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Comparison of Energy Efficiency and CO2 of Gasoline and Electric Vehicles

Many articles have been written about the comparison of the energy efficiency of gasoline and electric vehicles. Most such articles have various flaws. This article will avoid these flaws and will show, electric vehicles are more energy efficient than gasoline vehicles, on a source energy-to-wheel basis, which is the most rational way to make the comparison. Many studies fail to use the lower heating value of the fuel, or fail to use the correct heating value of the fuel.

Many studies calculate meter-to-wheel efficiencies of electric vehicles of about 70%, which compare favorably with the tank-to-wheel efficiencies of gasoline vehicles of about 22%, i.e., EVs are 3.2 times more efficient. But that is not even close to reality.

E10 fuel (90% gasoline/10% ethanol) has a source energy, which is reduced due to exploration, extraction, processing and transport, to become the primary energy fed to E10 vehicles. As a result, the energy fed to the tank has to be multiplied by 1.2639 to obtain source energy.

Electrical energy has a source energy, which is reduced due to exploration, extraction, processing and transport, to become the primary energy fed to power plants, which convert that energy into electricity, which after various losses, arrives at user meters. As a result, the energy fed to the meter has to be multiplied by 2.8776 to obtain source energy. After these factors are applied, the EV and E10 vehicles have values as shown in the below table. The below table is based on US 2013 CO2 emissions of 2053 million metric ton to match the available 2013 electricity generation data. See Table 8.

E10 Prius
mpg 28 34 40 52
kWh/65 miles, to wheels 16.67 16.67 16.67 16.67
Btu/kW 3412 3412 3412 3412
Btu/65 miles, to wheels 56878 56878 56878 56878
miles in one hour 65 65 65 65
Btu/gal 112114 112114 112114 112114
Btu/65 miles, T-t-W 260265 214336 182185 140143
eff, T-t-W 0.219 0.265 0.312 0.406
SE factor 1.2639 1.2639 1.2639 1.2639
eff, SE basis 0.173 0.210 0.247 0.321
gal/65 miles, T-t-W 2.321 1.912 1.625 1.250
Btu/65 miles, SE basis 328948 270899 230264 177126
lb CO2/gal, SE basis 23.95 23.95 23.95 23.95
lb CO2/mile, SE basis 0.86 0.70 0.60 0.46
g CO2/km, SE basis 241 199 169 130
g CO2/km, T-t-W 191 157 134 103
L of E10/100 km, T-t-W 8.40 6.92 5.88 4.52
EV 2013
kWh/65 miles, to wheels 16.67
eff, M-t-W 0.684
kWh/65 miles, M-t-W 24.371
kWh/mile 0.375
Btu/kW 3412
Btu/65 miles, M-t-W 83155
SE factor 2.8776
Btu/65 miles, SE basis 239287
lb CO2/kWh, SE basis 1.2712
lb CO2/mile, SE basis 0.477
g CO2/km, SE basis 134
Energy efficiency, SE basis
EV better than E10, % 27.3 11.7
EV worse than E10, % 3.9 35.1
CO2, SE basis
EV better than E10, % 44.3 32.3 20.4
EV worse than E10, % 3.5

Effect of a “Cleaner” Grid in 2016: If the 2016 CO2 emissions of 1821 MMt were used, and the 2016 electricity generation data were assumed to be about the same as in 2013, then the above 1.2712 would become 1.1275 and the EV CO2 emissions would become 0.423 lb/mile (119 g/km). Only E10 vehicles with about 45 mpg (5.23 L/100 km), or better, would have less CO2 emissions than an EV with a real-world, annual average meter to wheel of 0.375 kWh/mile (0.233 kWh/km). See below table and sections and Table 9.

EV 2016
kWh/65 miles, to wheels 16.670
eff, M-t-W 0.684
kWh/65 miles, M-t-W 24.371
kWh/mile 0.375
Btu/kW 3412
Btu/65 miles, M-t-W 83155
SE factor 2.8776
Btu/65 miles, SE basis 239287
lb CO2/kWh, SE basis 1.1275
lb CO2/mile, SE basis 0.423
g CO2/km, SE basis 119
Energy efficiency, SE basis
EV better than E10, % 27.3 11.7
EV worse than E10, % 3.9 35.1
CO2, SE basis
EV better than E10, % 50.6 40.0 29.4
EV worse than E10, % 8.2

High-efficiency Vehicles More Efficient Than Electric Vehicles: The table shows high-efficiency E10 vehicles, including hybrids, such as the 52 mpg, 4.52 L/100 km Toyota Prius, have greater energy efficiency than EVs, and less CO2 emissions than EVs, on an SE basis. It would be much less costly and quicker to significantly increase the US hybrid fleet, than to build out the EV fleet, which is still in its infancy, and would require major, expensive changes to supporting infrastructures.

Tesla Model S: An upstate New York owner of a Tesla Model S measured the house meter kWh, vehicle meter kWh, and miles for one year. There was significant kWh/mile variation throughout the year. His annual average was 0.392 kWh/mile, M-t-W. The Model S has regenerative braking as a standard feature. The above analysis used an annual average of 0.375 kWh/mile, M-t-W, which means I used a higher EV efficiency than measured by this owner.

Data as measured by owner in New York State. See URL

Tesla, Model S
Electricity cost, c/kWh 19
Miles in one year 15243 c/mile
kWh, vehicle meter 5074 6.3
kWh/mile, vehicle basis 0.333
kWh/mile, vehicle basis 0.301 Apr-Oct
kWh/mile, vehicle basis 0.290 Jul
kWh/mile, vehicle basis 0.371 Nov-Feb
kWh/mile, vehicle basis 0.400 Jan
Vampire/charging 0.85 c/mile
kWh, house meter 5969 7.4
kWh/mile, house meter basis 0.392

http://www.greencarreports.com/news/1090685_life-with-tesla-model-s-one-year-and-15000-miles-later

Tesla Model S Driving Ranges on Non-urban Interstate Highways Under Varying Conditions

Interstate Highway speed limits; non-urban, contiguous 48 states; 12 states @ 65 mph, 20 states @ 70 mph, 14 states @ 75 mph, 1 state @ 80 mph (Texas). See: www.ghsa.org

Tesla Model S 85 kWh. Range advertised by Tesla as 300 miles at 55 mph

Sources: www.teslamotors.com and Tesla battery engineer claims.

Table 1. Ideal driving conditions: no AC, no heat, level terrain, 300 lbs aboard, windows rolled up, constant speed, no wind.

Table 2. Ideal driving conditions, but using average AC, and average heat

Table 3. Assuming additional 15% energy consumption due to non-ideal driving conditions, heavier AC and heavier heat

Table 1 65 70 75 80
Age mph mph mph mph
New 262 241 222 200
4.5 years 243 223 205 185
9.5 years 220 203 187 168
Table 2 65 70 75 80
Age mph mph mph mph
New 236 217 200 180
4.5 years 219 201 185 167
9.5 years 198 183 168 151
Table 3 65 70 75 80
Age mph mph mph mph
New 197 181 166 150
4.5 years 182 167 153 139
9.5 years 165 152 140 126

http://images.thetruthaboutcars.com/2012/08/Model-S-range-Tables.pdf

Debunking the Phony EPA Fuel Consumption Numbers – all numbers are on a source energy basis:

 

An E10 vehicle, 28 mpg, uses 2.321 gal x 112114 Btu/gal = 260265 Btu of E10 to go 65 miles in one hour (tank-to wheel basis), per Table 6, or 328948 Btu, on a SE basis.

– An EV uses 24.371 kWh x 3412 Btu/kWh = 83155 Btu to go 65 miles in one hour (meter-to-wheel basis), or 239287 Btu, on an SE basis.

