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Article Post

An Electric Car Revolution Will Require Perpetual Subsidies

Highlights:

  • Battery electric vehicles (BEVs) can be economically attractive as commuter cars in city traffic.
  • Attractiveness fades for longer-distance travelling due to larger battery packs, a smaller efficiency advantage, and more fast charging at on-peak rates.
  • As a result, displacing just a low single-digit percentage of global oil consumption through BEVs will require perpetual subsidies. 
  • A strong argument can be made that future overall cost reductions could be greater for hybrids than BEVs.
  • Autonomous driving technology does not change this outlook. 

Introduction

This article follows up from a widely read earlier article on why a fully electric transportation future is unlikely to arrive any time soon. Battery electric vehicles (BEVs) certainly represent an important wedge in any transportation emissions reduction plan, but they are no holy grail.

BEVs have the same ideological appeal as wind and solar power. They are very easily marketed as perfectly clean and sustainable alternatives with rapid cost reductions that will soon relegate dirty fossil fuels to the dustbin of history. As in the case of wind and solar, this ideological appeal has attracted a broad fan-base and an equally broad range of technology-forcing policies.

Similar to wind and solar, however, the truth is that market penetration beyond a certain, relatively modest, level will require perpetual subsidies. A previous article quantified this point for wind and solar. This article will do the same for BEVs.

BEV saturation point

All energy technologies have strengths and weaknesses. That is why a healthy mix of technologies is generally the optimal solution, allowing each technology to serve the market segment it suits best.

BEVs have totally different strengths and weaknesses to ICE vehicles, implying that this technology class will diffuse easily into certain market segments, but have a much tougher time in others. Indeed, BEVs will penetrate the mobility market according to the well-known S-curve, struggling not to saturate well below 10% of current oil consumption.

Greater clean mobility contributions will likely come from much less hyped solutions such as car-free lifestyle options, efficiency improvements (including hybrids), sustainable fuels, conservation (downsizing), and fuel cell technology. It is vital that we leave ideology aside and replace current BEV technology-forcing policies with technology-neutral policies creating a level playing field for all clean mobility options.

Quantifying BEV competitiveness

As an illustrative example, we will calculate the combined fuel and drivetrain costs of a BEV and a hybrid as a function of driving patterns. The following graph shows the assumptions employed.

Here we assume that BEVs will be available with ranges between 200 miles (sales below this range have been poor even with large incentives) and 500 miles (comparable to a conventional car). At the low end, BEVs will be used as commuter cars, accumulating 10000 miles per year. At the high end, BEVs are often used for longer trips, racking up 15000 miles per year. Based on fuel economy of the Hyundai Ioniq hybrid and electric versions, BEVs are assumed to be 3x more efficient than hybrids at the low end (primarily city driving) and 2x more efficient at the high end (primarily highway driving).

Finally, electricity is assumed to cost $100/MWh at the low end due to off-peak charging at home (cost of home charger included), but $180/MWh at the high end due to more peak-time charging at more expensive fast charging stations (half way between home charging and $260/MWh at Tesla’s “non-profit” California superchargers).

Other important assumptions are as follows: BEV and hybrid drivetrain costs of $2500 and $7000 respectively (1, 2, 3), BEV efficiency of 270 Wh/mile (including charging losses),  gasoline price of $2.1/gal before taxes ($60/bbl oil), 20 year lifetime, 6% discount rate, and 30% gross margin on drivetrain and battery packs.

Three technology improvement levels are assessed for BEVs and hybrids. For BEVs, it is all about battery pack costs over a range of $50/kWh to $150/kWh. For hybrids, a scenario of 50% higher efficiency as well as a scenario of 50% increase in efficiency and power/cost ratio is assessed. The results look as follows:

BEV vs hybrid drivetrain and fuel costs

As shown, BEVs just start to become competitive at the low end for the three different levels of technology advancement. Thus, BEV economics are attractive when the required range is small, driving occurs in stop-start city traffic and charging happens at home during off-peak hours. On the other end of the spectrum, BEV costs are generally more than double hybrid costs.

It should also be mentioned that future car-free lifestyle options may well remove a large chunk of demand for shorter city trips where BEVs are at their most attractive.

Technology uncertainties

BEV technology development is heavily focussed on batteries. Simple extrapolation of learning curves (e.g. the method used in BNEF‘s projections) yields impressively low numbers:

However, lithium ion batteries face harsher physical limits than microchips or PV cells. Even though cumulative battery production will need to increase 1000-fold (10 doublings) from today’s level to displace 10% of oil consumption, lithium ion batteries are already approaching their commercially achievable energy density limits. Recent impressive cost declines were primarily due to the establishment of global value chains and economies of scale, and are not repeatable. Future cost reduction efforts are therefore likely to be hampered by diminishing returns as technology development encounters physical limits.

More importantly, lithium ion batteries rely on several relatively rare technology metals. Given the absolutely enormous scale-up that will be required to have a substantial impact, this potential limitation is getting increased attention. The recent spike in the price of cobalt, a critical technology metal produced primarily in the unstable Democratic Republic of Congo, is shown below as an example.

Interestingly, oil offers a very good analogy in this case. At the start of the ICE revolution, oil was very cheap. One simply needed to drill a hole in the right place and oil would just come gushing up. At that point, oil was a minor component of gasoline prices next to refining and distribution costs. This is the point where we are now with BEVs: technology metals are a relatively minor cost in battery packs.

Of course, we all know what happened next. Despite continued technological advancements, oil prices eventually increased 5-fold as demand boomed and the easy resources dried up, making oil the dominant component in gasoline prices. The same is likely to happen with technology metals. At current spot prices, only the raw materials required for Tesla’s battery cathodes already cost $50/kWh. If the oil price history is anything to go by, material costs could really spoil the battery cost reduction story going forward.

