facturers [www.q400.com], uses 3.81 litres per 100 passenger-km (at a cruise
speed of 667 km/h), which is an energy cost of 38 kWh per 100 p-km. The
full 747 has an energy cost of 42 kWh per 100 p-km. So both planes are
twice as fuel-efficient as a single-occupancy car. (The car I’m assuming
here is the average European car that we discussed in Chapter 3.)

#### Is flying extra-bad for climate change in some way?

topic [3fbufz]. Flying creates other greenhouse gases in addition to CO2,
such as water and ozone, and indirect greenhouse gases, such as nitrous
oxides. If you want to estimate your carbon footprint in tons of CO2-
equivalent, then you should take the actual CO2 emissions of your flights
and bump them up two- or three-fold. This book’s diagrams don’t include
that multiplier because here we are focusing on our energy balance sheet.

The best thing we can do with environmentalists is shoot them.
Michael O’Leary, CEO of Ryanair [3asmgy]

page no.

35Boeing 747-400 – data are from [9ehws].
Planes today are not completely full. Airlines are proud if their average full-
ness is 80%. Easyjet planes are 85% full on average. (Source: thelondonpaper
Tuesday 16th January, 2007.) An 80%-full 747 uses about 53 kWh per 100
passenger-km.
What about short-haul flights? In 2007, Ryanair, “Europe’s greenest airline,”
delivered transportation at a cost of 37 kWh per 100 p-km [3exmgv]. This
means that flying across Europe with Ryanair has much the same energy
cost as having all the passengers drive to their destination in cars, two to a
car. (For an indication of what other airlines might be delivering, Ryanair’s
fuel burn rate in 2000, before their environment-friendly investments, was
above 73 kWh per 100 p-km.) London to Rome is 1430 km; London to Malaga
is 1735 km. So a round-trip to Rome with the greenest airline has an energy
cost of 1050 kWh, and a round-trip to Malaga costs 1270 kWh. If you pop
over to Rome and to Malaga once per year, your average power consumption
is 6.3 kWh/d with the greenest airline, and perhaps 12 kWh/d with a less
green one.
What about frequent flyers? To get a silver frequent flyer card from an in-
tercontinental airline, it seems one must fly around 25 000 miles per year in
economy class. That’s about 60 kWh per day, if we scale up the opening
numbers from this chapter and assume planes are 80% full.
Here are some additional figures from the Intergovernmental Panel on Cli-
mate Change [yrnmum]: a full 747-400 travelling 10 000 km with low-density
seating (262 seats) has an energy consumption of 50 kWh per 100 p-km. In
a high-density seating configuration (568 seats) and travelling 4000 km, the

Figure 5.4. Ryanair Boeing 737-800. Photograph by Adrian Pingstone.
energy per distance
(kWh per 100 p-km)
Car (4 occupants) 20
Ryanair’s planes, year 2007 37
Bombardier Q400, full 38
747, full 42
747, 80% full 53
Ryanair's planes, year 2000 73
Car (1 occupant) 80
Table 5.3. Passenger transport efficiencies, expressed as energy required per 100 passenger-km.