The EPA mpg gasoline equivalent is based on the energy content of gasoline. The energy obtainable from burning one US gallon of gasoline is 115,000 Btu, or 33.705 kWh, or 121.3 MJ. If a different fuel, such as E10, is used, then the Btu of that fuel is used to determine EPA MPGe.

https://en.wikipedia.org/wiki/Miles_per_gallon_gasoline_equivalent

EPA EV mileage = total miles/(fuel energy/energy/gal) = 65/(83154/112114) = 87.6 MPGe. The EPA deliberately ignores the US electrical system upstream SE factor and the E10 upstream SE factor. If the US SE factor were applied, the real mileage would be 87.6/2.8776 = 30.4 mpg, similar to the 28 mpg of the E10 vehicle, as one would expect.

The car manufacturers are in on the deal, because they are allowed to take those low MPGe numbers and average them into their CAFE mpg, making it look lower than it really is to befuddle the public, which is somewhat of a sham.

The official explanation of the EPA is that people are familiar with miles/gallon, and EPA decided to call it “miles/gallon equivalent”. Engineers may not be befuddled, but Joe Blow likely is. Just ask some average people what it means. They have no idea. That means what EPA came up with was confusing.

US-DOE/Argonne National Laboratories GREET Program: ANL wrote the Greenhouse gases, Regulated Emissions, and Energy use in Transportation, GREET, computer program. The program enables comparing the well-to-wheel efficiency of gasoline and electric vehicles. If I had used the program, the inputs would have been a fuel mix to power plants for determining the CO2 of the EV, and E10 for determining the CO2 of the E10 vehicle.

https://greet.es.anl.gov

However, lacking sufficient familiarity with the GREET program, and always wanting to see equations, instead of just accepting printed results, readily available EIA data regarding CO2 emissions from the US electricity generating system, and EIA data regarding the generation of electricity, and data from various other sources, referenced in this article, were used to perform the analysis of this article.

NOTE: The article, “Is Ethanol a Cost Effective Solution to Climate Change?” shows, after a detailed analysis of the GREET computer program, the Argonne analysts relied on less-than-fully accurate international data bases, and overestimated well-to-wheel fossil fuels consumption (and associated CO2 equivalent emissions) of petroleum fuels by up to about 9%.

http://www.theenergycollective.com/jemiller_ep/172526/ethanol-cost-effective-solution-climate-change

Quick Charging of Batteries: Because low-voltage (110V+) charging of batteries takes a long time, higher voltage (220V+) charging is often used, because it reduces charging times. However, that negatively impacts:

– Overall charging efficiencies, which increases energy consumption and costs

– Battery aging, which requires earlier battery replacement, because of a loss of storage capacity, kWh, which negatively affects driving range

– Delivering energy at required rates, which negatively affects acceleration and uphill driving.

New England and EVs: With snow and ice, and hills, and dirt roads, and mud season, all-wheel drive vehicles, such as the Subaru Outback, SUVs, ¼-ton pick-ups, minivans, are a necessity in rural areas. There are a few EVs, such as the Tesla Model S, $80,000-$100,000, which offer road-clearance adjustment and all-wheel drive as options. Here is a list of EVs and Plug-in Hybrids. Very few have all-wheel drive and some of them cost 1.5 to 3 times as much as a Subaru Outback.

http://www.plugincars.com/cars

Driving an EV in winter, with 5 cm of snow, uphill, at low temperature, say – 10 C, with the heat pump heating the battery and the passenger cabin, would be slow going, unless the EV has a large capacity, kWh, battery. The additional stress causes increased battery aging and capacity loss.

Batteries likely will come down in cost, because of mass production, and weight, due to clever packaging (which would decrease rolling resistance), but the lithium-ion chemistry is pretty well maxed out, according to Musk, CEO of Tesla.

People switching from E10 vehicles to EVs likely will not happen anytime soon. There are no compelling CO2 reasons, as shown by the above table, unless the government compels people to do so, which would be a folly, as there are so many, less expensive ways, to reduce CO2. In fact, it would be best, if the government stopped interfering with the energy business.

Efficiency of US Light Duty Vehicles: LDVs are cars, SUVs, ¼-ton pick-ups, and minivans. The average efficiency of LDVs has not changed much these past 15 years. Even though new vehicle efficiency increased during the past 15 years, it caused just a very minor increase in the efficiency of all LDVs. See table. A similarly slow increase could be expected if EVs were to replace E10 vehicles.

https://www.rita.dot.gov/bts/sites/rita.dot.gov.bts/files/publications/national_transportation_statistics/html/table_04_23.html

However, if more LDVs were required to be hybrids (such as the Toyota Prius), which could be more rapidly implemented by manufacturers, then an efficiency increase of at least 25% could be expected during the next 15 years, etc. Toyota has a proven line-up of high-efficiency hybrids in various sizes and shapes. Other manufacturers could have the same.

LDVs 2000 2015 2000 2015 Better
mile/gal mile/gal L/100 km L/100 km %
Existing 20.00 22.00 11.76 10.69 10.0
New cars 28.50 36.40 8.25 6.46 27.7
New trucks 21.30 26.30 11.04 8.94 23.5

A Better Future Pathway: Future E10 vehicles likely would become more efficient, more quickly, and at much less cost, especially by increased use of hybrids, than:

– EVs could improve their efficiency, because lithium-ion technology is “just about maxed-out”, according to CEO Musk of Tesla. Such future EVs likely would become less costly, but not much more efficient.

– The US electrical system could reduce its CO2 intensity, kg CO2/kWh, such as with additional capacity, MW, build-outs of renewables and enlargements of the US electrical system. With higher-efficiency E10 vehicles, no such highly visible build-outs and enlargements would be needed. In fact, the capacity of the existing E10 fuel supply systems would be more than adequate for decades.

CO2 can be much less expensively reduced by:

– Making E10 vehicles more efficient

– Increased use of hybrid vehicles, such as Toyota Prius hybrids

– Increased building efficiency (having energy surplus buildings)

– Replacing existing nuclear plants with new nuclear plants, and, in New England,

– Getting more, low-cost, near-zero-CO2, hydro energy from Hydro-Quebec.

The Source-to-Wheel Efficiency of an E10 Vehicle

Per US-EPA, the energy of the gasoline is allocated, in percentages, approximately as shown in Table 1.

http://www.fueleconomy.gov/feg/atv.shtml

Table 1 Combined City Highway
% % %
Engine 68.0 73.0 65.5
Parasitic 5.0 6.0 3.5
Drive train 5.5 4.5 5.5
Wind 10.0 4.0 15.5
Rolling 6.0 4.0 7.5
Braking 5.5 8.5 2.5
Total 100.0 100.0 100.0

At a steady velocity, on a level road, and with no wind from any direction, the propelling force of the engine offsets the external resisting forces acting on the vehicle, which are wind and rolling resistance.

Wind Resistance: The wind resistance of a medium-size vehicle was calculated using 0.5*c*A*d*V^2, where; c is drag coefficient, 0.32; A is cross-sectional area of vehicle, 2.600 m2; d is air density, 1.293 kg/m3, V is velocity, 104.607 km/h. The wind resistance is 454 newton. See Table 2.

Table 2 Units Units
Drag coefficient c 0.32
Cross-section A 2.600 m2 27.986 ft2
Air density d 1.293 kg/m3 0.0807 lb/ft3
Speed V 104.607 km/h 65 mph
Wind resistance 454 N 102.063 lb force

Rolling Resistance: The rolling resistance was calculated using m*g*f*cos (a), where; m is mass, 1250 kg; g is gravity, 9.807 m/s2; f is tire deformation, 0.01 m, a = 0.5 of tire radius, 0.2032 m. The cosine (a) is about 1. The rolling resistance is 123 N. See Table 3.

Table 3 Units Units
Vehicle mass m 1250 kg 2755.75 lb
Gravity g 9.807 m/s2 32.175 ft/s2
Tire deformation f 0.010 m 0.033 ft
0.5 of tire radius a 0.203 m 0.667 ft
cosine a 1 1
Rolling resistance 123 N 27.549 lb force

Wind + Rolling Resistance: The useful power to the wheels, kW, was calculated using f, the total of wind and rolling resistance, 577 N; d, the distance travelled in one hour, 104.607 km; J = N*m, the work done, 60,331,767; t, the time 3600, seconds; W = J/s = 16759, or 16.67 kW. See Table 4.

