Electric Vehicles Fight Climate Change

Electric vehicles can be a potent factor in combating climate change. Even though producing electricity for these vehicles creates CO2, electric engines are so much more efficient than internal combustion engines that there is an overall net decrease in greenhouse gasses compared to gas-driven vehicles. Proof is in my calculations posted at alanpeg.wordpress.com

Most of the discussion of greenhouse-gas reduction has focused on electricity generation, which is the largest source (1). However generation by transportation is not far behind (34% vs. 39%). The advent of electric vehicles (EV) provides a major opportunity to reduce carbon dioxide (CO2) emissions using current technology. As shown in the Appendix to this discussion, CO2 emissions would be reduced by about 1.51 billion metric tons of CO2 annually (about 28 percent) if all gasoline-powered vehicles were replaced with electric vehicles. This savings is far in excess of the approximately 400 metric ton decrease needed to meet the goals of the Paris Accords (2).

Such a drastic change would take many years, even if there were no barriers. For example, it is well known that ranges of gas cars are greater and refueling them is more convenient. But these handicaps should diminish with time. The critical question is overall cost.

On average, electric vehicles cost about $2,500 more than similar gas cars (3). But electricity costs are less than gas costs and the initial price difference is made up as miles pile up. However, the $7500 federal tax credit keeps electric vehicle prices artificially low. Only the two Tesla models are cheaper than comparable gas cars without the tax rebate (3). It is difficult to believe that the tax credit will survive if electric vehicles start to make a significant dent in gasoline usage.

Used electric vehicles are inexpensive (4), which means that they depreciate faster than gas cars do. The owner is selling a car with a used battery and the $7,500 tax credit no longer applies when the battery is eventually replaced.

In summary, both high initial cost and rapid depreciation are likely to be serious barriers to growth of electric vehicles.

References

(1)LLNL, Carbon Flow Charts, https://flowcharts.llnl.gov/commodities/carbon. The most recent is 2014.

(2) Michael Liebreich, Bloomberg New Energy Finance Summit, April 25, 2017, https://data.bloomberglp.com/bnef/sites/14/2017/04/2017-04-25-Michael-Liebreich-BNEFSummit-Keynote.pdf

(3) Zach McDonald, How Long Does It Take To Recoup the Extra Cost Of An Electric Car?, EV Industry; Green Fleet, June 16, 2016, https://www.fleetcarma.com/miles-recoup-cost-electric-car/

(4) Jim Gorzelany, Why You Should Consider Buying A Used Electric Car, Forbes, Septembe 18, 2017, https://www.forbes.com/sites/jimgorzelany/2017/09/18/why-you-should-consider-buying-a-used-electric-car/#3e3aa2af4383

 

APPENDIX – CALCULATIONS

Car Mileage

Gas

U.S. fleet average is about 25 mi/gal (A-1), with the average energy provided by one gallon of E10 being about 120,000 BTU (A-2), which equals 126 MJ (A-3). Putting everything together, gasoline-powered cars require about 5 MJ of energy per mile.

Electric

Electric vehicles are rated in kWh/100 mi. The average is about 30 kWh/100 mi (A-3). Since one kWh is 3.6 MJ, electric cars require abut one MJ of energy per mile.

Summary Electric cars require 1/5 of the energy that gasoline cars do.

Overall Changes

U.S. Energy consumption is reported in a very large energy unit – quads or quadrillion BTU (A-5). Total U. S. energy consumption is 97.3 quads. Transport uses 27.9 quads, which are from fossil fuels. Since electric cars are 1/5 as energy intensive as gas cars, a complete switch to electricity would lower this amount to 1/5 the current value, or 5.6 quads, giving a decrease of 22.3 quads or 23 percent in total energy consumption. Electricity generation, now 37.5 quads, would have to rise by 5.6 quads, or about 15 percent.

Total carbon dioxide (CO2) emissions are 5.41 billion metric tons (A6). Switching to electric cars eliminates the 1.83 billion metric tons CO2 produced by gasoline. But the 15% added release in electricity is estimated at 0.3 billion metric tons (A-7), for a net decrease of 1.5 billion metric tons or 28 percent of CO2.

