Europe: Improve emission factors for gas

[madsnedergaard]

Description

We are aware that the current emission factors based on EU-ETS could be improved further.

See past discussions here: #5417
And the great work by @w-flo here: https://github.com/w-flo/eu-emission-factors/tree/main

This issue is intended to gather knowledge and details about how we can improve this further for next time we can update the numbers, as EU-ETS is supposed to release new data quite soon (during April as far as I can tell).

[w-flo]

EU-ETS data is now available for 2023 (under "Documentation").

As I see it, there are three issues:

• It's difficult to map Entso-E electricity production data to the corresponding EU-ETS emissions data. Some automatic mapping based on power plant names is possible, but only in somewhat lucky cases. I have the manual_matches.csv file in the repo you linked, as a best-effort manual mapping for cases where the automatic attempt fails, but that's not really straight-forward either. It probably has some incorrect entries (e.g. sometimes smaller units / turbines of a power plant are missing from Entso-E, but EU-ETS reports emissions for all units of the power plant). Still, I'd say it's possible to mostly solve this issue by using something like my manual_matches.csv file and manually filtering plants where units are missing etc.
• How to handle combined heat and power plants (CHP). A simple "emissions divided by production" calculation is not the right approach in this case, because some emissions should be attributed to heat provision instead of electricity production. However, I couldn't find a data source for the amount of heat provided by each CHP plant per year, so finding a solution for this problem is difficult. I'm not convinced by my attempted solution in the linked repo. As I understand it, it is possible to extract the amount of heat provided by each ETS power plant in the baseline period (2014 to 2018) from the ETS "free emission allowances" allocation. However, using that old data for current years might be problematic, and I'm not sure how this works with new power plants (I think they use some kind of estimation in their first year, and then recent data instead of data from 2014 to 2018?). Related to this, some CHP plants provide heat (and/or steam) to nearby industry. If that industry needs to use ETS itself, the power plant won't receive free emission allowances for that heat, so the estimation based on that "allocation" fails. Another case for manual filtering.
• Small power production units (<100 MW) do not publish any unit-level data in Entso-E or emissions data to ETS. For example, in 2023, my tool reports that Germany produced 28.8 TWh of gas power based on Entso-E unit-level data (29.1 TWh according to energy-charts). However, total gas power production in 2023 was 50.1 TWh according to Entso-E. My tool matched 25.3 TWh of unit-level production data to corresponding emissions data, estimating a direct emission factor of 437 g/kWh. But that's based on only one half of the total gas-based electricity production. I don't think it's correct to take this as the (direct) emission factor for all gas power plants in Germany, because we don't know anything about the other half. It would probably be better to weight that number of 437 by a factor of (25.3 / 50.1) and assume some IPCC emission factor or similar for the "unknown" other half of the total German emission factor. Maybe electricity-maps already does this, but I think it didn't a few years ago.

Of course, the same applies to coal and oil. At least coal is slowly going away and oil is rarely used.

[cgicgi]

awesome work and explanation, thank you!
Small correction: energy-charts reports 27.2 TWh based on Entso-E unit-level data (your link points to EEX as data source with the mentioned 29.1 TWh)

[madsnedergaard]

Thanks for sharing the update @w-flo, we are planning on addressing this soon and updating the numbers - hopefully we can include your great work! We will get back in touch soon :)

[madsnedergaard]

This list (shared here) might be useful to look at what power plants are active:

https://www.bundesnetzagentur.de/DE/Fachthemen/ElektrizitaetundGas/Versorgungssicherheit/Erzeugungskapazitaeten/Kraftwerksliste/start.html