wmcbrine
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The Coal-Powered Car

Thu Jul 02, 2015 9:13 pm

Somewhere on the Internet, the other day -- I didn't keep track of where -- I stumbled onto some people talking about how electric cars shouldn't be encouraged in areas were burning coal was a principal source of electric power, suggesting that in such a situation, CO2 emissions could actually increase. And they were so matter-of-fact about it that I had to wonder -- did they have a point? So, I did a little research and a few calculations.

My i-MiEV's "tank" is 16 kWh, on which I can travel about 64 miles. According to the U.S. Energy Information Administration, burning coal yields a little over 2 pounds of CO2 per kWh -- call it 32 for a "tank", or 0.5 lbs CO2/mile.

With my old Prius, although the EPA rating was 50 mpg, I needed longer trips to achieve that -- with my usual driving pattern, what I got was more like the mid-30's. Call it 32 mpg for simplicity. So, 2 gallons to cover 64 miles. The EIA says that burning a gallon of gasoline yields almost 20 pounds of CO2 -- so, 40 for the 64-mile trip, or 0.625 lbs CO2/mile.

So, the electric car is already ahead (quibbles with my rounding aside)... but it gets better. In practice, most electricity comes from a mix of sources. In my case, the overall mix of sources used by the electric company yield slightly less than a pound of CO2 per kWh -- less than half the pure fossil fuel CO2 yield.

This analysis doesn't take into account the costs of extraction, refinement, etc., but AFAICT, adding in those costs would only make the gasoline side of the comparison look worse.

Phximiev
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Re: The Coal-Powered Car

Thu Jul 02, 2015 9:43 pm

I read, or saw something on the internet that described the electric energy needed for extraction, refining (which in a number of cases is entirely powered by coal fired power plants, delivery to wholesale centers (either by pipeline or by truck), final delivery to the gas station, and finally pumping it into an auto. My recollection is that it was a large amount of energy per gallon. The argument then went to the energy avoided in these steps if one has an EV as you avoid the fuel and use of energy at each step.

The difference, the argument went, was that it was still better to have an EV even if it was recharged with a coal fired plant because of the avoided processing.

Here in Phoenix, the APS site says they get 4k Mw from nuclear, 3.5k mw from coal and about 2k Mw from natural gas, and a small amount from other renewable. So this info combined with the avoidance argument, it would seem to make even more sense to have an EV. So the source is still at least an element of the argument.

Then for those with an EV plus solar panels, perhaps the ideal?
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PV1
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Re: The Coal-Powered Car

Fri Jul 03, 2015 6:27 am

Your math sounds really close to mine.

Tailpipe emissions are 20 lbs./gallon. With the (now dated) electricity mix in my area, emissions per kWh worked out to 1.95 lbs./kWh (mostly coal with some natural gas). I've done the math on straight coal electricity (at 2.2 lbs./kWh) powering an EV (at 3.5 mi./kWh, wall to wheels) vs. just the tailpipe emissions of a 30 MPG gasoline car. For each car to travel 40 miles a day, the EV would produce 25.14 lbs. of CO2, and the gas car would produce 26.67 lbs. of CO2.

You are right that adding in externalities makes ICE vehicles look worse. Assuming the electricity source is the same, everything up to that point remains the same for both sides. Where it differs is the electricity consumption (still not including the oil consumption) for extracting, refining, and distributing gasoline. I've heard numbers all over the board, but the one I found was 12.5 kWh per gallon. With this electricity usage, the overall CO2 emissions of gasoline usage increases from 20 lbs./gallon to 44 lbs./gallon. With the electricity consumption included for gasoline, the comparison favors EVs even more.

Emissions comparison:

EV with 100% coal electricity - 25.14 lbs. over 40 miles
EV with SWPA electricity mix - 22.29 lbs. over 40 miles
EV with solar electricity - ~0 lbs. over 40 miles
ICE - tailpipe emissions only - 26.67 lbs. over 40 miles
ICE - tailpipe with electricity - 58.67 lbs. over 40 miles

(SWPA is South-Western Pennsylvania)

So, while 100% coal-powered EVs are better, it's not by much. Fortunately, only a few number of EVs are solely powered by coal. Most are powered by a mix with at least 5% of non-coal fired electricity (nat. gas, nuclear, hydro, mixed renewables, etc.) Although Tesla doesn't have it on their website anymore, they used to have a map with each state's energy mix. It was either Idaho or Oregon with the cleanest electrical grid, with nearly all power coming from hydro. Kentucky was the worst.
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Phximiev
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Re: The Coal-Powered Car

Fri Jul 03, 2015 9:20 am

Here's an interesting site on coal fired power plant statistics.

http://www.sourcewatch.org/index.php?ti ... oal_Plants

Its seems that in addition to advocating for EVs, we should also advocate to replace these plants with something else (in the near term probably gas).
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Don
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Re: The Coal-Powered Car

Fri Jul 03, 2015 4:09 pm

Since we bought our first iMiEV, our local power plant (Plant Jack Watson in Gulfport MS) has converted from mostly coal to 100% natural gas. The reason this happened is very interesting

Mississippi Power is currently building a brand new 'clean coal' generating plant in Kemper County - Google that and you can read all about it. The plant was originally supposed to cost less than 3 billion, which is still about 50% more than if they had just built it for natural gas in the first place. It's now about 2 years behind schedule and the cost has more than doubled to 6.2 billion. They will strip mine the local area for a low grade coal, convert it to a gas and use the gas to burn to run the turbines . . . . with natural gas as a back-up

The Sierra Club fought this fiasco tooth and nail and eventually settled lawsuits with MS power with the power company agreeing to an early conversion of a couple of their older plants to natural gas - Our power plant (one of the dirtiest on the list of worst offenders) was one of them

Former governor Haley Barbour's lobbying firm has taken tons of lobby money from Mississippi Power's parent company and he got legislation passed whereby MS Power could increase it's rates and charge it's current customers *in advance* to pay much of the cost of building this boondoggle, even if it never produces a single mega-watt of power! The courts have struck this aspect of it down and as it now stands, MS Power has to begin refunding money they had already collected. Lucky for us, we live just outside the area MS Power provides service to and since our Co-Op buys their power on the free market, we didn't get hit with any of the rate increases, despite the fact that most of our power is actually bought from MS Power

Just what the world really needs in 2015 - A new coal fired generating plant! Only in Mississippi!!