Notes

(A-1) Reuters, U.S. vehicle fuel economy rises to record 24.7 mpg: EPA, January 11, 2018, https://www.reuters.com/article/us-autos-emissions/u-s-vehicle-fuel-economy-rises-to-record-24-7-mpg-epa-idUSKBN1F02BX

(A-2) Data from:Alternative Fuels Data Center – Fuel Properties Comparison, https://www.afdc.energy.gov/fuels/fuel_comparison_chart.pdf

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Greenhouse Gas Decreasing in Ohio – II

Revised – 25 April 2018

My previous blog posting was based on a report that carbon dioxide (CO2) produced by electric plants in Ohio was reduced by 38 percent between 2005 and 2015 (1). To bring the data up to date, I shifted the time frame to 2008-2017 (a) and showed that Ohio’s production and consumption were about the same in 2008. Since then production has fallen faster than consumption and Ohio has become a net importer of electricity. It is not surprising that CO2 production has fallen in view of our heavy dependence on fossil fuels.

The decrease in electricity generation starts with coal. Plant retirement in the past nine years has reduced coal capacity by about thirty percent (2) and the remaining plants are running only about half time (2,3). As sown below, the shortfall has been replaced by natural gas, imports from other states, and a decrease in demand (4).

Since 2008 CO2emissions in Ohio have decreased by about 48 million metric tons, or about 29 percent (b)(5).

This decrease has the following components in million metric tons (mmt):

Coal = -59 mmt

Natural Gas = +11 mmt

The overall 48 mmt CO2 decrease has two parts:

Decreased demand = 8 mmt (c)

Emissions avoided by importing electricity = 40 mmt

The biggest driver in greenhouse gas reduction is less use of coal. Ohio’s situation is improved considerably by importing electricity from out of state, which is approaching 20 percent of demand (4).

Notes:

(a) Dating from passage of electric deregulation in 2008 (127-SB221)

(b) Actual 2015 CO2 data have been extrapolated to provide 2017 estimates.

(c) Regression analysis of data from Ref. (4) shows that Ohioans are reducing usage by about 900 million kWh per year or a total of about 8000 million kWh over the nine year period. Comparison of Refs. (4) and (5) shows that col produces one metric ton of CO2 for each 1000 kWh of electricity generated.

References:

(1) EDF This Midwestern state is the surprising standout on cutting carbon pollution, Jan 4,2018, http://blogs.edf.org/energyexchange/2018/01/04/this-midwestern-state-is-the-surprising-standout-on-cutting-carbon-pollution/

(2) EIA Electric Power Industry Capability by Primary Energy Source, 1990 through 2016, https://www.eia.gov/electricity/state/Ohio/

(3) EIA, Electric Power Monthly, Jan. 2017, https://www.eia.gov/electricity/monthly/

(4) EIA, Electricity Data Browser, https://www.eia.gov/electricity/data/browser

(5) EIA, State Carbon Dioxide Emissions Data https://www.eia.gov/environment/emissions/state/

Greenhouse Gas LTE & Comment

LTE: Cynthia Allen recently stated the people are unwilling to make the kind of sacrifices that are needed to combat climate change (Dispatch, 12 June). Her column shows a limited understanding of greenhouse gas production.

Ms. Allen is wrong when she implies that home heating and cooling are a major source of energy wastage. Actually, homes and businesses together generate a small fraction of greenhouse gasses. The three largest sources are electric power plants, motor vehicles, and industry.   Together they account for over three-quarters of greenhouse gasses.

But there is good news on all fronts. Emissions from power plants have been dropping sharply. Bloomberg recently predicted that electric cars with efficient motors will become cheaper than gas autos within ten years.  And industry has been saving energy. All in all carbon dioxide emissions have fallen 14 percent in the last ten years.

We are living in an era of great technological change. There are many opportunities for people to save money by saving energy. But we need to realize that the big changes will come from outside the home.

Alan R. Rosenfield

Columbus

Comment: Electricity generating is the largest user of energy in the U.S., and the largest source of greenhouse gasses.  The basic problem is that generation is extremely inefficient – almost two-thirds of the energy supplied goes up the smokestack as heat.

