{"id":105901,"date":"2020-10-04T09:30:52","date_gmt":"2020-10-04T13:30:52","guid":{"rendered":"https:\/\/valorguardians.com\/blog\/?p=105901"},"modified":"2020-10-04T10:53:12","modified_gmt":"2020-10-04T14:53:12","slug":"so-how-much-evil-carbon-dioxide-do-electric-vehicles-cause","status":"publish","type":"post","link":"https:\/\/www.azuse.cloud\/?p=105901","title":{"rendered":"So, How Much “Evil” Carbon Dioxide Do Electric Vehicles Cause?"},"content":{"rendered":"

In a previous article<\/i><\/a>, I discussed how much fuel is actually \u201cburned\u201d (in terms of gasoline MPG) to support driving a popular and representative electric vehicle, the Chevy Bolt. Bottom line: that \u201c100+ MPG equivalent\u201d claim made by both the manufacturer and the EPA is pure . . . garbage. (smile)<\/p>\n

But another thought occurs: just how much of that \u201cevil pollutant\u201d carbon dioxide is produced to support charging such a vehicle? After all, the \u201cmankind is killing the planet through AGW\u201d crowd gets their collective panties\/manties in a wad over the production of that horrible, nasty gas. <\/p>\n

Sidebar<\/u>: I guess the \u201cmankind is killing the planet through AGW\u201d crowd must hate plants, too. Because plants produce carbon dioxide 24\/7 via respiration in order to stay alive – including when there’s no sun and they therefore can’t use photosynthesis. (smile)<\/i><\/p><\/blockquote>\n

Contrary to what the electric vehicle crowd might claim, the answer isn\u2019t \u201cnone\u201d. The electrical energy wasn\u2019t put in the battery pack by faeries or unicorns; it had to be generated, transmitted, converted, and stored there. Those processes incurs losses. And even if your electrical power normally comes from \u201cenvironmentally friendly\u201d sources, well, sometimes it doesn\u2019t. As California is finding out the hard way, depending on power sources that on average only produce 15% of design capacity on a daily basis \u2013 and which can be shut down entirely by extended adverse weather conditions \u2013 isn\u2019t a particularly good idea. It\u2019s a good thing that electricity can be transmitted over distance, albeit at a price.<\/p>\n

So, let\u2019s \u201crun the numbers\u201d. As before there\u2019s some math involved. But it\u2019s simple math, and this time there\u2019s not much of it.<\/p>\n

Introduction<\/b><\/p>\n

So, just how much carbon dioxide is generated to charge a Chevy Bolt enough to allow the owner to drive one mile? (See author\u2019s note below for the reason the Chevy Bolt was selected.) I\u2019m only going to consider two cases: coal-fired power plants and combined-cycle power plants. <\/p>\n

I\u2019m ignoring nuclear because although it generates zero carbon dioxide it only represents about 18-20% of US electrical power production and is used exclusively for base load power anyway. If an EV is charged any time other than between about midnight and 6 AM, it\u2019s getting some or all of it\u2019s charging power from other (peak-load) sources. <\/p>\n

I\u2019m ignoring oil-fired plants because, frankly, these are few and far between today. They\u2019re thus a negligible contribution to the current US power grid, and the numbers are only slightly better than coal-fired anyway.<\/p>\n

Similarly, I\u2019m ignoring hydro as it\u2019s only a minor contributor. Plus, it\u2019s so heavily regulated today (min\/max flow restrictions) it\u2019s getting more and more difficult to use anyway.<\/p>\n

Finally, I\u2019m ignoring \u201crenewable sources\u201d because I live in the real world vice Neverland. Fifteen percent average availability (with respect to installed capacity) and occasional mass outages due to weather just ain\u2019t gonna cut it.<\/p>\n

Bolt Calculations<\/b><\/p>\n

From my previous article linked above, on reasonably level roads at a speed of 70 MPH (e.g., normal freeway driving) the Chevy Bolt uses 0.293 kWh of electrical energy stored in its battery pack<\/i> to drive one mile. But as I explained previously, that\u2019s not the total answer. <\/p>\n

For starters: the Bolt\u2019s battery charging circuity dissipates a chunk. Assuming 92% efficiency here (probably a touch high), that means you need (0.293 kWh \/ 0.92 ) = 0.3185 kWh at the wall socket to put a one-mile highway speed charge into the Chevy Bolt\u2019s battery.<\/p>\n

Approximately 5% of US electricity is dissipated via transmission losses. Thus, on average at the generating plant ( 0.3185 kWh \/ 0.95 ) = 0.3353 kWh must be supplied to produce that one-mile drive charge.<\/p>\n

However: we still haven’t generated the power in the first place. When using any thermal source (e.g., fossil fuel, nuclear, or solar thermal), that step is always the \u201cbiggie\u201d, efficiency-wise. For fossil fuels, we have two realistic possibilities: combined-cycle natural gas and coal.<\/p>\n

Case 1: Combined-cycle natural gas<\/u><\/p>\n

Here, we have the best case for fossil fuels. Per this source<\/i><\/a>, when burned natural gas (methane) produces 0.18 kg of carbon dioxide per kWh of thermal<\/u> energy produced. Further, combined-cycle plants fueled by natural gas are very efficient (I used 58%, or just above the midpoint of the typically-quoted 55-60% range for the efficiency of combined-cycle plants, in the previous article). So if a Bolt owner gets their electricity from such a plant, that means the generating plant needs to burn enough methane to produce roughly ( 0.3353 kWh \/ 0.58 ) = 0.578 kWh of thermal energy<\/i> in order to generate the electricity needed to charge said vehicle enough to drive one mile at 70 MPH. Since each kWh of thermal energy from burning methane produces 0.18 kg of carbon dioxide, under these conditions the Bolt owner is responsible – indirectly – for producing 0.104 kg of carbon dioxide per mile of highway driving. That\u2019s very good.<\/p>\n