As a result of physical limits on technological advancement and technology metal availability, sustainable production of $100/kWh lithium ion battery packs may well be impossible, with even the $150/kWh level proving difficult to maintain at the massive production volumes required to make a significant dent in oil consumption. Of course, oil also offers a good example of the potential geopolitical implications of technology metals.

I am therefore less confident about the optimistic technology assumptions for the BEV than the hybrid in the graph repeated below. Hybrids still have significant headroom for improvements in efficiency and cost, and are much less exposed to battery material limitations due to much smaller battery packs.

BEV vs hybrid drivetrain and fuel costs

As an example, Mazda is targeting 56% thermal efficiency in the longer term for its new SPCCI engine technology illustrated in the video below (current hybrid engines are about 40% efficient). The first generation SPCCI engine is due to enter commercial production next year and beta version test drives have been encouraging (1, 2, 3).

As outlined in an earlier article, my view is that such advanced combustion engines will eventually end up in a hybrid configuration where the electric motor is much more powerful than the engine. This will allow the engine and transmission to be strongly downsized, saving costs and allowing for operation within the optimal operating range almost all the time. As a result, efficiency, reliability and longevity will go up, while cost and emissions will go down. A drivetrain cost breakdown from the previous article is repeated below as an example.

Such a hybrid configuration can conceivably increase overall efficiency by 50% over the current state of the art with no cost penalty relative to conventional ICE cars, thus achieving the most optimistic hybrid technology scenario considered in this study. The most optimistic BEV scenario, on the other hand, will most likely require a new battery technology. If such a technology emerges, it will take 2-3 decades and hundreds of billions of dollars to establish a new fully cost-optimized global value chain and scrap outdated lithium ion battery infrastructure.

Autonomous vehicles

The previous article outlined why autonomous driving technology may well favor ICEs more than BEVs. Besides, the competitiveness picture does not change much if we increase the distance traveled per year by a factor of 5, reduce the vehicle lifetime to 7 years and add $2000 for autonomous hardware costs:

The hybrid will probably perform even better than suggested by the above graph. Autonomous traffic flow will be much smoother, allowing hybrids to also achieve highway efficiency at the low end. Also, such high-utilization applications will encourage developers to further enhance hybrid efficiency through waste-heat recovery systems, thus further reducing fuel costs. The ability of hybrids to refuel very rapidly at any time (without having to worry about electricity price fluctuations) will also be a significant advantage in an autonomous fleet.

That being said though, I maintain that we are unlikely to achieve broad deployment of full autonomy within the timeframes demanded by climate science.

Conclusion

Adding all of these observations together, it is difficult to see BEVs displacing more than 10% of LDV fuel consumption (2% of oil consumption) without perpetual subsidies. Displacing 10% of oil consumption may be possible at a substantial subsidy cost, but pushing beyond that point really sounds increasingly wasteful.

As mentioned earlier, substantially larger cuts in oil consumption and greenhouse gas emissions can be achieved through a range of other channels such as car-free lifestyle options, efficiency improvements (including hybrids), sustainable fuels, conservation (downsizing), and fuel cell technology. It will be a real shame if we get so distracted by BEVs that we fail to harness the great potential of these clean mobility options.

Content Discussion

Rick Engebretson's picture
Rick Engebretson on April 9, 2018

I fully agree with your conclusion. “Hybrids have headroom.”

You probably didn’t see the “ADM supermarket to the world” saturation US advertising decades ago. Cartoons of corn growing along freeways with an ethanol gas pump hose growing from stalks. Today, the US trade deficit, federal budget deficit, and growing mideast conflict make the 1980s “the good old days.”

A remarkable fact applies. In 1865 the US was finishing the Civil War. 100 years later, 1965, we were almost putting men on the moon. Then science all but stopped while government “policy” grew. Hopefully, we will have meaningful transportation and energy innovation by 2065. But I sure don’t see it coming from the “policy pushers.”

Willem Post's picture
Willem Post on April 10, 2018

In New England, plug-in hybrids are about 80% of all plug-ins, largely because of adverse conditions compared to California and range fears. All-electric are very sluggish in cold weather, with snow and ice on roads, and on dirt roads.
Prius, 54 mpg EPA combined (less in New England), is the most popular plug-in.

http://www.windtaskforce.org/profiles/blogs/comparison-of-energy-efficiency-and-co2-of-gasoline-and-electric
http://www.windtaskforce.org/profiles/blogs/evs-and-plug-in-hybrids-in-new-england-and-norway

Engineer- Poet's picture
Engineer- Poet on April 10, 2018

The omitted technology in this essay is the hybrid between hybrids and BEVs, the PHEV.

Speaking from experience, it is quite feasible to replace 2/3 to 3/4 of liquid fuel consumption† using a battery just 10% of the size required by a long-range BEV.  There’s also progress in battery chemistries using materials much more abundant than lithium, and ultracapacitors of truly stunning performance look ready to take the surge-power burden from smaller batteries.  Combined with the ability to eliminate mechanical driveshafts and add features like torque vectoring in an electrified drivetrain as well as opportunities to manage power transients and thus emissions on the engine side, it looks like the hybrid and PHEV are going to be strong regardless.

† I am actually getting closer to 80% savings over conventional, and more than 2/3 over normal hybrid.  My 2013 Fusion Energi is currently reporting a lifetime average fuel economy of 129.8 MPG (it’s actually somewhat less due to evaporative losses).  Estimate for the hybrid is 41 MPG, and just 27 MPG for the 4-cylinder Ecoboost.

