Because we recently ran a story that was highly critical of electric cars, here’s a positive story for balance. – Anthony
Guest essay by Jan Kjetil Andersen, Jkandersen.no Csens.org
I want to share some thoughts and experiences about using electric vehicles (EV) and how they compare to traditional internal combustion engines (ICE).
My personal experience is based on being a user of Nissan Leaf in my daily commute for the last four years. We do also have two ordinary cars in the family, but what we see is that the EV is the car everyone chooses first. The reason is obvious; it is simply a much better car to drive. The noiseless engine let you hear the wind blowing and the birds singing, or you can turn on music and hear it without any disturbing engine in the background. The gearless drivetrain gives a unique smoothness, and the acceleration is just superb.
My experience so far have made me to be an enthusiastic EV supporter, not because I think I save the planet, but because I find the EV much more enjoyable to drive.
With that as a prologue, let us take a look on the more theoretical and technical constraints of electric versus fossil fueled cars.
Efficiency of combustion engines – theoretical limits
Efficiency is the relationship between the total energy contained in the fuel, and the amount of energy used to perform useful work.
Let us first analyze the theoretical limits given by the physical laws for an “ideal” frictionless engine.
The most fundamental limit of efficiency for a combustion engine is given by Carnot’s Theorem which states that:
The Maximum Efficiency = (T2-T1)/T2
Where
T2 = The maximum temperature in the process in Kelvin
T1 = The minimum temperature in the process in Kelvin
If for instance the minimum temperature is 300K (27 Celsius), and the maximum is 1200 K (927 C), the maximum theoretical efficiency is (1200 – 300)/1200 = 900/1200 = 75%
The main point to take from this is that the maximum theoretical efficiency is substantially below 100%, even if the machine is without any friction.
But even though all gasoline and diesel engines are covered by the general Carnot process, they are far from a Carnot processes. We come one step closer to reality by looking at the theoretical upper limit for Otto cycles and diesel cycles for gasoline and diesel engines respectively. The theoretical efficiencies of an Otto cycle, diesel cycle or any other thermal cycle can never beat the Carnot cycle, but they set an upper limit for those engines.
The maximum efficiency of an Otto engine is given by the compression ratio, the higher compression the higher efficiency. However, the compression ratio of Otto cycle engines is limited by the need to prevent the uncontrolled combustion known as knocking. Modern engines have compression ratios in the range 8 to 11, resulting in theoretical ideal cycle efficiencies of 56% to 61%.
The Diesel cycle is less efficient than the Otto cycle when using the same compression ratio, but this is more than compensated by the higher compression ratio. Diesel engines therefore have slightly higher efficiency than gasoline engines.
Efficiency of combustion engines – in practice
Real engines are obviously not ideal. The actual cycle of a four-stroke gasoline engine is very different from the idealized Otto cycle. In addition, there are of course frictions in all moving parts which results in truly existing engine efficiency in the range of 25% – 30% in ordinary gasoline automobiles.
In addition to that, there are losses in the drivetrain between engine and wheels, resulting in actual power to the wheels efficiency of only 18% – 25%.
So how does this compare to the efficiency in an EV?
Well first of all, there is no theoretical upper limit for efficiency like the Carnot theorem for EV. A frictionless electric engine has a theoretical efficiency of 100%.
In practice we see that there are losses in charging batteries, using batteries and friction in the electric drivetrain, but the actual power to the wheels is here about 82 percent, i.e. several times better than an ICE.
The figure above show development in the efficiency for steam, gasoline and electric engines. James Watt revolutionized the steam engine by improving the efficiency from Newcomen’s puny 0.5% to 3%. Later triple expansion engines reached about 10% efficiency. Nicolas Otto’s petroleum motor had 12% efficiency, and the Spague electric motor had about 70% efficiency.
The superior efficiency of electric motors is also illustrated by the fact that it makes sense for diesel electric railway locomotives to use an electric generator combined with an electric motor as a replacement for a mechanical transmission.
The Battery vs the gasoline tank
The electric automobile engine is in my opinion superior to the combustion engine. In low and moderate speeds, you get the noiselessness and smoothness of a luxury car, the acceleration of a sports car and the energy use of a moped. That combination is unbeatable by any single fossil fueled car.
However, when the features of energy storage in a battery is compared to a gasoline tank there is no doubt that the battery is far inferior.
The battery in my Nissan Leaf has a capacity of 24 KWh, which is equivalent to 2.6 liters (0.7 US Gallons) of gasoline.
Imaging having a car with 0.7 gallons gasoline tank, which it takes 8 hours to fill at home, or 25 minutes on a supercharger, would you, buy it?
Well I have, and I must say that in spite of the low range, I am overall very satisfied with it.
Due to the good energy economy, it has a driving range from 140 km with modest speed in the summer to about 80 km in the coldest winter months. Those ranges may seem puny, but in my experience, it covers the vast majority of most people’s driving needs.
