Greener Airports

Franz-Josef Herchenbach, Director Portfolio & Innovation Management for Siemens Airports, explains how ‘Green’ airports need not cost the earth.

Modes of transport are a prime focus for green initiatives as we all look for a more environmentally sustainable approach of getting from A to B and better ways to reduce energy usage.  The airport industry has taken its fair share of criticism as a polluter, but on a closer look at the CO2 emission figures, that ‘fair share’ comment should be re-evaluated.  The aviation industry currently accounts for approximately 13% of all CO2 emissions from global transport and 2% of the global CO2 emissions, yet its profile as a polluter is undoubtedly much higher than these percentages would suggest.  Of that 2%, an estimated 10-15% is related to the airport itself.  It is important to appreciate that even within these numbers, not all of the emissions are under the direct control of the airport.  Did you know for example, that up to 50% of the on-ground emissions are actually caused by aircraft taxiing and queuing?  The second largest CO2 contributor is the public transportation of passengers, staff and delivery services to and from the airport – as much as 40% of an airport’s CO2 footprint.
However, even allowing for the fact that the airport can only directly influence a fairly small proportion of its total CO2 output, the airports, quite rightly, take their responsibility for the environment seriously and do whatever they can.
Before I come to a few best practices and what measures can be taken, it is important to establish some news, both good and bad.  Starting with the bad: there is no single solution or energy saving figure which fits all.  Each airport is unique and must be treated individually.  Randomly proposing a saving potential – for example – product xyz will reduce your energy consumption by 30% – is not really helpful, unless you specify pre-requisites under which the goal can be achieved.  Now, turning to the good news – there are a number of solutions out there, including detailed analysis based on CAPEX (Capital Expenditure), OPEX (Operational Expenditure) and ROI (Return on Investment).  This is an important point.  Despite the many pressures that airports face – public perception, growing traffic averaging 5% year on year, increased energy costs and increasingly stringent policies to name but a few – ultimately the decision to invest can be difficult as short term financial targets invariably remain a prime performance indicator.
 
Best practices
Taking a typical process flow for an airport environment as our starting point, here are some examples of best practices that can be adopted.
 
After landing and before take-off
LED technology for airfield lighting has been in use on taxiways for a number of years, but LED lighting for the runway itself is now becoming more readily available. Energy savings of up to 80% are possible, depending on the defined baseline.  It makes a difference comparing just a standard airfield lighting inset with an LED lighting inset – an even greater difference if you extend that to the overall airfield lighting system with all its components.  Besides headline energy savings, reduced maintenance and less downtime could also contribute to the overall equation.
An advanced surface movement and ground control system is a further lever to improve the CO2 footprint of an airport.  Optimising taxiing times, bearing in mind their significant impact alluded to earlier, will reduce the fuel burn, which again has a positive impact for the CO2 footprint.  Airport operators can also influence fuel consumption of on-the-ground aircraft by asking for one engine to be turned off during taxiing, or by providing power and pre-conditioned air to parked aircraft, thereby reducing their need to run their engines.
Moving beyond the aircraft, recognising the role of the supporting ground fleet can have an environmental benefit.  Hybrid cars and buses using the latest drives, inverter and energy storage technologies – for example, ultra capacitors that store the braking energy – can save up to 40% of fuel.
The ROI depends on the mileage per year and the fuel costs.  Cars solely powered by electricity are a further option, with reduced energy costs of 60% compared with a conventional fuel based vehicle.  Tax incentives for electric cars and reduced maintenance cost make this technology a viable option.  And, when using renewable energies, this would be a CO2-free solution.  Smart charging infrastructures are underdevelopment with the main challenge still being the battery with its limited storage capability and high cost.
 
Inside the terminal
Turning to an airport’s buildings and primarily the airport terminal, significant opportunities exist here for energy saving measures.  Inside the terminal, creating the right environment is an important factor in what is an increasingly competitive arena.  An airport’s success depends upon loyal and happy customers and this is not just about efficient logistics and timely operations, but also the safety, security and comfort of the airport’s buildings and facilities.
The majority of an airport’s energy consumption is a result of the movement of passengers and their baggage and maintaining the comfort and well-being within its buildings.  ‘Green’ airports typically ensure optimum levels of fresh air, the best use of natural resources and daylight and greater passenger and staff comfort to create a more hospitable environment.  There is now proof that green buildings reduce life-cycle costs and improve staff productivity.
One of the major technology shifts in building technologies over recent years is the move to direct digital control (DDC) systems and open communications, i.e. transparency between cost and pricing.  The three main direct benefits of DDC are improved communication, improved operational efficiency and increased energy efficiency.  An intelligent Building Management System (BMS) within an airport can provide more effective control of heating, ventilation and air conditioning (HVAC) systems by providing the potential for more accurately sensed data and a range of proven, library-based control algorithms that can be easily implemented and modified.  A BMS allows thousands of data points to be monitored across the whole facility and provides airport operators and engineers with the flexibility to adjust plant schedules, many different set points and the overall control strategies to suit the growing needs of the airport.  A BMS is also an ideal tool to implement energy saving features and optimise the performance of airport equipment and services.
 
