Wikipedia:Reference desk/Archives/Science/2018 November 16

= November 16 =

Car running cheaper with electricity than gasoline
How come it's cheaper per mile to drive electric cars than to drive gasoline ones? For me, electricity is the "most pure" form of energy. It's an energy that can be easily be converted into anything you wish: heat, movement, cooling, light. Shouldn't it be more expensive per kW to use electricity instead of gasoline (which can be useful everywhere else)? --Doroletho (talk) 15:15, 16 November 2018 (UTC)
 * Are you saying electricity is cheaper per mile than gasoline, or that gasoline is cheaper per mile than electricity? ←Baseball Bugs What's up, Doc? carrots→ 15:21, 16 November 2018 (UTC)
 * Sorry, corrected. --Doroletho (talk) 15:35, 16 November 2018 (UTC)


 * There's lots of contributing factors. Generating stations are more efficient and don't pay the same tax. Petrol engines are not efficient at all speeds - this is why diesel electric trains are so much better than pure diesel.. There's a small gain when going downhill with electric. There is also the gain from less pollution in cities which will lead to better health and perhaps intelligence which should I'd have thought also be counted in any monetary evaluation. Dmcq (talk) 15:42, 16 November 2018 (UTC)
 * (Personally I consider less pollution in cities a Pyrrhic victory. Better if the polluters smoke up their own town and leave the rest of us alone... 78.0.230.255 (talk) 22:23, 16 November 2018 (UTC))
 * Regenerative braking to recover energy also makes the car much more efficient overall, for example a Toyota Camry hybrid is 10-20 mpg more efficient than the base version depending on driving conditions. shoy (reactions) 16:04, 16 November 2018 (UTC)


 * See also Electricity pricing which can vary greatly depending on the area. EniaNey  15:55, 16 November 2018 (UTC)  — Preceding unsigned comment added by EniaNey (talk • contribs)


 * Economically most developed countries established high taxes on fossil fuel to finance the road system. Electricity is generally much lower taxed, if at all. Technically electric engines are close to 100% effective in converting energy to movement. Electrical Battery storage is typically around 80%. Combustion engines only achieve 20-30% and of course a fuel tank stores fossil fuel at no loss. Additionally Electricity is produced at much higher efficiency in huge power stations. Even if they burn fossil fuel, they can achieve over 60% efficiency. Power stations based on renewable energy practically produce electricity for free since their energy source is endless/renewable. Last factor is the power grid that may lose another 10-15% electricity over longer distances. So electrical mobility is clearly more effective. But fossil fuel cars or trucks etc. still have a huge advantage in refueling time and reach with one filling. Much more even big planes. An A380 can fly almost 16000 Km with one tank filling and refilled in maybe 10 min or less. The Tesla Model X 100D may reach 475 km but then needs at least 75 min to charge.


 * So its a mixed comparison since combustion and electrical engines are at the end of possible development but batteries are still believed to have huge development potential. Thus slight advantage for electrical mobility. Besides electrical Trains beat everything in efficiency since they where used the first time. --Kharon (talk) 19:01, 16 November 2018 (UTC)


 * 80% x 60% x 85% isn't a lot more than 30%. I think a hybrid running on propane should easily outperform this figure, not to mention it'll be much cheaper and much more convenient. 78.0.230.255 (talk) 22:23, 16 November 2018 (UTC)