Battery development
The prices of Li-ion batteries have dropped considerably recent years and the drop is projected to continue. How fast the prices drop can be debated, but approximately 14% annually, as is described in this article, is a conservative bet.
Fourteen percent drop each year translates to halving the prices in five years. This development can be seen on the new generation EV now brought to the market. The prices have not halved, but the battery size and range have approximately doubled compared to the ones we saw five years ago.
Tesla is leading the range contest with 500 km (310 mile) range and a supercharging rate of 270 km (170 miles) in 30 minutes. With those figures, the range and filling time properties starts to close in on fossil fueled cars.
In practice no more time on filling station than for a gasoline car.
Personally, I do not use more time on supercharger stations than I used to use on gasoline stations. The reason is that I charge at home, and do not use supercharges station more than approximately 10 times per year. I may stay there 20 minutes each time, which amounts to 200 minutes annually. A petrol car with the same driving distance would have to be filled about 50 times per year, which would have taken about the same time in total when the stop, opening tank, payment et cetera is included.
Toque and rotational speed
Torque is a measure of the turning force on an object such as a bolt or a crankshaft. It is important to understand this unit to get a grip of a fundamental benefit of the EV, so let us examine it a bit.
Torque is measured internationally in Newton*meter. As an example to illustrate the amplitude of the unit; you should use about 100 Nm on each bolt if you want to fasten your wheels on your car.
The conversion factor between torque and power delivered is that power in watt equals torque multiplied by rotations per second multiplied by two Pi:
P = T * R*2*Pi
The reason it has to be like this, is that Watt is just Nm per second and the perimeter of the circle with on meter radius is 2 Pi as seen on the figure below.
If the crankshaft for example has a rotation speed of 10 rotations per second and 100Nm torque is applied, the power delivered is 6.26 Kilowatt (KW). The same torque applied at 100 rotations per second thus gives 62.8 KWFigure: If you push a handle of 1 meter one rotation in one second you deliver a power in Watt of 2 Pi times the torque.
The rotation speed given by tachometers in automobiles usually show rotations per minute (RPM), not per second, so I will continue with the most common form here.
Figure, the tachometer in an ordinary petrol vehicle. Here showing 2000 RPM on a scale going to 7000RPM.
The reason we are interested in torque is that it gives valuable information about the engine behavior with different rotational speeds. A typical plot for petrol and electric automobile engines is shown in the figure below.
Figure. Typical torque/RPM diagrams for traditional gasoline engine, modern electronically regulated gasoline engine and electric vehicles.
Gasoline engines have a useful rotation range approximately between and 1500 to 6000 RPM. However, in ordinary smooth driving you want to stay between 2000 and 3000 RPM.
The electronics in modern cars modern cars usually cap the torque to an upper fixed value, which is seen as a flat torque curve. There are two advantages with this. The first is that the drive chain must be scaled to handle the maximum toque, and it is uneconomical to have those dimensions just for a narrow peak range.
The second is that a flat toque curve feels smoother because, as long as the air resistance is negligible, constant toque gives constant acceleration. The G-force you feel against the seat is therefore constant, and that feels better than a varying acceleration.
The torque delivered by an EV is high and even from zero to about 4000 RPM, and thereafter slowly decreases. An EV operate over a very broad rotation spectrum. This eliminates the need for a gearbox.
You can do without shifting gears on a gasoline car too, just put it in second gear, start with some careful clutching and you may accelerate up to motorway velocity and stay there without using any other gears. The tachometer will then show around 6000 RPM. It is of course not recommendable to drive like that since it may damage the engine. You will also use extra petrol and it gives a lot of vibrations and noise.
Nevertheless, this demonstrates one aspect of the difference between ICE and EV; an EV has no engine noise even at 12 000 RPM.
The torque curve and wide rotational spectrum show that an EV has some features that is just better than what you find on a similar ICE.
Comparison
The table below gives a side by side overview of EV vs ICE features
| Combustion vehicles | Electrical Vehicles | Plus / minus for EV | |
| Engine Noise | Varying | None | + |
| Acceleration | Varying | Excellent | + |
| Gearing | Varying | No gearing | + |
| Energy economy | 7 – 8 L/100 km
(35-40 Mpg) |
Approximately: 2 KWh /100 Km = 2,0 L /100 km
( 120 mpg) |
++ |
| Engine Oil | Change every 10 000 km | No oil | + |
| Transmission oil | Change very 100 000 km | No transmission oil | + |
| Brakes | Tear out after approximately 100 000 km | Almost never tear out because of regenerative braking is used instead of brakes | + |
| Driveline complexity (increase cost) | Complex, hundreds of moving parts | Small, few parts, very few moving parts | + |
| Engine durability | Good | Good | equal |
| Energy storage | Gasoline tank | Li-ion battery with 5 – 8 years warranty
Replacing battery may cost 10 000 – 20 000 USD |
—
(but battery prices are falling) |
| Range | Approximately 700 km | Up to 500 km | – |
| Fill up time station | 2 minutes | 30 – 60 minutes | — |
| Availability of gas/supercharging stations | Good | Sparse, but improving | – |
| Option to fill up at home | In practice: no. | Yes, but slow | ++ |
| Total economy | Depends on oil prices | Improving as battery prices continue to drop | In transition from minus to plus? |
There is a large uncertainty concerning the total economy because of the yet unknown lifetime of the battery.
