
More than 100 coal-fired plants have been converted to natural gas since 2011 - lawrenceyan
https://www.eia.gov/todayinenergy/detail.php?id=44636
======
gok
…but over 546 have been retired permanently

source:
[https://www.eia.gov/todayinenergy/detail.php?id=40212](https://www.eia.gov/todayinenergy/detail.php?id=40212)

~~~
mikece
And replaced with what? While coal is dirtier than natural gas the calorific
value is far greater so you get a lot more heat and electricity per unit of
combustion by-product. If these coal plants were replaced by gas-burners then
emissions haven't been eliminated, only reduced. If we really want to
ELIMINATE emissions we need to be looking at base-load sources that emit zero
carbon such as nuclear.

~~~
NineStarPoint
Based on [https://www.eia.gov/energyexplained/us-energy-
facts/](https://www.eia.gov/energyexplained/us-energy-facts/) So in 2011 we
had: Coal at 19.66 quadrillion BTU Natural Gas at 24.95 quadrillion BTU
Petroleum at 34.63 quadrillion BTU Nuclear at 8.27 quadrillion BTU Renewables
at 9.20 quadrillion BTU

In 2019 we had: Coal at 11.31 quadrillion BTU (-8) Natural Gas at 32.10
quadrillion BTU (+7) Petroleum at 36.72 quadrillion BTU (+2) Nuclear at 8.46
quadrillion BTU (+0.2) Renewables at 11.45 quadrillion BTU (+2)

Basically we replaced the use of Coal with natural gas, and used Renewables to
add on new capacity. Indeed not exactly a rosy picture of lowering our
emissions. And what’s not captured here is that we dropped our fuel use
drastically during the 2007-2009 financial crisis and only just recovered from
that drop. But our Real PCE (Personal Consumption Expenditures) went up 30% in
that same time frame. While it’s not a 1-1 correlation or anything, increased
consumption without increased electricity use probably means we’ve just off-
shored a lot of our usage to less developed countries in the last 13 years
anyway.

~~~
Retric
Natural gas is a net benefit as it releases significantly less carbon per kWh
than coal. Coal is almost entirely C + 02 = C02 but with natural gas you also
get energy from 4H + 02 = water. Even better it’s far more flexible easily
accommodating a renewable heavy grid.

Natural gas is also in vastly shorter supply than coal, naturally forcing a
transition away from it fairly soon.

~~~
opo
In terms of climate change, natural gas is comparable to using coal. The CO2
emissions from a natural gas plant are much lower than a coal plant, but it
isn't clear that if you account for methane releases during
production/transporting/storage that it is better for climate change than
coal.

>...Back in August, a NOAA-led study measured a stunning 6% to 12% methane
leakage over one of the country’s largest gas fields — which would gut the
climate benefits of switching from coal to gas. We’ve known for a long time
that methane is a far more potent greenhouse gas than carbon dioxide (CO2),
which is released when any hydrocarbon, like natural gas, is burned. But the
IPCC’s latest report, released Monday (big PDF here), reports that methane is
34 times stronger a heat-trapping gas than CO2 over a 100-year time scale, so
its global-warming potential (GWP) is 34. That is a nearly 40% increase from
the IPCC’s previous estimate of 25. ...The IPCC reports that, over a 20-year
time frame, methane has a global warming potential of 86 compared to CO2, up
from its previous estimate of 72. Given that we are approaching real,
irreversible tipping points in the climate system, climate studies should, at
the very least, include analyses that use this 20-year time horizon. Finally,
it bears repeating that natural gas from even the best fracked wells is still
a climate-destroying fossil fuel. If we are to avoid catastrophic warming, our
natural gas consumption has to peak sometime in the next 10 to 15 years,
according to studies by both the Center for American Progress and the Union of
Concerned Scientists.

[https://thinkprogress.org/more-bad-news-for-fracking-ipcc-
wa...](https://thinkprogress.org/more-bad-news-for-fracking-ipcc-warns-
methane-traps-much-more-heat-than-we-thought-9c2badf392df/)

As we use more and more natural gas, we can expect more and more methane
disasters like the leak from Aliso Canyon in CA which was the largest methane
leak in US history. This released over 100,000 tons of methane into the
atmosphere and required 11,000 residents to be evacuated.

[http://www.bbc.com/news/science-
environment-35659947](http://www.bbc.com/news/science-environment-35659947)

>...Natural gas is also in vastly shorter supply than coal, naturally forcing
a transition away from it fairly soon.

