Comments tdmeeh has made

  • Algal oil energetics

    Want to learn something about the energetics of algal oil production? See below.  

    http://www.massey.ac.nz/~ychisti/TLReprint.pdfOn High energy requirements make the manufacture of algal biofuel prohibitive posted 9 months ago 35 Responses

  • Enough with the dogma

    I am continually frustrated by the attitude that all biofuel schemes are net negative propositions and are thus worthy of ridicule.  Visit the WBM conference website and you will see a substantial showing of algal, cellulosic, and waste stream fuel folks.  In the right context, these technologies represent important wedges in the effort to reduce GHG emissions.On Bob Geldof takes a big ol' swig of biofuel posted 9 months, 2 weeks ago 6 Responses

  • More maps

    For more maps of flooded coastal areas with sea level rise, see Jonathan Overpecks's website:

    http://www.geo.arizona.edu/dgesl/research/other/climate_c ...
    On West Antarctic ice-sheet collapse means more catastrophe for U.S. coasts posted 9 months, 3 weeks ago 5 Responses

  • Another view on LCOE

    Here is a link to an interesting paper on levelized cost of electricity with and without external environmental costs included.

    http://www.warren-wilson.edu/~tmeehan/Sovakool_2008.pdf

    Best,

    TimOn Proposed renewable-energy bill is better than nothing posted 9 months, 3 weeks ago 26 Responses

  • Got grass?

    Jon,

    I'm glad you called attention to the greenhouse gas output due to space heating.  It's especially important in the northern half of the country.  I came across a neat report recently that explains how native perennial prairie grasses grown on marginal farmland can be an excellent source of energy for space heating.  

    1. Grasses are native and you mow them once after the growing season, so fields provide decent wildlife habitat.
    2. The annual yields are pretty darned high (~10 tonnes/ha) even with minimal fertilizer inputs. Legumes can be sown in so nitrogen input is reduced.
    3. You densify the grass after cutting (briquettes or pellets) which is not a very energy intensive or technologically involved process. The end product is pretty portable.
    4. Then you burn it in a boiler. There is no further processing so the net energy yield is pretty high (13 units energy out per 1 in).
    5. The plants are perennial so tillage is minimal and carbon accumulates in the soil from root biomass production.
    6. Farm income from harvested grasses offsets the drive to convert CRP grasslands to corn.

    There has been a lot of talk about switchgrass as a feedstock for cellulosic ethanol production.  But the net energy yield for switchgrass to ethanol is much lower.  Maybe we should use wind/solar/geothermal electricity to drive our cars and grasses to heat our houses.

    Just a thought.

    The link to the report:

    http://www.agrecol.com/AgrecolADDReport.pdf

    Another good grass site:

    http://grassbioenergy.org/

    Best,

    TimOn Slicing and dicing global greenhouse gas data posted 10 months, 3 weeks ago 17 Responses

  • Wake up Asheville

    Hopefully, this will serve as a wake-up call for Asheville. For all its claims to ecogrooviness, it is fundamentally a car-culture town. The city bus system stinks (1 bus per hour, where there is one), there are very few sidewalks in the city besides downtown, and bike riding there is extremely dangerous because there are practically no dedicated bike lanes. In fact there is often no gutter to ride in.On Gas shortages plague the Southeast posted 1 year, 2 months ago 6 Responses

  • JMG, Tom,

    I do agree with you that we should work to eliminate the subsidies, tax credits, and mandates for corn and soy based fuels.  I suppose the main point my comment was that more evidence against these fuels is not necessary - most folks, even many politicians, now see them as a net negative.  I apologize if I gave the impression that getting this message out to the general public and overturning existing incentives was a waste of time (I do appreciate your efforts, Tom).  I only meant to say that environmentalists hardly need to debate the issue anymore - we have the information and consensus to proceed.  On World Bank finally releases 'secret' report on biofuels and the food crisis posted 1 year, 4 months ago 65 Responses

  • Urban gardening

    I appreciate the recent posts on urban food production, and I am excited to hear about the various and creative ways in which people are becoming more connected with their food.  I wouldn't want to discourage anyone from growing, or paying someone else to grow, food in their yard or community garden, but thought I'd mention that new gardeners should look into the quality of their soil - past inhabitants may not have been very careful about where they dumped things like lead paint and used motor oil.On Edible landscapes can outgrow the elite posted 1 year, 4 months ago 2 Responses

  • Bombshell?

    I appreciate the in depth analysis, but don't see the report as earth shattering.  I think that most reasonable people (lobbyists and politicians excepted) have concluded that biofuels from corn and soy are not the best solution to global energy problems.  Nearly everyone agrees that the push to produce corn ethanol and soy diesel has increased food prices - the argument is over how much.  Other studies have shown that corn ethanol and soy diesel production have marginal net energy ratios and unfavorable carbon balance characteristics if they lead to further land conversion.  So the days are numbered for these technologies, and most folks accept this.

    There are many different proposals floating around for how other types of biofuels (cellulosic ethanol; algal diesel; biological, catalytic, and pyrolytic conversion of waste stream carbohydrates to liquid fuels) could be part of the future energy mix.  It might be time to shift our analytical energy away from first generation biofuels and onto these other propositions, so that they are properly evaluated before they are scaled up.  Continuing a polarizing debate on "biofuels" based on the pros and cons of corn ethanol and soy diesel seems to me like beating a dead horse.On World Bank finally releases 'secret' report on biofuels and the food crisis posted 1 year, 4 months ago 65 Responses

  • Are biofuels a core solution?