The warranty for most EVs batteries today is that there shall be at least 70% capacity left after 8 years or 160 000 km (100 000 miles). This guarantee may not seem very assuring since a modern car of good quality should at least last twice as long as that. That means that the owner run a substantial risk of having to replace the battery at least one time in the car’s lifetime.
The battery pack is the most expensive item in an electric vehicle. The current cost is approximately 300 USD/KWh which gives a price of USD 22 500 for a car with 75 KWh battery. If the prices continue to drop by 14 % annually, the price will be USD 6732 eight years from now, still a considerate amount, but at least it is more acceptable than the current price.
My experience there is that after four years and 91 000 km, I see no performance drop at all. I use my daily commute as a benchmark, and on days with mild temperatures, I have always used exactly 20% battery capacity on 29 km.
Conclusion
The EV driving experience is superb, but the range and recharging time is still inferior compared to traditional cars.
However, the technology is now evolving quicker for EV than for traditional cars and the battery prices are cut in half every fifth year.
Many different sources all forecast that the market share of EV will grow from the current 0.2 percent. BP forecast a slow growth up to six percent market share in 2035, while Bloomberg new energy forecast that EV will outsell ICE in 2038.
Personally, I think the evolution will go even quicker. The much better energy efficiency and torque curves are revolutionary improvements which are impossible to match for any ICE. The EV will soon have both better total economy and better driving performance than any ICE, and most people will then buy the best and most economical vehicle. My bet is that EV will outsell ICE before the year 2030.
I do recommend them now in 2018, may be not yet for the economy, but definitely for the driving experience.
References:
1. Fuel economy: https://www.fueleconomy.gov/feg/atv.shtml
2. Nature: http://www.nature.com/nclimate/journal/v5/n4/full/nclimate2564.html?foxtrotcallback=true
3. Bloomberg: https://www.bloomberg.com/news/articles/2017-07-06/the-electric-car-revolution-is-accelerating
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So your Leaf is more efficient than my Shelby GT350. That is important why?
‘The noiseless engine let you hear the wind blowing and the birds singing’
Up to 20 mph. Then wind and tire noise make it sound like any other car. That electric cars are silent is true only at low speeds.
‘Noiseless’ is a bug, not a feature. My Shelby GT350 makes the most beautiful sounds. Many people tell me so.
And I will here your Shelby (plus I would much rather see your Shelby then his Leaf) coming when I try to cross the parking lot, not so much the Leaf in fact in many places they are requiring devices on the cars so they make noise just for this reason.
I won’t be sneaking up on anyone.
Tesla makes an excellent luxury car, independent of its drive train. Making Leaf/Tesla comparisons silly. Depreciation of the Leaf is catastrophic. Tesla depreciation is actually low.
Up until recently, Tesla had a guaranteed buy back program for used Tesla’s which distorted their resale value.
RE Tesla depreciation …. low my **%$
Make Avg Price Last 30 Days Last 90 Days YoY
2012 Tesla Model S $41,058 -7.72% +3.86% -18.63%
2013 Tesla Model S $44,159 -3.12% +3.68% -13.61%
2014 Tesla Model S $53,934 -2.57% +8.33% -6.21%
2015 Tesla Model S $61,550 -7.55% +7.01% -17.13%
2016 Tesla Model S $72,850 -8.68% +0.20% -15.69%
2017 Tesla Model S $86,727 -0.02% -2.02% +18.80%
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Have you considered that high demand and scarcity drives the price up, until the stimlation of greater production volumes, due that demand and money flood, produces an oversupply, and price then drops to sell the excess production?
Teslas are expensive for the same reason hybrids are, people love them, so the excess demand bids up the price.
More production volume is expensive, it is a long term investment, and needs to be paid for. Once the factory is paid for the price of what you make can drop.
The same thing occurred with the ramping of hybrid production. They could sell them faster than they could make them, so could ask a higher price, and the subsidy covered the difference.
Remove the subsidies and the price will fall to meet demand again.
Lithium is a limited resource. Current usage gives us about 300 years worth! Extrapolate and …… oh dear we need something else!
Buy stock in lithium mining companies.
It’s being worked-on – a plastic battery technology that holds ~twice what a Li battery does, and charges insanely fast. Will we ever see it? – who knows, but better batteries are always in the offing. A friend’s brother-in-law works in the battery industry, and said 30 years ago that they could make a lithium battery the size of a coke can that could power an electric motorcycle – and would have the explosive power of a half-stick of dynamite, and frequently would explode. Energy density is energy density, however you do it.