Not really. The U.S. Energy Information Administration estimates in the Annual
Energy Outlook 2020 that as of January 1, 2018, there were about 2,828.8
trillion cubic feet (Tcf) of technically recoverable resources (TRR) of dry
natural gas in the United States. Assuming the same annual rate of U.S. dry
natural gas production in 2018 of about 30.6 Tcf, the United States has enough
dry natural gas to last about 92 years.

[https://www.eia.gov/tools/faqs/faq.php?id=58&t=8](https://www.eia.gov/tools/faqs/faq.php?id=58&t=8)

And if extracting natural gas becomes too expensive, countries can just make
synthetic natural gas from coal like China does.

~~~
Retric
Methane’s global warming impact is front loaded, it breaks down in the
atmosphere so in a steady state future leaks only maintain but don’t increase
the amount of methane in the atmosphere. In other words there are significant
benefits from eventually moving to something else, but little long term
advantage due to methane from doing so sooner.

“technically recoverable resources“ is what’s possible to extract at _any_
price making it a very poor measurement of economically viable reserves.
Considering natural gas is already more than twice as expensive as solar power
it’s primary benefit is flexibility and the limited amount of solar
manufacturing currently available.

Further the absolute worst case from known reserves of 92 years worth of
natural gas is the equivalent of less than 28 years worth of coal production
at those rates. Which means any coal offset with natural gas is at worst
equivalent to zero coal in 2048 and very likely significantly better than
that.

PS: 1998 methane levels are 5% lower than current levels because we have
significantly increased output over the last 20 years. But looking at the
graph it’s nothing like a linear increase.

~~~
opo
>Methane’s global warming impact is front loaded,

Methane is 34 times stronger a heat-trapping gas than CO2 over a 100-year time
scale. This is the timeframe we need to worry about right now to avoid the
worst affects of climate change.

>...“technically recoverable resources“ is what’s possible to extract at any
price making it a very poor measurement of economically viable reserves.

Yes, but technology improves and all of sudden they are viable. People knew of
those big oil deposits in North Dakota for decades and then with fracking it
became feasible to extract it. As I pointed out, even today China is going
forward with making synthetic natural gas from coal (which is even worse for
climate change than just burning methane.)

>...Considering natural gas is already more than twice as expensive as solar
power it’s primary benefit is flexibility and the limited amount of solar
manufacturing currently available.

The major weakness of solar is that having 100% capacity at noon in July on a
sunny day in Arizona, doesn't help at midnight when you want to run medical
equipment.

It is possible grid storage will become feasible in the future to cover the
daily and seasonal variations of capacity for wind/solar, but if we end up
having the grid rely on natural gas will make it very difficult to avoid the
worst problems associated with climate change.

~~~
Retric
“Methane is 34 times stronger a heat-trapping gas than CO2 over a 100-year
time scale.“ That’s intentionally deceptive.

Over 20 years it’s 86 times more powerful than CO2.
[https://en.wikipedia.org/wiki/Global_warming_potential](https://en.wikipedia.org/wiki/Global_warming_potential)

34 = (86/5) + 4x/5 so Average from years 20 to 100 = 21.

You can graph it based on in initial GWP and final GWP. CH4 = 16.04246 g/mol
and CO2 = 44.0095 g/mol. So after breaking down it’s 2.75x the global warming
potential of CO2 which is almost exactly the GWP from years 60 to 100.

PS: Now sure that’s greater than 1, but compared to the scale of CO2 released
vs accidental methane releases it might as well be.

~~~
opo
>...That’s intentionally deceptive.

Part of the Hacker News guidelines is to assume good faith.

As the IPCC says:

>..There is no scientific argument for selecting 100 years compared with other
choices (Fuglestvedt et al., 2003; Shine, 2009). The choice of time horizon is
a value judgement since it depends on the relative weight assigned to effects
at different times.

I chose 100 years since you seemed to imply that since methane was "front
loaded" then "...there are significant benefits from eventually moving to
something else, but little long term advantage due to methane from doing so
sooner."

Trying to ignore the problems of methane in the atmosphere is not helpful. As
the Think Progress article says

>...The IPCC reports that, over a 20-year time frame, methane has a global
warming potential of 86 compared to CO2, up from its previous estimate of 72.
Given that we are approaching real, irreversible tipping points in the climate
system, climate studies should, at the very least, include analyses that use
this 20-year time horizon.