Case 2: Coal-fired generation<\/u><\/p>\n

The situation is very different if the Bolt owner lives in an area where his\/her electricity is primarily generated from coal-fired plants, or if they charge during peak hours in an area where single-stage gas turbines are used to satisfy peak load. Here, generating plant efficiency is far lower \u2013 roughly 37%. So in either case, the generating plant needs to burn enough fuel to produce roughly ( 0.3353 kWh \/ 0.37 ) = 0.9062 kWh of thermal energy to charge his\/her Bolt enough to drive one mile at 70 MPH. <\/p>\n

If the Bolt was charged using peak load power generated by a single-stage gas turbine, calculations using data from the same source as used above in Case 1 show that they\u2019re responsible for 0.163 kg of carbon dioxide per mile driven at 70 MPH. That\u2019s fairly good, but not great.<\/p>\n

However, if they charged overnight and their locality\u2019s baseload power is produced by a coal-fired plant fueled by bituminous coal, it’s a different story. When burned, bituminous coal produces 0.28 kg of carbon dioxide per kWh of thermal energy produced. In that case, they\u2019re responsible for 0.2537 kg of carbon dioxide per mile driven at 70 MPH. <\/p>\n

For comparison, let\u2019s look at a gasoline vehicle getting 41 MPG at 70MPH on reasonably level highways. Per the same source as above, one gallon of a 90\/10 mixture of gasoline\/ethanol (E10 gasoline, or “gasohol”) yields approximately 8.851 kg of carbon dioxide when burned. (That number was calculated by adding the carbon dioxide produced by burning 0.9 gal of pure gasoline and 0.1 gal of pure ethanol; both of those fuels are listed in the second source linked above.) So a gasoline powered vehicle – conventional or hybrid – getting 41 MPG at a constant 70 MPG and using normal E10 gasoline produces 0.2159 kg of carbon dioxide per mile driven under those conditions.<\/p>\n

Conclusion<\/b><\/p>\n

Depending on the source of electricity used to charge it, it\u2019s entirely possible that that \u201cenvironmentally friendly\u201d electric vehicle cruising down the highway at 70 MPH is actually responsible for MORE carbon dioxide being created per mile driven than a reasonably fuel-efficient conventional gasoline-powered vehicle driving next to it. Specifically: if the electric vehicle is a Chevy Bolt and the gasoline-powered vehicle gets 41 MPG or more at 70 MPH, the Bolt is responsible for at least 17.5% MORE carbon dioxide than the gasoline-powered vehicle if it was charged by a coal-fired generating plant.<\/p>\n

So, electric vehicle owners: enjoy your vehicles. I hope it serves your needs \u2013 both for transportation and any psychological need for \u201cvirtue-signaling\u201d you might have.<\/p>\n

But don\u2019t wear out your arm patting yourself on the back for \u201csaving the planet\u201d. Because depending on the source of electricity used to charge your electric vehicle, it\u2019s entirely possible that you\u2019re doing more \u201charm\u201d (in terms of producing carbon dioxide) to the planet while cruising down the freeway at 70 MPH than a fuel-efficient gasoline-powered auto cruising right beside you. <\/p>\n

And remember: you probably spent at least $10k more than they did for that privilege.<\/p>\n

—–<\/p>\n

Author\u2019s Note<\/b><\/u>: No, I\u2019m not picking on Bolt owners. I used the Bolt for comparison because that\u2019s the real-world hard data I had.<\/p>\n

If someone can find real-world hard data<\/u> (as opposed to often-specious \u201cmanufacturer\u2019s claims\u201d and blatantly false \u201cEPA fantasies\u201d) regarding another electric vehicle\u2019s documented actual energy consumption per mile under realistic highway driving conditions<\/u>, I\u2019ll run those numbers too. But don’t bother with EPA or manufacturers’ “MPGe” or range numbers; when compared to real-world hard data, those claims turn out to be somewhere between moderately inflated and ridiculous.<\/i><\/p>\n","protected":false},"excerpt":{"rendered":"

In a previous article, I discussed how much fuel is actually \u201cburned\u201d (in terms of gasoline … So, How Much “Evil” Carbon Dioxide Do Electric Vehicles Cause?<\/span>Read more<\/a><\/p>\n","protected":false},"author":623,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[98,503],"tags":[],"class_list":["post-105901","post","type-post","status-publish","format-standard","hentry","category-global-warming","category-science-and-technology"],"_links":{"self":[{"href":"https:\/\/www.azuse.cloud\/index.php?rest_route=\/wp\/v2\/posts\/105901","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.azuse.cloud\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.azuse.cloud\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.azuse.cloud\/index.php?rest_route=\/wp\/v2\/users\/623"}],"replies":[{"embeddable":true,"href":"https:\/\/www.azuse.cloud\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=105901"}],"version-history":[{"count":1,"href":"https:\/\/www.azuse.cloud\/index.php?rest_route=\/wp\/v2\/posts\/105901\/revisions"}],"predecessor-version":[{"id":105902,"href":"https:\/\/www.azuse.cloud\/index.php?rest_route=\/wp\/v2\/posts\/105901\/revisions\/105902"}],"wp:attachment":[{"href":"https:\/\/www.azuse.cloud\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=105901"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.azuse.cloud\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=105901"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.azuse.cloud\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=105901"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}