Friday, August 30, 2019

Coal's last hope: carbon capture



CCS (Carbon capture and storage/sequestration) is a process whereby CO₂ is extracted from the exhaust flues of fossil fuel power stations and pumped into underground caverns.  The argument goes that if we could only stop emitting CO₂ when we burn fossil fuels, then we could go on burning those fuels.  Unfortunately, it's not that easy.

From OilPrice.com:

Coal usage continues to fall and the coal industry wants to do something about that. So does the Trump administration. Their proposed solution to the problem of waning coal usage is carbon capture and sequestration (CCS)—a technology that has been around for a long time.

The basic idea behind CCS is to remove the carbon dioxide from the exhaust stream after burning the coal. Then the “captured” CO2 can be redirected.

But in the US, the Southern Company and others attempted to develop an additional process. Their ultimate goal was to use cheap and plentiful Mississippi lignite and convert it chemically into clean-burning synthetic gas. The CO2 produced from combustion would also be captured. One actual use is to pump CO2 into older, less productive oil field reservoirs to enhance oil recovery. One suggestion is to replace the oil with CO2 storage after the field has been depleted.

At present Southern Company’s Kemper County facility is synonymous with failure. A proposed $2.5 billion CCS plant was eventually completed at a cost of over $7 billion. What’s even worse, operation of the coal gasification unit has been suspended and the plant burns purchased shale gas. And there is no carbon capture whatsoever.


The first problem with CCS is the cost.  The gas must be extracted from the exhaust gas of power stations, compressed (which uses a lot of energy), transported (which uses more) and then pumped into underground caverns.

This is ultimately being described in the language of finance. Coal-fired power plant owners are stating that their assets are relatively new. And their expectations are for a continued, long productive life. If not the assets would have to be written down. This would imply negative financial implications at the corporate level for both earnings and balance sheets.

Leaving aside the question of whether past (not fully depreciated) power plant investment should influence future decisions (the sunk cost issue), the real policy question is: what are we doing—limiting greenhouse gas emissions at the lowest possible cost or saving the coal industry?

One recent study by the Institute for Energy Economics and Financial Analysis produced these approximate costs (in cents) per KWH:

  Wind power with storage                         2.1
  Coal                                            3.0  
  Solar power with storage                        3.5
  Coal with sequestration (long term goal)        6.3        Coal with sequestration (current)               9.6 
The absolute numbers in this table are not as important as their relative values and their credibility. Builders are already bidding on wind and solar at relatively low numbers, so the quotes can be depended on as can costs for coal since we know how to build those plants.

The problem simply is that electricity produced by coal-fired plants using the latest CCS technology is several times the cost of other existing carbon-free technologies. With respect to a commodity product like electricity, these numbers are politically and financially untenable. To overly simplify, coal is already losing on price to wind. The CCS advocates propose to double the price of coal (from about 3 to at least 6 cents per kwh).


The second problem is that no one is sure just how long CO₂ pumped into underground caverns will stay there.  What if it all just leaks back into the atmosphere? 

CCS is a delusion.  It won't make coal or gas "clean".  And it will cost us 2 or 3 times as much as wind and solar with storage.  But we will need carbon capture to reduce levels of atmospheric CO₂ already emitted, storing the CO₂ by dissolving it in water and storing it as rock.  And it will be costly.  Will society pay for it?  Only when the cost of the climate emergency becomes so great that the political pressure to act will be irresistible.  And if people are still whinging about the cost of wind turbines when they're actually cheaper than fossil fuels, what hope is there?

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