>...If we are to avoid catastrophic warming, our natural gas consumption has
to peak sometime in the next 10 to 15 years, according to studies by both the
Center for American Progress and the Union of Concerned Scientists.

~~~
Retric
_I chose 100 years since you seemed to imply that since methane was "front
loaded" then "...there are significant benefits from eventually moving to
something else, but little long term advantage due to methane from doing so
sooner._

Ahh, ok I genuinely assumed you understood what that number meant and chose to
use it incorrectly.

As to 86 for 20 years still being important. These methane leaks from natural
gas are nowhere near 1/86th of global CO2 production. They are not even 1/86th
of the displaced CO2 from reduced coal use age.

Compare ~10 megatonnes of methane leaks worldwide from _all_ sources of
natural gas with global Fossil CO2 emissions at ~37,000 megatons per year and
740,000 over 20. Except your natural gas emissions don’t stack linearly for 20
years with past emissions. So natural gas power plants are easily a net
reduction in global warming over your 20 year timetable.

~~~
opo
>...Compare ~10 megatonnes of methane leaks worldwide

It isn't clear we fully understand the extent of methane leaks in the US and
probably have less info on many other countries.

This is illustrated in the Aliso Canyon leak:

>..The authors believe there are important lessons to be learned from the leak
- particularly the need to monitor oil and gas facilities more carefully. They
say that there has been little co-ordinated oversight of the biggest oil and
gas leaks in recent years. They point to Aliso Canyon, the BP spill and the
Total Elgin rig blowout in the North Sea as examples where luck more than
intent ensured the impacts on the environment were monitored. In the case of
Aliso Canyon, the surveying aircraft was working on another project searching
for pipeline problems, when the scientists were asked to overfly the leaking
well. "The state's response to Aliso Canyon was teed off by the first
measurement we took, at that point no-one had any clue that this was 50,000kg
per hour of gas," said Dr Conley.

This report discusses the overall level of uncertainty in this area:

>...However, given limited current evidence, it is likely that leakage at
individual natural gas well sites is high enough, when combined with leakage
from downstream operations, to make the total leakage exceed the 3.2%
threshold beyond which gas becomes worse for the climate than coal for at
least some period of time.

[https://www.pnas.org/content/109/17/6435](https://www.pnas.org/content/109/17/6435)

Using coal for fuel is almost a crime against humanity considering the health
costs, so switching to natural gas is harm reduction. The amount of reduction
in GHG production though is more uncertain due to lack of investments in
monitoring and reducing methane leakages.

~~~
Retric
That’s from 2012, we currently have vastly better satellite monitoring of
leaks. This provided dual benefits of better measurement and reduction in the
number of active leaks thus reducing emissions.

------
arkh
I "like" the use of the term natural to make it sound like gas powered plants
are a good thing.

~~~
tialaramex
Historically it was common to make a useful "town gas" which could be used to
make heat and light in homes or factories. Often "coal gas" was the town gas
used, you make it by processing coal, so, unsurprisingly, the carbon emissions
are worse than coal. When it was discovered that the planet has a whole bunch
of natural methane we could harvest that's a _natural_ gas you can use
instead. It's cheaper, it burns cleaner, once you discover it there's nothing
not to like...

Coal gas is also poisonous and its density means it's inclined to lay in a
room, so when e.g. Britons mostly cooked with coal gas ovens that's where you
get the phrase "Put your head in the oven". The idea isn't that you could
somehow suicide by cooking yourself, but instead that the poisonous gas will
kill you.

These days if you have a gas oven (they're rarer) and try this it won't work,
the gas isn't poisonous and will escape from most spaces - although you
_might_ if you're unlucky manage to collect the right amount of methane
somewhere to cause an explosion.

The reduction in suicide from upgrading from town gas to natural gas is a
success story and a model for other interventions. It showed very clearly that
"displacement" isn't a big deal. People didn't go "Huh, my oven didn't kill
me. Oh well I'll jump off a building". Thus, other interventions can be
expected to be effective, such as anti-suicide fencing on bridges or platform
screen doors at railway stations.

~~~
jdeibele
My house was built in 1914, which is fairly old for Portland. It's been heated
by 5 different technologies:

1) Manufactured Gas, which I assume is the same as coal gas. The pipe for this
is about 3 times as large as natual gas. 2) Wood chips (still a spot in the
concrete floor where the "octopus" furnace (called because of the vents coming
off it) sat. This was a byproduct of the timber industry. 3) Oil. The
underground tank in the side yard was filled in. 4) Natural gas 5) Air heat
pump powered by electricity (partially fed by solar panels)

I'm not sure of the exact order but I think that's basically correct, as the
development of trucks meant it was possible to drop off a big bunch of wood
chips or later a tankful of oil.

I've read that some towns are not allowing new natural gas connections because
of pollution issues. With the explosion yesterday in Maryland and our problems
keeping up infrastructure, it seems like a reasonable approach to me.

