How to Do a Basic Energy Audit
I have surveyed hundreds of facilities and wanted to share some best practices in the hopes that it will help more people save more energy. I once surveyed a facility that had a $21 million annual energy bill, yet they had no dedicated full-time energy manager. Although surprising to some, I have seen many facilities that are willing to spend multiple millions on energy expenses, with little to no oversight or management. Many facility managers perceive energy as a “necessary evil” and believe there is little that they can do about it. This is literally amazing when you consider that with some basic oversight, a 10 percent savings is highly probable, especially if there has been no energy management practice within the last 5 years. A 10 percent savings on $21 million is $2.1 million, which should be enough to fund an energy department and even some capital improvements… every year.
An energy audit (probably better to call it a “survey”) is one of the first steps to obtaining savings, so this article focuses on the basic steps to conducting an energy survey for a facility. The process is very similar to going to a medical doctor, where you get a routine physical exam, so you can see the big picture and where savings opportunities exist. The procedures described below are some of the things I do almost every time.
Before you go on any audit, you should collect one to three years of historical energy bills (water/sewer bills can also be helpful to review as well). The goal is to understand the basic trends of the building throughout the year to determine if energy consumption is increasing and if there are seasonal trends. I usually ask for the historical energy bills before I will even schedule a site visit, because if they cannot provide the bill data, they may not really be committed to the energy survey.
Beyond the historical consumption data, it is critical to understand the utility rate schedules (the demand and kWh costs per unit). Without understanding the rate structure is analogous to going on a diet without understanding that eating chocolate cake has a lot of calories in every bite! The rate structure should influence the direction of your survey. For example, if the facility has a high demand cost, you may want to focus your efforts on opportunities that reduce or shift load to off-peak hours. Many facilities may have a “ratchet clause,” which can mean that they pay all year for their high demand during a few peak hours. FYI, in my discussions with people from thousands of facilities, many have reported that demand charges are 20-30 percent of their total electric bill…sometimes even a higher percent!
If you are lucky and can get bill data for other similar facilities, you can benchmark the specific facility against “peers” and see how they compare. Getting good data from other facilities can be easy for office or school type buildings, but more difficult for manufacturing operations as it is unlikely to get data from a factory with similar processes, operation hours and location.
Other pieces of information to collect before the site visit date are a list of primary energy consuming equipment and a plant layout (on an 8 x 11.5 sheet of paper). During the walk-through, I usually note the operation hours of each area (office, shipping, cafe?, etc.) and where the large pieces of equipment are located (you can even use a fire escape plan and make notes on it).
On the day of the site visit (for a one-day walkthrough survey), I usually spend one to two hours meeting with the plant manager, then walk the site up until lunchtime. At lunch, the survey team will formulate a list of opportunities, confirm the opportunity list with the facility manager and then spend the rest of the day quantifying the opportunities and collecting measurements.
During the one to two hour interview, I try to discover the facility’s material and personnel flows so that I don’t recommend something that is infeasible or not aligned with the long- term plans. Usually the facility manager has “projects” that they would like to do and incorporating these into the energy survey is important, because if the facility manager doesn’t like the direction of your report, it will end up on a bookshelf (unread) somewhere for years.
Probably the most important outcome of the meeting with the facility manager is to appear non-threatening and supportive. If the facility manager believes that you are there to make his team look “bad” (by finding lots of savings within their existing operations), the facility manager will probably not want you to be successful. I have seen facility managers (or team members) withhold information or even sabotage a report effort when they felt threatened. To overcome a negative impression, I usually say, “I am here to help them quantify the savings that will justify getting more projects done that will make their lives easier,” and it really is true!
It is also critical to understand the hurdle rate, MARR or financial criteria that the facility manager expects for projects. This information helps you eliminate projects that are “beyond the payback period.”
Understanding maintenance is key to the long-term success. If the maintenance team doesn’t understand the new system (that might be proposed in a project), it will fail. An analogy is the microwave oven in my kitchen: it can do all sorts of cool functions, but I have no idea how to do those and I just “get by” with the basics: open the door, input the time and push start. So if a maintenance team is “getting by” without training on things like economizer controls, waste heat recovery, etc., there will be opportunities for improvement. Also, if the facility does not have a maintenance policy towards compressed air leaks, motors, chillers, etc., that lack of policy usually correlates with a lot of opportunities… usually 5 to 15 percent savings!
Finally, safety is important (if you want to survive to the next audit). Safety glasses, ear protection, hard-hats in construction areas are good things to have in your toolbox. Don’t touch electrical systems (high voltage buses, etc.), be aware of potentially very hot surfaces in the mechanical room and never wear a neck tie (especially around motors). If a factory does not supply you with adequate safety gear, they probably won’t make energy management a priority either — so you could be wasting your time (and risking your life).
If you follow these fundamentals, you should be off to a good start.
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