This is despite a paucity of charging opportunities.  If current infrastructure was co-opted to help serve PHEVs, large shifts could be achieved in a fairly short time.  Half of all LDV mileage is driven in the first 6 years, so a new-car fleet consisting of 50% PHEVs would lead to a 33% drop in liquid fuel demand in just over half a decade.

Engineer- Poet's picture
Engineer- Poet on April 10, 2018

Congratulations.  You just re-invented AC Propulsion’s charger-trailer, circa 1998.

Willem Post's picture
Willem Post on April 10, 2018

EP,
129.8 MPG EQUIVALENT, which is 129.8/2.8776 = 45.1 GPM actual, on a mine/well to house meter basis.

Going from a to b requires energy to overcome drag + rolling resistance.

Your electric vehicle requires about the same energy as similar other vehicles.

That energy comes from mines and wells, goes through a process, and comes out of your plug as electricity. That is the reason for the source factor.

The EPA says it magically comes from the plug and thus ignores the source factor.

It is all explained in this article.

http://www.windtaskforce.org/profiles/blogs/comparison-of-energy-efficiency-and-co2-of-gasoline-and-electric

wind smith's picture
wind smith on April 10, 2018

If the grid gets 80 to 100% decarbonized and a big if of getting our act together with a significant US and/or global carbon tax so that the cost of electric power diverges
significantly from oil prices, how will that affect the competitiveness of all three options?
At what carbon price will the cross over be made? Is there any downside to making the hybrids less competitive thru carbon taxing?
Will future large vehicle markets such as the EU, China, India, California, ?, with much less domestic oil resources such as the US, be enough to move the market in the direction of BEV’s inspite of what US consumers do?

Roger Arnold's picture
Roger Arnold on April 10, 2018

You just re-invented AC Propulsion’s charger-trailer, circa 1998.

Yeah, kinda. Cocconi deserves credit for a lot of things. The Long Ranger was one of them. But Long Ranger was a 2-wheeled trailer that stayed hitched to the T-Zero for the duration of any trip. It didn’t have the ability to decouple after delivering a recharge and then drive itself to the next refueling / pickup point.

I think that makes a significant difference. More like mid-air refueling for a military jet, as opposed to trying to fly an extended mission carrying big wing tanks. A rolling recharger could service dozens of EVs per day and pay for itself quickly.

Engineer- Poet's picture
Engineer- Poet on April 10, 2018

129.8 MPG EQUIVALENT

Wrong.  That is liquid-fuel consumption at the engine (not input) as measured by the vehicle, divided by odometer miles travelled.  It does not count electric consumption at all; that is reported separately.  Electric power can come from anything from low-grade geothermal heat to CCGTs, ancient inefficient coal-burners to nukes, plus hydro, PV and wind.  There is no direct relationship between kWh consumed, BTUs of primary energy and emissions in the production.

I hope to have that number up to 129.9 before my next out-of-town trip, which will drive it down a few tenths.

Your electric vehicle requires about the same energy as similar other vehicles.

The difference being that the source of that energy is far more easily shifted to sources other than petroleum, and the electric energy is almost certain to be non-petroleum (few plants outside of Alaska, Hawaii and Puerto Rico burn oil regularly, and petcoke is so dirty most coal plants won’t/can’t burn it; that’s why it’s piling up along the River Rouge south of Detroit instead of taking a very short barge trip to Monroe MI to be burned in the 3400 GW of coal plants there).  (Not sure what else can be done with petcoke, maybe it can be used to shore up played-out salt mines or something.)

That energy comes from mines and wells, goes through a process, and comes out of your plug as electricity.

Most of it does.  A bit comes from hydro, wind and PV.  Around 20% still comes from mines of non-carbon energy supplies.  It all depends.

That is the reason for the source factor.

There is no one single source factor.

Schalk Cloete's picture
Schalk Cloete on April 11, 2018

Yes, fuel cells are certainly still in the hunt. Personally, I don’t understand why current models are not making use of larger battery packs to greatly reduce the size of the expensive fuel cell stack. The Mirai fuel cell has a maximum power output of 114 kW (153 hp). They could make the car a lot cheaper by halving the fuel cell capacity and putting in about 5 kWh of battery capacity. Then the much cheaper fuel cell can work closer to maximum output most of the time, using the battery an an energy buffer to supply the varying power output required in normal driving patterns. Maintaining an average power output of greater than 50 kW for the time required to drain 5 kWh of battery capacity is pretty much impossible without breaking several traffic laws.

Schalk Cloete's picture
Schalk Cloete on April 11, 2018

Yes, PHEVs are certainly also a legitimate option. Developers can still improve the energy management in PHEVs significantly with intelligent GPS route planning. For example, the larger battery capacity can ensure that EV mode is always used in stop-start traffic, while hybrid mode is used in free flowing traffic where the engine is at its most efficient. The engine can also be downsized significantly, relying on the larger battery capacity to supply shorter power bursts for acceleration and hills. Having a significant portion of the fleet that can run on either electricity or gasoline will also improve the price elasticity of oil demand, thus avoiding economically damaging oil price spikes.

Schalk Cloete's picture
Schalk Cloete on April 11, 2018

I looked at the issue of CO2 emissions in the previous article: http://www.theenergycollective.com/schalk-cloete/2412528/electric-car-hype-overblown. You will see that CO2 emissions are actually quite a small factor for such efficient vehicles.

The crossover electricity carbon intensity for current hybrids is about 0.45 kg/kWh. Future improvements in hybrid efficiency can lower this threshold to 0.3 kg/kWh. Current global average electricity carbon intensity is 0.56 kg/kWh with China and India sitting much higher. It will take several decades for these large future auto markets to reach the electricity mix required to make BEVs less carbon intensive than gasoline hybrids. By that time, biofuels may already have reduced hybrid carbon intensity significantly.