I agree with the author’s position that for some situations an electric vehicle is ideal. For mine, it isn’t – a 1,200-mile road trip in 18 hours with two tons of trailer on the back is something my diesel does with ease. Full-sized diesel trucks, notably the { – brand-name withheld – } Eco-diesel, do highways lightly-loaded at 40+ mpg; a friend has one. Electrics are not practical for fast long-distance travel, especially in the winter. And having destroyed two electronic devices in my comparatively mild winter by leaving them in the car, I can attest that lithium batteries don’t like sub-freezing temperatures – of course the battery could have a self-heating circuit, for as long as it could power it, but don’t leave it parked for a month or even a week.
The article’s plot of comparative efficiencies is skewed and incomplete – modern steam powerplants exceed 50% efficiency, and diesels are not mentioned. One of the Asian car-makers is on the verge of offering a gasoline engine that runs like a diesel – homogenous charge compression ignition, recently announced. ICE efficiencies are improving all the time as well, and have doubled in the last 30 years as digital engine controls have improved.
Finally, the article claims that electric efficiencies are why locomotives are commonly diesel-electric; this is inaccurate. Geared transmissions are even more efficient than electric motors, it’s just that nobody has yet figured-out how to do it with the enormous gears that would be required at those power levels – there are also diesel-hydraulic locomotives. And undeniably, the electric motor has monstrous starting torque, which is where a locomotive does its hardest work.
I’d like to see what the clutch looks like for a 10,000 ton train. Wow.
300 years with current usage but if every US vehicle were electric, usage would jump 300 fold and lithium would last 1 year
Litium last forever. The planet has just as much litium now as it had a billion year ago.
We can therefore recycle it forever.
The 300 years is known resorces, more will be found if we look.
/Jan
Oh yeah, it’s not like we’ll develop a vastly better battery technology in a mere 300 years of R&D.
Many of the advances in conventional cars have come from motor racing. When electric cars move out of the special Formula E class and start to compete in such events as the Daytona 500, the Monte Carlo Grand Prix, Le Mans or the Safari Rally, I will not be convinced of their overall efficiency.
That won’t happen until somebody invents a way to swap a battery pack as quickly as they can currently refill the tank.
As long as the design of the vehicle places the battery pack in an easily accessible location, it should take hardly any time to yank out the current pack and plug in a new one. So shouldn’t be that hard to invent. The bigger problem is having a battery pack that provides the amount of energy needed without having to swap any more often than they currently need to refill the tank. Every stop, no matter how quickly the mechanics do their thing, costs the driver time in the race.
Yes, I would much rather see EV’s compete in the Daytona 500 than the Daytona 50!
Solomon Green
“the Monte Carlo Grand Prix”
I think you mean the Monaco GP.
🙂
No subsidies no issue!
In a free market you can choose what fits best for you and you don’t have to justify your decision to anyone but yourself as long as it fits your needs and priorities more power to you. The issue comes when the government uses a non-existent crisis to use tax dollars to subsidies a market and give it advantage over another to push a political narrative and or to enrich friends and cronies.
AGREED!
Why were the inefficiencies of the electrical grid that you charge an EV from ignored? 7% just for grid. Gas Turbine efficiency is about 60%. 40% from coal. And no, renewables are a sham unless you are charging at home using your own solar power.
At the end of the day, Electric vehicles are no more efficient than gas vehicles.
I like the idea of them, from a torque perspective.
The Norwegian grid is only 2% fossil fuel so this is a special case.
That will increase if they increase electricity demand by electrifying their transportation fleet.
If all the approximately 3 million cars in Norway were replaced by EV, we would need about 12 TWh more annually, i.e. increasing the electricity production from 150 TWh to 162 TWh.
I think it is room for that with additional hydro and wind.
/Jan
JKA: Norwegian electricity production would only need to increase from 150 to 162 TWH to support all EVs? Like to see your calculations for that. A recent calculation on this site for the U.S. said a 125% increase would be required, and a similar calculation for Australia on the JoNova website said a 132% increase is required.
Graeme,
We have 3 million cars in Norway.
Back of the envelope calculations:
Assuming each car travel 20 000 km annually and use 0.2 kWh per km gives 12 TWh
(20 000 km is probably too much though, so the need is probably lower.)
Norwegian Electricity production is 150 TWh annually.
I have calculated for the US here:
https://wattsupwiththat.com/2018/04/25/a-positive-perspective-on-electric-vehicles/#comment-2799946
Jan Kjetil Andersen
Try this from the late Dr. David MacKay, a committed green who proves renewable’s can’t work, but says we should do them anyway!
https://www.ted.com/talks/david_mackay_a_reality_check_on_renewables
Jan,
Firstly apologies for mis-quoting David Middleton’s recent figure of 25% extra requirements as 125%.
