Saturday, September 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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Wednesday, September 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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Friday, September 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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Thursday, September 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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Sunday, September 7, 2008

Solar Energy and Nuclear Energy in India

Recently, I ran across a detailed discussion on implementation of solar energy in rural India. The article is written by Swaminatan SA Aiyar, who is the author of the popular column/blog SWAMINOMICS. Some of the key points brought about are the land intensive nature of renewable energy [the staggering amounts of land (10,000 acres/week for 1000 MW new capacity)], need for water in dusty desert areas to clean the parabolic solar mirrors, the common lack of trust in government and corporations by villagers and use of "wasteland" (as defined by govt) for use of grazing and travel paths by rural folks. The article in the online news portal times of India, brings forth the need to go ahead of solar technology in India even as the government is trying to get a civilian nuclear deal ironed out (Update: the deal did go through, whew! for now.). One of the listed problems is that the government subsidies or tax breaks are now good only for small scale 5 MW scale solar projects in India. There is not much backing for larger scale (50 MW and above) plants according to the author.
Some of the other issues discussed mention the opposition to nuclear plants in India (Koodangulam, in Tamil Nadu) or the resistance to Uranium mines in Kadappa, in Andhra Pradesh. We do see a big similarity here between the environmental permitting process in the US, resistance to Uranium mines in Virginia, the absence of new nuclear plants in past several years.
Virginia is one of just four states that ban uranium mining. The ban was put in place in 1984, to calm fears that had been sparked by the partial meltdown of a nuclear reactor on Three Mile Island outside of Harrisburg, Pa., in 1979.
This is an interesting issue because Virginia in US has 2 nuclear power plants and a nuclear submarine/naval command in Norfolk VA. To make a long story short, in many of these cases, there is not enough exchange of information between the authorities and the people who might be in harm's way if a disaster were to occur. Until that exchange of information and dialogues remain inadequate, large scale energy projects would always have big question marks against them.
Note: I have decided to leave this topic a little open ended in order to encourage comments and informed discussion. In addition, in the next several weeks I would be writing more about the prospects for solar and nuclear energy in India.


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