
Zeroing in on Decarbonization - chmaynard
http://news.mit.edu/2020/zeroing-decarbonization-nestor-sepulveda-0115
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pjc50
I'm not sure this really advances what we know; the "100% intermittent
renewables + storage" strategy does get asymptotically more expensive as you
move towards 100%. So the referenced article points out that a blend of
dispatchable gas+capture and "advanced" nuclear can produce a cheaper overall
result.

But! Nuclear takes ages to build, advanced nuclear even longer, and
gas+capture is deployed almost nowhere because there's no negative carbon
pricing for it.

So perhaps they are viable in the long term. For 2020? Countries need to be
accelerating their wind and solar rollouts and using them to push carbon-
emitting sources down the dispatch order as far as possible.

The UK is surprisingly far ahead on this, having eliminated coal for most of
the year and running a gas/nuclear/wind mix currently at 30% wind.

~~~
mscrivo
Ontario, Canada is even further ahead, having eliminated coal completed by
2014. They botched much of it, with setting up bad contracts, which led to a
lot of wasted taxpayer dollars. Even still, it shows it's possible and the
outcome was fantastic. Complete elimination of smog days and far lower
incidence of asthma cases.

~~~
toomuchtodo
They also export clean power to US markets at the border. We thank them!

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jlevers
> In work published last year in the journal Joule, Sepulveda and his co-
> authors made a powerful case for using a mix of renewable and “firm”
> electricity sources, such as nuclear energy, as the least costly, and most
> likely, route to a low- or no-carbon grid.

> Recognizing that “absolutes exist in people’s minds, but not in reality,”
> Sepulveda sought to develop a tool that might yield an optimal solution to
> the decarbonization question.

The second part, I think, is very important to keep in mind when discussing
whether or not to use nuclear to help solve the climate crisis. I'm not a big
fan of nuclear, but if deploying huge amounts of it is what it takes to get us
to zero carbon emissions by 2050, I'm for it. Yes, nuclear has its risks, and
it's not renewable, but I think it would be worth pursuing as a stepping stone
to get us to net-zero emissions sooner, while we figure out how to power the
entire world via truly renewable energy. IMO, the potential risks of failing
to address climate change rapidly enough are _much_ larger than the risks of
wide-spread nuclear power.

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manfredo
Nuclear is renewable through uranium seawater extraction:
[https://www.pnnl.gov/news/release.aspx?id=4514](https://www.pnnl.gov/news/release.aspx?id=4514)

~~~
fulafel
The uranium in seawater is same as uranium in the ground, not renewable.

~~~
manfredo
Uranium in seawater is available in much larger quantities. We would not
consume the amount of uranium over the next billion years even if we used
nuclear for all of humanity's energy demands [1]. It is renewable in all but
the most literal sense.

Uranium in seawater is the same as the hydrogen in the sun: it's not
renewable. The hydrogen in the sun will eventually be fused to such an extent
that no further energy will be released. There is no such thing as a renewable
energy source because the laws of thermodynamics dictate that there is a
finite amount of usable energy in the universe.

[https://www.forbes.com/sites/jamesconca/2016/07/01/uranium-s...](https://www.forbes.com/sites/jamesconca/2016/07/01/uranium-
seawater-extraction-makes-nuclear-power-completely-renewable/#34309e4a159a)

~~~
jlevers
While I agree with you that it's virtually impossible for humans to use up the
uranium in sea water at our current energy consumption rate, I think it's
worth thinking about that if we had "unlimited" energy, we might use orders of
magnitude more of it than we currently do.

That being said, for that to be an issue, we'd have to increase our energy
consumption at least 1000x, and if we get to the point of using that much
energy, it seems likely we'll also have advanced technologically to such an
extent that we'll figure out another solution. It's just an interesting
exercise to consider how what seems impossible today, might be totally routine
in 10/100/1000 years.

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cagenut
I'm in favor of an 80/20 policy. 80% renewables, 20% nuclear.

The thing is, we're already at 20% nuclear. So the "debate" over it is largely
a distraction/delay-tactic.