Yes, energy security is an important factor to consider when it comes to oil. Policies to promote energy security can benefit alternatives such as BEVs, FCVs and locally produced synfuels/biofuels. Still, I doubt that it will be economically feasible to displace more than 10% of total oil consumption through BEVs. The potential technology metal security issues of batteries mentioned in this article is also an important factor to consider in a scenario of rapid BEV growth.

Engineer- Poet's picture
Engineer- Poet on April 11, 2018

If we’re going to fast-charge in motion, I offer my “charging lane” idea for reconsideration.  The vehicle extends an arm with sliding or rolling contacts, most likely through a slot in the guardrail, and charges more or less directly from the grid.  This requires only one vehicle to have self-driving systems, and eliminates the conversion from electricity to hydrogen and back.

Engineer- Poet's picture
Engineer- Poet on April 11, 2018

I’ve at least come close, but I was driving a car/trailer combo loaded to more than 3 short tons up a 5% grade leading up to a tunnel through a mountain.

Engineer- Poet's picture
Engineer- Poet on April 11, 2018

Given the rate of announcements of breakthroughs in battery chemistry, such as materials which solve troublesome problems of solid-electrolyte interfaces, I suspect we’re on the cusp of breakthroughs in non-lithium and metal-air batteries which will use far cheaper, more abundant materials.  Simply replacing lithium (~43000 tons/year, harvested from specific brines) with magnesium (766,000 tons/yr and harvested from seawater) would eliminate most resource issues.

Willem Post's picture
Willem Post on April 11, 2018

EP,

Efficiency of Battery Electric Vehicles: The energy from mines and wells is fed to the US electrical system, which converts it into electricity and distributes it to house electric meters. The source factor, mine/well to house meter, is 2.8776. Source factor for E10 (90 gasoline/10 ethanol) is 1.2568. Prius mileage is 52 mpg EPA combined. Prius efficiency, tank to wheel is 0.418

Source energy, Prius, mine/well to wheels = 1.2568 x 1/0.418, eff = 3.001 times the energy to wheels.
Source energy, 38 mpg, mine/well to wheels = 1.2568 x 1/0.306, eff = 4.107 times the energy to wheels
Source energy, BEV, mine/well to wheels = 2.8776 x 1/0.700, eff = 4.111 times the energy to wheels.
Source energy, 25 mpg, mine/well to wheels = 1.2568 x 1/0.201, eff = 6.253 times the energy to wheels.
http://www.windtaskforce.org/profiles/blogs/comparison-of-energy-efficiency-and-co2-of-gasoline-and-electric

Willem Post's picture
Willem Post on April 11, 2018

Energy on the Grid: Once electricity is fed into an electric grid, it travels as electromagnetic waves, at somewhat less than the speed of light, on un-insulated wires, i.e. from northern Maine to southern Florida, about 1800 miles in 0.01 of a second, per Physics 101. On insulated wires, the speed, on average, is about 2/3 the speed of light. The electrons vibrate at 60 cycles per second, 60 Hz, and travel at less than 0.1 inch/second. It is unfortunate most high school teachers told their students electrons were traveling and likely never told them about EM waves, or did not know it themselves.
http://www.djtelectricaltraining.co.uk/downloads/50Hz-Frequency.pdf

This article explains in detail what happens when electricity is fed to the grid.
http://www.windtaskforce.org/profiles/blogs/popular-misconceptions-regarding-energy-mix

Willem Post's picture
Willem Post on April 11, 2018

Because BEVs will be everywhere, and travel across state lines, to simplify analyses, it is best to use US grid data as the basis (so one analysis can be compared with another, because they are on the same basis), instead of having analyses based on a large number of local grid data.

B W's picture
B W on April 11, 2018

Hi Schalk,

An additional point regarding autonomous vehicles: they use substantially more energy than non autonomous vehicles for powering sensors communication and processing devices.

An additional additional point: if autonomous vehicles come to fruition they would presumably be used in fleets, and best economic outcome would be achieved by very long run times.

So batteries look to be a very unlikely powertrain for autonomous vehicles.

B W's picture
B W on April 11, 2018

Because in the not-so distant future the fuel cell stack looks like it will be the cheaper and (more importantly) more profitable component for the automaker to manufacture rather than source. I say this based on both formal projection and materials/process involved in manufacture. Pt Catalytic loading in PEM FCs is now more or less inconsequential, and cost is expected to come down rapidly in the next decade as as investment in scaled automated manufacture finally begins.

A comparison between ultra-efficient combustion ignition ICE-hybrids fueled by carbon neutral fuel and PEM fuel cells fueled by hydrogen might actually be the best comparison for mass market decarbonisation, and there may be a case for both.

Schalk Cloete's picture
Schalk Cloete on April 11, 2018

Yes, I have seen some impressively low future cost assumptions. Given the dramatic fall in battery costs with economies of scale, there is no reason to believe that this will not happen with fuel cells also. Do you have a good reference with cost projections over time?

But still, even if fuel cell costs come down to $60/kW, halving a 120 kW fuel cell stack to 60 kW by installing a 5 kWh battery for $200/kWh will save a cool $2600.

What about efficiency? For example, the Mirai (67 MPG) does not get much better mileage than the Eco Prius (56 MPG). Can future fuel cells become much more efficient than the current state of the art?

Schalk Cloete's picture
Schalk Cloete on April 11, 2018

I’ve actually tried to find some power consumption specs for autonomous vehicles, but the few estimates I could find are very low (insignificant). Do you have a reference that shows significant power consumption from autonomous technology?

