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"I really wish that articles like this would give more context for all the numbers that inevitably get thrown around. > China Huaneng Group Corp.’s 845-megawatt power plant What percent of the city's electricity is that?"

Humanity uses about 17 terawatts of generated power (electricity plus transportation plus …), about 15 from fossil fuels, of which coal generates more GHG that all but the dirtiest oil and the leakiest NG facilities. That plant is probably used about 80% of the time, so it represents about 675/17,000,000 of humanity's power use and something like twice that much of our GHG generation.

We think we can generate about 500GT CO2e of GHG net before reaching 3°C warming (but that involves a lot of guesses), which is a level that seems civilization-destablizing to many observers (wild, but necessary guesses). Coal creates about 1kg per kWh, so convert from 675MW … 60sec60min24h365d675,000kW = 21,286,800,000,000 kg/yr, or ~21GT/yr, or 4% of that budget.

Coal has an energy density of about (depending on type) 24 MJ/kg, which is a shade under 7 kWh per kg, so your final number is off by a factor of 7 or so [EDIT: I think? Or you're saying that coal creates 1 kg CO2 per kWh? Ok... Yeah, I think that's right!]

is the budget yearly?

The 500GT budget is total. That plant is using roughly 4% of our let's-not-wildly-destabilize-civilization GHG budget every year. We've got about 30 years to radically restructure our energy use. More here (among many places): http://www.ipcc.ch/report/ar5/syr/

Are you sure this is right? There must exist more than 25 coal plants in the world? Do we expect to hit this budget w/in a year? Is this coal plant much bigger than most others?

[Edit: an up-to-date piece focusing directly on the carbon budget: http://www.theguardian.com/environment/keep-it-in-the-ground... ]

There are a lot more than 25 coal plants in the world, and we must stop using them very very soon. Here's an EPA-citing source claiming 1 Gt coal -> 1.8 Gt CO2e, and 3.5 Gt used by China in 2011, the latter amounting to ~6.5 Gt CO2e, and ~20% of world emissions that year. [1] If Chinese coal use is now about the same, and if we have 650 Gt left before some particular nasty tipping point is reached, then China's coal is currently using that budget at a rate of 1% a year. There's a lot of uncertainty in the rate measurements, and significant uncertainty in the tipping points, but there is no uncertainty that world will be like nothing humanity has ever seen at 500ppm CO2, and we have no reason to think that, say, Pakistan, India and Bangladesh can adjust smoothly to regular high temperatures of 54° with sporadic heat waves at 57°, or that America and the US can smoothly adjust to most of the farmland that currently feeds them becoming unusable and most of the fisheries collapsing.

Finally, note that we're not going to get to near carbon-neutrality in 30 years by dropping radically next year, continuing at a flat 1/30th of our budget for 30 years, and then dropping to 0. Any plausible route will accelerate GHG reductions something like linearly.

[1] http://www.sourcewatch.org/index.php/Existing_U.S._Coal_Plan...

Oh, note that @voodoomagicman was right; 4% for one coal plant was off by a factor of about 100, mostly b/c I overestimated how much coal it used.

Ok, thanks for the info, now I have a better sense of proportion. So that means that 25 years brings it to 1% globally. I see how breaking the cap might not be totally inevitable but it doesn't seem very evitable either. I think we could see a major food price increase in our lifetimes.

China has very dirty coal compared to the US. We also have much better environmental tech installed for our plans, while in China they don't bother since enforcement of environmental laws are weak.

Another way to think about that point is that the error ranges for many of these values are quite large.

I don't know much but there are definitely more than 25 coal plants in the world... http://en.wikipedia.org/wiki/List_of_coal_power_stations

There's a nice quote from Randall Munroe on context with numbers that I think applies perfectly here.

> A good rule of thumb might be, “If I added a zero to this number, would the sentence containing it mean something different to me?” If the answer is “no,” maybe the number has no business being in the sentence in the first place.

8,450-megawatt power plant. 130 million metric tons. 850.9 micrograms per cubic meter. Etc... They're still just groups of symbols to me.