~~~
pfdietz
But that doesn't work. If you go 80% renewable, there will be long periods
where 100% of demand is being satisfied by the renewables (because they are so
variable). This makes the economics of nuclear just horrible, as it needs to
be selling its power at a good price most of the time to make ends meet.
Nuclear and high penetration renewables just don't mix well.

~~~
adrianN
You still need storage when you go 80% renewable, so any extra production by
renewables can be used to generate hydrogen or charge batteries or something
so that the nuclear plants can still sell their energy. It's not like they
don't get any subsidies today, there is no reason why they shouldn't get any
in the future.

It's just a question of what is cheaper or faster to achieve. I don't know
enough details to say either way.

~~~
malpighien
I don't think here are available storage solution for renewables and even if
there was it would need to be a solution scalable without a risk of running
out of resources to make the batteries. Renewables are great but they work on
the shoulders of nuclear/coal which need to pick up the load when there is no
sun/wind. Renewables feel like paying more for getting less with different but
not necessarily less pollution issues.

~~~
mrec
Storage doesn't have to mean batteries. I'd have thought approaches like
pumped hydro [1] could scale pretty well. I vaguely recall a similar story
from a couple of years back that basically involved lifting giant concrete
blocks.

[1] [http://www.british-hydro.org/pumped-storage/](http://www.british-
hydro.org/pumped-storage/)

~~~
malpighien
If those solutions were viable at scale then countries like germany or england
using lot of renewables and coal (gas or gb) would have been using them
already.

~~~
pfdietz
They'd only be using them now if they cost less than gas + current carbon
taxes.

The question is: at what level of carbon taxes would nuclear displace gas, vs.
what level would renewables + storage displace gas. In the US, CO2 taxes would
have to exceed $300/ton for new nuclear to displace gas CC baseload, and for
intermittent applications the needed tax would be far higher.

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adrianN
I wish we did less modelling and more shutting down coal plants in favor of
basically anything else.

~~~
toomuchtodo
Not snarky: when was the last time you called your utility to tell them you
demand renewables? Or your state (for renewable mandates) and federal
(national policy) Congressional reps? Protest at a coal plant?

Wishing is cheap, action pays the bills. I do all of the above. And there are
signs of progress. The federal gov approved one of the largest PV plants in
the US for California. Nevada is prepping for a 1.2GW PV facility with 600MW
of storage.

Utility won’t switch off fossil fuels? Get rooftop solar and capture every
damn incentive you can, or convince your local government to form a coop or
muni utility to source clean power with a PPA at scale.

~~~
agumonkey
When did anyone called a large company to ask them to operate differently ?
and succeeded into being heard ?

~~~
topkai22
“Hi regulated utility, I’d like to pay more for a premium product that your
government overseers will have no problem with your providing.” :)

Less jokingly, actions like contacting a company (especially as a customer or
as a potential customer) is more effective then you think- companies want to
keep their customers happy and it’s pretty well assumed that one customer
complaining means many more (probably thousands) thinking the same thing.

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alikim
Here is the referenced article if anyone is interested:
[https://www.dropbox.com/s/kj3ny5wk93bxj44/Sepulveda%20et%20a...](https://www.dropbox.com/s/kj3ny5wk93bxj44/Sepulveda%20et%20al%20-%20Firm%20low-
carbon%20resources%20-%20Joule%202018%20with%20SI.pdf?dl=0)

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planck01
It's not enough to reach zero on carbon emission. There is way too much in the
air already that we need to get out of it and somehow bind it to the
(sub)surface of our planet to keep it out. And we need to find a way to do
that on scale and in an economical viable way or it will never happen.

------
CaptArmchair
I saw 3 interesting diagrams on Wikipedia that basically tell a big part of
the story.