Table 4 Units Units
Wind + Rolling f 577 N 129.612 lb force
Distance d 104.607 km 343,195 ft
Work done f*d 60,331,767 N.m = J 44,482,152 ft.lb force
Time t 3600 s 3600 s
Watt 16759 W= J/s 16759 watt
Useful power 16.67 kW 16.67 kW

The Fuel: The vehicle is assumed to use E10, a mixture of 90% gasoline and 10% ethanol. Its lower heating value is 31.25 MJ/L. In engines, the LHV must be used. See Tables 5 and 6.

Table 5 HHV HHV LHV LHV
Btu/gal MJ/L Btu/gal MJ/L
Gasoline 124340 34.65 116090 32.35
Ethanol 84530 23.56 76330 21.27
E10 120359 33.54 112114 31.25

http://www.straferight.com/forums/general-chit-chat/178951-ethanol-vs-gasoline.html

http://hydrogen.pnl.gov/tools/lower-and-higher-heating-values-fuels

https://en.wikipedia.org/wiki/Gasoline_gallon_equivalent

http://www.afdc.energy.gov/fuels/fuel_comparison_chart.pdf

Source-to-Wheel Efficiency: The tank-to-wheel efficiency is the useful power of Table 4 divided by the supplied power in Table 6.

Table 6 Units Units
E10, LHV 112114 Btu/gal 31.25 MJ/L
EPA combined 28 mile/gal 11.905 km/L
Steady speed 65 mile/h 104.607 km/h
Fuel 2.321 gal/h 8.787 L/h
Energy 260217 Btu/h 274.55 MJ/h
Time 3600 s 3600 s
Supplied power 76.27 kW 76.26 kW
Tank-to-wheel efficiency 0.219 0.219
Upstream factor* 1.2639 1.2639
Source-to-wheel efficiency 0.173 0.173

* The well-to-tank upstream factor accounts for the energy used for exploration, extraction, processing and transport of the E10 fuel. See Table 7.

Table 7 E10
kg CO2/L
Combustion 2.271
Extraction 0.240
Transport 0.030
Refining 0.300
Distribution 0.030
Total 2.870
Upstream factor 1.2639

http://www.cleanskies.org/wp-content/uploads/2011/06/staple_swisher.pdf

http://www.afteroilev.com/Pub/CO2_Emissions_from_Refining_Gasoline.pdf

http://energyoutlook.blogspot.com/2008/08/back-door-on-co2.html

http://www.reuters.com/article/2009/07/28/oil-cost-factbox-idUSLS12407420090728

http://www.accenture.com/SiteCollectionDocuments/PDF/MOD-019_CarbonAccountingPoV_083010_LR.pdf

https://www.vcalc.com/wiki/MichaelBartmess/CO2+from+Diesel+Fuel

NOTE: The UK, cleanairchoice and GREET claim the factor is 1.203, 1.23 and 1.2568, respectively. In this analysis 1.2639 was used which attributes more CO2eq to E10 vehicles, which makes EVs look better, in comparison. See Table 2 in second URL and Page 8 in third URL.

http://www.lowcvp.org.uk/initiatives/leb/TestingandAccreditation/WTTFactors.htm

http://www.cleanairchoice.org/fuels/E85C02Report2004.PDF

https://www.arb.ca.gov/fuels/lcfs/lcfs_meetings/12132016wang.pdf

Source Factor for US Electrical System: Various fuels, extracted from the earth, are fed to US electrical power plants. For exploration and extraction mostly diesel is used, for processing mostly diesel, gas and electricity are used, and for transport mostly diesel is used.

Table 7 shows the well-to-pump source factor for E10 is about 1.2639. The well-to-user source factor for gas and the mine/well-to-meter source factor for electricity are about 1.090 and 2.8776, respectively.

Also there is the energy consumed for O&M and on-going replacements/upgrading of the infrastructures used for exploration, extraction, processing and transport of the source energy that is converted to primary energy for the US economy. The US electrical system uses about 40% of all primary energy.

This results in an upstream factor of the US electrical system of about 1.08, i.e., the equivalent of about 8% of the source energy is used to obtain the primary energy fed to power plants. That 8% usage causes CO2 emissions. See Table 8. Excluded is the embodied energy of all the required infrastructures.

The Source-to-Wheel Efficiency of an EV

The US economy was supplied with about 25,451.00 TWh of primary energy in 2013. See Table 8. In this analysis, I used the 2013 emission data in conjunction with the 2013 electricity generation data.

The EIA 2013 emissions data is higher than at present, due to gas replacing coal. It is ironic, I could find the 2016 GERMAN electricity generation data, but not the 2016 US data.

https://en.wikipedia.org/wiki/Energy_in_the_United_States

Table 8 % TWh
US Primary energy 25451.00
Electrical fraction 0.40
Electrical primary energy 10180.40
Gross generation 4227.62
Self-use, % of Generation 3.82 161.55
Net generation to grid 4065.97
Conversion factor 0.3994
Imports, % of net generation 1.15 46.74
To grid 4112.71
T&D, % of To grid 6.50 267.33
To electric meters 3845.38
System efficiency, PE basis 0.3777
Upstream factor 8.00 0.9200
System efficiency, SE basis 0.3475
EV efficiency
Inverter AC to DC 0.950
Battery and charger 0.800
Motor and drivetrain 0.900
Meter-to-wheel 0.684
Source-to-wheel 0.228

German 2016 Electrical Data: Here are the corresponding numbers for Germany. In 2016, domestic electricity consumption = gross generation (648.4), less self-use (30), less net exports (53.7), less transmission and distribution (30), less pumped storage and misc. (19.4), = about 515.3 TWh at user meters. (CO2 of the gross generation) / (515.3 TWh) = grid CO2 intensity at the meter, which should be multiplied by the kWh drawn by an EV. However, this CO2 is based on primary energy grid intensity. It has to be adjusted by a factor to get source energy grid intensity, similar to the Table 8 procedure.

http://www.ag-energiebilanzen.de

CO2 Emission Reduction Due to less Coal and More Natural Gas Combustion: The URL shows the unusually rapid decrease of CO2 emissions during 2015 and 2016. Such a rapid decrease likely will not occur during the next few years, as natural gas prices likely will increase due to exports, and as changes in EPA rules likely will cause fewer coal plants to close. A “cleaner” US grid would mean EVs would compare more favorable with E10 vehicles regarding emissions. See Table 9.

https://www.eia.gov/totalenergy/data/monthly/pdf/mer.pdf

Table 9 2016
CO2, MMt 1821
To meters, TWh 3845.38
kg CO2/kWh 0.4736
lb/kg 2.20462
lb CO2/kWh, PE basis 1.0440
Upstream factor 1.08
lb CO2/kWh, SE basis 1.1275

Photo Credit: Frank Hebbert via Flickr

Willem Post's picture

Thank Willem for the Post!

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Discussions

Sean OM's picture
Sean OM on May 11, 2017 4:13 pm GMT

Many studies fail to use the lower heating value of the fuel, or fail to use the correct heating value of the fuel.

Heating value of fuel does not correlate to rotational motion.
Whatever conclusion you are trying to present is flawed, literally from the first sentence.

Bob Meinetz's picture
Bob Meinetz on May 11, 2017 4:59 pm GMT

Willem, you are to be commended on your diligent pursuit of the truth. It’s a lot of hard work, and as you know – the devil is in the details.