However, I still think both David and you are calculating the additional power required wrongly. You both appear to use average figures, whereas the recent Australian calculation by “James” in JoNova on March 29 uses the TOTAL fuel consumption for one year that would have to be supported by additional power for EVs. James’ calculation thus arrives at a vastly different, and I believe more accurate, way of determining the power requirement. James’ figures were a total of 32,732 million litres of fuel consumed in Australia in 2016, or 174,618 GWh of petrol and 157,600 GWh of diesel. This total of 332,218 GWh significantly exceeds Australia’s annual total electricity usage of 252,000 GWh, so if all vehicles were EVs, the power requirements go up by 132%.
Energy is generally not the issue. Power is. Power requires investment in the grid, in Norway this is a real problem. And it is costly.
Graeme said:
I looked up James comment in Jonova here: http://joannenova.com.au/2018/03/another-way-to-destroy-a-grid-add-a-million-electric-vehicles/#comment-1994089
Ha makes a grave error because he convert the energy content in petrol and diesel to kWh without taking the much better energy effiency of EV into account.
The correct number is only a quarter of James calculation.
/Jan
If you live in a cold climate and have to heat anyway, cogeneration makes sense. Then the fuel cost of your electricity is zero. The capital cost has to be reckoned with. Compared with my old, low efficiency, cheap furnace, the cost of cogeneration is astronomical. Compared with my new high efficiency furnace (mandated by law) the cost of cogeneration is not quite as crazy.
It’s not hard to imagine a situation (some time in the future) where heating your house and driving an electric vehicle is the most economical use of fuel.
Thanks for the article. I do not think many/most people need to be convinced about electric cars; since my childhood it generally has been a constant wish.
Regarding efficiency: I saw no mention of the weight of the batteries. How does this compare with weight of motor fuel in ICE vehicles and affect efficiency?
As for cost. If the current energy used to provide electrical energy in the USA is X, with what factor will X need to be multiplied to replace all or most of the energy from motor fuel with electricity?
What then will be the cost to do this taking into account the enormous increase in number and capacity of generating stations (of whatever type) to provide the increased output, the significant extension of grid infrastructure to handle the load, and distribution infrastructure to serve the various charging points?
Is using current prices of electricity a fair comparison with ICE costs?
The British Government when settling its energy policy (such as it is) on wind power, assumed that although electricity prices would rise significantly, the price of oil would hurtle every skyward so that wind generated power would be very expensive, but still cheaper than fossil fuel generated electricity… and so people would not notice.
They were wrong. Fossil fuel prices have significantly fallen, yet electricity prices in the UK, and elsewhere in Europe outside nuclear France, climb steadily upward as more and more wind and solar are added to the mix.
with what factor will X need to be multiplied to replace all or most of the energy from motor fuel with electricity?
==========
A gal of gasoline is 33 kWh. About the same price at the gas station or the power company depending where you live.
A car averages 30 miles per day. About 2 gallons of gasoline a day. A house uses about 1 gal of gasoline equivalent a day.
So depending upon EV efficiency you are going to have to double or triple existing generating capacity. Given the time and capital expenditure involved to build the current grid this is going to be a problem unless there is spare capacity due to time of day factors.
“A car averages 30 miles per day. About 2 gallons of gasoline a day. A house uses about 1 gal of gasoline equivalent a day.”
if your car is using 2 gallons for only 30 miles (ie a rather poor 15 miles/gal), I’d suggest trading it in for a newer car. Most ICE cars made today easily double or triple that value.
Great article. It fails to capture the true cost of fueling an EV compared to a ICE. Perhaps in areas like Europe and maybe even California, where taxes make up the bulk of fuel costs, but for most of the world it costs more per mile to operate an EV and usually by a factor of two or more. Depreciation and battery costs not withstanding, the main benefit to the author is quiet motoring and that is not a benefit in my book. I enjoy rev matching snarls. That said, if BMW can pipe it in why can’t Tesla synch any motor soundtrack?
Ed. Check this out https://youtu.be/HXCXsrfzvtY just add a speaker on the outside of your car and you can warn others to get out of your way or you could just use your horn.
The article mentioned that rail locomotives use diesel-electric instead of diesel mechanical. I understand that the electric motors can be reversed into generators for braking, with the energy dumped through massive radiators on the top of the locomotive. This is a major advantage of the diesel-electric configuration.
Dumping energy is not an advantage.
In 100% electric systems the energy can be returned to the grid or to a battery and that is an advantage.
You might ask, why not just run straight diesel with a mechanical drive, like trucks and cars? There are a number of reasons. link It depends on operating conditions. Ships use mechanical drive to the propellers. Draglines use electric drive. One big deal with trains is that you can hook together as many diesel-electric locomotives as you want. You can even have locomotives in the middle of the train. Electric drive is relatively easy to control and electric motors ‘play well’ with each other.
