reduce fuel and emissions at their facility. If the project were to be repeated, it would use smaller, newer equipment which is more environmentally friendly and results in greater energy savings.

Date modified:

2012-02-16

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