Marginal power

[JRP3]

I suggest looking at Glenn Doty's article previously linked, and the comments, on marginal load. There are good discussions on why EV's are marginal load, serviced by NG and coal.

 

[JRP3]

If I'm reading this correctly, NYS uses almost no coal for marginal power.

That looks to be in state generated power. PA right next door has a large coal power base which they can send to NY.

 

[Doug_G]

FWIW, economists consider all load in an hour to be marginal. There's nothing about order or historic operation. Prices on the grid paid by all load are set by the most costly generator. We don't assign the cheapest generation to "old load" and the more expensive generation to "incremental load." Everyone pays the clearing price. The same logically holds true for carbon. If we priced carbon, all loads in an hour, at a place, would pay the same marginal carbon tax.

Right, so arbitrarily assigning "marginal load" to EVs is total nonsense.

 

[GSP]

......... solar power can be installed independent of EV's.

In some (most?) areas, if your solar panels generate more energy in a given year than you use, the utility will not pay for the surplus you generated. So the EV allows you to install more generation and transition your gasoline bill to solar, in addition to the electric bill. So in real life the EV can drive installation of more solar capacaty than a Prius.

You made a good attempt at a similar line of reasoning in one of your comments in the linked blog. To paraphrase: without a home to power, there is less incentive to install a solar array, since you cannot get paid retail electric rates, as you would get with net metering.

GSP

 

[stopcrazypp]

I suggest looking at Glenn Doty's article previously linked, and the comments, on marginal load. There are good discussions on why EV's are marginal load, serviced by NG and coal.

Johnny Edwards makes the same argument I'm making, which is the fact that Glenn Doty's analysis assumes EVs will always be marginal no matter what (even if EVs are established and the baseload already adjusted to account for it). And his argument is that nothing ever gets assigned to baseload (so we will always only look at marginal generation and ignore baseload generation). While at the same time he compares to "U.S. average life-cycle carbon intensity of a gallon of gasoline," which is a huge logical fallacy (why aren't we looking at the emissions of the "marginal" gasoline, rather than the average?). Critically, we have to assume all refineries use "marginal" electricity, rather than average electricity to be consistent.

 

[Norbert]

which is a huge logical fallacy (why aren't we looking at the emissions of the "marginal" gasoline, rather than the average?)

That would be the one from oil from tar sands.

Game Over for the Climate - NYTimes.com

Canada’s tar sands, deposits of sand saturated with bitumen, contain twice the amount of carbon dioxide emitted by global oil use in our entire history. If we were to fully exploit this new oil source, and continue to burn our conventional oil, gas and coal supplies, concentrations of carbon dioxide in the atmosphere eventually would reach levels higher than in the Pliocene era, more than 2.5 million years ago, when sea level was at least 50 feet higher than it is now.

 

[Norbert]

That looks to be in state generated power. PA right next door has a large coal power base which they can send to NY.

NYS itself has coal, but it is not used for marginal power.

 

[Jason S]

I suggest looking at Glenn Doty's article previously linked, and the comments, on marginal load. There are good discussions on why EV's are marginal load, serviced by NG and coal.

Air conditioners are marginal load because that's a spike of load during already heavy loads. Middle of the night loads just let whatever baseline stuff continue without reducing amounts. EVs flattening the demand curve actually reduce the margins, so therefore you are back at baseline loads.

I've read a good portion of this thread and frankly can't tell why there is even a discussion. What difference does it make anyhow? Reducing carbon loads is the overall goal, isn't it? And until you can make an argument that an EV is using as much or more energy/carbon than an ICE then the origin of the electricity used for refining the fuel versus charging the battery seems to be so much noise.

 

[VolkerP]

Wow this thread got a life of its own. May I establish what seems to be consensus?

1. generated electricity is sold at the price dictated by the most costly power plant involved ("merit order" principle). I know this is established in U.S., Germany, and Spain.
2. electricity is traded beyond borders of federal states (U.S.), or even country borders (Europe), making it harder to attribute CO2 or nuclear waste to every kWh used in a household.
3. extensive studies are done to attribute GHG/CO2 emissions to "marginal power" generated but they focus on generation. See point 2.
4. the U.S. grid will become cleaner in the years to come due to renewables
5. renewables do replace a significant amount of conventional "dirty" generation *) but it is under discussion if they do it in a 1:1 ratio **)
6. electrifying personal transport will add to overall electricity consumption. This will not be offset by reduction of electric power usage in refineries.
7. it is desirable to move pollution from the tailpipe to the power plant, given that scrubbing there is at least a technical possibility (though perhaps not economical)
8. in any case, reducing residential electric consumption is a win for consumers and the environment. Effects on utilities and grid vary.

*) surplus renewable power can be put to good use in hybrid power plants. See enertrac hybrid power plant.
**) In my opinion, rooftop solar can compensate overall electricity consumption by more than 100% because electrical losses in the distribution grid are reduced.

 

[JRP3]

That would be the one from oil from tar sands.

Game Over for the Climate - NYTimes.com

Glenn uses tar sands oil in his calculations.

 

[JRP3]

In some (most?) areas, if your solar panels generate more energy in a given year than you use, the utility will not pay for the surplus you generated. So the EV allows you to install more generation and transition your gasoline bill to solar, in addition to the electric bill. So in real life the EV can drive installation of more solar capacaty than a Prius.