There are two ways to improve this situation:

  1. Consumers can use less energy.
  2. Electricity can be produced more efficiently.

In my LTE, I suggested that the second approach should be more effective. Generating electricity produces about two and a half times as much greenhouse gasses as residential and commercial users combined.

The technology for reducing generation-caused greenhouse gasses is available. Natural gas is better than coal, while renewable energy emits no greenhouse gasses at all.

To reiterate, if we are going to reduce greenhouse gasses, electricity generation will play a major role.

Soources:

EPA “Sources of Greenhouse Gas Emissions” http://www.epa.gov/ghgemissions/sources-greenhouse-gas-emissions, accessed 27 June 2017

EIA “Electricity Data Browser”

http://www.eia.gov/electricity/data/browser/#/topic/7?agg=0,1&geo=vvvvvvvvvvvvo&endsec=vg&freq=A&start=2008&end=2014&ctype=linechart&ltype=pin&rtype=s&maptype=0&rse=0&pin=

Accessed 26 June 2017

 

LLNL “Energy Flow Charts” flowcharts.llnl.gov, Accessed 26 June 2017

Sources of CO2

Cynthia Allen recently stated the people are unwilling to make the kind of sacrifices that are needed to combat climate change (1). Her column shows a limited understanding of greenhouse gas production.

Ms. Allen is wrong when she implies that home heating and cooling are a major source of energy wastage. Actually, homes and businesses together generate a small fraction of greenhouse gasses. The three largest sources are electric power plants, motor vehicles, and industry.   Together they account for over three-quarters of greenhouse gasses (2).

But there is good news on all fronts. Emissions from power plants have been dropping sharply (3). Bloomberg recently predicted that electric cars with efficient motors will become cheaper the gas autos within ten years (4).  And industry has been saving energy (5). All in all carbon dioxide emissions have fallen 14 percent in the last ten years (6).

We are living in an era of great technological change. There are many opportunities for people to save money by saving energy. But we need to realize that the big changes will come from outside the home.

References

(1) ‘Few are willing to support climate control at home’, Columbus Dispatch, June 12, 2017

(2) US EPA ‘Sources of Greenhouse Gas Emissions’, http://www.epa.gov/ghgemissions/sources-greenhouse-gas-emissions, accessed 13 June 2017

(3) Georgina Gustin, ‘U.S. Power Plant Emissions Fall to Near 1990 Levels, Decoupling from GDP Growth’, Inside Climate News, 14 June 2017, insideclimatenews.org/news/14062017/us-power-plant-co2-carbon-emissions-fall-1990-ceres

(4) Jess Shankleman ‘Pretty Soon Electric Cars Will Cost Less Than Gasoline’, http://www.bloomberg.com/news/articles/2017-05-26/electric-cars-seen-cheaper-than-gasoline-models-within-a-decade, Bloomberg, 26 May 2017

(5) U.S. energy Information Administration, Electric Data Browser http://tinyurl.com/EIABROWSER

(6) ‘Retiring nuclear plants may undercut climate goals’, Columbus Dispatch, June 14, 2017

Global Warming is Alive and Well (in Columbus)

To illustrate some of the poor reasoning that goes into claims of global cooling (15,000,000 hits on Google) I determined the trend in annual degree days for Columbus from 2000 to 2013 (a).

Heating degree days can be used to estimate how much you need to use your furnace in the winter. Typical values for Columbus are around 5000. The number of heating degree days has been decreasing at a rate of 0.2% per year, indicating a trend towards slightly milder winters.

Cooling degree days can be used to estimate how much you need to use your air conditioner in the summer. Typical values for Columbus are around 1000. The number of cooling degree days has been increasing at a rate of 1.7% per year, indicating a trend towards warmer summers.

Of course, this does not prove that global climate change is real.   It actually illustrates a common fallacy – drawing a conclusion from one measure of change over too small an area over and over too short a time.  The web site < http://www.skepticalscience.com/> covers all of the faulty reasoning that characterizes climate-change skepticism.

(a) The degree day annual totals for zip code 43215 were obtained from http://www.weatherdatadepot.com/ using a reference temperature of 65 F. Degree days are defined in <http://www.thefreedictionary.com/degree-day&gt;