What are the overall CO2 emissions (complete assessment including embodied energy) of an electric car and how does it position itself compared to a thermal car?
Let us try to answer the question to the question by a detailed reasoning ...
This reasoning was originally done in this topic: ecological comparison between the Peugeot iOn and a diesel clio.
Eco balance on the CO2 of a car: what are the direct and indirect emissions
It is necessary to compare: indirect and direct CO2 releases in 2 cases.
Indirect = manufacturing, recycling ...
Direct = CO2 from fuel and / or electricity production.
In global eco-balance, Mitsubishi has said that the i-Miev was throwing on his batteries 41gr / km.
Since the iMiev and the iOn are binoculars (false but binocular anyway), we can keep the same number.
It is then necessary to add the grams of CO2 per electric kWh: 90 gr / kWh for France.
There are then 2 approaches.
1st approach: the energy approach, kWh and CO2.(excerpt from this topic)
To drive a small car in the city, it takes about 0,2 kWh / km (low estimate).
In France, the average is 90 g / kWh, so you have to add 18 grams to these 41 g, or 59 g / CO2. So good! (thank you nuclear ...)
On the other hand, in Germany it is a disaster since the average is at 600 g / kWh (300 in Belgium) or in the end 161 g / CO2. Equivalent to an HDI consuming 6,2 L / 100
2nd approach: on range and vehicle performance
According to the list of 2011 electric cars, the iMiev / iOn have an autonomy of 150 km for a battery capacity of 16kWh
Assume a 80% charge efficiency, we must consume 16 / 0,8 = 20kWh to 150km.
We therefore consume 0,13 kWh / km from catch to wheel.
This is a lower figure than the 1st approach (0,2 kWh mechanical from the plug to the wheel) probably because:
- braking regeneration and other optimization of electrical energy management
- the charging efficiency is also lower in reality
From 50 to 60 gr of CO2 / km for a small electric vehicle… in France…
So in the end, in France, we get 41 + 0.13 * 90 = 53 gr / km in France! This is close to the value of 59 gr / km found above.
It is interesting to see that the “CO2 displacement” part is much less important than the “gray” part, the proportion being from 1/5 to 4/5 in the case of an electric car ...
Please note that this value is only valid for France where nuclear power allows a low level of CO2. In Germany, at 600 gr / kWh we would have: 41 + 0.13 * 600 = 119 gr / km or the equivalent of a recent average diesel car in economical driving and more than a small urban gasoline !!
But as we often say to "defend" the electric car: contrary to a dogmatic, popular and current marketing thought which is very fashionable: there is not only CO2 in life!
In France, air pollution in cities kills almost 8 times more than road accidents, the thermal private car contributes to this pollution, the interest of the urban electric car is not only in CO2 and primary energy!
What about the gray energy and the gray CO2 of combustion vehicles?
To be completely honest in the process it is also necessary to take into account the gray energy and gray CO2 of combustion vehicles! The CO2 / km figures circulating in car catalogs do not take them into account ...
It is recognized that the manufacture of a car represents approximately the equivalent of 20 km traveled (very variable but average figure), see this link for details: ecological impact, CO2 and gray energy of manufacturing a new car.
Quote of this link: (…) Around 2.5 Tons of CO2 / car manufactured! 2500 kg of CO2 ca represents 140 g / km approximately 18 000 km traveled !!
Over a lifetime of 200 000 km these 2.5 T of CO2 are therefore an increase of 2 500 000 / 200 000 = 12.5 gr / km
Let's say that the CO2 recycling represents the same (which seems credible), 25 gr / km.
So in the end, it would be necessary to increase the rate of CO2 / "catalog" km of a thermal car of 25 gr / km to take into account the embodied energy of its manufacture and recycling. This is obviously an average value for an average vehicle!
It is very interesting to note that we find ourselves in the same proportion but reversed:
Thermal = 1 / 5 gray CO2, 4 / 5 of propulsion CO2
Electric = 4/5 of gray CO2, 1/5 of propulsion CO2 (in France, etc.)
Conclusion: draw on CO2 and energy?
In France, according to this method of calculation, the small electric cars are competitive on the CO2 compared to the thermal cars: between 50 and 60 gr CO2 / km. The best gasoline cars can not do better now.
This is only possible because France has one of the lowest CO2 rates in the world on its electricity production!
In Germany, where 50% of electricity is made from coal, we would obtain l19 gr of CO2 / km, the equivalent of a small petrol or diesel car at 95-100 gr CO2 / km taking into account the 20 at 25 gr CO2 / km of its gray CO2. Catalog figures of course ...
The European average is 460 gr CO2 / kWh, the attentive reader will estimate for Europe… the world value must be around 500 gr CO2 / kWh
We must therefore keep in mind that by driving electrically, neither CO2 nor primary energy are really advantaged significantly: the electric car will not change the depletion of resources or global warming ... Except of course, to recharge directly (without going through the "perverse" system of bonuses and subsidies) your car with a renewable source (hydraulic, wind, solar, etc.)!
It is indeed much easier to place photovoltaics in your garden than to drill a well of oil!
On the other hand, the electric car can help make urban air healthier, polluted air that kills more than 30 000 people in France… And this is priceless!
- List of new electric cars for France in 2011
- 2011 ranking of car manufacturers and car models by CO2 according to ADEME
- CO2 pollution of electric cars by country (method without embodied energy)
- Forum on the electric car
- The deaths of air pollution in France
- The Opel Ampera would consume only 1,6 L per 100 km? Info or intox?