Just because you don't understand it, doesn't mean it's not relevant to others. The kind of thinking you're proposing is how we end up with stupid car analogies and comparisons of hard drive size to libraries of congress.

Corollary to the rule-of-thumb: if you replaced meaningless numbers with a meaningless analogy, it also does not belong in the sentence.

Generalization of the rule-of-thumb: write sentences that have meaning.

845MW is a typical coal power plant unit size for a large plant. A plant can contain multiple units; the biggest coal fired plant is in Taiwan, with 10 units totaling about 5GW. Most big power plant units today are in the 500MW - 1GW size. Smaller, and you need too many with a lot of duplicate equipment; bigger, and the turbines become too massive.

It took the US about 10 years after the Clean Air Act to clean up air pollution in major industrial cities. London once had air quality problems comparable to Beijing. Pittsburgh and Cleveland were almost as bad. China has the advantage that the technology is known and most of their cars already have good emission controls. The current situation in China coal plants seems to be that most of them have electrostatic precipitators to remove the big particles, but not bag houses (giant buildings full of filters) to remove the small particles. Then there's NOx and SO2 removal. The pollution control facilities for a big coal plant are bigger than the power production facilities.

Here's an overview from Power Magazine on the subject.[1]

[1] http://www.powermag.com/chinas-war-on-air-pollution/?printmo...

This is from Bloomberg Business's Energy section not USA Today, this article is written for people who are familiar with the energy market and the units of megawatts and million metric tons of coal.

You would be complaining if every article written for a technical audience had to take a paragraph and explain how many songs or movies X TB could hold.

85 is the average, it routinely goes above 300 and is above 170 right now; in winter we can get to 600, 700, even 800; going outside is painful in thst case. If the 2.5PM rating gets over 100 in the states, it is a huge scandal.

Coal is used for heating in winter, all heating plants are owned by the city. That is why the air gets immediately cleaner when the heating goes off (last week or so). It's complicated.

A bit more info, here's the EPA's PM2.5 scale:

http://www.airnow.gov/index.cfm?action=pubs.aqguidepart

Above 100 is unhealthy for sensitive groups, above 150 is unhealthy for everyone, above 200 is very unhealthy, and above 300 is dangerous.

Here's China's current PM2.5 as relayed by the US Embassy (To prevent official tampering):

http://aqicn.org/city/beijing/us-embassy/m/

The average over the last 5 days is 150, the peak over the past 5 days was 201.

Worth noting that the AQI scale you are citing (100, 150, etc.) and the ug/m3 used in the article are different numbers. AQI of 85 is not so bad. 85 ug/m3 isn't good.

This week has been sucky, I expected better. Anyways, the win will pick up today and we'll have a bit of clean air for a few hours, at least.

Never mind. Dust storm, pm2.5 is low, but the pm10 rating just shot up to 900! Shit.

>Beijing plans to cut annual coal consumption by 13 million metric tons

China uses over 50% of all world coal production (and produces nearly half itself, on top of importing an amount roughly equal to 40% of American production).

Of the ~7800 million metric tons produced, China used about ~4000 million metric tons of coal between power and steel industry.

Unsure of source quality (but then again, original article is based on numbers from unnamed/anonymous PRC Party Official, so this source is probably just as good/bad): http://www.worldcoal.org/resources/coal-statistics/

To answer one of your questions, the US EPA's standard is 12 ug/m^3 averaged annually, and at most 35 in any 24-hour period[1]; the EU's is 25 annually.[2]

[1] http://www.epa.gov/pm/2012/decfsimp.pdf

[2] http://ec.europa.eu/environment/air/quality/standards.htm

The US embassy in Beijing runs their own particulate pollution monitor, as the Chinese government's are somewhat suspect. A few years ago, the level became so high that it ran off the end of the scale. The programmer had put in a descriptor of "Crazy Bad" for that level as a joke, and that ended up being posted to the official Twitter feed.

http://blogs.wsj.com/chinarealtime/2010/11/25/shanghai%E2%80...

> it's hard to know whether this is really a big deal or just a normal retirement of older power plants for newer, cleaner alternatives.

