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.
To add to this: if you burn one mol (16g) of CH4 you get one mol of CO2 (44g) and water and 900 KJ of energy. If you burn one mol (12g) of C you get the same mol of CO2 (44g) and only 400 KJ of energy. Overall you get more than twice the same thermal energy for the same amount of emitted CO2. What's more, the most efficient power plant can only convert 42% of the thermal energy into electricity, while the most efficient gas power plant can convert 62%.
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.
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.
>...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.
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.
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.
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.
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.
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.
>...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.
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.
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.
Natural gas is also in vastly shorter supply than coal, naturally forcing a transition away from it fairly soon.