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In or Out, Fair or Foul: Code, Baselines, and Savings

By June 5, 2012December 26th, 2021Briefs

ConEdison forecasts which equipment in their grid is at risk of being overtaxed and offers incentives for reducing demand for those specific pieces of equipment. Your bodega might qualify, but the deli across the street (and on a different substation) doesn’t. This approach has successfully deferred hundreds of millions of dollars in capital expense; think about what goes into repairing electrical infrastructure in Manhattan! But the flip side of that success is the high cost of failure, and so they have a unique level of scrutiny.  They inspect every site before and after to verify that the projects will deliver the promised savings.

It’s an expensive prospect.  I don’t know any other program that would consider 100 percent inspection to be cost-effective. This raises an interesting question, however. What if we don’t know exactly what “before” and “after” look like?  And, specifically for today’s discussion, what about new construction programs, where the “before” is strictly imaginary?  How do savings get calculated? For most program folks, getting it wrong may not cause a blackout on the Lower East Side, but the public service commissions that mandate most programs and the evaluators who verify their savings are very serious about getting it as right as can be. So, just like in baseball, we use baselines to determine whether a project is in or out, fair or foul.

Stepping up to the plate

For new construction and equipment replacement, we evaluate savings using baselines derived from building codes. Code comes in many stripes, varying from state to state and even municipality to municipality, but for non-residential buildings it always points back to ANSI/ASHRAE/IESNA Standard 90.1. Many states already use the 2007 version of 90.1; by next summer, the US Department of Energy will require that every state’s building code meets or exceeds its energy efficiency provisions. (They currently mandate everyone meet 90.1-2004; meanwhile, 90.1-2010 has been released.)

This impacts savings, and therefore programs, by defining the minimum acceptable efficiency of many systems. Sometimes it’s a direct reference, such as the minimum acceptable insulation levels or air conditioner efficiency.  These values become the “before” inputs in a savings calculation. Sometimes it’s somewhat indirect, such as for lighting, where the standard is based not on minimum equipment efficiencies but on Watts per square foot. This also creates a useful “before.”

A line drive

When Michaels evaluates the savings of new construction or equipment replacement projects, we look at every aspect of the building energy usage that can be compared to a 90.1 standard. If the project doesn’t exceed what’s specified in that standard, there can be no savings.

That said, being built to code is not the same thing as being built with optimal energy efficiency. For instance, the building code permits the use of electrical resistance heating, one of the biggest energy wasters of all time. It can be a challenge to compare more innovative approaches in arenas where code has not caught up with the newest and best thinking, but when simple one-to-one comparisons don’t suffice, we find a new approach—for instance, modeling a code-compliant building and using this as the “before” to be contrasted with a more efficient “after.”

Hitting It out of the park

When code gets better, it generally means new buildings will save money by using less energy, but improved code squeezes a lot of energy programs. When standards are low, relative to increasing equipment efficiency, it’s easy to achieve savings by helping customers buy better equipment. But when standards are high, relative to stabilized equipment efficiency, there is often not a cost effective way for users to buy their way to savings. This is because in many cases, today’s equipment is approaching absolute efficiency limits.  Successful programs will need to find alternative approaches to reducing users’ on-site energy use.

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