Why isn't retirement of older power plants for newer, cleaner alternatives a big deal? If it's a lot of power plants and they're a lot cleaner, that's an impact.

>If it's a lot of power plants

That's exactly the problem, though. If you don't already know something about the power industry, there's no way to tell from the article whether this is "a lot" (enough to be an intentional trend) or just one or two aging out.

As of last year about 12,000 mines - they are trying to close smaller mines which are often illegal and have high death rates. However, they are still expanding capacity [2] - so the closure of mines isn't a good proxy to production of coal.

Putting the 13 million metric tons cut into context - China produced 3 billion and change from 2010-2014 [2]. So, while it might be important for Beijing and may signal a change of stance (?), from a China usage perspective it isn't a big difference, by itself.

[1] http://www.wsj.com/articles/SB100014240527023046263045795090...

[2] http://www.ft.com/cms/s/0/669c44d2-a780-11e4-8e78-00144feab7...

from wikipedia[1] it looks like 845MW represents about 9% of Beijing's total power generating capacity.

[1]http://en.wikipedia.org/wiki/List_of_major_power_stations_in...

To frame this a little bit, think of news articles as a git repository. You don't necessarily want to wait until you have every piece of code finished to push it. There is benefit to getting some information out, even if it isn't all the information. As you said, research takes time. Already since the story was published it has an update:

    (Updates to add coal’s contributions to the U.S.’s electricity mix in 10th paragraph.)

Harder to research facts and connections can get added over time, like commits in a repository to make the story more complete. It's the difference between operating a business news wire and a magazine.

You've got a strong argument to say "the reporter should do a little bit more work to put these numbers in context" but the reporter has an equally strong argument for "This is a news wire, not a journal. I just report today's news as succinctly as possible, it's the readers responsibility to read further and put this stuff in context if that's really important". As a side note though, I like the Economist because they tend to do what you're talking about - put things in context.

I have to agree with you on context, especially for technical and energy-issues stories. And yes, journalists are exceptionally lacking and poor in this regard.

That said, there are tools out there which help. There's an immense wealth of information available online -- we can look up the population of Beijing (20 million, via Wikipedia), the International Energy Agency and other sources have various energy statistics.

A favorite tool of mine is gnu 'units', a commandline calculator that many people associate with simple transformations from feet to meters. But that misses out on its key capabilities -- it's really an advanced units-aware calculator with a large number of built-in values. I just found earlier today that this includes paper sizes:

    $ units 'A4paper'
            Definition: 210 mm 297 mm = 0.06237 m^2

It's also extensible -- I've added 'hiroshima' as an energy unit. Given the context of the current discussion, that in tons of coal equivalent:

    $ units '1 hiroshima' 'toncoal'
    	* 1942.6672
    	/ 0.0005147562

For more discussion, features, and use:

https://www.reddit.com/r/dredmorbius/comments/1x9u0f/gnu_uni...

Getting back to your question, how does one 845 MW plan compare with Beijing's energy usage?

    You have: 845MW / 20 million
    You want: watt
            * 42.25
            / 0.023668639

... I presume China's power supply exceeds 42 watts per capita (though I happen to know from context that third-world nations are at roughly this level). Wikipedia again tells us that the national average is 458 watts/person, which probably includes less-developed rural areas. So it's likely that the shuttered power plant is at best 1/10 Beijing's power supply, quite possibly less than that.

https://en.wikipedia.org/wiki/List_of_countries_by_electrici...

That said, yes, poor and sloppy contextualization on the part of Bloomberg and Feifei Shen.

I'm guessing they just took the figures from the Chinese press release and turned it into an article. Lazy journalism at its best.

this is probably how most journalism is done today

Probably?

A similar journalistic annoyance is that when articles want to say something is expensive, there are only two values.

"X costs millions."

or

"Y costs billions."

An artist impression of how the city will look like in terms of smog in 5, 10 and 20 years from now would also be nice.

Why don't you research those answers yourself if they're of paramount importance to you?

You're completely missing the point. He's saying that for everyone's sake, contextualizing the numbers improves the quality of everyone's understanding and helps determine the actual significance of the news. You and I both would benefit, not just him.