68 comments on Energy For a Changing World: A Credible European Energy Strategy for the 21st Century
Comments can no longer be added to this story.
User login
Personnel
Editors
Contributors
Peak Oil Primers
Archives
- December 2008
- November 2008
- October 2008
- September 2008
- August 2008
- July 2008
- June 2008
- May 2008
- April 2008
- March 2008
- February 2008
- January 2008
- December 2007
- November 2007
- October 2007
- September 2007
- August 2007
- July 2007
- June 2007
- May 2007
- April 2007
- March 2007
- February 2007
- January 2007
- December 2006
- November 2006
- October 2006
- September 2006
- August 2006
- July 2006
- June 2006
- May 2006
- April 2006
- March 2006
Vital Trivia
License
This work is licensed under a Creative Commons Attribution-Share Alike 3.0 United States License.
GAIA Host Collective
Euan,
One way to do hydro so that fish are preserved is to build run of the river plants. This means that power is produced when the river flows rather than stored, but this also means that you can build your storage in a place that is less environmentally sensitive. This is partly because the extra altitude in a for-the-purpose pumped storage site means less water is needed for the same power capacity. You have Ben Cruachen and Foyers as examples.
When considering hydro power, it seems to me that the effects on the downstream and upstream ecosystem needs to be considered. Removing predator species such as salmon can have a big impact on the way things go in the surrounding ocean, for example. This may, in turn, affect carbon uptake by the ecosystem. one wants to know if these effects are comparable in scale to offsets in fossil fuel use. In the US, our hydro projects are often accompanied by irrigation and increased nitrogen runoff which tends to put a damper on carbon sequestration through the formation of sea shells. Changing the way farming is done can help, but absent such efforts hydro may have a larger net carbon impact through increased farming. It kind of depends upon the potential of the watershed and its esturary to sequester carbon compared to farming elsewhere without hydro, all balanced against fossil fuel use displacement.
Nationalism is Scotland looks like it might have an effect on how UK emissions reductions are counted. This seems like an interesting topic to explore.
Chris
If you do that, you lose the benefit of storage in your main hydro plants and have to build it separately. That is going to add cost to the system, and you are going to have trouble building pumped storage systems with capacity to buffer seasonal variations.
If conventional hydro must be ruled out because of environmental impact, the main energy storage will have to come from supplies which are naturally harvested in storable form. For this reason, we should be putting a heavy emphasis on R&D in e.g. direct-carbon fuel cells able to burn biochar; a stockpile of biochar is a compact buffer of energy and storable for decades.
Direct carbon fuel cells are interesting in that they have potential for very high efficiency. But, I am beginning to think of biochar a too valuable to burn because its micro structures seem to be quite good at buffering nitrogen. Buffering nitrogen seems to me to be key to land use changes that can help to restore the carbon sequestration potential of coastal waters while at the same time sequestering carbon in soil. I also feel that while one can get some parasitic energy production from making biochar, the inefficiency of rooted plants at collecting solar energy makes solar PV and wind power look much more attractive as energy sources. The electrification of transportation leads to about 0.5 days of storage total power consumption if batteries are used because transportation grade batteries are of such high quality that they are still useful after they have partially degraded. If the compressed air method of transportation becomes popular, then the air tanks and engines might also see a second life as stationary storage with the heat from compressing air being used for heating water and the cooling from use of the engines having application in refridgeration. Potentially, this could lead to even more storage than going with batteries and even greater overall system efficiency in the aftermarket application. So, just from converting transportation we will see substantial storage which should allow renewable penetration up to 70% or more.
