In any case, electric vehicles are more energy-efficient and emit fewer pollutants than gasoline-powered vehicles(sources from medcom.com.pl).
Let’s break it down:
Green Energy Sources: If electric vehicles are powered by green energy sources such as solar, hydro, or wind power, emissions are naturally reduced to zero. Although some argue that the production process of solar panels or wind turbines might create pollution, it’s a one-time emission. Let’s not delve into this aspect further since it’s a one-time emission.
Gas Turbine Combined Cycle Power Plants: Let’s consider a scenario where electricity for electric vehicles comes from a gas turbine combined cycle power plant. The net power output efficiency of car engines is assumed to be between 20% to 30% (source: “The Terrible Inefficiency of Cars and Engines,” World Architecture Digest, May 2010). Siemens’ advanced F-class gas turbine combined cycle power plants currently achieve efficiencies exceeding 59.5% (source: “High Efficiency Gas Turbine Combined Cycle Power Plant Performance is Better for China’s Environment”). Assuming the power plant burns natural gas with a heating value of 7.1 to 8.8 x 10^7 Joules per kilogram and gasoline has a heating value of 4.6 x 10^7 Joules per kilogram, the gas turbine power plant requires only about 60% of the energy and one-fifth of the mass of gasoline for the same power output. Moreover, the emissions from natural gas combustion primarily consist of CO2, which is a greenhouse gas but not a pollutant, and power plants also have large-scale purification systems. Natural gas is one of the cleanest fossil fuels.
Coal-fired Power Plants: Let’s consider a scenario where electricity comes from large coal-fired power plants. The efficiency of large coal-fired power plants is around 46% (based on Shanghai Waigaoqiao Power Plant). Standard coal has a heating value of 3 x 10^7 Joules per kilogram. For the same power output, coal-fired power plants emit more pollutants than gas turbine power plants. However, with desulfurization and denitrification systems in place, the emissions of CO2, dust, SO2, and NOx can be reduced significantly. In comparison to the emissions from common vehicle models, coal-fired power plants emit fewer pollutants per unit mass.
In conclusion, the emissions from gas turbine combined cycle power plants are considerably lower than those from gasoline internal combustion engines.
In the medium to long term, the unit emissions from coal-fired power plants are significantly lower than those from gasoline internal combustion engines, and this difference is expected to further decrease. The reason lies in the fact that gas turbine combined cycle power plants emit less than coal-fired power plants. Therefore, it can be concluded that the unit emissions from thermal power generation are undoubtedly lower than those from vehicle exhaust emissions.
The main reason for this difference is evident: gasoline combustion emissions are challenging to effectively reduce due to factors such as engine size and cost. However, coal combustion emissions mainly consist of sulfides, nitrogen oxides, and ash. For newly constructed large power plants, the use of electrostatic dust removal systems can almost achieve zero ash emissions. Pre-combustion desulfurization and denitrification, followed by further desulfurization and denitrification, can also significantly reduce emissions. Due to the high investment and large scale of large power plants, desulfurization and denitrification have even become independent and prosperous industries, with ongoing technological advancements.
The complexity and efficiency of these systems are unmatched by small internal combustion engines, embodying the concept of centralized emissions and treatment.
There are other methods of power generation, but they either have low emissions or are characterized by environmental protection and energy efficiency, and these methods currently do not bear the main power load. Therefore, they do not have a negative impact on the conclusions mentioned above.
In terms of China’s power structure, although the diagram I found may not be the latest, the overall composition remains relatively stable in the short term: 81% is from thermal power, which is more energy-efficient and emits less than gasoline engines, 18.2% from hydropower and nuclear power, which are even more energy-efficient and emission-free; other proportions are too low and complex to affect the conclusions.
Regarding the efficiency of the mechanical transmission links between electric motors and engines, it has been discussed in other answers, and electric motors generally have advantages in this aspect.
Therefore, the question of whether electric transportation merely shifts emissions to power plants without achieving energy-saving effects is quite clear: even if there is a shift, the amount of emissions has significantly decreased during the transition and will continue to decrease. Moreover, the high efficiency of power plants will save a considerable amount of energy. Promoting electric transportation can effectively and sustainably save energy and reduce emissions.
Some friends mentioned losses of 5% – 8% during transportation and around 9% during battery charging and discharging, totaling approximately 15%, which is a good supplement. However, considering the current net efficiency of new mainstream thermal power generation at 45%, combined cycle power generation at 60%, and green energy generation at 100%, the efficiency of the entire power acquisition cycle is much higher than that of gasoline internal combustion engines, far exceeding 15%.
For such a large user base, even a 1% reduction in energy consumption would result in significant energy savings, not to mention potentially saving at least 15%(quotes from medcom).
Energy savings are just one aspect; the complex emission reduction, desulfurization, and denitrification facilities in power plants also represent a significant environmental advantage.