But you’re barely scratching the surface. The U.S. DOE has an ongoing, comprehensive analysis of full-spectrum, well-to-wheels emissions for every conceivable fuel and powertrain combination known as “The Greenhouse Gases, Regulated Emissions, and Energy use in Transportation Model” (under the tortured acronym of GREET). The following list describes only updates to the 2016 version of the model:

• Updated water consumption factors for the refining processes of petroleum fuels, thermoelectric and hydroelectric power generation, and hydrogen production processes.
• Updated high-octane-fuel (HOF, with research octane number of 100) pathways in GREET with E10, E25, and E40 ethanol blends.
• Developed new pathways for hydrogen production from dark fermentation of lignocellulosic biomass, high temperature steam electrolysis, and reforming of bio-derived liquids.
• Expanded and updated wastewater sludge-derived fuels and waste-to-energy pathways.
• Updated CCLUB to include N2O emissions associated with LUC GHG emissions for ethanol production scenarios.
• Updated emission factors for agricultural equipment and nonroad emissions.
• Updated DME production from fossil natural gas, natural gas-derived methanol, and renewable feedstocks.
• Updated the fuel economy and material composition of the light duty vehicles.
• Added bio-based ethanol-to-jet pathways from corn and cellulosic biomass, and sugar-to-jet from cellulosic biomass.
• Updated energy intensity and emissions for freight and intercity passenger rail transportation.
• Developed in GREET.net emissions within various regional aggregations of the United States, including regionalization at the state, eGrid subregion, NERC levels.
• Updated methane leakage emissions for natural gas pathways.
• Updated vented, fugitive, and flaring greenhouse gas emissions from crude oil production.
• Updated fugitive CH4 emissions from open channel transportation of vinasse for Brazilian sugarcane ethanol pathway.
• Updated U.S. electricity generation mix based on Energy Information Administration (EIA)’s Annual Energy Outlook (AEO) 2016.
• Updated U.S. crude oil mix and weighted average distance using EIA’s company level imports data and AEO and Canadian Association of Petroleum Producers’ market report.
• Updated farming energy and fertilizer intensity of corn, soybean, willow, poplar, miscanthus, and switchgrass.
• Added LiNCA battery for battery electric vehicles into GREET2, including the NCA cathode production, Aluminum hydroxide and alumina sulfate production.

GREET can be downloaded in Excel format and you can substitute any of its default values for your own. So I put your values into the model, for comparison. Here are the results:

http://www.thorium-now.org/images/greet_ic-vs-ev.jpg

As you can see, the model shows an EV creating 2 grams/mi fewer GHG emissions than E10 gasoline. Not that impressive. But for the electricity generation mix I had entered for this scenario, nearly half came from coal (in California in 2017, less than 8% comes from coal).

Highly recommended, if you use Excel, to download and run it yourself (it gets addictive).

Willem Post's picture
Willem Post on May 11, 2017 5:57 pm GMT

Sean,
Engines designers use LHV, not HHV, to determine performance.
Just look it up.

Willem Post's picture
Willem Post on May 11, 2017 6:00 pm GMT

Bob,

I used US emissions of CO2 and US generation for 2013. See Table 10 and URL
https://www.eia.gov/todayinenergy/detail.php?id=18511

It is essential to deal with the electricity arriving at the meter (after all losses), and use either primary energy into the power plant, or source energy from well and mine.
http://www.windtaskforce.org/profiles/blogs/source-energy-and-primary-en...

I do not trust Excel programs of which I have not seen the equations and assumptions.

I started using Excel in the 70s. I always want to know equations and assumptions.

I suggest you go through the tables and find an obvious error.

In the meantime, the most complete, expanded, and up-to-date revision of the above “gasoline vehicle versus EV” article is on this website.

http://www.windtaskforce.org/profiles/blogs/comparison-of-energy-efficie...

Bob Meinetz's picture
Bob Meinetz on May 11, 2017 7:11 pm GMT

Willem,

I’m suspicious of any model with hidden calculations, as are the scientists at Argonne. That’s why all of the calculations in both the Excel version of GREET and online are in full view.

I don’t know there are errors in your calculations, I suspect they’re 100% accurate. That your model represents “electricity arriving at the meter (after all losses)” is inaccurate – you’re considering a fraction of the criteria necessary to make such a calculation.

I’ve met the team which developed GREET – they are single-minded about the job before them. When I asked a team leader why nuclear plants are being closed, his reply was “we don’t consider politics or policy matters.” That’s socialism at work, and why you’ll never get an honest answer about energy from the private sector.

And why I won’t be surprised if the GREET model disappears during the Trump administration’s tenure or assumptions disappear from view, replaced by “alternative assumptions” based on “alternative facts”.

Willem Post's picture
Willem Post on May 11, 2017 8:48 pm GMT

The US grid intensity, lb CO2/kWh in the table is based on US primary energy and electricity arriving at the meter, as published on EIA websites.

If I am considering a fraction of the criteria, please name one that would significantly affect my calculations.

If there were only 2 grams/mile difference, that would hardly be a reason to ditch E10 vehicles.

Greet calculates 475g/mile x 65 miles is 68 lb.

I calculated 82.4 lb, using 0.32 kWh/mile, and my CO2/kWh (based on EIA data), on a source energy basis, using a 1.08 source factor.

The mileage of future E10s could be upped from 28 to 34 to 40 mpg, which is not possible with Lithium-ion, because, per Musk, that chemistry is about maxed out.

Here are the corresponding numbers for Germany:

In 2016, domestic electricity consumption = gross generation (648.4), less self-use (30), less net exports (53.7), less transmission and distribution (30), less pumped storage and misc. (19.4), = about 515.3 TWh at user meters.

(CO2 of the gross generation) / (515.3 TWh) = grid CO2 intensity “at the meter”, which should be multiplied by the kWh drawn by the EV, as I have done in my article.

However, this is primary energy grid intensity. It has to be adjusted by a factor to get source energy grid intensity, as I have done in my article.

Does the GREET program do a similar accounting?

http://www.ag-energiebilanzen.de

Hops Gegangen's picture
Hops Gegangen on May 11, 2017 9:57 pm GMT

Seems like this is missing that EVs are the killer app for renewables — they will soak up the excess power during peak wind or sunshine and use it for transportation, and the used batteries will serve as backup supplies in homes, businesses, and utilities.

Bob Meinetz's picture
Bob Meinetz on May 11, 2017 11:04 pm GMT

Willem, right off the bat –

• You have no accounting for regenerative braking, which saves 20% of energy consumption in an EV in urban driving.

http://large.stanford.edu/courses/2016/ph240/brown1/

• You choose the least efficient mode of driving as representative for both gasoline and EVs – 65 mph for one hour. Lithium-Ion batteries are up to 8% less efficient under high load.

https://www.researchgate.net/figure/231169804_fig12_Figure-16-Peukert-co...

• 2 g/mi less than internal combustion when half of an EV’s electricity is generated by coal. ~30% less when generated with an average California mix.

• What’s the source of your figure 4065.97 TWh for electricity generation, or any of the other figures in “The Source-to-Wheel Efficiency of an Electric Vehicle “?

• What’s the source of your estimate that “future E10s” will be capable of a 30% improvement in efficiency?

You’re trying hard to pick the worst assumptions for EVs/best for E10, rather than ones representative of average vehicles and driving situations.

Engineer- Poet's picture
Engineer- Poet on May 12, 2017 12:43 am GMT

You’re way, way overestimating what EVs can do any time soon.

Take Tesla’s Gigafactory, with a capacity of 50 GWh of battery packs per year.  Average grid load in the USA is about 450 GW.  One Gigafactory-year’s worth of battery packs could support the average US grid load for…

about 6 minutes 40 seconds.  After 9 years of production, you could buffer a whole HOUR! /sarc

It would be a bit more for the unreliables alone.  WInd plus solar came to 263,239 GWh in 2016.  Dividing by 8784 hours, that’s 29.97 GW average.  That would give you a whole 100 minutes, average.

EVs are just not going to be a large-scale energy buffer for the grid for a long time.  They can buffer power on a scale of minutes, but that’s a very different thing.

Willem Post's picture
Willem Post on May 12, 2017 2:08 am GMT

EP,

The battery systems currently used mostly are for regulation, when many solar systems on a grid would cause too much disturbance, and for peak shaving, which works only if on and off peak rates are wide apart, and for reducing the capacity and grid charges imposed by a grid operator on a utility.

Several utilities in New England started up battery systems of about 4 MW/8 MWh capacity @ $800/kWh-$1600/kWh, for those uses, instead of using a quick-starting diesel generator, which they have been doing for decades, as part of the “microgrid/islanding” rah-rah.

http://www.windtaskforce.org/profiles/blogs/batteries-for-solar-energy-s...