Don
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NeilBlanchard
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Re: The Coal-Powered Car

Mon Jul 06, 2015 10:01 am

This seems to be accurate, compared to the study that UCS did a while back.

PV1 wrote:Your math sounds really close to mine.

Tailpipe emissions are 20 lbs./gallon. With the (now dated) electricity mix in my area, emissions per kWh worked out to 1.95 lbs./kWh (mostly coal with some natural gas). I've done the math on straight coal electricity (at 2.2 lbs./kWh) powering an EV (at 3.5 mi./kWh, wall to wheels) vs. just the tailpipe emissions of a 30 MPG gasoline car. For each car to travel 40 miles a day, the EV would produce 25.14 lbs. of CO2, and the gas car would produce 26.67 lbs. of CO2.

You are right that adding in externalities makes ICE vehicles look worse. Assuming the electricity source is the same, everything up to that point remains the same for both sides. Where it differs is the electricity consumption (still not including the oil consumption) for extracting, refining, and distributing gasoline. I've heard numbers all over the board, but the one I found was 12.5 kWh per gallon. With this electricity usage, the overall CO2 emissions of gasoline usage increases from 20 lbs./gallon to 44 lbs./gallon. With the electricity consumption included for gasoline, the comparison favors EVs even more.

Emissions comparison:

EV with 100% coal electricity - 25.14 lbs. over 40 miles
EV with SWPA electricity mix - 22.29 lbs. over 40 miles
EV with solar electricity - ~0 lbs. over 40 miles
ICE - tailpipe emissions only - 26.67 lbs. over 40 miles
ICE - tailpipe with electricity - 58.67 lbs. over 40 miles

(SWPA is South-Western Pennsylvania)

So, while 100% coal-powered EVs are better, it's not by much. Fortunately, only a few number of EVs are solely powered by coal. Most are powered by a mix with at least 5% of non-coal fired electricity (nat. gas, nuclear, hydro, mixed renewables, etc.) Although Tesla doesn't have it on their website anymore, they used to have a map with each state's energy mix. It was either Idaho or Oregon with the cleanest electrical grid, with nearly all power coming from hydro. Kentucky was the worst.


Thank you for posting.
Sincerely, Neil

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Mart
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Re: The Coal-Powered Car

Mon Jul 06, 2015 10:41 am

The UCS report:
http://www.ucsusa.org/sites/default/fil ... report.pdf

PNNL's two part report reached similar conclusions, though it is a bit older, and US coal usage has noticeably declined in the interim.

EPA's Power Profiler based on zip code:
http://oaspub.epa.gov/powpro/ept_pack.charts

DoE's site allows you to compare vehicles GHG pollution levels by choosing the "Energy and Environment" tab and selecting your state, tailpipe and upstream, and zip code drop downs.
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jray3
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Re: The Coal-Powered Car

Mon Jul 06, 2015 10:57 am

Don wrote:Since we bought our first iMiEV, our local power plant (Plant Jack Watson in Gulfport MS) has converted from mostly coal to 100% natural gas. The reason this happened is very interesting
......................
Just what the world really needs in 2015 - A new coal fired generating plant! Only in Mississippi!!

Don


Thanks for the update Don, I was at the original community meetings 20 years ago and then the groundbreaking for the Red Hills Power Project in Ackerman, MS. It seems to be a template for the Kemper County project, despite going through a 'troubled asset' takeover when Southern Co. took over the plant from the original developer. Very interesting to see that when an additional generating unit was built in 2006 (700 MW, far larger than the 440 MW original), they built a natural gas-fired plant right next door to the lignite coal mine! Lignite, or 'brown coal' is barely evolved beyond peat moss, and still has a significant moisture content that must be contended with, not to mention 120+ new acres of cut-n-fill strip mining each year...
The original proposal was to include 245,000 tons per year of wood waste and other biofuels, which apparently never happened, plus greenhouses and aquaculture to make use of the CO2 and waste heat from the power plant and other ventures that would fill the "Red Hills EcoPlex". None of that came to fruition... :roll: Now that the plant is halfway through its 30 year contract and design life, I just hope that the promises to restore the site back to rolling hills with both pine forest and bottomland hardwoods get kept. Nothing should remain afterwards other than the 1200 cubic yards of concrete that went into a deep hole under the smokestacks.
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Don
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Re: The Coal-Powered Car

Wed Jul 08, 2015 6:47 am

jray3 wrote:Now that the plant is halfway through its 30 year contract and design life, I just hope that the promises to restore the site back to rolling hills with both pine forest and bottomland hardwoods get kept. Nothing should remain afterwards other than the 1200 cubic yards of concrete that went into a deep hole under the smokestacks.
The 'promises' are buried under stacks of legalese - They're more like "we'll try" than anything. Nothing is guaranteed
http://exp.grist.org/clean-coal
No matter how you look at it, it's a dirty, corrupt business. As the article above points out, what began as a 1.88 billion dollar project is now 6.17 billion dollars and counting . . . . and it remains to be seen who is going to get stuck with the bill

Don
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