~~~
tialaramex
> I've read that some towns are not allowing new natural gas connections
> because of pollution issues. With the explosion yesterday in Maryland and
> our problems keeping up infrastructure, it seems like a reasonable approach
> to me.

Yes. In Britain there was a three way choice offered to central government
towards the end of last century. They could discontinue household natural gas
service (perhaps gradually over time) and shut the delivery network of pipes
under roads across much of the country OR they could replace the entire
network of cast iron pipes which are gradually failing so as to prevent
explosions OR they could accept that gradually gas explosions would become
more and more common as the pipes fail.

The last mile gas delivery is notionally in the hands of private company
National Grid, because Tory ideology holds that this is better, but of course
the private company exists only to collect profits, government must pay for
all the inevitable costs of delivering the service, and thus had to make this
decision. In the event they picked replacing all the pipelines, section by
section ever since the cast iron gas pipes are being dug out of roads and
replaced with plastic pipes expected to last many more decades.

Given that burning gas helps force climate change we don't want, in hindsight
probably switching off the network would have been a wiser choice. The plastic
pipes may last until say, 2100 but burning natural gas to heat UK homes in
even 2050 will be very obviously stupid.

------
baybal2
Rankine cycle natural gas plants are less efficient than Bryton cycle plants.

Converted plans will always loose out to gas turbine plants.

~~~
pfdietz
More specifically, Brayton cycle with a Rankine bottoming cycle (combined
cycle). Open cycle gas turbines are about as efficient as supercritical steam
plants (but are much cheaper to build).

~~~
baybal2
An _ _average_ _ steam turbine plant is nowhere near as efficient as a big
enough single cycle gas turbine.

A top tier boiler plan of course may well be approaching a smaller/cheaper
turbine.

------
melling
A little over 20% of US electricity is generated from coal. There are around
2400 coal power plants in the world.

My understanding is that if we could turn off all the coal plants tomorrow we
could actually significantly reduce greenhouse gas emissions.

Would it buy us a significant amount of time if we accelerated the
conversation to natural gas?

~~~
abejfehr
I don't think natural gas is actually a carbon-neutral alternative to coal, my
understanding is that methane leakage makes it almost as bad as coal in the
long term.

[https://www.vox.com/energy-and-
environment/2019/5/30/1864381...](https://www.vox.com/energy-and-
environment/2019/5/30/18643819/climate-change-natural-gas-middle-ground)

~~~
causality0
True, but it doesn't have the incredibly horrific non-carbon pollution
problems of coal. The things almost every coal plant in the world does to
nearby rivers would nauseate most people. Fly ash produced by coal plants
releases one hundred times the radiation into the environment as a nuclear
plant of the same capacity.

~~~
avalys
That’s only true because the amount of radiation released by a nuclear plant
in normal operation is also negligible.

~~~
willis936
The actual number closer to 1,000 than 100. There is a lot of uranium and
thorium in coal. Not all of it is captured when coal is burned.

[https://www.scientificamerican.com/article/coal-ash-is-
more-...](https://www.scientificamerican.com/article/coal-ash-is-more-
radioactive-than-nuclear-waste/)

~~~
makomk
"A lot" is relative. From what I can tell, coal ash contains about the same
amount of uranium and thorium as granite and slightly more than ordinary soil.
(Of course, it's less concentrated in the coal itself, which is largely carbon
and hydrocarbons that gets burnt off.) The main reason coal power releases so
much radiation compared to nuclear because there's a lot of coal burnt and
normal operation of nuclear power plants also releases very little.

What's more scary is the production of things like rare earth minerals - that
quite heavily concentrates the uranium and thorium as part of the extraction
process, producing large quantities of relatively radioactive mining waste.

------
LatteLazy
Which is great, except that we're emitting vastly too much still and emissions
are growing and it will soon be too late to avoid disaster.