Roger Arnold's picture
Roger Arnold on May 12, 2017 8:01 am GMT

Nice article. Always a pleasure to see honest and informed numeracy brought to bear on policy issues. Even it there’s room to challenge some of the numbers presented or omitted, at least the numbers are there and the assumptions are spelled out. The quality of the debate is enhanced.

I won’t weigh in about the differences between the GREET model that Bob recommends and the model that Willem put together. But Willem notes that he does not trust “Excel programs of which I have not seen the equations and assumptions,” Fair enough, but why not download the spreadsheet and take a look? The equations should be there, and one can generally figure out the assumptions. Spreadsheets aren’t rocket science.

What I’m more interested in is the issue of applying the current mix of generation resources to calculate emissions for electric vehicles. As it happens, most of the individuals I know of who drive electric cars have solar panels on their roofs, and do most of their vehicle charging at home. Granted, I live in Tesla country, and Tesla owners are a preselected lot. But Hops’ observation about vehicle charging being the “killer app” for renewables still stands. And a rigorous analysis of the effective carbon emissions of electric vehicles needs to consider not the current raw mix of generation sources, but rather the marginal effect of EV sales on the generation mix. That’s assuming that anyone can figure a way to calculate the marginal effect.

I also wonder about Willem’s assertion that “future E10 vehicles likely will become more efficient more quickly, than the US electrical system will reduce its CO2 intensity, lb CO2/kWh.” Could be, but it’s not obvious to me. In fact, I rather expect the opposite. I think we’re approaching an inflection point, where the rate of decarbonization of the electricity supply will accelerate noticeably.

Be that as it may, I think it’s important to keep in mind that what we need to do is not to reduce carbon emissions by some target amount ‘X’, after which we’ll be fine. If ‘X’ is any value less than 100%, then we won’t be fine; we (or our children) will just take a bit longer to hang. So, yes, electric vehicles do have indirect carbon emissions, but as the electricity supply shifts to lower carbon intensity, the carbon intensity of the electric vehicle fleet shifts with it. The same cannot be said for the E10 vehicle fleet.

Hops Gegangen's picture
Hops Gegangen on May 12, 2017 8:29 am GMT

By then of 2017, Tesla will announce the locations of 4 more gigafactories.This just starting, and will not be static or even linear.

Willem Post's picture
Willem Post on May 12, 2017 9:59 am GMT

Roger,

I did download the GREET spreadsheet, and could not find the assumptions and equations. I did watch some tutorials, which showed the steps of well to wheel, etc., for various pathways.

Go to my above comment to Bob Meinetz. You see I added the corresponding numbers for Germany. See Table 8.

I obtained my numbers by correlating the 2013 EIA energy flow diagram data with the 2013 data of various EIA websites on a combined spreadsheet.

I have seen no evidence of GREET doing the same.

Folks at Argonne are not gods. They are like you and I. They went to similar engineering schools.

Lithium-ion chemistry is maxed out, per Musk. Only EV cost reductions can be expected.

This is far from the case with E10 vehicle fleets, which can go from 28, 34, 40 GPM in the future, especially with more hybrids, as Toyota has shown for more than 15 years.

Germany has had the same CO2 since 2009, i.e., no inflection point.

Any worldwide downward trend will take decades, whereas going to hybrids to get 40 MPG is a snap, by comparison.

http://euanmearns.com/blowout-week-176/

Darius Bentvels's picture
Darius Bentvels on May 12, 2017 10:24 am GMT

Willem,
You forget to calculate the far more important benefit of electric cars:
The much lower emissions of small particles*) as that kills people.
_______
*) Particulate matter (PM) causes a life shortening of ~2 years for people living in city centers with busy traffic, or living along busy highways (EU study)!
So nowadays older cars and diesel cars are no longer allowed in many cities in Germany and also in some cities of NL, etc.

Willem Post's picture
Willem Post on May 12, 2017 12:27 pm GMT

B,

The particles are emitted by central power plants in Germany, etc., and by E10 vehicles in built-up areas.

E10 vehicle fleets, can go from 28, 34, 40 GPM in the future, especially with more hybrids, as Toyota has shown for more than 15 years, which would greatly reduce small particulates.

Europe, and especially the Netherlands, is just too crowded for human sanity to remain healthy and survive.

Willem Post's picture
Willem Post on May 12, 2017 1:51 pm GMT

Denis,

You are right, which means I have to change some numbers in the article. Yikes!

The EV draws 20.8 kWh from the grid to go 65 miles.

But it took the equivalent of 20.8/0.339 = 62.3 kWh of source energy to have 20.8 kWh at the meter. That source energy created the CO2.

EV CO2/mile = 20.8 kWh x 1.323 lb CO2/kWh x 454 g/lb x 1/65 miles = 192 g/mile.

E10 CO2/mile = 2.321 gal/65 miles x 18.95 lb/gal x 1.2639, upstream factor = 388 g/mile

Per Bob’s inputs, GREET calculates for the EV 475 g/mile (GHG CO2 equivalent), for the E10 vehicle 477 g/mile.

I do not know how GREET obtained those high g/mile values.

Mark Heslep's picture
Mark Heslep on May 12, 2017 5:09 pm GMT

Tesla will announce the locations of 4 more gigafactories.

Thus extending EPs calculation to 30 minutes from six. Hundreds of giga factories are required to make a grid sized storage play, and then some new facility distribute, and collect, millions of tons of battery. Don’t forget the associated expansion of lithium ore. The price is rising.

Also, if Tesla does build four more, they lock in current battery performance within 5% or so for the following decade, maybe two. The latest, greatest laboratory battery by press release simply won’t matter.

Mark Heslep's picture
Mark Heslep on May 12, 2017 5:15 pm GMT

Tell it to German coal and Volkswagon diesel. Don’t bother with the cut n paste on how coal will retire in 2022, 3032, or whatever.

Willem Post's picture
Willem Post on May 12, 2017 6:55 pm GMT

Denis,

Thank you for spotting that.

I agree, have revised my numbers and text, and Aaron will soon post the revision.

In the meantime, the most complete, expanded, and up-to-date revision of the above “gasoline vehicle versus EV” article is on this website.

http://www.windtaskforce.org/profiles/blogs/comparison-of-energy-efficie...

Willem Post's picture
Willem Post on May 12, 2017 7:07 pm GMT

Bob,

Thank you,

I agree with the points you are making.

The E10 vehicle fleet average would have to become about 40 mpg, before it would be more efficient than an equivalent EV fleet.

I took the national energy mix 2013 rather than any regional mix.

Energy travels as electro-magnetic waves at near the speed of light on bare wires, i.e., about 180 miles in 0.001 second. Once fed into the grid, it is all over the place.

The 4065.97 TWh is generated electricity, from EIA 2013 data. Plant self use is substracted before feeding into the grid, then T&D is subtracted to get what arrives at user meters.

Also see my above comment to Denis.

Roger Arnold's picture
Roger Arnold on May 12, 2017 8:50 pm GMT

I agree that going to hybrids ASAP will have the most immediate impact on reducing emissions. I’m on record predicting that in the near future (5 – 10 year timespan) virtually ALL new production vehicles will be either pure BEVs or hybrids. They will have electric drive systems, because once the supply chains and production lines are established for it, electric drive delivers better performance and reliability at potentially lower cost than mechanical drive.

In this case, “performance” includes not just torque and acceleration, but precise control of torque to individual wheels for features like traction and skid control and enhanced cornering. Those features have all been implemented for high-end mechanical drives, but there they cost more and are clumsier. With electric drives, they’re just controller firmware. Those benefits are over and above regenerative braking and non-idling that give hybrids superior mileage.

Given the above, the issue becomes how big to make the hybrid drive batteries and whether to include plug-in capability. For me, it’s a no-brainer in favor of plug-in capability. Statistically, it only takes 10 – 15 kWh of battery to enable more than 50% of miles driven in battery-electric mode. 10 – 15 kWh isn’t exactly trivial, but it’s a hell of a lot less than the 100 kWh that pure BEVs are trending toward. With 10 – 15 kWh of storage, the per-mile driving cost plunges and the effective long term mileage gets into 100 mpg range.

