For the "Greens"

[sd_matt]

Can anyone point me to one or more analyses of CO2 reduction/dollar comparison of various energy tech? I want to give links to the "greens" when they assert that wind and solar are top dogs for CO2 reduction. I have seen people break it down before and it points to nuclear fission (barring a fusion breakthrough) being the current best option.

[KitemanSA]

When you include the entire power system, buffered windand solar are actually WORSE than coal on a greenhouse drive standpoint. This is because buffering W&S typical requires NatGas turbines, and the NG systems leak by 2% to 6% of total gas extracted. That means that the drive is between .02 X 88 (1.76X) and .06 X 88 (5.28X) that of the CO2 produced by burning it. Thus, NG is about 2.7 to 6.3 times the CO2 alone. Coal is only about 2X the CO2 alone from NG.
Some say CH4 is only ~25X the driver that CO2 is, but that is the integral over many years as the CH4 converts slowly thru atmospheric processes into CO2. In the “12 years” we have (‘kkkkkkkk) the 88 is the better estimate.
I had all that stuff until I was evicted from facebook.

I found the reference.
Markadya A & Wilkinson, P. (2007). Electrical Generation and Health. Lancet 370(9591), 979-990

This provided the basic data I calculated the effect of buffering.

[Giorgio]

I had all that stuff until I was evicted from facebook.

I found the reference.
Markadya A & Wilkinson, P. (2007). Electrical Generation and Health. Lancet 370(9591), 979-990

Sadly these are truths that almost no one wants to hear...

[sd_matt]

I see the article intro says that nuclear cannot be implemented in time to make a significant CO2 reduction. Is that based on construction times within the U.S.?
Would a U.S. version of France's Messimer Plan have an impact?

[charliem]

When you include the entire power system, buffered windand solar are actually WORSE than coal on a greenhouse drive standpoint. This is because buffering W&S typical requires NatGas turbines, and the NG systems leak by 2% to 6% of total gas extracted. That means that the drive is between .02 X 88 (1.76X) and .06 X 88 (5.28X) that of the CO2 produced by burning it. Thus, NG is about 2.7 to 6.3 times the CO2 alone. Coal is only about 2X the CO2 alone from NG.
Some say CH4 is only ~25X the driver that CO2 is, but that is the integral over many years as the CH4 converts slowly thru atmospheric processes into CO2. In the “12 years” we have (‘kkkkkkkk) the 88 is the better estimate.

It is worse than that, according to this 2017 paper, methane is 120 times as potent as CO2 in regard to green-house effects.

But, isn't your argument incomplete? As stated I read that NG is worse than coal in general, either for direct electricity production, or for backing renewables. How do we get from that to "buffered W&S is worse than coal"?

For the record, my favorite option would be "everything", with a medium term goal of [mostly] renewables backed by nuclear (and a good pinch of all else kept in standby, at least for a while).

[KitemanSA]

It is worse than that, according to this 2017 paper, methane is 120 times as potent as CO2 in regard to green-house effects.

But, isn't your argument incomplete? As stated I read that NG is worse than coal in general, either for direct electricity production, or for backing renewables. How do we get from that to "buffered W&S is worse than coal"?

For the record, my favorite option would be "everything", with a medium term goal of [mostly] renewables backed by nuclear (and a good pinch of all else kept in standby, at least for a while).

If you use a mass based measure, 120 might be correct, but I assumed a molar measure.

Buffered W&S is mostly NG used inefficiently. The CO2 output for the NG is reduced by the use of W&S but the leakage remains no matter how high the CapFac is for the W&S.

W&S have their place, But providing large grid power for a middle class civilization is not one of them.

Some places rely on diesel-electric plants for their grid. In such locales, W&S can be integrated easily and to the degree their cost is lower than the marginal cost of the deisel fuel, they can be a benefit. Such places are an exception to my statement.

Some places have the need for long term, cheap, but not continuous power (Holland and their need to pump out the low lands for example). Wind does well for such uses too.

As for “all of the above”, if you have reliable nuclear, why in the world would you want to screw up your grid with UNRELIABLES like W&S???

[charliem]

Thinking it twice, GWP per kilogram, or per mole, seem a bit unwieldy. GWP/kWh of electricity produced would make comparisons easier.

Let's see, in GWP/kg the numbers are:

• Coal : 1 (by definition)
• NG.. : 120 according to that paper I mentioned.

If we approximate coal as pure carbon, and NG as pure CH4, 1 mole of C is 12 g, and 1 mole of CH4 is 16 g, ergo, GWP/mole should be:

• Coal: 1
• NG..: 90

The heat content of C is 394 kJ/mol, and for CH4 is 802 kJ/mol. So, in GWP/kJ:

• Coal: 1
• NG..: 44.2

To obtain GWP/kWh we need the relative efficiency of generating electricity from coal, and from NG. St. Google says that the average NG electricity generation factory is, approximately, 1.5 times as efficient as one using coal. So, in GWP/kWh:

• Coal: 1
• NG..: 29.5

OK. A bit better for NG but still clearly in favor of coal.

