Plan, Audit, Commission, Measure and Verify: Steps To A Successful Energy Upgrade
First of a two-part article explaining the detailed process of planning and executing an energy efficiency project.
When developing ways to improve energy efficiency in commercial facilities, two words stand out: Plan ahead. While some efficiency options are almost literally plug-and-play, maximizing benefits while avoiding pitfalls involves steps taken long before choices are made and equipment specified. New technologies, incentives, and codes need to be integrated into any strategy for saving money through energy use reduction. Done well, those steps may lead to higher quality, greater savings, lower costs, and happier occupants.
Ensuring that later steps are successful may require some actions to be taken early in the process. For measurement and verification of savings to work, for example, a baseline of data on usage and demand must be developed before implementing any changes. To cover the cost of commissioning (to ensure new equipment is working properly), that expense should be built into the base project budget. Securing utility incentives may require an inspection and filing of forms prior to altering the existing equipment. To focus a project’s design, establishing budget or rate-of-return guidelines in advance may help avoid potential conflicts or disappointments.
The same general advice may be applied to any type of efficiency upgrade. As an example, let’s walk through a lighting upgrade to see what’s involved.
Has a professional lighting audit (not just a quick walk-through by a fixture vendor) been performed? Such an analysis looks beyond merely replacing one lamp (or fixture) with a more efficient version. It should include attention to the tasks that are being illuminated to ensure that the new equipment will provide what is needed instead of merely maintaining existing foot-candles and distribution. Doing so may foster savings that would not otherwise have occurred. Through more appropriate design, an audit may address complaints related to the existing system, such as glare or darkened walls. It may also highlight new savings opportunities, such as perimeter daylight dimming and demand response options.
Audit develops baseline
A good audit will develop a baseline of electric consumption and demand for the existing lighting system and the costs and savings related to each of its recommendations. It will utilize sampling, surveying, or data logging of occupancy patterns to establish realistic burn hours and the savings potential for occupancy sensors. A good audit will list a variety of options by payback period rather than merely trying to promote a vendor’s equipment preference. It should also address relevant energy codes that could impact cost or result in unforeseen delays (e.g., requirement for bi-level lighting).
To ensure such issues are covered, review an audit done by the same professional for a comparable facility before accepting his or her services.
A back-of-the-envelope calculation may be fine when trying to initially ballpark possible dollar and energy savings, but keep those numbers to yourself until they have been firmed up by an experienced energy professional. It’s standard for a contractor to tantalize a customer with a proposal so apparently lucrative that accepting it looks like a no-brainer.
Such proposals may overestimate annual burn hours, or use electric rates higher than actually paid by a customer for lighting. In some cases, contractors (and even a few energy professionals) may try to include savings due to interactions with other systems. It is not uncommon, for example, to find direct savings from changing lighting equipment to be “boosted” by adding cooling energy savings that may result due to reduced cooling load from new lights. While possible in regions that use little energy for heating, other parts of the United States may also see a heating penalty in winter due to the lower heat output of new lights. The same may occur in buildings having electric reheat coils. The end result may cancel the cooling energy savings. Unless additional potential savings are confirmed by a computer model that takes hourly loads into account, it may be best to limit savings claims to those related solely to lighting wattage reductions.
Failing to achieve a promised rate-of-return or payback period could damage credibility and limit future efficiency opportunities. To avoid disappointment (or worse), some energy service companies (ESCOs) discount even carefully calculated savings by 20 percent. It’s always better to end up with more savings than promised, rather than less.