Also, with that much electric capacity, emission reductions for transportation would benefit from de-carbonization of the grid.

Darius Bentvels's picture
Darius Bentvels on May 12, 2017 11:32 pm GMT

Particulate matter (PM) emissions by power plants are very insignificant compared to that of traffic. Nowadays power plants here are obliged to filter all PM out of their exhaust gasses. They use a.o. cycloned, electrostatic filters, etc.

Dutch life expectancy is almost two years higher than that of USA…
Furthermore USA spends substantial bigger part of its GDP for health care than Netherlands (in 2010: USA, 16.2%; NL, 10.8%).
So relevant facts indicate the opposite of your assumption:
“NL being too crowded to remain healthy.”

Though it’s also clear that US citizens get less value for their health care money (also corrected for GDP/PP). Probably because US health care is reigned by huge oligarchical private enterprises which make good profits.

Engineer- Poet's picture
Engineer- Poet on May 13, 2017 4:51 am GMT

Can confirm.  Data point:  my car maxes out at mid-high 20 miles all-electric range in optimal weather, but I’m achieving well over 100 MPG average.  (The car reports 131.3 MPG lifetime as of getting home this evening.)  It does this with less than 8 kWh of battery.

Down at the actual hybrid end, we have a lot more options than just batteries.  Ultracaps are great for high power/mass and help relieve compromises that engines have to make to “driveability” by sacrificing efficiency.  If you’ve got a fat energy buffer that gives instant response, your engine can lag like crazy and the driver doesn’t care.  If the designer can go all-in for efficiency and emissions they can both be quite a bit better.

Willem Post's picture
Willem Post on May 13, 2017 12:02 pm GMT

EP,
How many kWh from the meter for 25 miles of travel?

That kWh required about 3 times as much energy as source energy to arrive at the meter, as shown by the article.

Real world efficiency = output/input energy

One of the reasons I wrote the article is to debunk these irrational 100 mpg and up numbers, which in reality are about 33 mpg.

Debunking The Phony EPA Mileage numbers: An E10 vehicle, 28 mpg, uses 2.321 gal x 118.28 MJ/gal = 274.58 million joules to go 65 miles. An EV uses 24.371 kWh/0.2778 kWh/MJ = 87.73 MJ to go 65 miles.

The EPA states, with a straight face, the EV uses the energy equivalent of 87.73/118.28 = 0.742 gallons of E10 to go 65 miles. Thus the “phony EPA mileage” is 65/0.742 = 87.65 mpg. The car manufacturers are in on the deal, because they are allowed take those high mpg numbers and average them into their CAFE mpg, making it look higher than it really is to befuddle the public, which is somewhat of a sham.

The EPA deliberately ignores the upstream factor of 2.995 of the US electrical system. If that factor were applied, the real-world mileage would be 87.65/2.995 = 29.3 mpg. My calculation puts real numbers on a reality.

The official explanation of the EPA is that people are familiar with mpg, and EPA decided to call it “mpg equivalent”. Engineers may not be befuddled, but Joe Blow likely is. Just ask some average people what it means. They have no idea. That means what EPA came up with was confusing.

It is intuitively obvious an E10 vehicle and an equal weight EV, going 65 miles for 1 hour, would have about the same wind and rolling resistance, and therefore about the same energy to go from a to b, and therefore the same mpg. To say one has about 3 times the mileage, equivalent or not, is a deception.

http://www.windtaskforce.org/profiles/blogs/comparison-of-energy-efficie...

Roger Arnold's picture
Roger Arnold on May 13, 2017 5:39 pm GMT

Is that truly how the EPA calculates mileage for plug-in hybrids?

I know that the mileage that is displayed on the car console (for the Prius, anyway) is a straightforward “miles driven / gallons consumed” since reset. For a plug-in, that number would obviously vary a lot depending on driving pattern. (It would go down substantially, e.g., if the car were driven on long trips, with little opportunity for charging, and would go up if it were driven on a lot of short trips with recharging in between most trips.)

My assumption — and that’s all it is — has been that the EPA rating was calculated on the basis of a standardized driving cycle that accounted for length of trips and opportunities for recharging. That’s what would make sense, and it’s consistent with the standardized driving cycles used to calculate figures for “city driving” and “highway driving” for non plug-in vehicles. But I’ve never looked into it.

I’ll raise a separate flag about trying to compare technologies on the basis of “primary energy” consumed. A megajoule is precisely defined in physics, but “primary energy” is a fuzzy concept. What’s the “primary energy” consumption for hot water from a solar thermal collector? And does it really make sense to equate a unit of thermal energy from coal with a one from natural gas or one from cow dung?

What really matters in terms of transportation efficiency and global warming is GHG emissions per distance travelled. The significant fact about E10 is that for a given vehicle make and model, that number will be relatively constant over the life of the vehicle — and will never be zero. For a BEV or plug-in hybrid, the number will depend on the carbon intensity of the charging source. It will decline as the carbon intensity of the grid in its region declines, or go to zero if the vehicle is charged exclusively from solar panels.

The latter isn’t improbable — at least in California — since in addition to rooftop solar on vehicle owners homes, there’s a trend for businesses to install solar panels in their parking lots. Free vehicle charging for employees during work hours is a nice perk that appeals to workers of the type that many companies here want to attract. (Not to mention being good for corporate image in California’s culture.)

Engineer- Poet's picture
Engineer- Poet on May 13, 2017 5:40 pm GMT

How many kWh from the meter for 25 miles of travel?

I put it on the Kill-A-Watt once and it took about 7.5 kWh from the wall.  (Okay, the post in the garage.)  IOW it’s about 300 Wh/mile depending how I drive it.

What this incurs in emissions depends on the generation mix of the moment.  If the marginal watt is coming from the 3400 MW of coal-fired plants in Monroe, it’s one thing.  If it’s coming from the Donald C. Cook nuclear plant or the wind farms in Berrien county, it’s close to zero.  If it’s coming from the Midland Cogeneration Venture it’s intermediate.  If it’s coming from the pumped storage station at Ludington, it’s perhaps a 25% multiplier over whatever was used to fill it (probably wind or nuclear power these days, so also close to zero).

If we figure the emissions of a CCGT plant running in load-following mode at 400 gCO2/kWh, that plant is generating the marginal watt, and 300 Wh/mile, net emissions for the vehicle come to 120 gCO2/mile or about 75 gCO2/km.  If we allow 30% non-emitting generation and credit the vehicle with that, it falls to 84 gCO2/mile.  Pegging the emissions of E10 at 17.68 lbs (8.018 kg) per gallon, this is equivalent to an E10 vehicle achieving 66.8/95.5 MPG respectively.

Bob Meinetz's picture
Bob Meinetz on May 13, 2017 6:28 pm GMT

Thanks Willem. Here’s one I will hand to you: the inefficiency of EVs in cold weather.

I think we’d both conclude that EVs can produce significant benefits in the right circumstances, and that gasoline/E10 vehicles are less dependent on circumstance.

A study came out a few years ago by a national environmental org (forget which one) which showed EVs were significantly worse for emissions in select parts of the country (basically, the Southeast – coal country). There was a flurry of denial in the EV community, but try as I might I could not fault the conclusions they drew therein.

I would like to think in the bigger picture – where government has more say in the collective emissions we generate, as it should – generating our energy collectively from point sources like power plants enables us to improve everyone’s emissions en masse, and not rely on individual incentive. When it comes to finding solutions to societal problems, I don’t believe we can count on the judgment of individuals to carry the day.

Roger Arnold's picture
Roger Arnold on May 13, 2017 8:48 pm GMT

When it comes to finding solutions to societal problems, I don’t believe we can count on the judgment of individuals to carry the day.

Hoo boy! As it happens, I agree with you on that. But you’re poking at a hornets’ nest. It’s certain to raise the hackles of libertarians and small-government conservatives. As perhaps it should.

I’m not unsympathetic with the libertarians and small-government conservatives. My dad was a consulting engineer; he constantly railed against the idiocy of petty bureaucrats and the way blind code compliance inflated costs for projects in situations where compliance wasn’t functionally necessary. He hated what we now call the “nanny state”. His views rubbed off on me. For much of my life, I identified as libertarian.