One thing that could increase energy consumption is the “empty miles” driven by an autonomous vehicle between dropping off one customer and picking up another.

I see some role for BEVs as part of autonomous fleets deployed in cities. Such cars can probably get away with a range of about 300 miles, which will be just enough for one day so that they can recharge gradually overnight at low rates.

Schalk Cloete's picture
Schalk Cloete on April 11, 2018

Let’s see. I just hope this breakthrough happens before current technology-forcing policies build the entire world full of Li-ion gigafactories that will need to be scrapped as soon as the improved battery technology is brought to scale.

Nathan Wilson's picture
Nathan Wilson on April 11, 2018

“… why current models are not making use of larger battery packs to greatly reduce the size of the expensive fuel cell stack ..”

I think this is done to boost efficiency. Fuel cells behave as though their output is resistance limited. This means that Voltage and efficiency drop linearly with output current, and at maximum output power, device’s equivalent series resistance eats half the power; so the maximum efficiency at max load is 50%, even before accounting for other losses. If you then cycle the energy in and out of a battery or ultra-capacitor, the efficiency gets ever lower.

Given the importance of high efficiency when using a fuel which costs more than gasoline (e.g. hydrogen), I think you’ll find that all FCVs use the battery only for regen (braking energy recovery) and perhaps hiding a stack warm-up delay.

Nathan Wilson's picture
Nathan Wilson on April 11, 2018

Autonomous charging trailers depend on successful deployment of highly functional autonomous driving; maybe someday, maybe not.

A variation that can use simpler autonomous “platooning” technology (in which cars can autonomously follow closely behind another cooperating vehicle) would use special charging pods that attach to the trailers of big rigs, and gives the rig operator an extra source of income. The customer uses a phone app to find one nearby, pulls up to the big rig, automatically docks with the pod, jacks into a 100kW power source, and charges for 30 minutes (electronically paying for the privilege), then undocks and cycles to the back of a group of 3 cars platooning behind the big rig for 60 minutes of disconnecting platooning.

Platooning has been studied for gas cars too, since it boosts fuel economy if the cars follow very close behind one another to stream-line, as well as boosting the vehicle carrying capacity of the freeway (because computers can pack cars more closely than human drivers).

Of course, before the auto industry can deploy autonomous platooning, they have to admit that full self-driving cars are not on the ten-year horizon. Then someone has to hype it enough to push through the chicken-and-egg barrier (getting enough platoon leaders on the road to make the feature useful & vice versa). Probably the BEV market is not growing fast enough to drive deployment of platooning. But probably platooning’s ability to solve the major problems of autonomous driving (by having a human driver in the lead vehicle) is enough that it could happen.

Engineer- Poet's picture
Engineer- Poet on April 11, 2018

Willem, I admire your work but this time you’re out of your depth.

Once electricity is fed into an electric grid, it travels as electromagnetic waves, at somewhat less than the speed of light, on un-insulated wires, i.e. from northern Maine to southern Florida, about 1800 miles in 0.01 of a second, per Physics 101. On insulated wires, the speed, on average, is about 2/3 the speed of light.

You should not presume to lecture someone who has made far more intimate study of the subject than you have.

All electric transmission lines, whether line frequency or RF, are insulated.  The specific type of insulation (air, foam, solid polyethylene, sulfur hexafluoride gas) determines the “velocity factor” of the line.  For air it is close enough to 1.0 to make little difference from vacuum, for solid PE it’s about 0.65, for foam it’s in between.  I have never studied the electrodynamic details of SF6 but it’s so little used in transmission that it doesn’t really matter.

NONE of this has squat to do with how electric power traverses the grid.  That is determined by the impedance of the long lines, which is primarily due to inductance.  Inductance limits how much power can be transmitted from one end of a line to the other.  The point of maximum power transmission is when the phase difference between the two ends is 90°, as driven by the inductance of the line and the current through it; you cannot push more power through the line as increasing the phase difference beyond 90° DECREASES the real power transmitted.

In practice, even approaching 90° phase difference between ends of a line is dangerous.  It leads to massive changes in phase for small changes in power, which is a threat to stability.

What this means in practice is that your velocity-of-energy-propagation assertion is irrelevant.  There is no way for massive amounts of wind power in Maine to make their way to Florida—or vice versa—over conventional AC lines because of these physics constraints.

Physical transmission constraints mean that the power you’re consuming in any given locality is largely from local generation.  If your local power generation is mostly from coal, it’ll be coal.  This also goes for nuclear, hydro and NGCCGT.  Wind and PV vary by weather and time of day.

The upshot?  There is no one single source factor.  It varies over space and is not even constant for any particular place.

Engineer- Poet's picture
Engineer- Poet on April 11, 2018

Having a significant portion of the fleet that can run on either electricity or gasoline will also improve the price elasticity of oil demand, thus avoiding economically damaging oil price spikes.

On the contrary, Schalk.  The fraction of the fleet which can run on either source will tend to use the cheaper (electricity) whenever possible.  It will use petroleum for the rest.  Unless that non-electric travel is flexible, the demand will not be flexible either… but slashing the fraction of travel which produces that demand will also slash the economic impact of its cost.  I use gasoline for maybe 1/3 of my net annual travel.  The cost of gasoline has very little impact on how I drive any more.

I’d do a back-of-the-envelope analysis example for this but I’m a little too fuzzed right now.

Bas Gresnigt's picture
Bas Gresnigt on April 12, 2018

@EP,
Don’t they use phase shifters in USA?
If so, why not?

Engineer- Poet's picture
Engineer- Poet on April 12, 2018

Already explained in the very comment to which you are replying.

Willem Post's picture
Willem Post on April 12, 2018

EP,

I agree regarding impedance.

