The New Version
modeling requirements have been
replaced with Options 1 and 2. As such,
you can complete your LEED application
by running one model instead of two. Last
quarter’s column titled “Give Me Options”
provides a detailed description of the new
modeling changes and the benefits they
provide to the district energy industry.
These changes reduce the burden on
designers to run multiple models, and
they put district energy on a more level
playing field compared to other options.
Tim Griffin, PE, IDEA USGBC Liaison
Editor’s Note: “LEED + District Energy”
is a quarterly column providing information about the U.S. Green Building
Council’s LEED® rating system and how
it applies to buildings served by district
out we still had more work to do. In fact, it
took yet another nine months. (Sure am glad
I did not have to tell my wife there was more
work to do after nine months of pregnancy!)
Since May 2008, our industry has been working with version 1.0 of the U.S. Green Building Council’s (USGBC’s)
guideline titled “Required Treatment of
District Thermal Energy in LEED-NC version
2. 2 and LEED for Schools.” The intent of
this document was to provide clear direction
to designers of new buildings as to how to
apply the LEED® (Leadership in Energy and
Environmental Design) guidelines to their
projects when these buildings would be
receiving chilled water, steam or hot water
from a district energy facility. While better
than nothing, this first version of the
guideline left a lot to be desired.
Shortly after its introduction, the
USGBC’s district energy work group
began developing a new and improved
version of the guide. In January 2009,
IDEA formed a task force to work with the
USGBC on the new version, which was to
be issued by October of the same year.
The IDEA task force consisted of members
from Con Ed Steam Operations, NRG
Thermal, Xcel Energy, Energy Systems Co.,
The University of Texas at Austin, Chem-Aqua, FVB Energy and RMF Engineering.
A nine-month plan, just like birthing
a baby. Sounded easy enough. However,
when the nine months were up, we found
Worth the Wait
This year, on Friday, Aug. 13 (let’s
hope the date is not foreboding), the
USGBC released the updated version 2.0
of the guideline: “Treatment of District or
Campus Thermal Energy in LEED V2 and
LEED 2009 – Design & Construction.” It
is currently available free of charge on
the USGBC’s Web site (see http://tinyurl.
com/2boq7kc). This version is the original
release of the formal guidance for LEED for
New Construction (LEED-NC) 2009 and can
be used in lieu of version 1.0 on all LEED-NC 2. 2 applications.
So how does this baby look? A lot
prettier than version 1.0, but it’s a lot
thicker as well. Version 1.0 was 12 pages
printed in a large font. For version 2.0,
they shrank the font and still barely got the
document under 30 pages. I guess that’s
what happens with an extra nine months
in the oven.
Thermal Energy Storage
Thermal energy storage (TES) systems
use more energy than non-TES systems but
can have an overall net positive effect on
the environment. As a result, the USGBC
did not purposely discourage TES in version
1.0, but it did inadvertently create a
penalty for district energy with TES.
Here’s how: Version 1.0 required a
building modeler to use the building’s
electric rate structure in energy models
of buildings with on-site chilled-water
generation, as well as in models of
buildings receiving chilled water from a
district system. Therefore, a building project
could earn points for utilizing TES within
the building site by taking advantage of a
preferred TES electric rate structure; but
TES generated in a district plan would be
penalized because it is required to use the
building’s traditional rate structure.
As a result, one of IDEA’s goals was
to modify these guidelines to recognize the
benefits of TES in district energy applications. Through information provided by
our organization, the USGBC work group
recognized the environmental benefits TES
provides, as well as the economies of scale
that result from including TES with district
energy. This change has been accomplished,
as version 2.0 includes specific TES provisions aimed at accounting for the positive
benefits of TES in district plant applications.
Besides sheer length, there are many
differences between versions 1.0 and 2.0.
Following are a few of the key changes:
The modeling burdens and challenges
associated with version 1.0 have been
reduced. The old Step 1 and Step 2
One of the biggest obstacles that
version 1.0 created for district energy
was the requirement to overcome the
minimum energy prerequisite, better
known as Step 1 of the energy model.
Within Step 1, both the proposed and
baseline building had to use the actual
chilled-water, steam or hot water rate
© 2010 International District Energy Association. ALL RIGHTS RESERVED.