Trains use locomotives or railcars that convert energy into motion to pull (or push) the cars along the tracks. Many fuel sources have been used to power the engines, but today most train engines use electricity or diesel. In terms of tank-to-wheel emissions, electric trains have no CO2 emissions, whereas diesel trains produce CO2 and other pollutants through fuel burn. It is important to note that in the case of electric trains, there might be significant emissions on the well-to-tank component depending on how the electricity is generated. Capital investment would be required to electrify the railway lines being converted to electric trains. Another benefit of electric trains is the ability to recover energy when the vehicle is breaking. This is possible due to the ability of electric motors to also act as power generators. Up to a third of the total traction energy can be recovered through this process. The recovered energy is typically used to supply power for lighting or other on-board needs, but it can also be used by the following train or stored for later use if the network's infrastructure allows for it. For rail lines with high levels of traffic the much lower operational costs of electric trains can balance the high infrastructure costs associated with electrification.
Electrification of rail removes all of the CO2 emissions or other pollutants produced by rail, at least in a tank-to-wheel component. Diesel, the alternative power source for trains emits 2.68 kgs of CO2 when burned. In terms of CO2 emissions per passenger km, the value ranges due to engine efficiency and load factor. Common estimates place CO2 emissions per pkm in the range of 6-30 grams.
The use of electricity will also increase any emissions caused by the production of electricity and will depend on the energy mix of each country.
It is also worth mentioning however, that, as with any infrastructure development, electrification of rail will cause CO2 emissions in the implementation phase.
The energy recovered from braking does not reduce or affect tank-to-wheel CO2 emissions. It is used to power on-board train functions (such as lighting).
Electrification of rail has high implementation costs. It requires building new rail lines or adding infrastructure to existing lines to provide the train with continuous electricity. This can be done either by overhead power lines or by a third electrified rail.
The cost of electrifying railway lines varies depending on multiple factors, but several studies quote a range between 500k and 2 million Euros per km. The cost depends on the track characteristics and whether the track will be used by high-speed rail or not.
Energy recovery through braking does not have any implementation or operational costs and is quite standard on modern electric carriages.
Electrification of rail will also reduce the emission of other GHG and local pollutants caused by diesel engines.
Energy recovery through breaking will reduce the amount of energy needed to operate the train by converting up to a third of the total traction energy to electricity.
Electric powered trains have significantly lower operational costs. Because of the much higher energy efficiency of electric engines and the need for less maintenance the locomotion costs associated with operating an electric train can be four times lower than a diesel train.
• There is no 'loser' when applying virtual arrival, but commercial imperatives of cargo owners other than fuel savings can be obstacles to implementation, such as demurrage revenues of ship owners (ship owners continue to make money while the ship is waiting in a port).
• In the tanker business, waiting time is a common commercial practice used to speculate on commodity prices.
• Moorage waiting time may be used as a periods of needed rest for the crew or an opportunity to do work that is difficult to carry out while at sea.
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