Demand Controlled ventilation
One of the defining characteristics of an airport is that the throughput of passengers will quite naturally fluctuate significantly.  This means that strategies such as demand monitoring and peak-demand limiting, which can be easily implemented within BMS systems, are particularly suited to the airport environment.  Airport terminals are typically closed buildings, with 95% of passengers’ time spent inside the various buildings and concourses.  This makes the measurement of the indoor air a key issue for passengers’ health and well-being, but also provides a perfect measurement of room occupancy.  Mixed-gas sensors can detect oxidisable (combustible) gases such as C02 to determine when zones are occupied plus other additional odours (known as volatile organic compounds) from dirty ventilation systems, carpets, dust, smoke, fumes, people etc. – elements perceived by humans as bad air.  Consumption patterns throughout the airport, particularly those where fluctuating occupancy is at its greatest (passenger gates, retail areas, restaurants, bars and check-in areas), can be monitored and the actual demand of individual zones can be controlled by resetting various system set points (such as decreasing the requirement for cooling on a zone-by-zone basis).  During high occupancy periods, when air quality levels are poor, the volume of fresh air to the zones is increased to maintain comfort.  When no occupancy is detected, ventilation rates, temperature set points and lighting levels can be reduced to save energy.
 
Lighting
Large energy savings can be achieved from a reduction of an airport’s interior lighting levels, either by the use of energy efficient lamps, by scheduling according to usage or simply by shutting lights off when the occupants leave the room or with reference to indoor lighting levels.  LED lighting technology is now available for a wide variety of applications including indoor, shop, mood, street lighting and lighting for parking garages.  Determining the wattage of all light fixtures in the zone will enable an easy calculation of the instantaneous power (kW) saved, and the BMS building can create reports highlighting total lighting energy reduction in kWh.
Energy savings of up to 80% are possible by looking beyond the passenger buildings to the hangars, apron and roads, along with additional savings in maintenance due to the longer life afforded by modern lighting equipment.  Again, it always depends on the starting point: replacing old T8 lighting with modern T5 lighting incorporating electronic control gear, replacing mercury vapour with high pressure sodium lamps or replacing halogen with ceramic metal halide lamps will provide energy savings of between 40 and 80%.  Based on recent audits, ROIs of between one and three years are possible.  To minimize disruption, such activities can be factored into planned maintenance schedules.
 
Baggage Handling
The Baggage Handling Systems (BHS) is one of the larger energy consumers at an airport.  There are three main areas for improvement – the drive side, the mechanical side and the controls software.  As ‘a low hanging fruit’ you may start with software improvements which can be done without great efforts in replacing parts.  Energy savings of up to 50% are possible for an airport with inefficient controls logic.  For those employing belt conveyors, it might be worth replacing torn belts with low friction belts: energy savings of around 25% are possible.  A further option is the replacement of old drives.  Using highly efficient gearboxes and energy efficient motors can save up to 40% of energy.  Bearing in mind that nearly 95% of the total life cycle cost of a motor is down to the energy it consumes, you will get an ROI in less than two years.
You may also consider using variable speed drives.  With this technology you can run the BHS with load dependent speeds, lowering energy costs and reducing maintenance due to less wear and tear.  It is obvious that there is an optimal time for each individual measure to be adopted.  Software can be done right away, belt replacements at the end of life of existing belts and drive replacements typically if you have old drive technology.  And, don’t forget, there are interdependencies between the various levers, which will affect the overall saving if combined.
 
Green IT
Turning to information technology (IT), there are two main areas for environmental leverage.  One is smart IT solutions to optimise processes like resource management, fleet management, airport operations and collaborative decision-making.  The other area is more related to the hardware.  Today it is commonplace to have dozens of individual PCs and servers running at a fraction of their computing power capacity.  The solution could be application and desktop virtualization.  For example, instead of having 15 individual computers, each with its own application, adopt one powerful server on which the 15 applications are running.  Energy savings of up to 80% are possible.  An added incentive is that this new architecture makes it easier to implement redundant and backup concepts, while offering better dynamic load sharing.
This focus on integrating processes can ultimately be extended to command and control systems whereby a wide range of disciplines such as fire, intrusion, access control, video surveillance, public announcement systems, flight information displays, building management systems and other relevant security equipment are controlled and monitored from a single screen.  Although this is primarily used for incident management, through high level integration of the building management system, energy usage can be monitored.  An example is intelligent video, which can be used not only for security monitoring but also to assist with intelligent crowd management, matching the heating, venting and air conditioning requirements accordingly.
 