Yes regenerative braking is a major part of the improved efficiency of hybrids, also allows the IC engine to spend more time operating at its ‘sweet spot’.
charging at home is fine if you have off road parking or better still a garage. I contend that the great majority of cars in the UK are parked on the road overnight. It sounds like an EV would suit me fine except I’m not sure if it can tow a 500kg trailer too, maybe some time in the future…
Re compression ratios: diesel compression ratios had decreased over time to achieve cleaner combustion, while gasoline has increased. The latest Mazda’s skyactiv engines have a ratio of 14:1 for both diesel and gasoline. Racing engines reach higher compression but they sacrifice the idle mode.
Not that compression ratios will learn us much about the future of engines though.
The elephant in the room is how we propose to generate the electric power. Eventually mainly from the atom or we will have become a stupid species. How ridiculous it would be if we made such superb economies and convenience in the car but at the same time disco-balled the earth with solar panels or tufted it with sea to sea wind mills? And this is environmentalists’ thinking in our post normal world.
Henry Ford made a few electric cars in the early 20th Century and felt it was the ultimate car. The battery was the problem for a century.
The ICE is not done yet. There has been notable advances in efficiency and I suspect more is on the way. Compression ratios have increased to 14:1. Nissan has introduced a variable compression ratio engine. Toyota claims a 41% overall efficiency for the latest 4 cylinder engine plus CVT. On top of that lithium batteries suck when the temp drops. The new Mazda power plants have supposedly reach the holy grail of combustion engineering: gasoline compression ignition.
These guys claim to have an F-150 that gets 37 mpg. They seem credible to me.
http://achatespower.com/our-formula/opposed-piston/
Well, I’ve owned an e-Golf for three years in Iceland now, and I’m never buying anything that runs on fluids if I can help it. We also have a Honda Accord, and it literally feels like driving a tractor in comparison: unresponsive, powerless, and it frankly smells. I am currently waiting for an “affordable” SUV-ish EV that has great range (400-500 km), and comfortably fits five people and luggage. As Tesla doesn’t have a presence here, I’m waiting on one of the “usual” producers, so that we have local service. Hoping it’s no more than 2-3 more years? Then it’s goodbye ICE world! 🙂
Eco-fools seem to think batteries make electricity, they don’t batteries need to be charged and their charge/discharge efficiency is not 100%, the electricity needs to be generated and no method is 100% efficient. But regardless the ‘energy efficiency’ argument is a diversion, what matters is the cost; cost to the user and cost to the environment and eco-fools always seem to forget the environmental cost of lithium mining, the $ cost of connecting wind-mills to the grid, the CO2 cost of all that concrete the windmills sit in, the energy cost associated with PV manufacture. Anyone can pick and choose certain ‘facts’ to suit their particular world-view but when you look at the details the eco-fool solutions are never what they seem.
Honestly efficiency doesn’t matter if the fuel is cheap enough and the main by-products are water and plant-food.
Informative article. The 0.7 gal gasoline equivalent batter is the EV killer.
Fill the battery 1000 times which is about the Li lifetime and you get 700 gal gasoline equivalent. At $ 3 gal gasoline that is about $ 2100 gasoline but the battery costs $ 10000!!
So the battery costs much more that ALL the energy it can store in its lifetime. The battery is lîke a very heavy solid gold gas tank that holds almost no fuel and turns to lead once it is installed in the car.
Excellent image of the gold tank, reverse alchemy.
If you’re going to make the weight comparison you should also compare the weight of the engine and powertrains where the IC has offsetting weight penalties.
I’d have liked more information on the use or expensive materials including rare earths in the manufacture and the environmental costs of battery production and disposal.
If it eventually turns out that fossil fuels are not such a ‘bad’ resource as often stated then the electric vehicle option could be worse for the planet.
Several obsolete figures in the article – the author apparently is not well acquainted on the current EV scene. For example:
“The warranty for most EVs batteries today is that there shall be at least 70% capacity left after 8 years or 160 000 km (100 000 miles).” A recent survey found that Tesla vehicles with 160,000 miles still retained 90% of battery capacity. Battery lifespans are typically over 15 years.
“The battery pack is the most expensive item in an electric vehicle. The current cost is approximately 300 USD/KWh ” Last year Tesla claimed a price of $190 per kWhr and GM claimed $150 per kWhr. GM’s CEO also claimed prices will be significantly less than $100 per kWhr in the next few years.
As far as replacement of batteries – that is unlikely to happen – the batteries shoudoutlast the vehicle, but
if they do need replacement years down the road, the costs will be far less than they are today.