* [https://en.wikipedia.org/wiki/List_of_countries_by_carbon_di...](https://en.wikipedia.org/wiki/List_of_countries_by_carbon_dioxide_emissions) * [https://en.wikipedia.org/wiki/List_of_countries_by_GDP_(nomi...](https://en.wikipedia.org/wiki/List_of_countries_by_GDP_\(nominal\)_per_capita) * [https://en.wikipedia.org/wiki/World_population](https://en.wikipedia.org/wiki/World_population)

Turns out that the 3 countries who make up for the biggest share in greenhouse
emissions are:

* China * The United States * India

Moreover, this graph (a) tells you that the U.S. has the highest C02 emissions
per capita whereas India has the lowest CO2 emissions per capita in 2017. Way
lower then many developed countries such as the EU28. A Chinese individual
have emitted less then a German or South-Korean citizen in 2017.

(1)
[https://en.wikipedia.org/wiki/List_of_countries_by_carbon_di...](https://en.wikipedia.org/wiki/List_of_countries_by_carbon_dioxide_emissions#/media/File:Total_CO2_emissions_by_country_in_2017_vs_per_capita_emissions_\(top_40_countries\).svg)

The bigger story is in the 3rd graph: population per country as part of global
population:

* China: 18.1% * India: 17.5% * U.S.: 4.24%

Every other country below the top-8 only constitutes less then 2% of the
global population.

Now, you can draw a few quick conclusions from that.

The total energy consumption in China is far less driven by individual
consumption, but is more a factor of the total population. Lots of small
consumers drive consumption towards a heck of a big number. Coal is the
obvious answer as far as the Chinese are concerned because it provides a cost
efficient way of scaling energy production to cater to 18.1% of the World's
population.

Moreover, China isn't a particular rich country if you simplify things and use
GDP per capita as a metric. Most of the people are relatively poor by Western
standards, so their footprint in terms of how they live and consume isn't
anywhere near what it is in Europe or North America.

You'd see the exact same dynamic at play in India.

As far as China and India are concerned, they will keep preferring coal unless
clean solutions that could cater to the same vast demands become equally or
more cost effective and scalable such that they can easily replace coal.

Then there's the U.S. with only 4.24% of the world's population, it manages to
end up in the top-3 of most polluting countries, right after China and before
India. Moreover, an American seems to have emitted twice the amount of CO2 as
a Chinese person did in 2017. And finally, Americans are part of the top 10
richest individuals in the world if you look at GDP per capita.

Here you're looking at a different problem: individual consumption rather then
total population. Whereas China and India can't readily reduce energy
consumption because of their large population, the U.S. can easily reduce it's
huge dependency on energy if individual consumption can be radically reduced.

The big hurdle here is that the biggest consumers of energy are those that
fear they will have the most to lose: quality of life through existing
conveniences and affordances that they feel will go away because they aren't
sustainable. At this point, the whole debate often turns emotional and ends up
in yak shaving or bike shedding.

The only other pathway for the U.S is similar to China and India: find a cost
effective clean source of energy that can easily replace fossil fuels such as
coal.

I would put this moral conundrum in front of you: If drastically cutting back
emissions through a better management of personal consumption is clearly
within your power and can be achieved today; then why refrain from doing so
and passing on the responsibility to energy producers?

This doesn't just apply to the U.S. but to any country with significant CO2
emissions per capita, but it needs to be pointed out that countries with a
small fraction of the global population with a high CO2 emission number per
capita are those that can and will have the biggest impact on the problem,
which contrasts seriously with countries in the opposite situation.

Of course, I understand that my whole expose ignores many, many other
complexities that affect the balances such as global emission trade, global
transportation and global trade (import/export).

My main point was to demonstrate why seemingly irrational decisions elsewhere
in the world - such as investing in even more coal-based power plants - are
driven by very different regional economics; and that battle cries such as
"reduce carbon dependency" are blanket statements you can't impose everywhere
in the world without adjusting it's meaning to the local or regional context.

