jrissman
commented
2 years ago Small edit to item 3 above: I wrote:
Emissions from use of personal care products by households should probably be assigned as process CO2 to the "water and waste" industry, as there is no concept of "process emissions" outside of the industry sector.
and
Emissions from decay of chemical products should be assigned as process CO2 to the Water and Waste industry.
If we do this, we may need to structurally prevent the use of CCS on process CO2 emissions from the "water and waste" industry, because there is no way to use CCS to capture emissions from the use of personal care products in households. It probably isn't practical to use CCS to capture emissions from the decay of plastics and stuff in landfills either, because the decay rate is so slow that the CO2 concentration would be hardly different from the atmosphere (in which case, you might as well just use direct air capture). Capturing gases from landfills is more relevant for methane from organic decomposition, which proceeds much more rapidly than breakdown of chemical products like plastics.
Industrial feedstocks consist of the fossil fuels used by the chemicals industry to make petrochemicals, and metallurgical coal used to make coke used by the iron and steel industry. The EPS currently doesn't have any policies to decarbonize or use zero-carbon substitutes for these feedstocks (apart from CCS, which can target CO2 process emissions, and policies or financial effects that decrease the output of the chemicals or steel industries, which will scale down feedstock use proportionately to production).
Not all of the carbon in feedstocks ends up in the final products. For instance, the chemicals industry emits some process CO2, which consists of the difference in carbon content between what is in the feedstocks and what ends up in final products. Also, the coke used by the steel industry largely becomes CO2, only contributing a small amount of carbon to the steel. These are the process CO2 emissions that, currently, can only be targeted via the CCS policy.
For the chemicals industry, alternatives include green hydrogen + captured CO2 feedstocks, or bioenergy feedstocks. For industry, alternatives include hydrogen-DRI steelmaking, or electrolysis of iron ore. Either of these approaches could reduce or eliminate CO2 process emissions from these industries.
Additionally, the carbon that does go into the chemicals industry's final products may not stay trapped in those products. For instance, the carbon in fertilizers is released as CO2 soon after the fertilizers are applied to fields. Even plastics aren't intended to be a secure, long-term storage mechanism for carbon. Some plastics are incinerated at end-of-life (about 15% today, but projections are that the incinerated share will rise to 50% by 2050), and even non-incinerated plastics may break down over decades or centuries. (On the other hand, I think it's safe to assume carbon in steel remains trapped there, though it could be released if the steel fully corrodes.)
To properly represent the full benefits of decarbonizing industrial feedstocks, we need to add the emissions from the use or decay of chemicals products (fertilizers, plastics, solvents, personal care products, etc.) into the model. We might already be including these emissions in certain cases. For instance, CO2 emissions from fertilizer use would be process CO2 for the agriculture industry, which we may already account for. And incinerated plastics might be part of the emissions of MSW-fired power plants. Maybe the "water and waste" industry can have process CO2 from things like decaying plastics or personal care products. We need to review the current data and make sure the emissions from use of chemicals products are being accounted for.
Then, when the feedstocks are decarbonized, we need to subtract the emissions from the use and decay of these products (much as we use an adjusted lifecycle CO2 intensity for biomass power plants, reflecting the CO2 in the biomass came from plants).
So the work for this essentially involves a few parts:
Add new mechanisms to decarbonize feedstocks. I think these should be chemicals green hydrogen + captured CO2 feedstocks, bioenergy feedstocks, and iron and steel hydrogen-DRI, and maybe iron electrolysis.
Ensure the demand for fossil fuels declines correctly, with associated reductions in energy use, process emissions (such as methane leakage), cash flows, etc. for the fossil fuel supplying industries, when they no longer supply fossil feedstocks. Ensure the demand for hydrogen or bioenergy increases correctly, with associated impacts.
For chemical products only: Ensure all emissions from the use and breakdown of chemical products are included in the EPS. Emissions from use of products by industry should be assigned to the industry that uses the product. For example, CO2 from the use of fertilizers should be assigned to the Agriculture industry as CO2 process emissions. Emissions from use of personal care products by households should probably be assigned as process CO2 to the "water and waste" industry, as there is no concept of "process emissions" outside of the industry sector. Emissions from plastics incineration should ideally already be included in the emissions of the facilities that burn the plastics (like MSW power plants), but we need to track the amount that comes from incinerating plastic so we can decrease it in response to policies that decarbonize feedstocks. Emissions from decay of chemical products should be assigned as process CO2 to the Water and Waste industry.
For chemical products only: Reduce the process CO2 sources noted above as a percentage based on the percentage decarbonization of chemical feedstocks.
Feedstocks can represent a lot of fossil fuel production. Therefore, decarbonizing feedstocks can have a big impact on fossil fuel production, on the growth of the hydrogen or bioenergy supply industries, etc. These are important dynamics to include when modeling industrial decarbonization.