“Personally, I do not use more time on supercharger stations than I used to use on gasoline stations. The reason is that I charge at home, and do not use supercharger stations more than approximately 10 times per year. I may stay there 20 minutes each time”
There are many people out there who have no means of recharging their car at home – apartment and townhouse dwellers, condos, etc. and they have no choice but to always use public fast chargers. Tesla’s Supercharger networks ajoke – the stations are sparsely located – often 50 miles apart, and Tesla cannot expand the network , for lack of funds. so now Tesla is desperately trying to join CCS neetworks- in Euopre they have applied for inclusion in the IONITY network, set up by Euro automakers BMW, Mercedes, VW and Ford. They use the de Facto worldwide charging protocol, CCS (SAE Combo) which uses 350KW chargers, as opposed to the half as fast Tesla Superchargers (140KW). IONITY has contracted with three gas stations networks (including Shell) and is adding three more. The chargers will be located in gas stations, the obvious locations for fast public chargers. VW is installing 350KW CCS chargers in Walmart and Target stores – they can recharge to 80% inless than 15 minutes. Royal Dutch Shell bought a charger company. EvGo is installing CCS charger coast to coast. Porsche is installing 500 CCS chargers in the U.S. – 200 of them at Porsche dealerships. CCS public chargers will have to service the 120+ new electric models coming from the world’s automakers over the next several years. They will be located everywhere – mostly in gas stations, the most economically efficinet method.
Public charging costs a lot more than charging at home and Tesla recently increased the prices at their (soon-to-be-obsolete) Supercharger stations. Some charge 24 cents per kWhr, twice the national residential rate. The issue of energy efficiency is irelevant – the cost of fuel is what matters, and on the basis of residential electric costs, the EVs cost a lot less to fuel. But if public charging stations are used, the fuel cost differences between a gas powered vehicle and an EV are not great, and sometimes the EV costs more to fuel. Public charging rates vary rather widely, more so than gasoline prices.
As for operating costs, right now gas powered cars pay road taxes (in the price of gasoline – roughly 50 cents per galon as I recall) ) while electric cars generally do not. Any cost comparison will have to take account of the road taxes that electric cars will HAVE to pay in the near future. Annual odometer mileages will be used to determine how much taxes EV owners must pay.
You discuss diesel engines and petrol/gasoline engines being limited by auto-ignition issues.
A new generation of truck engines that burn LNG is just becoming commercially available:
http://www.westport.com/is/core-technologies/hpdi-2
https://www.dieselnet.com/news/2017/10volvo.php
Natural gas does not readily auto-ignite even at high compression ratios. With LNG fueled engines you can just keep dumping fuel in the cylinder as far as I know.
The 2018 generation of new LNG engines still use diesel like compression ratios, but there is no fundamental reason to do so as far as I know.
Regardless, it is my understanding these new engines will have much better low rpm torque because additional fuel can simply be injected without auto-ignition concerns.
And future designs have the ability to significantly further improve efficiency by venturing into higher compression designs.
NOx is produced in the engine as a function of peak temperatures. An LNG or Hydrogen fuelled engine will produce the same amount of NOx as a petrol engine at the same compression ratio. Though higher compression ratios are higher efficiency, it’s the NOx production that limits the compression ratio.
Thanks for many insightful comments
Many have asked why I have not included the loss in electricity generation and electricity transmission. It is a reasonable question because if we base the electricity production on coal or gas, we get only a fraction of the efficiency in the first place.
However, to be fair you then also have to take into account the loss on the oil exploration, extraction at the wells, transport to refineries, loss in the oil refineries and finally transport to the gas station. There are quite huge losses in several of these steps.
It is possible to make a comparison that way, but it is not actually so meaningful because we seldom burn oil in power plants, oil is too expensive for that.
The fuel used for electricity generation cannot easily be used to directly power a car.
Therefore, I think it is relevant to compare the energy effiency from the gas station/ charging station.
That’s like saying —- “Look, over there, a squirrel! I don’t see the elephant, just maybe a shadow.”
Anyway, nice post on the good aspects of an EV that would suit some users. But there is still a herd of elephants in the room that you have missed. Sometimes they can be hard to see, or miss.
RE: Therefore, I think it is relevant to compare the energy effiency from the gas station/ charging station.
From the standpoint of the individual user/owner, that is certainly true. However, EVs are being promoted mostly as a “green” solution globally and being subsidized heavily for that reason. In that broader picture, things are less rosy and I contend that, if all the energy and cost required to deploy the EV on the massive scale that the ICE has already been deployed are considered, it is not nearly as “green” as most seem to think. If even 50% of current ICE vehicles were replaced with EVs the amount of additional base load generating capacity required to keep them on the road would be enormous and the additional transmission line capacity and transformers and other infrastructure required is mind boggling. As an example, a typical home has a 200 amp service, which is about 44kW. So to charge your car with 22kWh in 30 minutes would require the ENTIRE capacity of that home electrical service. The typical city service station probably has something like a 500 amp service and normally uses only a fraction of that load. It’s not uncommon to see 4 or 5 vehicles at a time lined up fueling. Even with many customers charging at home the shorter range and longer time spent charging will probably mean 4 or 5 EVs charging simultaneously frequently. That amounts to 220kW or 1000amps for a standard 220 Volt service. That means each station will have to completely rewire (not cheap) with a very high capacity service and more than a few of these stations in any area will require extensive rebuilding of lines and substations. That or only deploy 1 or 2 charge stations and require customers to wait 30 minutes for the previous client to finish. I lived through the gas lines in the US during the Yom Kippur War in 1973 when that happened a lot, and I do NOT recommend going back to it. Even if most charged at home overnight, in LA there are over 6 million Total Vehicles. If half were EVs charging at a slow 2–3 kW each for 10 hours that would be 3gW, or 30% more than the entire output of Hoover dam.
