The 21st century showed big changes of economic growth in developed and developing countries, especially in China and India, substantial population increases and rapid urbanization worldwide.  Inevitably all these changes contributed to a dramatic increase in global energy consumption for transportation (trains, light-duty vehicles, trucks, buses, aviation, marine vessels). The worldwide energy consumption by every form of transport is projected to increase. It is estimated to reach 151 quadrillion British thermal units (Btu) in 2040 from 107 Btu in 2015. Petroleum-based liquid fuels (gasoline and diesel) currently account for more than 85% of global transportation energy consumption and will continue to do so through 2040. The same demand but on a smaller scale is for electricity to be used as a transportation fuel for cars and trains. 20 years ago it was the intention to change from gasoline to diesel fuel for cars, but this shift to diesel cars have been overestimated. Moreover, toxic NO x emissions of diesel cars have been underestimated up to 20 to 30-fold in officially announced data. Electric vehicles are expected in many countries to reduce the air pollution levels in big cities. In the last decade high levels of air pollution appeared in big cities in India and China. In 2014 the global car fleet was estimated at 1.25 billion vehicles. The popularity of diesel engines was to a large part due to their higher durability and higher fuel efficiency compared to gasoline cars. Also, cars diesel-engines are 20 to 40% more efficient, and they’re cleaner than ever. Diesels are wildly popular in Europe, accounting for roughly 50% percent of the car market. Volkswagen (VW) in 2016 was the world’s largest automaker by sales. It has maintained the largest market share in Europe for over two decades. The car manufacturer VW in the last years had a major advertising push to sell diesel cars in the USA, backed by a huge marketing campaign trumpeting its cars’ low emissions. When the VW cars were tested under controlled laboratory conditions (putting them on a stationary test rig) a “secret defeat” device appeared to have put the vehicle into a sort of safety mode in which the engine ran below normal power and performance. But when the vehicles were tested outside on the road, the engines switched out of this test mode. The result? The engines emitted NOx up to 15 to 35 times above what is allowed in the USA. On 18 September 2015, the US Environmental Protection Agency (EPA) announced that Volkswagen had installed a “defeat device” software code in the diesel models sold in the US from 2009-15. The code was intended to detect when an emissions test was being conducted, and altered emissions controls for better compliance. Off the test stand, the controls were relaxed, and emissions jumped 35 times of regulatory levels according to investigators at West Virginia University and the California Air Resources Board. The scandal was very important for the future demise of diesel cars and forced many countries to announce the support of electric cars in the next 20 years.

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