Sun. Oct 2nd, 2022
Here's what it could cost California to reach its zero-emission goal

In September 2018, California Governor Jerry Brown set a greenhouse goal for the state: net-zero emissions by 2045. It’s a very aggressive target. The easiest part of the energy transition is the first part: growing the meager share of renewable energy on the grid. But cleaning up the last 20 percent of our energy use is a bigger challenge and still needs to be tackled. From industry to air travel to agriculture, some things look like a very heavy burden.

However, reaching net--zero emissions are easier than “actual” zero because activities that use active CO. remove2 from the atmosphere (sometimes called “negative emissions”) could wipe out some of the persistent emissions we can’t get rid of. To find out how that might work in the case of California, a report from Lawrence Livermore National Laboratory analyzed options to estimate costs. It points to a hefty — though not impossible — price tag to meet that 2045 target.


The first question is how much CO2 California will have to suck from the atmosphere to achieve its goal. The Golden State’s current plan is to reduce emissions from more than 400 million tons per year to about 86 million tons by 2050. In that case, to reach net zero, negative emissions would have to grow to 125 million tons per year. in 2045.

The green line shows how much greenhouse gas California would need to remove from the atmosphere each year to reach net-zero emissions by 2045.
enlarge The green line shows how much greenhouse gas California would need to remove from the atmosphere each year to reach net-zero emissions by 2045.


The report calculates the cheapest and most plausible combination of negative emissions to reach 125 million tons. About 25 million tons per year could come from land management. Another 84 million tons could be supplied by a system that produces fuels and CO. captures2 of organic waste such as crop stems and shrubbery to reduce fire hazards. The last 16 million tons would be processed by facilities that use industrial processes to extract CO. to catch2 from the air, which currently exist only as pilot projects.

Land management involves a range of activities, some of which are really cheap. For example, by restoring agricultural land to grassland or wetland, it can absorb a lot of carbon. And changing the way cleared forest is managed by allowing longer growth cycles between harvests, or selectively removing dead trees to make room for something to grow, would also remove some carbon from the atmosphere.

About four of the 25 million tons per year in this category are related to increasing carbon build-up in the soil. That could mean swapping some annuals for perennials that grow bigger roots and reduce the need for tilling the soil. Compost or even charcoal produced from vegetable waste can also be added to the soil as inputs, improving soil quality while contributing to negative emissions.

The future of carbon

After that, the story gets a bit more unconventional. Most of the negative emissions in the report come from ‘waste biomass conversion’. This can take various forms, but the report highlights hydrogen production as the best option. Heating organic matter to a high temperature under controlled conditions that prevent combustion produces carbon monoxide, CO2, and hydrogen gas. The hydrogen gas can be separated for use as fuel and the rest can be stored underground.

The report notes that the hydrogen doesn’t even necessarily have to be sent to specific hydrogen combustion applications (although it could be). Without modification, a fair amount of hydrogen can be injected directly into existing natural gas pipelines.

As for the biomass fueling this process, the report identifies about 13 million tons of agricultural chaff every year, 13 million tons of things like wood and cardboard that are thrown away every year, and 24 million tons of wildfires to reduce the risk of wildfires. This would provide a market to pay for brushcutter equipment – something that is currently in great short supply. Finally, the report includes sewage and manure digesters that produce biogas.

The other big strategy would be “direct air capture” plants, which filter air through a chemical process known as CO. catches and separates2 gas. This is currently the most expensive option for obtaining carbon dioxide, but it has the advantage that you can scale about as much as you’d like. Since this technology is still in its early stages, there is plenty of room to bring that price down. The report even suggests California could “buy off” costs by providing the early investment the technology needs to mature. Specifically, it estimated that the cost per tonne of CO2 20-30 percent would fall after the first few factories were built.

The mix of
enlarge The mix of “negative emissions” options highlighted by the report. The cost of each option is shown on the vertical axis, with the amount of carbon that could be absorbed by the width of each bar.


A to B to CO2

This leaves two logistical questions: how are all these solids and gases going to be transported, and where does the captured CO . go?2 get dumped?

For all that brush and agricultural waste, rail is the cheapest way to move it. But rather than a random proliferation of facilities that handle or handle that, the report proposes a centralized mainline in the middle of the state along which everything would be located. In this way, trucks did not have to travel far to reach a railway line, which could carry it along that main line.

Along that central line there would be a single CO. to be2 pipeline. Gasification installations would process biomass and their captured CO . drive out2 in the pipeline, which would take it to the storage facilities that would pump it underground. Just like California has some oil and gas wells, it has rocks capable of holding and retaining CO2† Injected at a sufficient depth (where the pressure is high), CO2 gets denser, loses interest in bubbling up exuberantly.

The report estimates that California has enough geological capacity to store CO for at least 100 years. to accept2 capture at the speed discussed here. And the plan should be to eliminate the need for carbon storage anyway during that time.

The estimated total cost for the variety of actions outlined in the report that would bring California to net zero emissions by 2045 is approximately $8 billion per year. While no one will be thrilled to squeeze $8 billion into a budget, the report notes that it’s just 0.4 percent of the state’s current GDP. Or for another comparison, it equals just over 5 percent of the state’s current tax revenue.

Of course, if the state fails to make emissions cuts, it could cost a lot more to curb that extra carbon.

By akfire1

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