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Topics - Bruce Steele

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Policy and solutions / Improving EROEI numbers
« on: March 18, 2014, 02:02:51 AM »
I posed the question earlier whether producing food calories with solar cells and the power it yields should increase the EROEI numbers for solar. The question depends obviously on whether you actually do yield a net calorie gain.
 
My question was specific to gardening with a battery powered tiller powered with solar cells, but it could be expanded to pumping water, producing fertilizer or hauling the produce to market. You could expand it further to cooking or heating water with passive systems and probably much more I haven't considered, but this needs to be taken on in incremental fashion or things will quickly become unmanageable.

I have already started trying to get numbers to quantify K/cal of invested energy with K/cal of produced crops for the battery powered tiller. Since I believe even the calories used by the worker doing the gardening needs to be calculated to get to a real answer for my question, but I would like to start simple.

Anyone who has ever gardened, knows that with a shovel, a hoe and some effort you can overdose on zucchini squash. Producing food calories with very little fossil fuel inputs is not fantasy. So I would propose starting with a limited parameter (garden space) and doing as much work by hand as possible with a solar cell powered battery operated tiller as an assist. Count all inputs very carefully. The labor invested should also be tracked.

Because human time and energy is important, I also think timesaving technics that are not energy sinks should also be included. Paper mulch, scavenged cardboard paths, grafting for vigor, and trellises are all things I have included in my initial efforts and the energy costs of those need inclusion. JimD brought up fences and those would probably be a show stopper, so even fencing needs extra thought, but working to feed bunnies or deer will quickly cut into food calories produced so they do need consideration. For example, a woven willow fence might do the trick. My point is ALL inputs need tracking.

Water is a very real energy input unless you happen to live where rain is always right on time and adequate. Water will likely be reasonably equal to a conventional gardening effort, however, so initially I intend to focus on the solar tiller. To really get good EROEI results will require tricks and those take time to develop, but if I can prove up with tillers first, I think scale issues will be the next hurdle. Equipment will need to last a number of seasons, so amortizing equipment K/cal numbers will be necessary. The longer the equipment lasts, the better the resulting EROEI numbers that can be achieved.

To get a good handle on all this, I would need to run some sort of control, but honestly I don't have the energy for that. I suppose I will need to compete with traditional agriculture and their advantage of vast scale, but that is someone else's homework project. Mine is to show that a solar powered tiller can yield a positive EROEI and at the same time yield more tonnage of crops and calories produced than you can get with a shovel and hoe. Yes tonnage.

How does that sound for starters?         

2
Arctic sea ice / Ice Tethered Profilers
« on: April 10, 2013, 11:38:21 PM »
The WHOI Ice Tethered Profilers are a resource that has taken awhile for me to figure out how to use. I put the various ITP's in bins depending on where they were and where they are heading. ( fast Fram ) #49,50,51,57 and 60 ( Fram) #47,48 and 56. (Beaufort Gyre) #52,53,55,64,65 and 66 ( wedge) 63.  The composite temp./ salinity water column profiles can then be compared.Once in bins the profilers reflect the influence of either Atlantic halocline or Pacific halocline waters in the water column beneath them. Here is a summary on upwelling in the arctic by Jiayan Yang.          http://www.whoi.edu/fileserver.do?id=92424&pt=2&p=44107
Upwelling and how to read to profilers is a subject that interests me but there seems to be a lot of noise. Upwelling from very deep waters appears  to happen as it did during the great arctic cyclone but there also seems to be noise. So for me the upwelling data is confusing.   

           

3
Science / Carbon Cycle
« on: March 01, 2013, 04:59:16 PM »
Here is a model which gives future temps., pH, and productivity for the earths large water masses. In discussions you can download the full article.
 

Multiple stressors of ocean ecosystems in the 21st century: projections with CMIP5 models
Posted: 28 Feb 2013 12:44 AM PST
Ocean ecosystems are increasingly stressed by human-induced changes of their physical, chemical and biological environment. Among these changes, warming, acidification, deoxygenation and changes in primary productivity by marine phytoplankton can be considered as four of the major stressors of open ocean ecosystems. Due to rising atmospheric CO2 in the coming decades, these changes will be amplified. Here, we use the most recent simulations performed in the framework of the Coupled Model Intercomparison Project 5 to assess how these stressors may evolve over the course of the 21st century. The 10 Earth System Models used here project similar trends in ocean warming, acidification, deoxygenation and reduced primary productivity for each of the IPCC’s representative concentration parthways (RCP) over the 21st century. For the “business-as-usual” scenario RCP8.5, the model-mean changes in 2090s (compared to 1990s) for sea surface temperature, sea surface pH, global O2 content and integrated primary productivity amount to +2.73 °C, −0.33 pH unit, −3.45% and −8.6%, respectively. For the high mitigation scenario RCP2.6, corresponding changes are +0.71 °C, −0.07 pH unit, −1.81% and −2.0% respectively, illustrating the effectiveness of extreme mitigation strategies. Although these stressors operate globally, they display distinct regional patterns. Large decreases in O2 and in pH are simulated in global ocean intermediate and mode waters, whereas large reductions in primary production are simulated in the tropics and in the North Atlantic. Although temperature and pH projections are robust across models, the same does not hold for projections of sub-surface O2 concentrations in the tropics and global and regional changes in net primary productivity.


Bopp L., Resplandy L., Orr J. C., Doney S. C., Dunne J. P., Gehlen M., Halloran P., Heinze C., Ilyina T., Séférian R., Tjiputra J. & Vichi M., 2013. Multiple stressors of ocean ecosystems in the 21st century: projections with CMIP5 models. Biogeosciences Discussions 10: 3627-3676. Article.


 Also includes O2.  Many of these trends are stressors to biological communities and they also have synergistic effects , one stressor compounding another.

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