Now, if finally we repeat the computing of damage caused by NG leaks, between 2% and 6%:
.02 x 29.5 = 0.59
.06 x 29.5 = 1.77

Interesting, numbers favor NG if the leaks are kept under 3.5%, and in favor of coal otherwise.

I had never thought of this before. Thanks.

P.S.: Why do you say that "The CO2 output for the NG is reduced by the use of W&S but the leakage remains no matter how high the CapFac is for the W&S.". Given that most leakage is from the production sites (again, Google) shouldn't that leakage vary depending of the capacity factor of the backed renewables? Higher CF, less NG burned, less NG extracted, less NG leaked. No?

[KitemanSA]

By molar, I meant only the 88 multiplier for CH4 vs CO2.

I have no idea what you were doing with your number string.

For the same energy output, NG power plants release ~50% of the CO2 that coal power plants do because of the H in the CH4. BUT… NG also releases CH4 at 2% to 6% of the total used. That adds to the GHG driving at ~88 times the percentage of amount leaked.

And no, most leakage is the same no matter how much flows thru since it is a function of a pressurized gas leaking thru a numbers of seals (valves, flanges, etc). If the gas is available at the power plant, it effectively pressurizes the same number and quality of seals along the way no matter what the flow rate.

[KitemanSA]

P.S.: Why do you say that "The CO2 output for the NG is reduced by the use of W&S but the leakage remains no matter how high the CapFac is for the W&S.". Given that most leakage is from the production sites (again, Google) shouldn't that leakage vary depending of the capacity factor of the backed renewables? Higher CF, less NG burned, less NG extracted, less NG leaked. No?

Heck, one could argue that the opposite is true. If there is more flow, Bernoulli implies a LOWER pressure at the production site so lower leakage not higher. But somehow I suspect that flow THRU the drill pipe will not significantly alter the leakage around it. ICBW.

[charliem]

For the record, my favorite option would be "everything", with a medium term goal of [mostly] renewables backed by nuclear (and a good pinch of all else kept in standby, at least for a while).

As for “all of the above”, if you have reliable nuclear, why in the world would you want to screw up your grid with UNRELIABLES like W&S???

Economic reasons mostly, mixed with some politics, and a bit of a philosophical position.

Evidently, since we are in Talk-Polywell, my all time favorite energy generation way is fusion. But fusion is not here yet, and even if we see one or two startups reach break-even before 2030, like with any other previous technology this one's going to need time to perfect and deploy.

So, for the medium term, let's say up to 2050, what can we reasonably expect to set up that is both, economically viable, and the least environmentally harmful ?

Solar and Wind are unreliable, but also cheaper. Nuclear is reliable, but more expensive (at least until 4th generation nuclear is operational). So, my position is that, for now, our better option is to mostly keep with what we are doing, but adding some more nuclear to stabilize the system (avoiding overcapacity, the idea is to switch to fusion as soon as possible). That would minimize the average cost per unit of energy produced, while reducing black-out risks.

Then there is the question of politics. Renewables have the potential to reduce energy dependence at the national level for many countries, and when the main hydrocarbon producers are such a nice people as Russia, Venezuela, the Arab countries, etc., independence from them looks very desirable (just ask west Europe).

And not only countries, even at the individual level. I love my two power-packs. Bought the first five years ago (a small 0.6 kWh), and the second last year (2 kWh, the 4 years in between meant this one cost only a little more than the first). In the zone we live in blackouts are common (2, 3, 4 times a year), from a couple minutes to a few hours. When power goes out, of course those packs cannot feed our HVAC, but that's almost the only thing we can't use (heat and kitchen are NG), everything else works (fridge, lights, computers, TV, internet, ...) for 4-5 hours easily, more if we are careful. I know those two power-packs will never pay for themselves, but money is not the only consideration, the independence and safety they offer is valuable too (and outdoors they are really useful).

[charliem]

P.S.: Why do you say that "The CO2 output for the NG is reduced by the use of W&S but the leakage remains no matter how high the CapFac is for the W&S.". Given that most leakage is from the production sites (again, Google) shouldn't that leakage vary depending of the capacity factor of the backed renewables? Higher CF, less NG burned, less NG extracted, less NG leaked. No?

Heck, one could argue that the opposite is true. If there is more flow, Bernoulli implies a LOWER pressure at the production site so lower leakage not higher. But somehow I suspect that flow THRU the drill pipe will not significantly alter the leakage around it. ICBW.

From the sources I found until now, most of the leaked methane is at the extraction points, not transport or storage. Do you have other sources that I could read ?

Regarding my calculations. I think that power of greenhouse effects per mole of CH4 or CO2 is cumbersome, so I simply recalculated them per kWh of electricity generated. In my opinion that makes comparing easier. The 88 number you give for CH4 is almost equal to the 90 I obtained. From that, divide by 2 to obtain the number per unit of heat produced, and again divide by 1.5 to compensate for the difference in efficiency between coal and NG power plants.

