You are here

Doubt Cast on Carbon Capture by Stanford Study

Doubt Cast on Carbon Capture by Stanford Study – “It Usually Increases Air Pollution”

This is a great example of how to lie with numbers. If you have a fossil fuel plant, there are two sources of emissions: direct emissions, from operating the plant, and indirect (or upstream) emissions, from transporting the fossil fuels, building the plant, and so on. A carbon capture project is only able to capture direct emissions from the plant itself. If you include the upstream emissions, which the project is by definition unable to capture, then you limit its apparent efficiency. This is doubly dishonest when there are options for reducing those emissions, which the study ignores.

Jacobson then manages to be triply dishonest by specifically looking at cases in which the energy for the carbon capture is provided by fossil fuels without CCS. In a decarbonized grid, that energy would not be coming from dirty energy sources; it would be coming from either a) parasitic load on the plant the CCS is installed on, or b) other clean energy sources like solar and wind.

Also, I know I keep on harping on this, but buying electricity isn't like buying milk at the grocery store. When you buy milk, you have a bunch of similar products (whole milk, 2%, and so on) which work in similar ways and are offered at similar or prices. With electricity, different energy sources operate in different ways and fill different needs, and they have different prices. Energy sources need to be understood in the context of the entire energy system.

Wind is an energy source that is cheap and unreliable. That makes it most useful for satisfying baseload demand. Fossil fuels with CCS are expensive but can be used anytime you want. That makes them useful for load following (i.e. satisfying demand above baseload, like during the peak hours of the day), and for satisfying baseload demand when wind is unavailable. When balancing authorities decide which energy source to use to satisfy baseload demand, they choose the cheapest one, within operational constraints. This means that, given a choice between cheap wind and expensive fossil fuels with CCS, they'll generally choose to buy the cheap wind.

What all of this means is that fossil fuels with CCS will only ever be able to fill a niche role in a clean energy system. So it doesn't make sense for Jacobson to count emission reductions from using wind as an opportunity cost.

This doesn't mean that CCS is the only way to provide stability to the grid. There are plenty of other things that would (or could) help, like building long distance transmission lines, grid-scale energy storage, and shifting demand to match peak production instead of the other way around. An example of demand shifting would be if you built a bunch of wind turbines, and then, when production was higher than demand, you used that excess energy to power your standalone carbon capture equipment to pull carbon out of the atmosphere. Jacobson ignores this, even though it would allow for higher renewables penetration.

Make no mistake, CCS still has a LOT of unresolved issues, some of which Jacobson hints at, and some of which he does not. We also need more wind and solar power regardless of what happens with CCS. But dishonest papers like this do nothing to move the conversation forward.

Commenting on this Blog entry will be automatically closed on December 28, 2019.