That's an interesting piece of data I was not aware of.

 

[JRP3]

Air conditioners are marginal load because that's a spike of load during already heavy loads. Middle of the night loads just let whatever baseline stuff continue without reducing amounts. EVs flattening the demand curve actually reduce the margins, so therefore you are back at baseline loads.

If coal or NG plants don't throttle down as much at night because of the new load then emissions increase accordingly.

I've read a good portion of this thread and frankly can't tell why there is even a discussion. What difference does it make anyhow? Reducing carbon loads is the overall goal, isn't it? And until you can make an argument that an EV is using as much or more energy/carbon than an ICE then the origin of the electricity used for refining the fuel versus charging the battery seems to be so much noise.

Well the argument being made is that EV's do increase emissions over a Prius type vehicle when calculated on a well to wheels basis.

 

[JRP3]

*) surplus renewable power can be put to good use in hybrid power plants. See enertrac hybrid power plant.

Economics unknown, if it's not cost effective it won't be implemented.

**) In my opinion, rooftop solar can compensate overall electricity consumption by more than 100% because electrical losses in the distribution grid are reduced.

Transmission losses are small, and we still have the question about spinning reserves needed to be kept running to compensate for a drop in solar, or wind.

 

[Dave EV]

Transmission losses are small, and we still have the question about spinning reserves needed to be kept running to compensate for a drop in solar, or wind.

The need for spinning resources is minimal with proper wind/sun forecasting and distributed wind/solar generation. If reserves are still required to be "spinning" because they can't spin up/down fast enough, those plants should be upgraded to a modern CCGT plant with double the efficiency which are capable of very quickly and efficiently ramping up/down generation.

 

[Jason S]

Well the argument being made is that EV's do increase emissions over a Prius type vehicle when calculated on a well to wheels basis.

Please give the calculations for amount of energy used to create 10 gallons of gasoline versus 85Kwh of electricity. Both should give about the same range, we could make it 5 gallons of gas if you would like to compare to a hypermiler.

As you pointed out, if the energy is baseline then we can start with a maybe inaccurate but still workable figure for the base comparison. After that we can shift those numbers based on the idea of a marginal load being somehow different.

 

[Norbert]

Glenn uses tar sands oil in his calculations.

This sentence: "Gasoline refined from the Athabasca tar sands project was scored at a carbon intensity of ~14 kg-CO2/gallon."

suggests (to me) that he is talking about the CO2 in the gasoline *after* refining. If you read the NYTimes article, it is obvious (to me) that he can't be including the CO2 amounts which are described there.

 

[stopcrazypp]

This sentence: "Gasoline refined from the Athabasca tar sands project was scored at a carbon intensity of ~14 kg-CO2/gallon."

suggests (to me) that he is talking about the CO2 in the gasoline *after* refining. If you read the NYTimes article, it is obvious (to me) that he can't be including the CO2 amounts which are described there.

I'm not talking about tar sand oil only. His argument is the only thing that matters is the marginal, which means we have to look at the emissions to make that last gallon of gas. That means in terms of electricity usage in refineries, we have to assume "marginal" electricity (rather than the average that all studies use). This will be on top of the dirtiest source of oil.

 

[Norbert]

Oil Sands CO2 Emissions Could be Higher Than Thought: Scientific American

Previous studies have vastly underestimated the carbon footprint of the Canadian oil sands by not considering the industry's impact on peatlands, according to new research.

Study Finds Tar Sands Has Higher CO2 Emissions Than Thought, Calls Land Restoration Pledge | ThinkProgress

The study, “Oil sands mining and reclamation cause massiveloss of peatland and stored carbon,” finds that this destruction will release stored carbon equivalent to 42 to 173 million metric tons of carbon dioxide, “as much as 7-years worth of mining and upgrading emissions at 2010 production levels.

Claims by industry that they will “return the land we use – including reclaiming tailings ponds – to a sustainable landscape that is equal to or better than how we found it” (33) and that it “will be replanted with the same trees and plants and formed into habitat for the same species” (34) are clearly greenwashing.The postmining landscape will support >65% less peatland. One consequence of this transformation is a dramatic loss of carbon storage and sequestration potential, the cost of which has not been factored into land-use decisions. To fairly evaluate the costs and benefits of oil sands mining in Alberta, impacts on naturalc apital and ecosystem services must be rigorously assessed

 

[JRP3]

Please give the calculations for amount of energy used to create 10 gallons of gasoline versus 85Kwh of electricity.

10 gallons of gas at 33kwh equivalent per gallon is 330kwh. The entire petroleum chain from well to tank is about 80% efficient, so that means 20% is used to produce the final product, so the 10 gallons took 66kwh of energy, (not electricity). Now don't forget that the 85kwh's of electricity in a battery pack started out as a lot more energy than that using a generous 40% generating efficiency, (marginal power is probably lower), plus 93% transmission efficiency, a generous 90% charging efficiency, and not to mention the drilling/mining energy inputs, which I don't have the figures for. You have to apply equal criteria for all inputs when comparing gas to electricity.

 

[JRP3]

Oil Sands CO2 Emissions Could be Higher Than Thought: Scientific American

From that article:

A new finding comes amid a debate about the carbon footprint of the oil sands generally. Emissions released from burning them still would be small compared with those from burning coal and natural gas