[KitemanSA]

So, for the medium term, let's say up to 2050, what can we reasonably expect to set up that is both, economically viable, and the least environmentally harmful ?

That is 25+ years. France went from 0% to ~75% nuclear electricity in far less time than that. If we decided to do it, we could build and operate ~1TW of new nuclear power every year (about what I estimate is needed to power the world and return nature to itself) with an industry about the size of the commercial airline industry.

Solar and Wind are unreliable, but also cheaper.

This is just plain false. W&S MUST be buffered for grid use. Buffered W&S is about the most expensive power there is. The only time W&S is “cheaper” for grid use is when it replaces diesel fuel in a diesel-electric grid.

Nuclear is reliable, but more expensive (at least until 4th generation nuclear is operational).

Again, just plain false. Nuclear France has power costs ~1/3 of buffered W&S Germany. You simply MUST think about the entire system.

So, my position is that, for now, our better option is to mostly keep with what we are doing, but adding some more nuclear to stabilize the system (avoiding overcapacity, the idea is to switch to fusion as soon as possible). That would minimize the average cost per unit of energy produced, while reducing black-out risks.

“What we are doing” is creating a devolving civilization on the way to serfdom for the masses. Buffered W&S cannot support a thriving middle class civilization. The ERoEI (Energy Returned on Energy Invested) is not high enough.

[KitemanSA]

From the sources I found until now, most of the leaked methane is at the extraction points, not transport or storage. Do you have other sources that I could read ?

Have you ever seen an “extraction point”? Pipes coming out of the ground, “Christmas trees” capping the well pipe. Compressors, flasks, valves, etc. And when the plant is near a populated area, there are branches, flasks, yada yada yada. My source is personal experience growing up in an oil town.

Regarding my calculations. I think that power of greenhouse effects per mole of CH4 or CO2 is cumbersome, so I simply recalculated them per kWh of electricity generated. In my opinion that makes comparing easier. The 88 number you give for CH4 is almost equal to the 90 I obtained. From that, divide by 2 to obtain the number per unit of heat produced, and again divide by 1.5 to compensate for the difference in efficiency between coal and NG power plants.

You are over thinking it. The 88 is a driving factor and has nothing to do with unit heat nor efficiency. That came out in the statement that NG creates ~50% as much CO2 as coal so 50% the GHG driving power EXCEPT for the CH4 it leaks. That CH4 is multiplied by the 88 factor mentioned above. It is really very simple.

[sd_matt]

Somebody mentioned gen 4 fission. To me that would be a good pragmatic way forward until commercial fusion is available.

For the U.S. and other countries that already have fission plants the Elysium MSR makes the most sense to me. It's a "waste" burner and would be made of stainless. Seems the easiest and quickest to develop.

https://youtu.be/MQib5evaOC4?si=qB_jkkuca46IJLcH

[KitemanSA]

Somebody mentioned gen 4 fission. To me that would be a good pragmatic way forward until commercial fusion is available.

For the U.S. and other countries that already have fission plants the Elysium MSR makes the most sense to me. It's a "waste" burner and would be made of stainless. Seems the easiest and quickest to develop.

https://youtu.be/MQib5evaOC4?si=qB_jkkuca46IJLcH

Elysium is defunct, out of business. It’s principals have left Canada. Some Elysium folk seem to have formed an new company, Exodys, in the USA.

In theory, The MCSFR is nice because it can be started with converted and slightly processed SNF, but there just isn’t enough Pu in the world to fuel enough to make a difference nor do they breed fast enough to grow with projected demand. What they MAY be able to do is to breed Thorium into U233 fast enough to fuel THERMAL spectrum reactors fast enough to grow with demand. They take ~70 years to breed enough for a new MCSFR but only a few years to fuel a LFTR. After that, a LFTR can breed enough for a new unit every decade or two.

The U/Pu cycle is claimed to breed at ~14%/year. But that is 14% of fuel fissioned, not fuel in the core. A LFTR can do between !% and 6% per year, again, of fuel fissioned not fuel in the core. The LFTR breed numbers are highly dependent on core fuel cleaning (lost neutrons) and blanket fuel cleaning (lost Pa intermediary in the breed cycle).

• A MCSFR needs ~10 tonnes of fissile fuel in core to burn ~1tonne per year. 14% of 1 tonne =140kg extra/year. 10/0.14 = ~70 years.
  A LFTR requires ~200kg in core to burn that same 1 tonne per year. 1% of 1 tonne = 10kg extra/year. 200/10 = ~20years.

But LFTR design is still evolving and may need only 100kg in core, and may breed as high as 6%. In that case, 100/60 means a new core fueled every 1.67 years. Now THAT is growth potential.

But if the MCSFR can breed 100% replacement Pu AND 14% extra U233, that leads to a new LFTR core every 8.6 months. BUT that is a linear output, not an exponential. So, MCSFRs breeding for LFTRs at first, LFTRs breeding new LFTRs taking over later.