Thank you Bill, you are right that quick charging can be challenging, but most of the charging is slow charging in the nighttime when the power is cheap, and demand is low.
The total amount of extra power is not overwhelming.
Let us calculate it for the US:
Americans drive 13 000 km annually per capita. http://internationalcomparisons.org/environment/transportation.html
I we multiply with 320 million people and 0.2 kWh per km we get 832 TWh.
That is a 20% increase from the current production of 4000 TWh annually.
I do not think that is such a dramatic increase for converting all ICE to EV.
A bonus is that we would also save a lot in power to refineries and oil transport.
/Jan
Jan, 20% may not sound too difficult, but that 832TWh/year is greater than the output of all 99 commercial reactors in the US combined, or 3.7 times the total of all wind power generated in the USA or more than 3 times the total hydro power in the US. It’s also about a third more than the entire usage of Canada. It’s a major infrastructure investment by any standard.
http://www.world-nuclear.org/information-library/country-profiles/countries-t-z/usa-nuclear-power.aspx
All numbers are relative. I not saying that it is not big, but we are also talking about a major change in the society, replacing all fuel car with electric.
It is possible to generate the power with 80 new nuclear power stations or some massive investments in renewables and pumped storage hydropower.
But it will create a surplus of oil in the US that will improve the US trade balance substantially
/Jan
JKA: Think I can now see where your energy increase calculations are wrong. I believe that you need to look at the total energy consumed by today’s light (and heavy?) vehicles, and the need to replicate that energy for EVs. Ok, efficiency needs to be involved, but I still believe that your energy increase calcs are way off the mark.
The calculation above is for light vehicles only
/jan
“Toque and rotational speed”
Should be Torque.
The conversation is interesting, but the bottom line is this. I will buy an electric vehicle when I can expect the same performance out of an EV that I get out of a gasoline Vehicle (my Subaru Forester currently). That is 360 miles on a tank, with the air conditioner running full blast, in all wheel drive, with 4 people and luggage in the car. Until EV’s can do that, and recharge for another 360 miles or so in an hour, they are not going anywhere much.
one thing I notice, all advocates of EV never test in real world conditions in states like mine where for many months we can have well below zero F temps.
The electricity consumption increases by about 30% in those conditions in those months. And that’s it.
Battery capacity goes down a lot as well.
Everything about EV is fantastic.
Apart from the battery that is
heavy for the range
slow to recharge
limited lifetime (well below the motor)
expensive.
As far as lifetime goes 500 charge cycles of say 200 miles each is probably the best you can expect – so 100,000 miles before you need serious cash spent on a new one.
And no, they wont be worth recycling into grid storage.
Massive experience with abusing lithium batteries to the limit in RC models shows that you can probably fully recharge – with cooling – in 5 minutes, or you can achieve phenomenal discharge rates – 1 minute or less for serious peak power..or you can achieve multi year lifetimes…BUT NOT ALL TOGETHER.
And they are STILL too heavy for what they hold in terms of storage.
EVS do will a niche market – the second urban commuters car or school run for the well heeled with off road parking or as shuttles to and from airports and railways stations.
But they cant replace long hails stuff yet by a huge margin and no battery technology event theoretically exists that will make them.
They are supported entirely by subsidy and tax breaks. In the UK fuel is around 12.5p /KWh of which 80% is tax. at a vehicle efficeint of half that of electric, that puts a fule car about 50%-100% more costly per mile..because of TAX.
Domestic electricity is already above that due mainly to renewable idiocy. If people stopped buying fuel then taxes would have to be collected elsewhere.
EVs have their place, but in the limit unless lithium air technology can be made to work, it will never be a total replacement for fuel power in all road transport, let alone ships and planes…
“A frictionless electric engine has a theoretical efficiency of 100%.”
Right off the bat, the author has proven that he doesn’t have a clue about the subject.
He completely ignores resistance. He also is assuming that he only has to worry about the efficiency of the motor. He’s ignoring the losses in the battery charger, the losses in charging the battery, the losses in discharging the battery, the losses in regulating the power going into the motor, the losses in transmission of the power, and the inefficiencies in the power plant that generates the power.
Wow, so do you mean that it is only 95%? That makes the 41% eficiency of the best ICE in the market clearly the winner… or maybe not.
You get more than a 10% loss from the power distribution system alone. Then at best 90% efficiency in each of your charging and discharging cycles. You also assume that power generation is nearly 100% efficient.