I was merely illustrating the speed of light (Maine to Florida), not implying electricity would actually travel that way. Impedance is not an issue regarding HVDC lines.

Bare transmission lines in air; speed is a little less than the speed of light.

Insulated lines: likely not less than 2/3 the speed of light, depending on the type of insulation.

I agree, as electricity spreads out from a point source in, for example, Vermont, it gets consumed, usually well within 50 miles, which likely would include New Hampshire and New York State and Massachusetts.

In New England one could assume a New England mix.

One could not assume a Vermont mix, or a New Hampshire mix.

Texas, with its own independent grid, with minimal interconnections, is the only US entity that could assume a state mix.

Source factors:
There are as many source factors as there are sources of energy. For analysis, one would use the weighted average of these source factors.

One could make a complicated case (esoteric case?), since the mix varies, the averaged source factor would vary as well, and then say: “there is no single source factor”. What a nightmare that would be.

To maintain sanity in the analysis world, it would be better to take the yearly weighted average for a state, or better yet, take the yearly weighted average of the US, as BEVs travel all over the US, which I have done in my referenced article.
http://www.windtaskforce.org/profiles/blogs/comparison-of-energy-efficiency-and-co2-of-gasoline-and-electric

Engineer- Poet's picture
Engineer- Poet on April 12, 2018

Impedance is not an issue regarding HVDC lines.

To be pedantic, it’s much less of one.  Resistance is one component of impedance and HVDC lines still have resistance.

One thing that should be concerning is the difficulty of “branching” HVDC lines the way AC neatly works with transmission and distribution.  All installations to date appear to be point-to-point, with single converter stations at either end.  The gathering and distribution of power is done in alternating current.  This suggests that we don’t yet have the technology to scale HVDC, and the converter stations are expensive and the major site of losses.

as electricity spreads out from a point source in, for example, Vermont, it gets consumed, usually well within 50 miles, which likely would include New Hampshire and New York State and Massachusetts.

Vermont essentially went out of the electric generating business when Vermont Yankee (70% of state generation) closed.  Almost all its electricity now comes from elsewhere.

Source factors:
There are as many source factors as there are sources of energy. For analysis, one would use the weighted average of these source factors.

That’s valid if the PIV fleet’s load curve is the same as the rest of demand.

Thing is, that’s probably a grossly false assumption.  The PHEV fleet’s demand curve (and maybe shorter-range EVs too) is going to spike just after drive-time in the morning, with perhaps a smaller spike in the evening during errands.  After arriving home, both the PHEV and EV fleets are amenable to load-curve shaping during overnight charging.  The marginal generating mix which serves this demand is going to be substantially different from the average in most places, and so will the source factors.  The morning and overnight load won’t be met by peakers, for instance.

This can be good or bad.  Where the base and intermediate load generation is primarily coal-fired, the PIVs will be dirtier than hybrids and maybe even ICEVs.  Where the base load is met by NG CCGTs, nuclear or hydro, they’ll probably be substantially cleaner.  It makes sense to put the PIVs where that marginal generation is cleanest.

The game changes yet again when the new (and perhaps schedulable) demand curve starts to influence the type of generation.  Enough PIVs on the grid and California’s sunny-noon surplus and solar curtailment is a thing of the past, making the marginal kWh close to zero-emission.  If the smoothed net demand curve allows most simple-cycle gas turbines to be replaced with CCGTs, emissions will be substantially reduced across the board.  These things really have to be considered as a system, because the interactions will cause unforeseen effects if they aren’t.

Engineer- Poet's picture
Engineer- Poet on April 12, 2018

Okay, I’ve finally had time to decipher your web page and figure out what all this means (you need to put units on numbers where appropriate).

Source energy, BEV, mine/well to wheels = 2.8776 x 1/0.700, eff = 4.111 times the energy to wheels.

‘Sokay so far.  Now let’s look at the BEV receiving power primarily from a NG CCGT at 60% efficiency LHV.

17.172 kWh @ wheels / 0.7 -> 24.531 kWh @ meter
24.531 kWh @ meter / 0.935 -> 26.237 kWh @ plant
26.237 kWh @ plant / .60 -> 43.728 kWh(th) @ plant
43.728 kWh(th) @ plant / (50 MJ/kg / 3.6 MJ/kWh) -> 3.148 kg CH4
3.148 kg CH4 / 0.92 for overhead -> 3.312 kg CH4 total consumption

3.312 kg CH4 yields 9.108 kg CO2.  Dividing by 65 miles * 1.609344 km/mi yields a grand total of 87.1 gCO2/km.  This is considerably better than the Prius hybrid.

And of course, we can drive the source CO2 of electricity down to almost 0 using nuclear power.  We have no way to put nuclear-derived gasoline into a Prius yet.

Engineer- Poet's picture
Engineer- Poet on April 12, 2018

I doubt that whole factories would have to be scrapped for new chemistries.  From carbon-zinc to NiCd to NiMH to Li-ion, the AA form factor has always been available.  Some parts would be retooled, but a lot will remain in common.

Marcus Pun's picture
Marcus Pun on April 12, 2018

I find myself amused in the ongoing EV and Renewable arguments when “subsidies” are brought up in application to the new technologies. It’s as if the hundreds of billions in external costs of fossil fuel pollution and the trillions spent on wars to secure oil supplies never happened.
There is further weakness in the subsidy argument when in fact most vehicle trips are short, below 50 miles. The British have had similar experiences. http://www.sustrans.org.uk/sites/default/files/documents/guidelines_16.pdf
“23% under a mile, 33%
1 – 2 miles, and 79% 2 – 5 miles. In fact
69% of all car journeys were less than
5 miles long in 2005. ”
Granted it would be different in California but not by much. So no, most folks don’t need long range vehicles. So the EV subsidy argument falls apart.

