Deep Decarbonization: The MIT Study

[engineerpoet]

Mar 23, 2020 8:47:18 GMT 9.5 huon said:

Deep Decarbonization of the U.S Electricity Sector: Is There a Role for Nuclear Power?

A few things there:

1. They only go to 90% decarbonization; France is at least 95% decarbonized compared to a coal-based grid.
2. They ONLY address the grid, not other energy; "space heat" is not present in the document.
3. They don't allow for extra energy for atmospheric remediation.

They made an incomplete analysis and came to a misleading conclusion.

Today's best CCGTs running at their best operating point emit on the order of 330 gCO2/kWh.  At $120/ton CO2, that comes to 3.96¢/kWh.  IIUC, that's quite a bit more than the current cost disadvantage of nuclear power.  Then you have the tax that would fall on emissions from uses like space heat; in a condensing furnace operating at an effective 100% HHV efficiency, the carbon tax would cost an extra 62.7¢ per 100k BTU or 2.1¢/kWh of heat.  I strongly suspect that nuclear CHP would radically undercut the cost of renewables, especially given that no storage would be necessary.

[huon]

Here is the study Engineer-Poet is responding to:

Deep Decarbonization of the U.S. Electricity Sector:
Is There a Role for Nuclear Power?
Karen D. Ahumada, John Reilly, et al.
MIT Joint Program Report Series
September, 2019
globalchange.mit.edu/publication/17323

"...modest advances in lowering the cost of nuclear by about 2.5 cents per kilowatt hour [to 5 cents/kWh] create a substantial role for nuclear, and reduce the needed carbon price by two-thirds [my emphasis]."

[huon]

EP-- Let me start with my bottom line: Including competitively priced nuclear power in our energy mix will lower the cost of full decarbonization. If we agree on that point (as I strongly suspect we do), minor differences on the MIT study won't matter that much.

[engineerpoet]

The list of examples of bias/fraud in the study continues:

1. It assumes that biomass cofiring is a low-carbon technology.  It is not unless it includes CCS, and CCS is only considered for fossil-fired systems.
2. It assumes that nuclear plants have a lifespan of only 40 years (Table 2, p. 5); most US plants have been licensed to 60 years and at least one site is looking at 80 years.
3. It assumes that PHS can be expanded to meet need.  A quick analysis shows that the size of a PHS system required to buffer month-scale deficits in RE for the USA requires water volumes on the order of lake Erie.  This is clearly impossible.
4. The word "hydrogen" does not appear in the document; were it there, the cost in capital and round-trip losses would have to be accounted for.  This is sleight-of-hand.
   
5. The word "battery" does not appear in the document.

This looks like a Jacobsonesque effort to push a predetermined conclusion through cherry-picking of facts, ignoring contrary ones.  If the impossibility of mass-scale storage of unreliable energy flows is acknowledged, the cost of "renewables" rises much more steeply with penetration.  If more than 90% decarbonization is required, it is not clear that the MIT scheme could get there at all.

We do happen to require more than 90% decarbonization.  We need closer to 200% decarbonization (net negative emissions on the order of current emissions) and to sustain this for several decades.  As Bret Kugelmass explains, this pretty much puts us on the only zero-emission technology which can be scaled to such a degree.

[huon]

First of all, EP, thank you again for allowing me to shift this discussion here.

As for the MIT paper, from my perspective you seem to be directing friendly fire at researchers who share our views. You and I actually began this discussion on Nov. 17 and 18, 2019 in the SMR (Small Modular Reactors) thread of this section. Perhaps I will have a few more insights now (and perhaps not).

Let's begin with your point 1 from Mar 22: "They [the MIT authors] only go to 90% [decarbonization]...." Why this inadequate target?

Your answer appears to be that they are biased toward renewables and that their paper is, as you called it on the SMR thread, "propaganda".

My best guess in Nov. was they simply used a common target which grew out of the Paris talks in 2015.

But now I see that their reason really doesn't matter. They take on Jacobson (and the 100% renewables crowd) on turf favorable to Jacobson, and win decisively. If even the 90% scenario without nuclear incurs huge extra costs, what will happen when the 10% fossil backup is taken away?

[engineerpoet]

Mar 26, 2020 11:30:26 GMT 9.5 huon said:

As for the MIT paper, from my perspective you seem to be directing friendly fire at researchers who share our views.

Someone has to examine their assumptions and critique them.  I'm not known for mincing words and I'm too much of a curmudgeon to start now.

My best guess in Nov. was they simply used a common target which grew out of the Paris talks in 2015.

An assumption that really needs close examination.

But now I see that their reason really doesn't matter. They take on Jacobson (and the 100% renewables crowd) on turf favorable to Jacobson, and win decisively. If even the 90% scenario without nuclear incurs huge extra costs, what will happen when the 10% fossil backup is taken away?

What will happen when (not if) we have to race to -100% of baseline emissions to get back under a tipping point?  Milquetoast measures like 10% of baseline by 2050 are pathetically inadequate.

The situation is increasingly desperate, but I don't see anyone analyzing, let alone proposing, measures sufficient to back us out of the growing crisis.  We're looking at 1.5 meters of sea-level rise from the collapse of the Denman glacier alone[1].  When are we going to commit to action commensurate with the threat?

[1] www.sciencedaily.com/releases/2020/03/200323125627.htm

[huon]

EP-- Your various comments on this thread have helped me to clarify my thinking about the study. So I have just one question. According to the summary, "...modest advances in lowering the cost of nuclear by about 2.5 cents per kilowatt hour [to 5 cents per kWh} create a substantial role for nuclear, and reduce the needed carbon price [significantly]." Whatever qualms you may have about the study, do you find this conclusion plausible?

[engineerpoet]

I honestly can't say, because the premises underlying the study are so off-base as to render the whole thing worthless.

[huon]

Rather than "worthless" I would say "incomplete". According to the MIT study: "Our simulations show that the availability of nuclear [at 5 cents/kWh] reduces the needed carbon price in the power sector to meet the 90% reduction target from near $120/ton (2006$) of CO2 to under $40/ton (2006$) by 2050."

E-P correctly points out (Mar 23):

" 1. They only go to 90% decarbonization; France is at least 95% decarbonized compared to a coal-based grid.
2. They ONLY address the grid, not other energy; "space heat" is not present in the document.
3. They don't allow for extra energy for atmospheric remediation.

They made an incomplete analysis and came to a misleading conclusion."


So the carbon price needed for complete decarbonization of the whole economy will likely have to be higher than $40, and because of atmospheric remediation (CO2 removal) perhaps a lot higher. But the $40 does function as a lower bound for the long-term price and is a useful interim target.