Sep 27, 2008

Opinion: CO2 to fuels processes

The Green Car Congress blog has an article on a CO2 to fuels process by a company called Carbon Sciences.

Important features of this process are:
1) The use of biocatalysts (enzymes?) to effect the transformations under mild conditions.
2) The use of relatively “dilute” CO2 streams, which could lower the costs for CO2 separation from power plant-flue-gas streams.
My graduate research is in a closely related area, the photocatalytic conversion of CO2 to fuels in which CO2 and water react upon light-induced electron transfer to/from a suitable photosensitizer. This reaction is not very efficient. On the other hand, the heterogeneous hydrogenation of CO2 with H2 is fairly effective (but involves high temperatures), a Japanese company, Mitsui Chemicals will begin the construction of a pilot plant this year to produce 100 T/year of methanol (CH3OH) from CO2 and solar-produced hydrogen.
My opinion:
The conversion of CO2 to fuels is a hydrogenation reaction (add hydrogen, remove oxygen). However, I could not find information on the Carbon Sciences website about their hydrogen source.
One wonders how effective the scale up of this biocatalytic process will be. The main questions for me here are the source of hydrogen, enzyme stability and costs, and the product separation and purification costs. These factors would determine if this process indeed is cheaper than the heterogeneous catalytic process (using Cu/ZnO-like catalysts).
Hat tip: Green Car Congress blog.

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Recap:Water: The High Plains Aquifer

Here is a link to my erstwhile blog article on water depletion in the High Plains/Ogallala aquifer.

The High Plains aquifer underlies one of the most productive agricultural regions in the US. This region is semi-arid and does not get much precipitation, therefore most of the water used for irrigation is drawn from wells. Ground water levels here have been dropping and I thought of doing a zeroth order analysis of how many years will the water in the aquifer last. I used water level change data from USGS. According to USGS, there has been no major change in area under irrigation from 1988-2002. This report also points out that the total change in ground water storage from 1988-2000 was 47 million acre-feet and that the total ground water storage (estimated) in 2000 was 2970 million acre-feet. If we assume that ~30% of this water is recoverable, this gives us an approximate lifetime of 230 years (assuming that the irrigated acreage does not increase). However, the irrigated acreage did increase from 2002-2003, and the rates of depletion are approximately twice their value from 1988-2002. A map showing generalized water-level changes in the aquifer from 2002-03 are shown in the report. As expected, there is a lot of heterogeneity in the way water-levels dropped. Parts of central and south High Plains underwent more drastic water-level changes compared to their northern counterparts. Accordingly, the area-weighted water-level changes per state were more pronounced in Kansas, New Mexico, Oklahoma, and Texas compared to Colorado and Nebraska. Therefore, even if the water might still be around for another 2 centuries, parts of the High Plains might be facing depleted ground water levels sometime soon. These water-level changes might have important implications for US food supply.

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Sep 17, 2008

Projected (2030) greenhouse gas abatement potentials and costs



[SVG GHG abatement potentials and prices for clean energy technologies] (Using the link to view the image requires a stand alone SVG viewer and your browser needs to be configured to use this player)

The data are taken from a McKinsey report. I have compared only renewable energy technologies and carbon capture and sequestration (CCS) on this figure. The size of the circle approximately indicates the relative CO2 abatement potential in megatons of CO2 equivalents. (The report indicates that energy conservation, mainly by switching off electronics and computers, switching from incandescents to CFLs constitutes "low-hanging fruit". On the other hand, clean energy technologies such as wind, solar PV etc. require some investment in order to realize CO2 emission reductions. The cheapest among the renewables is producing cellulosic biofuels. Another obvious "low-hanging fruit" is the reduction of industrial non-GHG emissions; 250 MTCO2 equivalents at next to nothing prices represents a huge source of cheap carbon credits.This is my first SVG file (created using Gnuplot).

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Sep 12, 2008

Save energy, save money: Online videos

The MoneyTalksNews channel on YouTube (by Stacy Johnson) focuses on saving you money by making smart energy choices. The philosophy is that making big investments in "green" choices such as buying a hybrid vehicle, a solar panel etc. are not the only ways to go green. Shown below are the videos I add to my YouTube playlist (and are therefore filtered for spam, hopefully :-))


The videos are:
1. Simple energy saving tips: CFLs vs. incandescents, monitoring appliance energy consumption
2. Using less water
3. Environmentally friendly hotels
4. Warm/cold water for laundry
5. Saving money on dishwasher, microwave and oven operation
6. Cutting cooling bills by installing fans and cleaning your AC filters
7. Saving money by doing less paperwork
8. Saving money by borrowing CDs, switching off entertainment centers and reading online newspapers
9. Home energy-audits
10. Eco-friendly interior design

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Sep 11, 2008

Oil Roundup : 09/11/08

(Disclaimer: This article has no information related to September 9/11 attacks. I plan to do these "oil roundups" more frequently, and the timing was merely coincidental.)

Oil today closed at ~101 $/bbl, down from its July highs of 147 $/bbl. Meanwhile, gas prices in the gulf coast are rising, in anticipation of Hurricane Ike's landfall later this week. More from the AP's Money Minute


In related news, Petroleo Brasileiro (PBR) also reported a significant offshore medium crude-oilfield discovery, sending the prices of its shares up 6% (on the US markets) while oil was falling. A study by Masters Capital Management found that oil prices were indeed linked to speculation by large financial investors. I do not find anything wrong in speculation; some risk-taking is always good for the markets. However, I will read the report in greater detail to find whether they uncovered evidence for market manipulation.

Summing up, although crude prices seem to be falling because of institutional investors/stronger dollar/weakening oil demand, analysts believe that market fundamentals indicate an upward trend in oil prices.

Previous articles by Nari on price speculation:

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