I haven’t exactly changed my mind about those views. Now, however, I try to see things from a wider perspective. I look at society and the world in terms of system dynamics and game theory, rejecting ideologies as “what one falls back on in the absence of science and honest attempts to understand the issues”. It’s a pragmatic POV that starts with values and focuses on what will actually work to advance those values.

The tension between the interests of the individual vs. those of the group is incredibly fundamental. It has literally shaped the evolution of life on the planet. When you look deeply, the “prisoner’s dilemma” turns up everywhere. Evolution is just as much about cooperation and enabling win-win strategies as it is about competition and being a more successful predator.

So what works for solving societal problems when the interests of society collide with the short-term interests of individuals? Regulations are necessary. However, in formulating the regulations, one needs to be mindful of how they can be gamed. Engineering’s KISS principle (“keep it simple, stupid”) becomes supremely important. As a policy-maker, resist the temptation to specify solutions. Focus on incentive structures and alignment of incentives. People are very good at grasping incentive structures, and figuring out how to benefit from them.

Roger Arnold's picture
Roger Arnold on May 13, 2017 9:50 pm GMT

Saw an interview recently with a Tesla executive talking about the cost and capacity of batteries from the Gigafactory for Model 3. He said that they would be 30% cheaper (per kWh) with 30% higher energy density. IOW, the same cost per kg, but 30% fewer kg needed to do the same job.

His explanation should be a cautionary note for those counting on continued exponential improvement in the economics of battery storage. It was simple: once you’ve gotten to high production volumes with factory equipment designed and optimized for the production task, then cost of product becomes proportional to mass, regardless of complexity. (More properly, cost of product becomes dominated by the cost of raw source materials. A kilo of platinum is always going to cost far more than a kilo of iron — or of dirt.)

He didn’t say it, but the message I heard was that with the gigafactory, Tesla is now down near the limits imposed by raw materials and battery chemistry. Battery lifetimes will likely improve, and tweaks to the electrolyte and electrode structures will likely yield further gains in energy density. But the gains won’t be dramatic.

Hmmm. Does that shed a new light on Musk’s latest venture? Is his “Boring company” perhaps a covert sally into mining technology? It does kinda fit with his interest in Mars colonies.

Joe Deely's picture
Joe Deely on May 13, 2017 10:08 pm GMT

Battery lifetimes will likely improve.

Good prediction.

Recent article

Interesting and fun story that shows how important measurements are as a first step in almost any improvement.

John Miller's picture
John Miller on May 13, 2017 10:32 pm GMT

Willem, very well written and detailed article as usual. The following are a few issues that could impact and increasingly support your conclusions: 1) my detailed analysis of the GREET model well-to-wheel (WTW) calculations (re. my past TEC article: “Is Ethanol a Cost Effective Solution to Climate Change?” http://www.theenergycollective.com/jemiller_ep/172526/ethanol-cost-effec... ) which clearly showed that the Argonne folks relied on less-than-fully accurate international data bases, and overestimated WTW fossil fuels consumption (and associated carbon equivalent emissions) of petroleum fuels by up to about 9%., 2) what is often overlooked in evaluating EV energy usage and efficiency is the significant impact of ambient (battery) temperatures; which deteriorate quite significantly during cold winter environments (100 degree F). This factor also affects batteries’ capacities and lifespans. And, 3) the negative impacts of higher charging voltages, capacities and cycles (longer term charging frequencies) on battery charging efficiencies and full-available charge capacities. Higher voltage (220V+) definitely reduces charging times, but unfortunately, negatively impacts overall charging efficiencies and wear on batteries’ capacities. Those who perceived that EV batteries can be effectively used as residential/commercial backup battery capacities in order to directionally increase the capacity factors of intermediate solar and wind power, are going to be in for a big surprise as to the efficiency and wear on their EV battery packs; and shortened life’s/charging capacities’ impacts. Under these circumstances, EV owners will be very surprised as to the actual efficiencies and added cost of resultant shorten battery life’s.

Willem Post's picture
Willem Post on May 13, 2017 11:52 pm GMT

Hi John,

Thank you for your important comments. I may add some sentences to my article.

In the US northeast, cold-weather operation of an EV is a bummer.

Rolling resistance uphill, through a couple of inches of snow, at -10 F, with the heat pump trying to keep warm the cabin and the battery?

Denis spotted an error, which meant I had to change some numbers.

In that process, I found another error, which cascaded.

Finally the numbers and the text correlate, and I will ask Aaron to repost on Monday.

I already posted it on another site, where I have full control. Here is the URL.

http://www.windtaskforce.org/profiles/blogs/comparison-of-energy-efficie...

Bob Meinetz's picture
Bob Meinetz on May 14, 2017 4:36 am GMT

Roger, agree the KISS principle can be equally effective at constructing regulations as it is in engineering, if not more so.

That’s why reknowned climatologist James Hansen has been an advocate (some say founder) of the revenue-neutral carbon tax, aka “fee and dividend”. In Hansen’s version, a tax directly proportional to its molar carbon is added to any quantity of fuel extracted in or imported to a jurisdiction. Once a month, after deducting administrative fees, revenues are divided and distributed equally to all citizens. If your consumption is less than average, you make money. If more, your lose (taxes you pay at the pump will be more than your refund check).

KISS – it doesn’t get much simpler than that. And it works – British Columbia’s RNT has reduced gasoline consumption by 17%. Then why doesn’t the U.S. have a revenue-neutral carbon tax?

It would work too well – it would limit the profit potential of selling gasoline. There is your head-to-head collision of the interests of society with the short term interests of individuals, or corporations, or any special interest. If we permit self-interest to rule the day, we might as well give up on climate change – it is, quite literally, hopeless.

Simply-worded regulations are the worst of all for corporations, because they introduce the wild card of human judgment – there’s a judge somewhere who will interpret them, and quite possibly not in the corporation’s best interest. So today teams of lawyers construct reams of law, with carefully-designed loopholes to maximize profit.

In sum, these laws categorically defy public interest. My favorite example is the Energy Act of 2005, which repealed the Public Utility Holding Company Act of 1935 (PUHCA). EnACT2005 is a monstrous, 551-page behemoth which very specifically eliminated public protections inherent in the 59-page PUHCA. To restore some sanity to this situation, a start would be assigning word and amendment limits to any law before Congress.

And of course, Citizens United has got to go. Representative democracy in the U.S. has always been a tenuous balance of capitalism (self interest) and socialism (public interest). Citizen’s United has upset that balance by rendering public interest moot – it’s become a battle between exclusively private interests, one in which laws are shaped by campaign contributions instead of popular vote.

Interestingly, the 1802 standoff between Hamiltonian Federalists and Jeffersonian Republicans was identical, in both ideology and acrimony, to today’s Democrat – Republican split. We can hope for a stalemate, but never the twain shall agree.

Willem Post's picture
Willem Post on May 14, 2017 9:02 am GMT

Hi Roger,

“And does it really make sense to equate a unit of thermal energy from coal with a one from natural gas or one from cow dung?”

It sure does, because some sources require a lot of energy (and CO2 emissions) to convert the source energy to primary energy and other sources very little.

Some pathways have more embodied energy than others.
Some energy systems have longer lives than others.

A lifecycle analysis for each pathway would be required.

For example, because of the low price of gas, the CCGT pathway becomes very attractive to the detriment of the solar and wind pathways.

Willem Post's picture
Willem Post on May 14, 2017 9:06 am GMT

Hi EP,

Energy travels as electro-magnetic waves at near the speed of light on bare wires, i.e., about 180 miles in 0.001 second. Once fed into the grid, it is all over the place.

So, in fact, what goes into your meter is generic, no-one knows what goes into your meter.

Willem Post's picture
Willem Post on May 14, 2017 9:21 am GMT

Denis,

“Nothing “phony” about it – it’s very honest and simple, and serves a narrow purpose.”

