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32 • Green Project Management

thermal lag of the earth, structures can be made much more energy effi-
cient. An example is the library at Purdue University, in which the ground
level is the roof and the library continues downward for five stories. See
the article at http://www.homes-eco.com/underground-homes/ for more
about underground-energy savings.

sustainable Biomass

Sustainable biomass is probably one of the more interesting of the renew-
able-energy sources. According to the Biomass Centre (http://www.bio-
massenergycentre.org.uk) out of the UK, there are five basic categories of
materials used as sustainable biomass fuels: virgin wood, energy crops,
agricultural residues, food wastes, and industrial wastes and coproducts.
Virgin wood includes products from forestry operations. There is a wide
swath of land covering the northern parts of Vermont, New Hampshire,
and Maine that has been traditionally “logged” for the purposes of paper
production and building products. Those lands are also owned by various
lumber companies. These operations, while focused on the paper and lum-
ber production, do yield a large amount of by-product from debarking and
branch trimming, as well as trees that cannot be used in the actual prod-
uct production due to poor quality of one sort or another. Additionally,
virgin wood can also come from the production process, waste from the
lumber mills as an example. The third source of virgin wood is from tree-
trimming operations from large Christmas tree farms or other large oper-
ations providing ornamental products.
Energy crops are those crops that are grown specifically for use in the
generation of energy. The best known of these crops are corn and soy
beans, used in the production of ethanol, the additive in gasoline. The
Texas State Energy Conservation Office (http://www.seco.cpa.state.tx.us)
is looking at the possibility of other energy crops grown in their area like
sugarcane, switchgrass, and sorghum. Agricultural residue differs from
energy crops in that it is the by-product of agricultural processes—even
the by-product of energy crop production, like corn stalks or straw from
grains such as wheat and rice.

According to the National Science Foundation, “Green gasoline tech-
nologies recycle carbon instead of adding net carbon to the atmosphere.
The same carbon that comes out of a tailpipe when green gasoline is