About dontfly

FLYING CALCULATOR

Kyoto Protocol took effect in February 2005. At present emissions from air traffic are excluded from the European Union emission trading scheme. Air traffic is globally heavily subsidized and the aviation fuels are practically tax free.

People fly around the globe mostly for fun and at the same time pollute our planet. Climate change is a challenge we must meet. We are also approaching the so-called peak oil. Peak oil means that global oil output will gradually start to reduce. Replacing oil in the transport sector is challenging, particularly so in air traffic.

Luckily there are technically easy and readily available solutions, such as higher fuel efficiency standards and higher fuel taxation, which would lead to smaller cars and more sustainable use of them. In air traffic there are measures that should be taken, such as heavy taxation of aviation fuel. Unfortunately these solutions are politically difficult. Politicians want economic growth, and consumption walks hand in hand with economic growth.

The intent of this site is to affect attitudes and help people to adapt more sustainable living styles.  

The flying impact calculator is based on…

The distance calculators give the distance the “crow flies”. In practice, the flight distances are considerably longer. Hence the results given in the boxes are conservative.

The main data used in the calculations are from Eyers et al. [1], Whitelegg and Cambridge [2] and Heaps et al. [3]. The most recent detailed civil aviation (no military or non-commercial aviation was included) data were available for year 2002:

• 156 million tonnes aviation fuel consumed [1]

• 492 million tonnes carbon dioxide emissions from burning jet fuel [1]

• 3166 billion revenue passenger kilometers (rpk) [2]

• 93.49%, share of passenger traffic in civil aviation [3]

Crude oil consumption. Average aviation fuel (jet fuel) consumption per revenue passenger kilometer (rpk) is 46.06 g. The resulting carbon dioxide emission are 145.3 g per rpk. Ideal gas law is used in calculating liters of carbon dioxide released to atmosphere.

Today, for producing diesel fuel, the losses between oil wells and filling stations for transportation, refining and distribution, are about 13.22% [4]. Thus the well-to-tank efficiency of diesel is 86.78% per cent. This means that the real fuel (crude oil) consumption and the real carbon dioxide emissions are greater. The well-to-tank efficiency for jet fuel is assumed to be the same as for diesel. The following parameters have been used in determining the crude oil consumption and carbon dioxide emissions:

• 35.59 MJ/L, lower heating value of jet fuel jet fuel

• 33.56 MJ/L, lower heating value of crude oil

• 73.4 g CO₂/MJ, specific carbon dioxide emissions of crude oil

• 819.18 g/L, density of aviation fuel (jet fuel)

Heating and ventilation of the plane halls, deicing, land-vehicle fuel consumption etc. could also be taken into account. However, these factors raise the crude consumption only about 2% and in this analysis they are neglected. Manufacturing and scrapping of aeroplanes have not been taken into account.

"Tonnes of carbon dioxide released to atmosphere by the group/family, two-way flight"  2463.4 g carbon dioxide is released when one liter crude oil is burnt. In fact, this figure could be doubled, because the carbon dioxide in higher atmosphere is twice as harmful.

"Euros would cost to buy carbon emissions (if aviation was not excluded in the EU carbon dioxide trading scheme)" One CO₂ emission trading tonne is about 20 euros. However, it can be assumed that about 80% of the carbon emission allowances will be given free for the airliners. Thus, a tonne of carbon dioxide would cost just 4 euros.

"Euros more the flight would cost, if aviation fuel had the same tax as road transport fuel in EU" Aviation fuel price per liter is about 0.8 euros less than average EU-15 road-transport gasoline price. 

“Equivalent to idling a family car nonstop” is calculated using an assumption that a car consumes one liter of fuel an hour, when it is in idle motion. This means that the car must be refueled every other day. The result is given in days of nonstop idle motion.

“Equivalent to driving with a family car” is calculated for an average passenger car sold in European Union (EU-15 in 2001). The result is given in road kilometers for the car that equal the fuel consumption of the given flight allocated for the given number of passengers. An average new passenger car in EU-15 in 2001 had an EU combined fuel efficiency of 6.77 L/100 km [5]. Diesel share of new passenger cars was 33.27%. In the well-to-tank analysis for the fuel, 84.14% efficiency was used, the weighed efficiency of gasoline and diesel production cycle. 

Some time in the future we run out of oil. Flying to holidays and driving SUVs means that our grandchildren do not have this one-time gift anymore. Biofuels are one alternative to oil. “Hectares cropland needed for equivalent biofuel production” calculates the land required to produce ethanol from wheat to fuel the given flight. In the years 2004 and 2005, the average wheat crop production was 2863 kg/ha in USA [National Agricultural Statistics Service USDA, November 2005]. One kg of wheat yields 0.358 L of ethanol [Idaho National Engineering and Environmental Laboratory, D.E. Shropshire et al]. Hence the ethanol yield is 1024 L/ha. It takes some 1.5 liters of ethanol to give the energy of one liter fossil aviation fuel because of about one third lower energy content of ethanol. In the future, our agricultural land is used both in food and energy production. The ethanol yield per hectare used in the calculations is from modern fossil-based "industrial" agriculture. If ethanol is produced in a sustainable way, the cropland needed would be considerably higher.   

“Amount of breads the cropland could produce” calculates how many loaves of bread the above calculated cropland could produce, if it was not used for fuel production. It has been estimated that 7.5 tonnes of wheat is enough to make 11,500 loaves of bread [The flour and grain education programme, http://www.flourandgrain.com/facts].