by Judith Curry
This post is stimulated by an email I received from Georgia Tech alum Rutt Bridges, who asked for feedback on a recent article he published in First Break entitled “Economic Challenges for Carbon Capture-Storage and the Role of Natural Gas.”
Rutt Bridges has a very deep and interesting perspective on climate-energy challenges. For background, see his Wikipedia biosketch. He is a geophysicist that started his career at Chevron. He is founder of the Bighorn Policy Center (now defunct) and has been very active in the Democratic Party in the state of Colorado, including running for the U.S. Senate and declaring candidacy for governor (but withdrew from both races).
Here are excerpts from the email I received from Rutt, which summarize the paper and his motivations:
I have real concerns about the [impact of global warming] on our planet. However, I was asked to contribute an article to a Carbon Capture and Storage (CCS) special issue for the EAGE (European Association of Geoscientists and Engineers) First Break publication. Of course, I am always concerned about economic issues when looking at problems such as this, and the results of my research were quite troublesome. At this stage I am very skeptical of CCS and so-called “clean coal” as a viable solution. In addition, it appears that investment in alternative energy has fallen dramatically in the last year (72% drop in wind investment in the first 3 quarters of last year) due largely to anticipated expirations of subsidies. In the end I concluded that natural gas appeared to be a reasonable and financially competitive bridge fuel, in spite of the fact that it still produces significant amounts of CO2 (about 40% as much as coal).
Economics are a tough hurdle to clear, especially in times of recession. Given the current political environment, that is especially true. I am not very optimistic at this time that we will see any significant contribution carbon reducing carbon from the US in the next several years due to economic and political drivers.
I would welcome any comments, regardless of how critical they might be.
I encourage you read the whole paper, it is concise and well written. I have posted the paper online here.
Here is the concluding section to the paper:
Carbon capture and storage is the only currently known solution for burning fossil fuels without adding significantly to greenhouse gases. In America, given the challenges facing nuclear and renewables plus the lack of suitable hydro-electric sites, the continued development of CCS will be essential to achieve long-term goals for CO2 reduction. But given the lead times for CCS development, natural gas could well offer the only practical bridge to that future. It is not a perfect solution, but can we afford to let the perfect be the assassin of the good?
To summarize:
• In the US, additions of wind and solar power are likely to decline significantly without the renewal of subsidies and tax credits, and that decline appears to have already begun.
• Renewal of current subsidies and tax credits appears to be unlikely in the current political environment.
• The significant expansion of US nuclear power in America will be difficult to achieve.
• US electricity markets are increasingly price-sensitive, in part due to the recession and in part due to shifting political winds.
• Electricity generation is responsible for 40% of America’s total CO2. Coal produces 45% of US electricity but 80% of electricity-related CO2
• Opportunities for retrofitting existing US coal-fired plants to CCS are more limited in the US due to the low efficiencies of the installed base.
• Modern natural gas-combined cycle (NGCC) plants can provide electricity at a significantly lower cost than can new conventional coal-fired plants.
• NGCC plants produce 60% less CO2 per MW-hour than conventional coal-fired plants.
• America has a 100-year domestic supply of natural gas at current consumption levels and rapidly growing unconventional gas resources.
• Though such a change is unlikely, replacing all coal-fired electricity with NGCC plants would cut total US CO2 emissions by 20%.
• The low cost of electricity from existing coal plants will be a barrier to the greater use of natural gas, unless the external costs of greenhouse gasses and noxious pollutants are taken into account.
• Uncertainties regarding the stability of the price of natural gas are a deterrent to its expanded use, though long-term contracts, price hedging, and potentially utility-gas producer partnerships can mitigate this issue.
• Pollution control could offer a significant and immediate advantage for natural gas over coal in some markets.
• In spite of the challenges, ultimately a transition to renewable energy, nuclear, and/or CCS-assisted natural gas or coal will be necessary to meet long-term CO2 reduction goals.
Is the cure worse than the disease?
There is significant concern about possible adverse effects from natural gas fracking to obtain shale gas, see the Wikipedia for a summary:
As noted above, the Obama administration has sometimes promoted shale gas, in part because of their belief that it releases fewer greenhouse gas (GHG) emissions than other fossil fuels. However, there is growing evidence that shale gas emits more greenhouse gases than does conventional natural gas, and may emit as much or more than oil or coal. In a May 2010 letter to President Obama, the Council of Scientific Society Presidents [7] urged great caution against a national policy of developing shale gas without a better scientific basis for the policy. In late 2010, the U. S. Environmental Protection Agency [8] issued a new report, the first update on emission factors for greenhouse gas emissions by the oil and gas industry by the EPA since 1996. In this new report, EPA concluded that shale gas emits much larger amounts of methane, a potent greenhouse gas, than does conventional gas. Methane is a very powerful greenhouse gas, although it stays in the atmosphere for only one tenth as long a period as carbon dioxide. Recent evidence indicates that methane has a global warming potential that is 105-fold greater than carbon dioxide when viewed over a 20-year period and 33-fold greater when viewed over a 100-year period, compared mass-to-mass.[9] A recent study by Cornell University environmental professor Robert W. Howarth [10] and colleagues finds that once methane leak impacts are included, the life-cycle greenhouse gas footprint of shale gas is far worse than those of coal and fuel oil when viewed for the 20-year period after emission. On the 100-year time frame, this analysis finds shale gas comparable to coal and worse than fuel oil.
Chemicals are added to the water to facilitate the underground fracturing process that releases natural gas. The resulting volume of contaminated water is generally kept in above-ground ponds to await removal by tanker or injected back into the earth.
There is a good article on this subject at the americanprogress web site entitled “Drilling Down on Fracking Concerns: The Potential and Peril of Hydraulic Fracturing to Drill for Natural Gas
But previous assumptions that gas yields half or less carbon pollution than coal are coming under new scrutiny. What is needed is a definitive new EPA study of the so-called lifecycle greenhouse gas emissions—from extraction to distribution, to use to release into the atmosphere—from natural gas, one that takes into account changing industry practices as shale gas becomes more important and better estimates of fugitive methane emissions from sources such as leaky pipes and valves.
The potential threat of natural gas fracking to water supplies is discussed in this article.
My main issue with CCS is that I do not view it as a robust policy option. If greenhouse warming is less of an issue than currently envisioned, the expenses of implementing CCS will be sunk, with little or no benefit.
Moderation note: this is a technical thread, comments will be moderated for relevance. Rutt Bridges will be reading the comments, and you may also email him with comments at the email address on the article.