Hacker News Reader

Comment by mikegioia | Hacker News Reader

I think this is wonderful, but this chart [1] seems to indicate that the decrease in coal use is really only replaced by the increase in natural gas.

Natural gas seems to release less CO2 than coal burning, but it would be much nicer to see the nuclear and renewables climbing at a faster rate. Hopefully the 2015->2025 trend is far better.

[1] http://www.eia.gov/todayinenergy/images/2016.05.13/chart3.pn...

View on HN

Natural gas releases less CO2, but it releases more methane in the shipment process, which is far more potent as a climate change agent than CO2. Depending on which estimates you buy into on the amount of methane lost, natural gas may be worse than coal for climate change.

At least the Methane doesn't stay in the atmosphere for geological periods of time.

It's not quite that simple because the overall impact of an individual compound relies on both its atmospheric residence time and infrared absorption. This article[1] covers the basics.

[1] https://en.wikipedia.org/wiki/Global_warming_potential

That doesn't really contradict adrianN's point in any way. If you integrate methane's heat retention over now to 100 years from now it still beats carbon dioxide. That doesn't mean that if you integrate from 50 years from now until 100 years from now it would still win. Much less so if you look at a geological time period in the future.

What do you think happens to the methane in the atmosphere? It doesn't vanish. Most of it reacts in the statosphere and troposphere and oxidizes into ... you guessed it: Carbon Dioxide.

10% gets eaten by organisms in the soil, but at least 90% turns into CO2.

Of course, Natural Gas thermal combined-cycle electricity generation is MUCH more efficient than Coal, no matter which way you look at it. (Unless you have an old already-paid-for coal plant next to a coal mine and only care about dollars)

The damage caused to water tables and such caused by extracting natural gas does last that long though, it's not a very good solution.

There's still other reasons natural gas is a better fuel, though. Plants come on & offline more quickly, there's no need for emissions scrubbers & no truly noxious combustion byproducts. There's also no steam output or water consumption, though as there is still waste heat maybe that doesn't matter.

There's also potential to get natural gas plants up to 60-80% efficient, which means still less CO2 production compared to a 30-40% for coal.

The other thing about combined cycle plants is they are cheap. A big worry for anyone building a power plant is the long term economics, especially capital costs. Obviously you want the plant to run profitably long enough to pay off the bonds.

For Combined cycle low capital costs means the financial risk involved is much lower. Much more likely it'll pay off the capital costs. After that if the economics get dodgy it can be run intermittently or mothballed. IE, the utility isn't stuck paying off bonds on a plant that is shut down.

Flip side is coal fired plants have higher capital costs, longer payback and high financial risk. If carbon taxes make your plant uneconomic to run before the capital costs are paid off, the owners take a bath. (Nuclear and solar plants have the same issues, very high initial capital costs)

That is until things like this happen:

https://en.m.wikipedia.org/wiki/Aliso_Canyon_gas_leak

That's really something. We'll see if it stays plugged.

For apple to apple comparison Green House Gases values are converted to CO2e (CO2 equivalent). This was a standard practice when I was in the industry. The article it self does not mention it, But I am pretty sure the graphs have CO2e values not CO2.

> it would be much nicer to see the nuclear ... climbing at a faster rate.

Good luck convincing a nation of fear mongering people that nuclear energy is safe. The whole argument of not in my backyard comes to mind.

Solar panel prices are dropping fast enough that I may actually consider putting one on my house and keeping my house at a nice 70 degrees all year round.

Normally I feel AC is something we should try to do without. But come to think of it, if you can actually power an AC unit with panels on your roof, aside from manufacturing the system, it's fairly elegant. You're harvesting & then releasing energy that was bound for that patch of land anyway. Like capturing rainwater on your property and redirecting it through your garden.

> Good luck convincing a nation of fear mongering people that nuclear energy is safe.

I despise nuclear be its no longer cost effective, not because it uses uranium for energy production.

I'd live near a nuclear plant if they offered me free heat in the winter! But alas, nuclear's time has come and gone for commercial electrical generation.

The IEA World Energy Outlook, and other realistic detailed future energy scenarios (including IPCC reports) say we're going to double or even triple nuclear power production from now until 2050.

Have a citation? All OECD reports I've seen show little to no expansion of nuclear except in possibly China and India. Nuclear power is going to need to come in under 3 cents/kwh to compete against solar and wind.

Nuclear power doesn't have to compete with solar and wind during quiet winter nights-- it gets to compete against batteries + solar/wind.

Grids with a lot of renewables are also dealing with a lot of stress on the electrical grid: http://www.pri.org/stories/2015-04-07/when-grid-says-no-wind...

It's a solvable engineering problem, but the meta operations problem is: "is it cheaper to have a grid that is 50% nuclear and 50% renewable, or a grid that is 100% renewables with a lot of battery-stations to absorb/emit the variances"

Only in the most pro-nuclear estimate is that true.

The 2014 IEA report gives two numbers, 413 GWe (low nuclear) and 1092 GWe (high nuclear) estimates for 2050. Compared with today's 377 GWe.

And they've been revising those numbers downward each of the past several years since Fukushima.

http://www.world-nuclear.org/information-library/current-and...

Not an expert, but I thought nuclear waste disposal was a huge unsolved problem too, rather than plant safety.

8% to 13% in 10 years is not nothing.

Also, the idea behind the renewables push/subsidies was to get it past the early years where it is not competitive with fossils. We've been hearing rumblings that we are roughly at the point where this changes, so in another 10 years we might see an increased growth rate.

So, some good news.

I noticed the same thing. You could say it's because natural gas has become a cheaper fuel alternative to coal, or that the world is more interested in burning cleaner fuels. Perhaps it's a bit of both.

Definitely natural gas is cheaper. And also world leaders are starting to get spooked by global warming. Fear trumps banal economics.

The world needs an energy storage system for renewables the moment we find something the carbon emissions from power generation will fall of a cliff.

Reply on news.ycombinator.com