https://www.adac.de/verkehr/tanken-k...bilanz-studie/
The test is in German, so some highlights...
The test was done using the so-called Golf-class, using the car for 15 yrs and 15k kms/10K miles annually. The CNG car was obviously the cleanest. But not many cars use CNG (well, here in the Netherlands a lot of city council cars do, actually).
More interesting is the Electric vs Diesel and Fuel...
The electric car is cleaner than ordinary fuel but only after 8,5 yrs/127,500 km
The electric car is cleaner than a diesel car but only after... 14,6 yrs and 219,000 km!
It all has to do with the not-so-clean production of batteries and the fact that not all electric power plants are 'green'.
It might be correct, it might not, government policies are motivated by perpetuating automotive manufacturing and not environmental impact, we were all encouraged to buy diesels when it suited them, now its something else, soon they will ban Blue cars, the obvious answer is to cut car production of any sort...…...but there aren't going to do that!
It’s a very interesting comparison. Without doubt, battery production will improve, but they are certainly not environmentally ‘pure’....
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Hydrogen is likely to be the cleaner fuel of choice....when production and distribution improve.
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What about the impact on local air quality in cities?Originally Posted by thieuster
I don't read German so something could have been lost in (google) translation but the article didn't seem to be about electric cars per-se but about just how filthy Germany's electrical generation is and calls for an improvement on that score.
I'm not a big fan of hydrogen power as there seems to be a lot of unsolved issues around generation, distribution and storage that get whitewashed over when talking about using it as a transportation fuel.
Electric cars are by no means perfect but given that (in the UK) it's a lot easier to source green(er) electricity or even generate your own than is evidently the case in Germany, then, if your use case fits an electric cars profile then it's a better choice for the environment.
Yes, it’s true that electric cars are only as ‘green’ as the electricity used to charge them.
Germany’s brown coal based power generation is amongst the worst in Europe, so does skew the case for electric vehicles somewhat. The report states that with renewable electricity used for manufacture and charging, EVs ‘payback’ at 37500 and 40000 km for petrol and diesel respectively. A quote different result.
In Norway and even the U.K., the situation is different. With an EV, the ‘greener’ the electricity gets over time, then so the car does too.
The manufacture of EVs and in particular the batteries are a different issue, but that is changing quickly as well, VW batteries for the ID3 will be carbon neutral, and the new Tesla Gigafactory in Germany will be zero carbon as well.
I’m no EVangelist, and they aren’t the answer to the worlds ills, only consuming less of everything and limiting population growth will seriously impact that, but they do help with local air quality.
Hydrogen? Maybe for Trucks etc, but it takes a lot of electricity to make road hydrogen and it might be better to just use the electricity directly in an EV rather than use it to make Hydrogen to convert to electricity again with all the conversion losses.
I’ve also yet to see a comparison that includes the energy costs of production of petrol and diesel fuels, which surely need to be included to be valid. Some argue that petrol and diesel are a by-product of oil extraction which is why it isn’t included, but I’m unsure if that’s true or not. There surely must be energy consumed in refining, storing and distributing road fuels.
Last edited by Tooks; 28th August 2019 at 13:39.
Petrol and diesel are, of course, not 'byproducts' of oil extraction but the essential reason why oil is extracted in the first place: to turn it into road and airplane fuel. Don't think the oil industry extracted oil just because it is nice sticky black stuff and then says, oh gosh lets not waste all the lighter stuff and sell it as petrol !
Any batch of crude oil contains only a certains 'natural' percentage of lighter fractions that can be used to produce petrol (one of those, btw, is butane which is added to facilitate combustion, which is why a tankful of petrol is always under slight gas pressure). It is possible to 'crack' longer hydrocarbon molecules from heavier crude oil and thus to increase the production of petrol from it, but that takes additional energy. And as hydrocarbons consist for a very large part of hydrogen, one way to make better and lighter road fuels is to add hydrogen (basically, if you crack long hydrocarbon chains, you end up with shorter carbon chains but a shortage of hydrogen to complete the empty chemical bonds - which is why you then need to artificially add hydrogen using a 'hydrogen converter', a process introduced by Shell as HYCON. You need to get the hydrogen somewhere, which is either from the production of petrochemicals elsewhere that frees up hydrogen that can be captured and sent to the road fuel refinery, or from natural gas). In either case, it takes a shitload of energy to make more petrol than you can get from a given quantity of crude oil by simple distillation (meaning heating the stuff in a high reaction chamber with condensation plates at different heights/temperatures, so the lightest stuff (like methane, propane and butane) condenses out at the top and the very heavy stuff, basically asphalt and very heavy ship fuel, stays at the bottom - some of it being tapped and used as the actual heat source for the refining process. Stuff like petrol, kerosene and diesel condenses out at lower levels in the distillation stack. Light stuff logically 'cooks off' with less heat added than the heavy molecules, but once you try to break the heavy parts up to make more lighter chains, the balance changes.
There are more 'heavy' long hydrocarbon chaines in most crude oil than there are light, short chains as the latter have crept up through cracks in the earth's crust and evaporated out over millions of years. So not all of it can be turned into nice light petrol unless you are willing to spend unreasonable amounts of energy to do so, burning up far too much of the total crude to make the petrol.
Around 1990, Shell spent over a billion dollars on its first HYCON plant in Rotterdam to make more petrol from low quality crude. They lost a lot of money on that thing before it finally worked. Long before that, they built catalytic crackers and all that good stuff to do the same thing, but demand for petrol was too great so they got more inventive. Do note that many of these processes also involve catalytic tricks that use things like platinum for the catalysts. All for petrol.
I worked for Shell in the 1980s and 1990s (in communications) and did a two-week course where we were taught to make various products from crude oil on a lab scale. I vividly remember pooring liquid butane cooled to below freezing (zero Celcius) to the mix to make a standard petrol fuel. The course was informally called the 'oil cooking course'. It makes me look at some government 'ecological' policies with amazement.
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