Comments ngreene has made

  • NRDC's comments on Cape Wind

    Charlie et al., Just wanted to let you know that NRDC has submitted comments too. You can find them and a summary of our comments over at my blog. Here's the first paragraph from my post:

    Today we pressed send on our written comments on the Draft Environmental Impact Statement (DEIS) for the proposed Cape Wind offshore wind project.The DEIS was prepared by the Mineral Management Service as part of the permitting process for the project. Based on our review of this the information in the U.S. Army Corps of Engineers DEIS and other analyses that have been done on the project, NRDC has concluded that the project's environmental benefits will far outweigh its impacts.
    On Your last chance to be heard about Cape Wind posted 1 year, 7 months ago 54 Responses

  • Slow, but hopefully helpful

    Tom, sorry it has taken me so long. My day job keeps getting in the way. Here's my initial response. Not so much an opening salvo, as you'll see. Just trying to make sure we're looking at the challenges the same way. Looking forward to further discussion.

    Cheers,
    N-On Blogger Nathanael Greene takes on Philpott re: biofuels posted 1 year, 8 months ago 37 Responses

  • LCFS is the path forward

    Patrick is exactly right--no surprise what with him working with Climate Solutions and all. The low-carbon fuel standard is a technology-neutral and performance-based policy. To get a sense of why being technology neutral is so important take a look at the map of possible biofuels pathways developed by Jeremy Martin from UCS. With his permission I posted it here on my blog. I also address the importance and scale of GHG emissions from land-use change and the regulatory accounting and certification tools being developed by CARB and EPA in my latest post.On Scientist says biofuel boom endangers world's largest rainforest posted 1 year, 10 months ago 24 Responses

  • Benifits but let's not overstate them

    There are two real potential benefits from technologies such as LS9's: lower conversion energy and greater compatibility with current infrastructure. The fact that the fuel produced has an energy density (btu/gal) closer to petroleum fuels does not translate into our biomass feedstock producing more energy (btu/ton). The chemical energy in the cellulose can only be conserved; no more can be created. And the advanced paths to ethanol from cellulose already envision getting pretty close to the theoretical limit. Thus LS9's process might produce more energy dense gallons, but they will essentially have to produce fewer gallons.

    The place where the LS9 technology could make a difference on energy balance is in the process energy. Not having to distill out ethanol from water does save a lot of energy and that's energy that we can use somewhere else. The energy for conversion of cellulosic biofuels is generally assumed to come from the lignin part of the plant. (Cellulose is almost always chemically bound up with lignin in lignocellulose, so when we talk about cellulosic biofuels, we should really be talking about biofuels from ligoncellulose.) If less of the lignin has to be used to drive the conversion of the cellulose, then more can be used to make electricity or Fischer Tropsch fuels.

    Similarly in terms of carbon accounting, we have to be careful. Lower carbon content final fuels do not necessarily translate into lower lifecycle greenhouse gas emissions. The biomass carbon that doesn't end up in ethanol is generally released as CO2 during the fermentation process. So if more carbon ends up in LS9's fuel that just means that less is released during conversion. Again the real potential difference is in the process energy used to drive the conversion--less energy used doing this, less fossil fuel carbon released or more biomass carbon that can be used elsewhere to replace other forms of carbon.

    The benefits of greater infrastructure compatibility are mostly economic, but they're also important for consumer acceptance, which is important in determining how fast we can move away from petroleum to lower carbon alternatives.

    Fortunately, LS9 is not the only company pursuing different ways of converting lignocellulosic biomass into different liquid fuel molecules. One other company that I've heard of is called Virent (www.virent.com). I'm not making any claims about their technology's viability, but they are trying to take an entirely different, non-microbial approach. The important lesson here is not to get wed to specific conversion processes or even specific fuel molecules (or even molecules at all to keep the door open for electric power), but rather to focus on the environmental, economic, and end-use performance characteristics we want from low-carbon alternatives to petroleum.

    Of course, as you point out, starting with vehicle efficiency is the first, cheapest, fastest, best option, but we need to shift our biofuels policies away from ethanol gallon mandates to performance requirements. California has taken the first step in this direction with its plan to implement a low-carbon fuel standard that requires a reduction in average fuel lifecycle carbon intensity rather than requiring a specific number of gallons.

    I discuss all of these issues, including the GMO issues and land availability for biofuels regularly on my blog: http://switchboard.nrdc.org/blogs/ngreene/ I hope that's helpful.On New company says it can make better, cheaper biofuels posted 2 years, 4 months ago 40 Responses