    It seems to me that the answer is "it depends".  But then this is the answer for most energy alternatives - wind is well suited for some situations, solar for others, geothermal for others, and wave power for others.  Remember that we are looking for silver buckshot, not silver bullets.

    There are places where agriculture and forestry already produce sizable amounts of "waste" biomass.  This biomass decomposes, and about 90% of the carbon is returned to the atmosphere within a few decades.  If this same biomass were subjected to pyrolysis on a regional scale, then about 50% of the carbon could be sequestered in soil in the form of charcoal for thousands of years (compared to 10%, above - charcoal is very recalcitrant), another 25% would be returned to the atmosphere right away during pyrolysis, and another 25% would be returned after syngas and bio oil is used to fuel additional work (heating, electricity, transportation).

    Given that these "wastes" already exist and are decomposing as we write, you can figure that pyrolysis and biofuel production from these materials will not drive additional greenhouse gas emissions through land use change.  Indeed, the application of charcoal to soils has been shown to increase crop yields when soils are low in organic carbon to begin with.  This increase in crop yields could theoretically slow down current land conversion for food production.

    For a nice summary of the potential of biomass pyrolysis, see this article:
    http://agron.scijournals.org/cgi/reprint/100/1/178
    On Are biofuels a core solution? posted 1 year, 4 months ago 201 Responses

  • Assumptions

    A few comments on the assumptions embedded in wolverine's last post.  

    First, despite what you might think, wolverine, I am also very aware and very bothered by pervasive human impacts on ecosystems.  And, I agree with you that we should be advocating heavy duty conservation measures, local production and consumption of food and power, and thoughtful population control.

    Keep in mind, however, that these principles have been advocated for a long time, and that this has not substantially reduced human impacts on our environment.  "Progress" has marched on, all over our vision.  So it seems like it is time to expand our horizons and promote both local-scaled and large-scaled projects.  In my opinion, we have to offer up a utility-scaled substitute for the new coal and nuclear plants that are now being planned and built, or we are in for environmental damage on an unprecedented scale.

    The second assumption I'd like to highlight is the one that BLM land is dominated by natural habitats.  This, unfortunately, is not true.  There are some areas on BLM land where humans have had minor impacts, but the majority of BLM land is heavily influenced by humans.  

    This includes thousands of hectares that are obviously altered by natural gas, oil, and mineral exploration, extraction, and transportation.  Then there are the hundreds of thousands of hectares that are leased out to livestock producers and subsequently over-grazed.  What's even more destructive to native ecosystems are the huge expanses of invasive plants.  Cheatgrass, alone, covers whole basins and has now altered fire regimes.  Altering the fire regime effects every organism on the range, from the soil microbe to the large herbivore, and entirely rearranges ecosystem functioning.

    So, I don't mean to prolong a battle of opinions with this post.  Your message actually got me thinking about how it is important to guide society toward local-scaled sustainability, this seems to be a good endpoint to shoot for. I also got to thinking about how promoting large scaled solar and wind projects seems, at first, to be counter productive.  I guess I just see them as a fairly benign means for us to buy the time necessary for our society to value and adopt local-scaled solutions.On Feds freeze new solar projects on public land, pending review posted 1 year, 5 months ago 26 Responses

  • Lets be realistic

    I want to second the perspective of christophersj.  Rapid deployment of ALL TYPES of solar and wind projects is necessary to slow down coal electricity generation, and to reduce subsequent global-warming-induced damage to much more biologically diverse marine (e.g. coral reefs) and terrestrial (e.g., non-fire-adapted forests) environments.  We have to remember that we are in a critical, damage-control situation.

    Also, I am a terrestrial ecologist who has spent 15 years working in arid ecosystems on public lands in the West.  I agree that these systems have notable landscape scaled diversity (across habitats).  But, there are truly massive expanses of homogeneous habitat (e.g., arid grasslands and sagebrush steppe on the Colorado Plateau and in the Great Basin and Upper Chihuahuan) with fairly low species diversity, high functional redundancy, and homogeneous community composition.  It would not take long (one meeting of arid land ecologists followed by a concerted effort for one month to synthesize conclusions) for the BLM to come up with an initial set of criteria for reducing damage to critical habitats (avoid high elevation habitats, riparian forests, playas and other water features - there is diversity where there is moisture and topography).  This two year moratorium is an obvious stall tactic designed to give proponents of nuclear and coal power an opportunity to get some money out of Washington before renewable energy scales up and becomes less expensive and thus clearly economically superior.On Feds freeze new solar projects on public land, pending review posted 1 year, 5 months ago 26 Responses

  • Keep it up

    I think that you are doing great.  Its not your mower that needs to change (though it may need sharpening), it's our expectation for what cut grass ought to look like.On My yard, a source of shame posted 1 year, 6 months ago 18 Responses

  • Smaller farms?

    Thanks, all, for the information on the labor shortages on mid-sized farms and for the perspectives on a Teach For America type program.  It strikes me that such a program might be best pitched as a job training/internship type program since pay will be relatively low and because people tend to work for less if they are learning valuable skills.

    On a different note, I have been reading a book by Eliot Coleman called "The New Organic Grower".  In this book Coleman argues that an ideal scale for a truck farm is actually more like five acres, as this is a scale that can be maintained by a family with minimal expensive machinery.  

    Maybe the answer to our industrial farm problem is not mid-sized farms, but rather many more very small farms.  Where do all these new farmers come from?  Maybe they are idealistic youngsters fresh out of the Farm For America program?On To create a truly sustainable food system, we'll have to confront the farm-labor crisis posted 1 year, 6 months ago 14 Responses