The official explanation of the EPA is that people are familiar with mpg and EPA decided to call it “mpg equivalent”.

You and I are not befuddled, but Joe Blow is. Just ask some average people what it means. They have no idea. That means what EPA came up with was confusing.

But manufactures can take those high mpg numbers and average them into their CAFE, which is somewhat of a sham.

They and EPA know it, but the general public has no idea what is going on.

My calculation may not be so simple, but it is certainly honest as it put real numbers on a reality.

It is intuitively obvious an E10 vehicle and an equal weight EV, going 65 miles for 1 hour, would have about the same wind and rolling resistance, and therefore about the same energy to go from a to b, and therefore the same mpg.

To say one has about 3 times the mileage, equivalent or not, is a deception.

http://www.windtaskforce.org/profiles/blogs/comparison-of-energy-efficie...

Engineer- Poet's picture
Engineer- Poet on May 14, 2017 1:36 pm GMT

That’s why I specified “marginal watt”, Willem.  That’s the average of whatever sources are ramping up and down as demand varies in whatever locality, and of course it varies by region.

Willem Post's picture
Willem Post on May 14, 2017 1:55 pm GMT

EP,

What is a marginal watt?

How is this marginal watt so special, that it does not need to be treated as having to obey the laws of physics.

Bob Meinetz's picture
Bob Meinetz on May 14, 2017 3:29 pm GMT

Willem, you and EP are comparing two different quantities: energy and power.

Strictly speaking energy on a grid does not “travel” at the speed of light. Changes in power – the rate of transfer of energy – do, and it’s very possible to track them. SCADA networks at independent system operators record power changes at grid junctions every second of every day and, with some accounting, can determine with a fair degree of accuracy the sources of energy on a grid. That’s how generators get paid.

But I’m not an engineer, and I love to be corrected.

Roger Arnold's picture
Roger Arnold on May 14, 2017 4:42 pm GMT

Willem, I’m confused. The reasons you give for why it makes sense to equate units of thermal energy from sources with very different characteristics are exactly the reasons I’d use to argue that they shouldn’t be equated.

Did you perhaps take “make sense to equate” as “make sense to weigh”? I.e., “make sense to consider the differences”?

Willem Post's picture
Willem Post on May 14, 2017 4:57 pm GMT

Bob,

Every generator connected to the grid is monitored by the computers of the grid operator.

The operator knows the kWh fed into the grid to one to 3 decimals. That is how owners of generators get CREDITED.
The owners get PAID by whatever entity the owners have PPAs. The operator CREDIT slip is proof of delivery.

Once fed into the grid, the energy travels at near the speed of light, as electromagnetic waves, 180 miles in 0.001 second, i.e., it is all over the place and cannot be traced.

The electrons vibrate in place at 60 cycles per second, they are not going anywhere. OK, they move at less than one inch per second.

Bob Meinetz's picture
Bob Meinetz on May 14, 2017 5:35 pm GMT

Willem, you’re still confusing energy with power.

If you know the sources of energy fed into a grid, you know what comes out. There’s is no net surplus, otherwise by the first law of thermodynamics lines would melt from their poles. The mix going into everyone’s meter is exactly what is going into the grid at that time – nothing “generic” about it.

Energy is fed into the grid over time, not instantaneously. If one kW is added for one hour, the total energy transferred is one kWh. Transferring energy through a grid instantaneously would require an infinite amount of power:

P * t = E
For the case t = 0:
P * 0 = E
P = E / 0 (undefined)

Roger Arnold's picture
Roger Arnold on May 14, 2017 5:45 pm GMT

A point that I’ve made elsewhere is that a significant amount of EV charging is done from solar energy that doesn’t get to the grid. I don’t know how much; I’ve never seen specific statistics. But on the basis of very rough and unscientific sampling from California EV owners I happen to know, it could easily be half.

Even the indirect carbon emissions from EVs / PHEVs charged from grid will differ depending on when the charging is done. If it’s done while regional load is dropping, it will reduce the drop, and sometimes avoid the need for cycling of a dispatchable unit. Since nearly all dispatchable resources (other than storage) are inefficient during startup and shutdown, avoiding the need to cycle is good. It reduces operating costs and lowers emissions per kWh.

To reap those benefits, however, signaling between the system operator and the charging units is needed. A form of “smart grid”.

Willem Post's picture
Willem Post on May 14, 2017 6:23 pm GMT

All,

This article will be posted in updated form on Monday 15 or on Tuesday 16.

In the mean time, please go to this URL to see a complete update of the article.

http://www.windtaskforce.org/profiles/blogs/comparison-of-energy-efficie...

Willem Post's picture
Willem Post on May 14, 2017 6:28 pm GMT

Roger,
Batteries likely will come down in cost, because of mass production, and weight, due to clever packaging (which would decrease rolling resistance), but the lithium-ion chemistry is pretty well maxed out, according to Musk.

Willem Post's picture
Willem Post on May 14, 2017 6:47 pm GMT

Bob,

The energy fed into the grid is exactly in balance with the energy taken from the grid. Nothing is stored.

Power merely is energy per second. A big generator feeds at a higher rate than a small one.

All feed in exactly the same electromagnetic waves, which are indistinguishable from each other.

One cannot put an oscilloscope on the line and say, ah, there is a hydro electro-magnetic wave, and there is a nuclear one. That means they are generic.

I studied physics at near-PhD level at RPI.

Willem Post's picture
Willem Post on May 14, 2017 6:53 pm GMT

Roger,

1) That would require DC (from the solar panels) to go to a DC charge controller on the EV battery, i.e., bypassing the AC to DC inverter.

2) Typically, the AC from the plug goes to an AC to DC inverter, then to a DC charge controller, then into the battery.

Everyone who has set-up 1) would be charging their EVs with PV solar.
What percentage of households have that?
Do those households charge elsewhere?

If your own PV system, feeds your own batteries, which charge your own EV, then you can say for sure: “my EV runs on my solar energy”

Engineer- Poet's picture
Engineer- Poet on May 14, 2017 6:55 pm GMT

What is a marginal watt?

It’s the next watt of generation that will be added if demand increases.  It’s what determines the incremental change in emissions from adding load.  This works the other way also; the Joe Wheatley analysis of wind power in Ireland showed that the incremental decrease in emissions from adding wind was far less than 1:1.

How is this marginal watt so special, that it does not need to be treated as having to obey the laws of physics.

About those laws of physics…

Transmission lines have impedance.  The higher the impedance, the less power flows through them for a given set of conditions between the ends.  Ceteris paribus, longer lines have higher impedance.  This means that distant generators will contribute less to a load than a local generator.  Physics says that Iowa wind power isn’t going to contribute significantly to New York consumption given an AC grid in between (point-to-point HVDC is another matter).

This means that the emissions from charging an EV depend substantially on where it’s charged.  Also when, because in most places that aren’t using e.g. 100% hydropower the marginal watt comes from different generators at different times of day.

Willem Post's picture
Willem Post on May 14, 2017 7:06 pm GMT

Roger,

Diesel has a source energy factor of about 1.2639.

That means every time you burn a gallon as primary energy, you really are using 1.2639 times its Btus, and creating 1.2639 times its emissions.

The US electricity generating system has a source factor of about 1.08.

The energy fed to power plants is primary energy.

If the source energy is 100%, about 8% of the source energy is used up to create primary energy.

Willem Post's picture
Willem Post on May 14, 2017 8:11 pm GMT

EP,

You are right about impedance. It can be mitigated by higher voltages for HVAC, and reduced to near zero by HVDC systems.

“Physics says that Iowa wind power isn’t going to contribute significantly to New York consumption given an AC grid in between (point-to-point HVDC is another matter).”

Iowa’s up and down wind power goes, on dedicated lines, to nearly Illinois, which balances it with its many generators.

Now Illinois can send excess power to Cleveland, if necessary.

And then Cleveland can send excess power to New York and New England, if necessary.

It already does so every day, by firing up its generators early in the morning, before the US northeast wakes up.

But once energy is fed into the grid, it spreads all over, depending on the grid capacity to spread it quickly (to avoid congestion), so it can be consumed quickly.

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