Do EVs Really Do More Harm Than Good? (Excerpt)
Recently, my dearest friends are questioning my decision to own an EV (Tesla Model S 60kWh).
Arguments include:
1. "EV is at best an alternative form, not an effective reducer, of pollution, when societies are still relying on traditional sources of energy. Encouraging greater use of environmentally friendly means of mass transportation may be a more effective way."
2. "In a country that relies heavily on green sources of energy, EVs make sense. Till then, what EVs do is just shifting, not reducing, pollution."
3. "you can have all cars as EVs. But if your EVs are running on evergy generated by say, fossil fuels, you're back to square 1"
4. "Your EVs are using the energy generated inefficiently upstream in the first place. You can't compare bread with flour."
Ignoring all benefits of electricity as a vehicle fuel just for the moment, there are two aspects to answering all these questions -- scientific and personal.
Scientifically, none of the arguments above are wrong. In response to 1), "EV is at best an alternative form, not an effective reducer, of pollution, when societies are still relying on traditional sources of energy. Encouraging greater use of environmentally friendly means of mass transportation may be a more effective way", Everyone knows that EV does not offer sustainable energy production such as solar, wind and water, what it does is to offer a mean to sustainable energy consumption to tap into these renewable energies, which traditional ICE vehicles can never do. This is one of the top reasons why we should switch to EVs in the long run along with the increase in the use of renewable energies.
People in Hong Kong are no strangers to EVs, broadly speaking, the mass transit railway (MTR) is a kind of EV too, encouraging more people to take MTR is definitely a more effective way because the math can be calculated power use (W) per passenger per distance unit (km), so fitting more people into the same number of trains will lower the W/passenger-km. This friend stationed in Singapore shared SMRT's document,
"We can achieve a more sustainable transport system if more Singaporeans travel by public transport. Public transport is, by far, the more efficient mode of transport, both in terms of land and energy use. A single-deck bus transports up to 80 passengers while an average passenger car only carries up to 5 persons. A car carrying only the driver uses 9 times the energy used by a bus and 12 times that used by a train, on a per passenger-kilometre travelled basis. " (p.58)
Using this for our calculation, if an Internal combustion engine (ICE) car carrying on the driver uses 12 times the energy used by a train on a per passenger-km travelled basis with a 35% energy efficiency at best, while an EV can be greater than 90% energy efficient, then that means an EV is at least 2.57 times more energy efficient than an ICE car, which supports the ICE-to-EV comparison that EV is superior to ICE vehicles in terms of energy efficiency.
This brings us to a train-to-EV energy efficiency ration of 12 : 2.57 = 4.67 : 1. So yes, for the case of SMRT, it is more energy efficient than EV.
But I did't approve this to be the case for Hong Kong's MTR trains until I get hold of more statistics. My friend thinks that I am just arguing for the sake of arguing, as a researcher myself, what I do not want is to come to an early assumed answer as my reply because I do realise running a train system requires more energy than that in moving trains....
(Continue and read more on http://lockyep.blogspot.hk/2014/12/science-environment-do-evs-really-do....)