Here is an interesting discussion about Green Design vs Green Performance and LEED 3.0.
http://www.csemag.com/article/358074-Green_design_vs_green_performance.php?nid=3474&source=title&rid=11449764Here is my $0.02 on the matter:
I work for a large real estate development firm that operates >20 Million sf of office space. In the old days, we built, owned and operated buildings. While we still like to build, own and operate, the world is different today and we operate buildings for 3rd parties as well as own and operate buildings that we did not build (and we have sold buildings that we did build).
While it is not my direct area of expertise, we have a very large group of highly trained and motivated property managers and operating engineers who are intimately involved in operating buildings efficiently because we view it as a competitive advantage and the right thing to do. I think we have built and operate more Energy Star sf than any other private developer.
I work on the development side and we strive, along with the design team and contractor, to deliver a good and green building that is well designed, constructed and commissioned.
The hard part in all of this is knowing what the final use of the building will be during the design phase. Office buildings can have occupancy densities that range from a high of 1 person/100sf for the "back of house" of an accounting firm to a low to 1/350sf for a high end law firm.
Landlords usually have minimal control over the tenant's interior fit out. The "technology density" of a tenant is also an important consideration. Imagine a tenant with a large 24 hr computer operation or trading floor compared to a 9 to 5 marketing firm.
Throw tenant behavior (leaving lights and equipment on) into the equation and it is hard to predict energy use (and yes, we do work on tenant education). On the residential side, think of a family that likes the thermostat set at 78° in the winter in Minneapolis so they can wear shorts and t-shirts in the house.
These variables are what drove the LEED Core and Shell and Commercial Interiors programs into existence bacause a developer of speculative buildings simply cannot work under LEED NC.
I can also say that when we take over a building that was operated by others, we can usually reduce energy consumption by 10% to 30% over the course of 2 or 3 years, so operation does make a huge difference.
My longwinded point is that predicting actual performance is a complex issue. Correlating computer models to acutal use is hard to do for a variety of reasons. One of the guys that frequently posts to the Geothermal Forum has a signature that says "Without data, you have only an opinion". He is exactly right. Verification, finding WHERE the energy is being used and owner/user feedback will help the designers better undersand how things work in actual operation....and will identify the problem areas.
The management and use of a building are at least as important as the architectural and MEP designs and the build quality and we should not be too quick to blame the design team, LEED, contractor or the operator if a building uses more energy than forcast.......there MAY be a reason.
The challenge ahead for commercial office buildings (in my view) is the facade. The market, i.e., the tenants, like floor to ceiling glass. Even the best triple glazed IGUs are not as good as insulation (waiting for Chris Kavala here) and double glass facades are brutally expensive. It will take a strong energy code to change this behavior because I do not think it will change any other way.
Bruce