Energy generation
Efficient on-site energy generation is becoming more and more popular.  Today’s typical set-up with numerous local boilers, chillers and maybe an on-site electrical energy generator might not be the most efficient method, particularly if they are not centrally monitored and controlled.  The highest efficiency is achieved through combining various individual technologies into a single integrated system such as using a modern, gas-fired Combined Heat and Power (CHP) plant with heat recovery combined with district heating and cooling (tri-generation) may increase the overall efficiency by more than 50% compared to today’s individual systems.  A further opportunity to improve the CO2 footprint is through photo voltaic (PV) measures.  If the airport is based in a country with government supported feed-in tariffs, you may get quite good ROIs.  Depending on the tariffs, the cost per kWp for the PV plant, the financing costs you have to pay and the yield (kWh/kWp), ROIs within six to seven years are feasible.
 
External traffic and intermodality
Depending how you define the footprint of an airport, you may have to consider the impact of private and public transportation to and from the airport since external traffic is an airport’s second largest CO2 contributor.  Having efficient rail links to the city or into the catchment area is one possibility while an integrated high speed train station is another.  Just looking at how your existing car traffic is handled can reap benefits, with preferred lanes for eco-friendly taxis, free charging for electrical cars, VIP parking for low emission cars just some examples of initiatives that can be taken.
Further emission reductions can be achieved by optimizing the parking guidance system: dynamic systems directing cars to free spaces can reduce the time cars spend looking for a parking space, and, as a result, reduce fuel use/emissions.  For additional energy savings, CO measurement can also be used for demand-controlled ventilation.
 
Overcoming hurdles
Even if the potential savings, the CO2 reductions and the ROIs are quite obvious there are still a few hurdles to overcome.  One of the main problems is the fragmented nature of airport organization.  Products and solutions are often purchased on a pure CAPEX basis.  A more holistic approach based on OPEX or TCO (Total Cost of Ownership) tends to be the exception rather than the norm.  It is important to bear in mind that CAPEX are much smaller than OPEX if you consider the TCO.  If you consider a typical CAPEX / OPEX ratio for a building of 20/80 and if you spend maybe 20% more in CAPEX for a modern, energy efficient building, it is easy to calculate the timescale required for the ROI.
A further hurdle is obsolete specifications with products and systems which do not allow for migration and expansion to accommodate the changing needs of an airport. If you have specified such a product and later ask for a more energy efficient option, you usually have to pay a premium, so it’s much better to consider the capacity to upgrade at the outset.  Up-to-date specifications which recognize the increasing role of modern and energy-efficient processes and solutions will ensure that you get technology which is more cost effective in the longer term.
Last but not least, such a holistic approach needs the full commitment from the top management.  Without the support from this level with genuine and committed buy-in from the involved stakeholders, it becomes very difficult to achieve the goals.
As alluded to earlier, financing issues are, of course, a consideration in any purchasing process, particularly so given the impact on passenger and freight numbers from the economic crisis and the volcanic ash consequences, the various governments plans to introduce new taxes and increasing competition between airports.  One solution for certain areas could be the adoption of so called ‘performance contracting’.  This means the investment cost to implement a certain measure will be paid for by the contractor.  This investment is re-financed by the savings achieved through the new measure, with a typical contract period being about ten years.  After this time the system is handed over to the customer who will benefit from the savings thereafter.  The benefit to the customer is that an energy efficient solution which reduces the CO2 footprint is provided at no additional cost.
 
And to the future
Airports are continuously striving to reduce their environmental impact and this focus is only likely to increase.  Research is being conducted into smart energy grids, with consumers and producers managing the energy generation, distribution and consumption based on the data from intelligent metering devices.  Electrical cars may play a central role in storing renewable energy if there is a surplus, serving as the energy provider to shave load peaks.  Hydrogen might become a major source of energy, once the production cost based on renewable energies becomes more cost-competitive.  And, as reported in the ‘Tractors for Tomorrow’ feature in the Aug/Sept 2010 issue of Airports International, aircraft may well be moved around the airfield by Automated Guided Towing Vehicles (AGTV´s), thereby removing the need for aircraft engines to be used for taxiing.  This would lead to a significant reduction of fuel burn on the ground, of noise and of CO2 – a major contributor to the greening of airports given the estimated 50% of on-ground omissions from taxiing and queuing I spoke of at the outset of this article.
 
Green makes sense
Green airports make economic as well as environmental sense: a shorter ROI thanks to more efficient technologies and higher energy savings off-set initial investments quicker, as well as deliver measurable efficiency gains (cost, operations) and an improved customer experience.  A greater level of integration of both airport processes and systems brings greater levels of intelligence in airport operations, with significant benefits in terms of energy consumption and reduced environmental impact – a trend that will undoubtedly continue.  Furthermore, with the need for transparency increasing, it will be necessary to be able to compile the data from all relevant systems and sensors, analyze them, and report back on target achievements, etc.  Airports will therefore have little choice in the future, and the decision will not be about whether or not to invest in these new technologies, but rather which ones will yield the highest benefits, both in terms of ROI and social responsibility for each airport’s specific requirements.  And, importantly, which partner will be able to deliver this.  The best partners will be those who not only understand the intricacies of airport challenges (financial, social, operational, etc) but also how they fit into their wider regional, societal and economic issues.