At 30,000 feet, still a long way from the runway at San Francisco, the 777 pilots reduced their thrust levers to idle . . . all the way to touchdown. Referred to as a continuous descent approach, or CDA, this technique dramatically cuts fuel consumption by allowing aircraft to fly a gliding descent at low engine power, in sharp contrast to conventional operations that direct airliners to stair-step down to lower altitudes where flying takes more thrust and where jet engines are less efficient.
Here’s another tack: military experiments are mimicking the same formation flying methods that birds use to reduce induced drag – the component of drag caused by lift – to fly further with less effort.
The aviation world is under growing pressure to dramatically curtail fuel consumption and greenhouse gas emissions. Europe’s “Clean Sky” initiative calls for 20-30% reductions in fuel burn and emissions for airlines that energy service in 2025-2035 compared to today. The FAA’s NextGen Air Transportation System program contains similar goals. More efficient engines and aircraft with more efficient wings based on advanced materials are hitting the market. Further out, new configurations such as blended bodies and strut-reinforced, high aspect ratio wings, together with integrated propulsion and airframes will change the look of what we fly, and make airliners greener while reducing costs. One U.S. Air Force program is called “Revolutionary Configuration for Energy Efficiency.”
But hardware changes take a long time and cost lots of a different kind of green. Well before many of these innovations fly, airlines, government agencies, academia and vendors are teaming up to bring dramatic energy efficiency improvements to the skies through operational modifications – such as CDA — enabled by software, procedures and common sense policies, which don’t require big capital expenditures.
On the ground, technology can also change energy use through renewable and efficiency technologies: solar electric arrays, renewable thermal technologies, energy management systems and upgrades to building envelopes, better design of cars and trucks (like the initiative just proposed by President Obama), wind farms. The list goes on. But just like the technology that manufacturers can bring to aviation, making technology shifts – especially disruptive ones – in buildings and ground-based transportation also requires capital, time, political will, and yes, consumer will (including the commercial and industrial sectors).
Similar to the rational near-term steps being taken by aviation, decision-makers from homeowners to corporate energy managers to those responsible for energy use in municipal and state entities can make use of low and no-cost strategies to reduce and green energy use. The buildings in which we live and work can improve energy efficiency, often on operational changes alone. While these changes should be easy to effect, like any endeavor that involves human behavior they still require ceaseless pushing, nudging, talking, and more important, listening. We are making strides, but the direction and rate of change remains agonizingly slow.
So, put your pedal to the metal . . . well at least metaphorically; drive slower, you’ll save more gas and reduce emissions.