Need a multiplier to determine share of coal mining emissions from active mines to correctly calculate reduction from limited production

[robbieorvis]

Right now the model adjusts process emissions based on production from different industries. If we were to eliminate production of coal mining, process emissions would go to zero (mainly methane). However, most coal mining emissions are not from active mines, but from older mines that leak methane. Therefore, the reduction in emissions from changes in demand should be limited to the share of emissions from active mines.

This will require a new input variable and a small structural change.

[jrissman]

Good idea.

Do you know if the methane capture and methane destruction potentials for the coal mining industry, provided by the EPA in PERAC, assume most of those methane capture and destruction activities will be undertaken at inactive mines?

[robbieorvis]

Reading through the methodology, as far as I can tell the answer is that they don't assume anything will be done on abandoned mines. The latest inventory from EPA suggests about 10% of methane emissions from coal mining are due to abandoned mines (though I would bet this varies widely by state): https://www.epa.gov/cmop/coal-mine-methane-sources

For a starting point we could just assume only ~90% (using the actual number at the link above) of the emissions are abatable from ending coal mining.

[jrissman]

That link you found is a good source.

But it is a snapshot of what is happening in 2018. If we ended coal mining, some of the mines in the active category might move into the abandoned category, and their emissions would then decline, but not entirely vanish. Here's some text from this UN webpage about what happens when a mine is closed:

After mine closure, methane emissions decrease, but do not stop completely. In most cases, the remaining coal still contains considerable amounts of gas that is slowly released. While the gas flow initially declines, it can later stabilize and maintain a near-constant rate for an extended period of time. If not prevented by an adequate sealing, the liberated gas will migrate to the surface and escape to the atmosphere. Under certain conditions, it may also be vented to avoid build-up and possible leaks through cracks and fractures in the overlying strata.

One option is to find how much less methane an abandoned mine emits versus an active mine (of the same mine size and type), and coal mining industry closures only reduce active mines' emissions by that difference, rather than to zero. We might then need to scale PERAC abatement potential down accordingly, since we assume that PERAC measures can be used on abandoned mines, if those mines were in PERAC's total abatement potential already (because they were active mines in the BAU case).

Or, we could assume that, going forward, all coal mines that are closed down are properly sealed so no methane can leak from them. That would certainly be far simpler, methodologically. BPEiC says that coal mining methane emissions (including active and abandoned mines) in the BAU case are about 7 MMT/year now and decline to 4 MMT/year by 2050 in the BAU case, so we're talking about pretty small differences here, so it may not be worth going to great trouble for high accuracy, unless you think that stopping methane leaks from coal mines is a topic of particular interest to policymakers right now, and they need higher resolution data on this specific intervention.

[robbieorvis]

Thanks for this.

I think we should look into it for a subsequent model update. Nationally, it’s not that important, but the reason this came up is that I’m using this lever in Virginia, where there is more significant coal mining. And on the oil and gas side, this will definitely be an issue in the Colorado and New Mexico models (and if we ever do models for Wyoming, Kentucky, or West Virginia, the coal piece will be super important). It may also be more important in countries like China and India with a significant amount of coal mining.

Let’s file this away and revisit in 2021.

---

Robbie Orvis Director of Energy Policy Design Phone: 415-799-2171 98 Battery Street, Suite 202 San Francisco, CA 94111 www.energyinnovation.orghttp://www.energyinnovation.org/ [cid:image001.jpg@01D0D699.20A24470]

---

Check out our new book, Designing Climate Solutions: A Policy Guide for Low-Carbon Energyhttps://www.amazon.com/Designing-Climate-Solutions-Policy-Low-Carbon/dp/1610919564 Available wherever books are sold

[Policy Design book cover]

From: Jeff Rissman notifications@github.com Sent: Tuesday, November 24, 2020 3:06 PM To: Energy-Innovation/eps-us eps-us@noreply.github.com Cc: Robbie Orvis robbie@energyinnovation.org; Author author@noreply.github.com Subject: Re: [Energy-Innovation/eps-us] Need a multiplier to determine share of coal mining emissions from active mines to correctly calculate reduction from limited production (#121)

That link you found is a good source.

[CMM]https://user-images.githubusercontent.com/7120106/100144569-d2438f80-2e4b-11eb-8c07-edb903fd5b0e.PNG

But it is a snapshot of what is happening in 2018. If we ended coal mining, some of the mines in the active category might move into the abandoned category, and their emissions would then decline, but not entirely vanish. Here's some text from this UN webpagehttps://www.unece.org/info/media/news/sustainable-energy/2017/proper-management-of-abandoned-mine-methane-is-vital-for-reducing-greenhouse-gas-emissions/doc.html about what happens when a mine is closed:

After mine closure, methane emissions decrease, but do not stop completely. In most cases, the remaining coal still contains considerable amounts of gas that is slowly released. While the gas flow initially declines, it can later stabilize and maintain a near-constant rate for an extended period of time. If not prevented by an adequate sealing, the liberated gas will migrate to the surface and escape to the atmosphere. Under certain conditions, it may also be vented to avoid build-up and possible leaks through cracks and fractures in the overlying strata.

One option is to find how much less methane an abandoned mine emits versus an active mine (of the same mine size and type), and coal mining industry closures only reduce active mines' emissions by that difference, rather than to zero. We might then need to scale PERAC abatement potential down accordingly, since we assume that PERAC measures can be used on abandoned mines, if those mines were in PERAC's total abatement potential already (because they were active mines in the BAU case).

Or, we could assume that, going forward, all coal mines that are closed down are properly sealed so no methane can leak from them. That would certainly be far simpler, methodologically. BPEiC says that coal mining methane emissions (including active and abandoned mines) in the BAU case are about 7 MMT/year now and decline to 4 MMT/year by 2050 in the BAU case, so we're talking about pretty small differences here, so it may not be worth going to great trouble for high accuracy, unless you think that stopping methane leaks from coal mines is a topic of particular interest to policymakers right now, and they need higher resolution data on this specific intervention.

— You are receiving this because you authored the thread. Reply to this email directly, view it on GitHubhttps://github.com/Energy-Innovation/eps-us/issues/121#issuecomment-733204421, or unsubscribehttps://github.com/notifications/unsubscribe-auth/AK5N6SKARH7GUQZM45KWPN3SRQGZXANCNFSM4UBALO4A.