This article presents the results of the calculation of energy and CO2 emission intensities in relation to the unit of passenger transport activity for various modes of public transport, cars and motorcycles for Warsaw in 2015. The results are compared with similar information from other countries and regions that comes from international comparisons and are summarized in this article. The results for Warsaw show that intensity indicators are comparable to other cities, with noteworthy lowintensity indicators for city public transport buses. An important achievement of the author is calculation of the energy and CO2 emission intensities for various modes of transport in Polish conditions and for a single city: Warsaw.
GHG EMISSIONS AND TRANSPORT ENERGY INTENSITYEnrgy use in transport has become one of the most studied topics since the 1970s and first oil peak. Gradually, technologies and laws were upgraded, so that cars, trains and other modes of transport could become less energy-consuming and, at the same time, more environmentally friendly. In fact, initially, energy efficiency of vehicles was enforced by the air pollution regulations, which started with the 1970s USA Clean Air Act. Europe followed with regulations in this respect in the early 1970s with United Nations Economic Commission for Europe (UNECE) Regulation 15 amendments. Since the 1990s, this trend has increased with acceleration of climate change and the need to mitigate emissions of greenhouse gases (GHGs). The emissions of greenhouse gases, especially CO2, usually go hand in hand with the energy consumption of a given mode of transport; therefore, this led to an additional boost to increase the energy efficiency of transport and further to minimize the energy intensity of various modes of transport. Nowadays, some of the most important indicators of transport environmental performance are energy and GHG emission intensities. Many times, GHG emission intensity is limited only to CO2, which, for most modes of transport, except aviation [15], contributes the most toward GHG emissions. To fill the gap in calculations of such indicators, the main aim of this article is to show the results of energy and CO2 emission intensity calculations for various modes of transport in the Warsaw transportation system in 2015.
Energy and CO2 emission indicatorsThere are many ways to calculate the energy performance of various modes of transport. In various studies, results of these kinds of calculations can be found, shown as energy used divided by different factors such as GDP [19], vehicle use factor (vehicle-km) [3], mass of the transport mode (kilograms) [4,21], unit of transport activity (passenger-km or ton-km) [11,21], load factor (passenger, ton) [24] and population (number of inhabitants) [7,17]. Leaving the discussion about the relevancy of