 * Some fossil fuel power stations may achieve 60% efficiency, but your average 25 year old coal fired power station, designed in the 1980s, has an efficiency of about 40%. Factor in the other losses and it appears that a car with a petrol engine is probably more efficient at converting fossil fuel into movement than an electric car ultimately powered by a fossil fuel power station. The advantage of the electric car is that it won't kill your neighbour and that it can switch to clean electricity when available.
 * The point is that the fossil fuel power station isn't fuelled with petrol. It may use low-grade bunker oil, already much cheaper than petrol, but that's usually considered still too expensive. Most fossil fuel power stations burn coal or natural gas, which are just impractical for road vehicles. PiusImpavidus (talk) 11:50, 17 November 2018 (UTC)
 * In the UK at least, there are very few active coal power stations and no active oil-fired stations. More electricity comes from combined cycle gas (i.e methane, not petrol), nuclear, and wind than from coal.  Last year nearly 50% of the UK's electricity was zero-carbon at point of generation.--Phil Holmes (talk) 17:27, 17 November 2018 (UTC)
 * In the EU-28 in 2014 coal and lignite was 25% [//www.eea.europa.eu/downloads/76139b352a5e4663905a78ca388cd8da/1510587652/assessment.pdf]/[//www.eea.europa.eu/data-and-maps/indicators/overview-of-the-electricity-production-2/assessment] and natural and derived gas 15%. Oil was 2% and other fuels 1%. Nuclear 28% and renewables 29%. Nil Einne (talk) 20:14, 17 November 2018 (UTC)
 * In NZ, although electric cars are not very common and we're a tiny tiny percentage of the global production, [//www.mbie.govt.nz/info-services/sectors-industries/energy/energy-data-modelling/statistics/documents-image-library/electricity.xlsx]/[//www.mbie.govt.nz/info-services/sectors-industries/energy/energy-data-modelling/publications/energy-in-new-zealand/documents-images/Electricity.csv] in 2017 it was 58% hydro, 17% geothermal, 0.4% biogas, 4.9% wind, 0.2% solar PV, 0.012% oil, 1.2% coal, 13% gas and 4.91% cogeneration (I believe most of this is gas but I'm not certain). See also [//www.mbie.govt.nz/info-services/sectors-industries/energy/energy-data-modelling/publications/energy-in-new-zealand/documents-images/energy-in-nz-2018.pdf] and Electricity sector in New Zealand. However coal usage in energy overall remains higher [//www.stuff.co.nz/business/industries/97442361/new-zealands-coal-exports-are-on-the-decline] and per earlier sources. Also there's a lot of political controversy over whether the ban on new gas and oil exploration permits will lead to more use of coal for electricity generation (or just increase gas imports, or neither) [//www.nzherald.co.nz/business/news/article.cfm?c_id=3&objectid=12143888a] [//thespinoff.co.nz/politics/29-10-2018/if-the-oil-and-gas-ban-is-really-a-good-idea-why-are-they-rushing-it-through/] amongst the generally more international focus of the possible effects [//www.newsroom.co.nz/2018/06/05/113361/ban-likely-to-increase-emissions] Nil Einne (talk) 20:39, 17 November 2018 (UTC)
 * BTW the US in 2017 was 32.1% natural gas and 29.9% coal. Petroleum liquids are 0.3% and petrol coke is 0.2% and other gases are 0.3%. Nuclear is 20.0% and renewable 17.0%. Other sources are 0.3% and pumped hydroelectric is -0.2%. Nil Einne (talk) 22:16, 17 November 2018 (UTC)
 * Petrol engines can achieve 40% efficiency when they are in optimum conditions. But stopping and starting and or going at the wrong speed for maximum efficiency reduces that very considerably. It has far less effect with electric motors and they can actually gain a bit back from braking instead of it being a total loss. There is a very good reason so many big engines are diesel electric rather than pure diesel.  One of the major gains is that they enable the diesel engine to run with optimum efficiently or else be switched off. This is also used in hybrid cars. Dmcq (talk) 21:37, 17 November 2018 (UTC)
 * With regards to the efficiency issue, this has various comparisons [//www.theguardian.com/football/ng-interactive/2017/dec/25/how-green-are-electric-cars]. Although a news source, the data seems to come from the EU. It includes various sources for the electricity including the EU-mix and oil, but not coal. It includes the cost of extraction and transport for the petrol, and the various costs for the electricity. The full electric beats petrol, although plug in hybrid can beat full electric e.g. with nuclear. (To be clear, this is for energy, on a GHG basis full electric on nuclear does very well as you would expect.) There seems to be a colouring error with some of them relating to the highlighting but I'm assuming the data is still right. I don't know what sort of driving profile is assumed but I suspect it's the average city dweller in the EU. However for the full life cycle analysis it's mentioned at the end it's disputed if electric is actually better. Also we have a Environmental aspects of the electric car article, I don't know how good it is but it has a bunch of refs. Nil Einne (talk) 22:32, 17 November 2018 (UTC)

PAGE ]]) 16:11, 19 November 2018 (UTC)
 * There is a difference in comparing energy systems, manufacturer methods and material choices. Besides you can also re-equip old vehicles by ripping out their combustion engine and build in some electrical engines and batteries. I bet this becomes a "thing" soon. Would love to drive an "electrified" old luxury class Mercedes-Benz or Jaguar. --Kharon (talk) 01:03, 19 November 2018 (UTC)
 * In addition to the efficiency advantages discussed above, a lot of it comes down to the fact that gasoline or low-sulfur diesel are fairly expensive to refine and distribute. In fact, refining a gallon of gasoline takes enough electricity to drive an electric car about 20 miles. That gasoline then has to be trucked to one of thousands of gas stations, and those gas stations then have to add a markup to cover the cost owning the land and hiring staff. With an electric car, in the worst case the power comes from coal, which requires little to no refinement compared to automotive fuels, natural gas, which also takes little to no refinement (as is actually a byproduct of oil drilling), or a renewable source, which is generally cheaper than a gasoline-powered plant would be. There are transmission losses for electricity travelling between a power plant an you home, but those are only on the order of 5% or so. --Ahecht ([[User talk:Ahecht|TALK
 * Nitpick: a fair amount of wells these days are drilled entirely or primarily for natural gas. Doing so is economical because use of gas has boomed, and extraction technologies have advanced. --47.146.63.87 (talk) 10:29, 22 November 2018 (UTC)