The big advantage of standard hydro is that it can cover for the emergency shut down of a nuclear power plant because it is both large and responsive. This advantage seems to be disappearing in some places as decadal scale changes in precipitation reduce the availabilty of hydro power and the flow rate of rivers used to cool nuclear power plants. Further, I've been thinking in the last week about the sustainability of using biochar for sequestration, worrying about the ability of terra preta to regenerate itself. Could there be a problem with soils becoming carbon sinks that will continue to reduce the atmospheric carbon dioxide concentration below 280 ppm because, once started, they continue to accumulate carbon on their own? We may want to make estimates of how much terra preta surface area should be created. In that context, your picture of retaining biochar as energy storage for decades seems a little like Joseph's interpretation of Pharaoh's dream. I wonder if there is a place for a strategic biochar reserve at some point in the future. This would clearly be a distributed reserve rather than centralized. I think, though, that as wind and solar begin to become our dominant energy sources, it may turn out that liquid hydrocarbon reserves will be produced using carbon dioxide and water as feedstocks wih less disturbance of natural ecosystems just because we are substantially more efficient than rooted plants at doing this. With Lake Mead projected to go dry within 14 years or so, rethinking the usefulness of large scale hydro as energy storage is probably in order.
Chris
Chris - you or EP are maybe good people to ask a couple of questions. What % of annual N hemisphere vegetation growth is agricultural? So what is the practical limit of "pumping down" CO2 by say converting to char x% of all agri waste?
And how does spreading all this char into soil affect the oxidation state of the soil? Will filling your soil with char not create strongly reducing conditions as the char will eventually start to oxidise - using all available oxygen - creating a "stagnant pond"?
I'd just pile it up for barbecuing the last camel.
I don't know what fraction of growth is agricultural, but one can project from The Billion-Ton Vision that some 300+ million tons/yr of carbon (equivalent of 1.1 billion tons CO2) is available from various non-food plant matter already produced in the USA alone, and it may be possible to increase this substantially (1.3 billion dry tons @ 45% carbon is 585 million tons carbon, equivalent to ~2.1 billion tons CO2).
Note that there are several versions of "The Billion-Ton Vision" on the web, with different covers. I'm not sure how the contents differ; I'm citing the version linked from GCC (which also lists the authors prominently).
Almost not at all; the stuff appears to be stable on a scale of thousands of years. Normal soil carbon is lost far more easily.
Hi Euan,
I'm working on your first question now. I'll give you the estimates from the Climate Code Red report (on p. 58), these are worldwide I think. Citing Marris in Nature News 2006 442 624 they give 9.5 billion tonnes of carbon per year: http://www.nature.com/nature/journal/v442/n7103/full/442624a.html with a citation there to:
Lehmann, J., Gaunt, J. & Rondon, M. Mitigation Adapt.Strateg. Global Change 11, 403–427 doi:10.1007/s11027-005-9006-5 (2006). http://www.springerlink.com/content/etm7526m07672103/
This is more than we currently emit annually.
For crop wastes, another estimate they give is 1 billion tonnes per year from here: http://planetwork.net/climate/emergency.html
but this estimate does not seem be well supported.
On your second question, soils oxidize mostly through microbial action. One usually wants as much carbon in soil as possible because it grows plants very well, but agricultural activity provides oxygen to the soil and so the carbon decays and you need to add more. Grasslands continue to build up carbon through their continuing root formation.
http://www.sciencemag.org/cgi/content/abstract/314/5805/1598
This difference is the reason why biofuels produce more emissions that fossil fuels. If you need to disturb previously untilled soils because biofuel crops are displacing food crops, then all that soil carbon decays and enters the atmosphere. The thing about biochar is that it does not seem to be eaten much by microbes so that it remains in the soil without decaying as quickly as other biomass (manure, compost, dead roots etc.). This appears to also set up an ecology in the soil where carbon will be built up in deeper layers at least in the Amazon.
The amount of air in soil is dependent on its porosity. Biochar should add to this since it retains some of the structure of the original plant. This is why it buffers nitrogen and retains water. Since it is not itself decomposing much, it should not be creating anaerobic conditions though I think this could occur if the land converts to wetlands.
Not a full answer, but I'm still learning myself. One of the co-chairs of our EcoAction committee works with Danny Day so I'll be picking his brain as I go along.
I thought camels were better for milk and blood than for barbecue?
Chris