Max Kennedy's picture
Max Kennedy on April 12, 2018

You mean like over 100 years of direct and indirect subsidies for fossil fuels? As yet fuel cells have not demonstrated anything approaching electric costs, though there is potential and you failed to see/address on the go induction charging or the costs of global warming in your analysis. Externalising costs, ie not accounting for them, is just another way to lie by omission. I expect better here.

Schalk Cloete's picture
Schalk Cloete on April 12, 2018

Well, that depends on the oil price. If we ignore taxes (gasoline taxes will eventually have to be levied on electricity as well if EV market share becomes significant), $50/bbl oil yields gasoline costing only about $57/MWh. For highway driving where EV mode is only about 2x more efficient than gasoline mode, the breakeven electricity price is $114/MWh. Public chargers can cost much more than that. If oil goes back to $100/bbl and beyond, however, electricity can be cheaper also from most public chargers.

It is therefore quite possible that PHEV owners will be willing to invest the extra effort to find and utilize public chargers only when the oil price is high, thus reducing oil demand. When the oil price is low, owners will only charge at home because the use of public chargers is not only more effort, but also more expensive.This will be especially true if cars become smart enough to optimize drivetrain usage depending on the speed/traffic characteristics on the trip.

Schalk Cloete's picture
Schalk Cloete on April 12, 2018

Thanks, that is good information. But given the significant decrease in fuel cell efficiency with increasing load, would it not then make even more sense to use a battery for acceleration and hills? The fuel cell can then work constantly at low load (high efficiency) most of the time. Good batteries can have a round trip efficiency close to 90%, so cycling part of the fuel cell output through the battery pack will probably lead to significantly lower losses than using the fuel cell directly for the high power output required by acceleration and hills.

Jarmo Mikkonen's picture
Jarmo Mikkonen on April 13, 2018

Schalk, I think PHEVs are the way to go if you want to dent transportation emissions fast. It is much easier and cheaper to incorporate a small battery to existing designs than start brand new ones as you’d have to with BEVs.

Whether you support BEVs or PHEVs, the urgency to clean up the grids is a no-brainer. In countries like the Netherlands and China, a BEV is a fossil fuel car.

I personally drive a car that uses E85 ethanol fuel made out of waste products, not corn or any crop. It is actually a small fraction cheaper than using gasoline.

Willem Post's picture
Willem Post on April 13, 2018

NG CCGT @ 60% LHV is very optimistic in the real world.

I used a real world condition, i.e., the US grid, and get 129 g/km for the Prius, and 120 g/km for the electric vehicle.

BOTH vehicles were assumed to have the same rolling and wind resistance, i.e., use the same energy to go from a to b.

See first table in this article.

http://www.windtaskforce.org/profiles/blogs/comparison-of-energy-efficiency-and-co2-of-gasoline-and-electric

Engineer- Poet's picture
Engineer- Poet on April 13, 2018

You realize that those numbers add up to 135%?  Someone was sloppy with their clarity.

Sean OM's picture
Sean OM on April 13, 2018

The fraction of the fleet which can run on either source will tend to use the cheaper (electricity) whenever possible. It will use petroleum for the rest.

A -LOT- of Volt owners do just that. They plug in at night. Most people typically don’t drive over 40-50 miles a day. The limitation of course is they need to be able to plug in at night or at work.

Sean OM's picture
Sean OM on April 13, 2018

Even if the existing factories and equipment can’t manufacture the new technology. They are already paying back their equipment expenses, and have probably another 8-13 years to do so. which is enough time to finish writing down the equipment.

Daniel Duggan's picture
Daniel Duggan on April 13, 2018

It’s a change to see a carefully considered BEV article, rather than the usual faith-based breathless hype. In Ireland the hype and hypocrisy surrounding BEV policy is revealed by the inclusion of just four BEVs in a 6,600 strong government fleet. Widespread purchase of EVs by consumers has also failed to materialize despite a €10’000 BEV subsidy and free public charging. As of January 2018 the number of BEV registrations has grown to just over 1% of the 2020 target of 250’000 set in 2010 by Green Party leader and then Energy Minister Eamon Ryan. Even Ryan himself today in 2018 choses to drive an old and very polluting diesel fuelled VW Combi rather than one of the BEVs he so passionately promotes.

Sean OM's picture
Sean OM on April 13, 2018

Someone is trying to develop a drone for emergency recharging.

Sean OM's picture
Sean OM on April 13, 2018

It is better if we just kill FC technology. The only advantage it really has is faster fill up times. Which are being addressed in newer battery technology.

We already have to pay for the electric infrastructure, adding a new trillions of dollar infrastructure for Hydrogen and losing the ability to make your own at home is actually, as a society, a really, really stupid idea.

Engineer- Poet's picture
Engineer- Poet on April 13, 2018

It is therefore quite possible that PHEV owners will be willing to invest the extra effort to find and utilize public chargers only when the oil price is high, thus reducing oil demand.

This is true to a point, but you haven’t accounted for 2 things:

1.  For lots of drivers, plugging in is a habit.  They do it for fun or to be green, not just to save money.
2.  A number of businesses are installing chargers to help bring in traffic.

When the oil price is low, owners will only charge at home because the use of public chargers is not only more effort, but also more expensive.

I keep seeing more and more chargers that offer electricity free to the user.  One site near me has gone through several revisions; the latest has 3 posts for Teslas and a new 2-cable ChargePoint unit which is offered gratis.

I believe there’s an opening here for a type of charger which uses existing wiring (e.g. for street lighting) to offer low-power charging at very low installed cost per unit.  These could be rolled out into on-street and at-work parking in large numbers very quickly.  People who are going to be at work all day don’t mind if their vehicle is only charging slowly; they’re not waiting for it.  If the units are cheap enough, it would only take a small markup on electricity to pay for them and people would be much more inclined to use them.  5¢/kWh markup on 1.44 kW is 7.2¢/hr, figure 43¢/d if used 6 hours a day.  If used 200 days a year a $200 charger would be paid off in about 2.5 years.  This would require a sort of installation kit which could be bolted onto a light pole and wired up in a few minutes per unit, but I don’t think this is at all beyond current capabilities.

Engineer- Poet's picture
Engineer- Poet on April 13, 2018

Platooning has some great potential (I’ve achieved over 60 MPG at highway speeds by drafting a semi-truck) but the notion that a diesel-powered big rig is going to carry a fat battery (weight subtracted from its own paying cargo) in order to charge the first in a line of EVs strung out behind it seems to have a few bugs.

If the road can be electrified with overhead wires, this becomes a much more tractable problem.  The big rig can not only run itself, it can pass power along without toting a heavy battery.  Plus, you’re platooning anyway; instead of charging only the first in a line of EVs, why not daisy-chain them together and run them all on line power?  Any power in excess of road load can go to charging EV batteries.

Engineer- Poet's picture
Engineer- Poet on April 13, 2018

NG CCGT @ 60% LHV is very optimistic in the real world.

GE reports the efficiency of one 7HA.02 combined-cycle plant variant at 63.3% LHV.

I used a real world condition, i.e., the US grid

No, you used an average condition which is almost never exactly applicable anywhere and is grossly wrong at many places and times.

This condition is changing as a result of choices made by generators and consumers.  We can work to move the average toward the < 87 gCO2/km achievable with the 7HA.02, and probably better.  One way to accomplish this is to preferentially use EVs and PHEVs where the generating mix corresponds to EV emissions < 100 gCO2/km.  Where it’s substantially higher, use hybrids running on E10.

Schalk Cloete's picture
Schalk Cloete on April 13, 2018

Hydrogen has several other advantages over BEVs aside from faster refill. The first is that an H2 storage tank is much cheaper (and lighter) than a battery. Thus, for transport applications over long distances and/or with heavy loads (both of which require large quantities of energy stored on-board), FCVs will be cheaper than BEVs. More transportation fuel is used for these long/heavy applications than for short-distance light duty vehicles.

In addition, storing excess wind/solar energy as hydrogen is more practical than using it to power BEVs. In a solar dominated system, electricity will be cheap in the middle of the day, which is a much less practical time to charge a car than during the night. Such mid-day charging will also increase the peak load on the electricity distribution network, leading to substantial added costs. In a wind-dominated system, low electricity prices arise at random times, making it completely impractical to always charge a BEV with low-cost electricity. An electrolysis plant does not face these challenges.

I should also point out that faster charging of BEVs can easily become very expensive. The biggest cost component of fast charging stations is capacity charges accounting for the fact that a fast charging station will impose a very large peak load, often at a time of high system load. Increasing charging speeds will only add to this major expense. Thus, even though faster BEV charging may be technically possible, I doubt whether it will be economically feasible.

Personally, I think that more options for transportation energy is a good thing. There is certainly space for BEV, FCV, PHEV and ICE technology in the highly diverse transportation market.

Schalk Cloete's picture
Schalk Cloete on April 13, 2018

I think your first two points are valid at this stage where the plug-in fraction of the total fleet is still tiny and many owners are highly interested early adopters. For true mass market application, I doubt that these points will feature strongly.

The idea of a broad rollout of slow chargers is interesting. It would be good to get some data about the fraction of existing parking spaces that have easy access to wiring to set up such low-cost chargers. But still, the fuel cost of slow day-time charging will be comparable or slightly higher than an efficient hybrid, while its use will be more effort. Large-scale rollouts generally require a step change in practicality, performance or cost, and such low-speed chargers do not offer such a step change in my opinion.

Nathan Wilson's picture
Nathan Wilson on April 13, 2018

One more note on power transmission:

“… the difficulty of “branching” HVDC lines the way AC neatly works with transmission and distribution. … This suggests that we don’t yet have the technology to scale HVDC”

This is no issue at all, regardless of the long distance transmission technology used, local distribution works fine with AC.

Even AC transmission lines operate on completely different principles than local distribution. Local grids are “constant voltage like a copper sheet” (ignoring step ups & downs); power flow is varied by varying the impedance of the load (same as for HVDC long distance), which assumes the distance is short enough that the phase shift in transit can be ignored or corrected; if the line gets too long, you add phase shifters of some sort as Bas suggests (e.g. synchronous condensers).

Long AC transmission lines behave like RF transmission lines: they are always used with the load impedance nearly equal to the line impedance (with constant impedance, the phase shift is constant with changing power, and does not threaten stability, regardless of distance). This means that the voltage must be varied in order to control the power; this is done with adjustable-tap transformers (plus phase shifters). So instead of power flowing across the region however it wants (i.e. “copper sheet” approximation), there are people/computers in control rooms who order the flows to happen (and tracking who pays whom), just like with HVDC.

In terms of max distance, it is mainly just the higher voltage that boosts the upper limit; but HVDC is somewhat better for the same peak voltage, since the average voltage on an AC line is 30% below the peak.

Of course you’re correct that HVDC terminals costs more than HVAC terminals, and making bidirectional terminals costs more than single directionals. That will likely always remain true. So it is really limited near-term economic benefit (and deployment lag), rather than immature technology, that is holding back greater use of HVDC.

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