Improving Energy Efficiency in Convenience Stores

There are approximately 2,000 convenience stores in Minnesota, using an estimated 600 GWh of energy annually, as found in a Conservation Applied Research and Development (CARD) study which investigated opportunities for utility energy conservation programs in the sector.

As the business model for convenience stores has shifted from automotive services to retail sales of gas, food and drink, the plug load, lighting, and refrigeration loads for these stores have increased rapidly. A CARD grant study was completed by Michaels Energy in order to identify savings opportunities and recommend a program design for energy saving in convenience stores. Michaels Energy sampled 50 convenience stores for the study, including 21 independent stores and 29 corporate/chain stores. Since heating fuel use for the stores in this sample was so minor, electricity use was a primary focus of research in this study.

Figure 1:

Interior of a typical convenience store has many reach-in coolers (photo courtesy of Michaels Energy)

Michaels Energy found that the majority of the store energy is consumed by refrigeration (50%) and lighting (20%). Major differences in annual energy use within the sample population might be attributed to hours of operation (with higher lighting loads for 24-hour stores), the number of plug loads in the store, and whether there was a car wash on site. Generally chain stores with car washes had the highest energy use while independent stores had the lowest energy use.Average electric use for a convenience store in the study was 364,000kWh, with average savings estimated at 19%, corresponding to $5,000 annually (Figure 2). If energy measures identified in this study are applied to all convenience stores in Minnesota, almost 120GWh of energy and 7.5 million dollars could be saved by Minnesota businesses. Additionally, this could reduce the state’s peak demand by an estimated 21MW.

Average electric use for a convenience store in the study was 364,000kWh, with average savings estimated at 19%, corresponding to $5,000 annually (Figure 2). If energy measures identified in this study are applied to all convenience stores in Minnesota, almost 120GWh of energy and 7.5 million dollars could be saved by Minnesota businesses. Additionally, this could reduce the state’s peak demand by an estimated 21MW.

Figure 2:

Savings identified in fifty Convenience Stores studied

An observation of this study is that ownership structure of the store does affect energy use and management practices. Corporately managed chain stores typically used more energy on an annual basis but had, proportionally, a smaller opportunity to save energy. In addition, they were more likely to have a series of energy management practices already in place. Chain stores were also more likely to be open 24/7 and have a large plug load, which in part accounts for the higher energy use but it is energy use that is difficult to reduce without changing operating hours or eliminating equipment. Chain stores general employed corporate energy managers who had a good understanding of the variety of technologies available to reduce their stores’ energy use. Often the implementation of those technologies was only done in new store builds rather than as a retrofit, which means technology implementation company-wide will be a slow process and limit potential energy savings.

Independently-owned stores generally used less energy, but a larger portion could be saved, in part, because their energy use went to more controllable energy uses like refrigeration and lighting (rather than plug load). Independent store owners were appreciative of the information and recommendations from the audits. Many of the measures were new to them since, as busy small business owners, they don’t have time or staff to research energy conservation.

Michaels Energy included in their final report a list of the most cost-effective energy saving measures that may easily be implemented by convenience stores (Table 1). Recommendations include measures targeting lighting, controls, refrigeration and maintenance yielding potential overall annual savings of $6,090 to $7,420 with paybacks of 2 to 3.7 years.

The study concludes that convenience stores are a compelling market sector to focus targeted energy conservation efforts. The uniformity of their conservation opportunities and the ubiquitous nature of convenience stores mean that most every utility in Minnesota could benefit from energy reductions in this sector. For more details on project results see the final report, Improving Energy Efficiency in Convenience Stores. Michaels also produced a webinar on convenience store energy efficiency which summarized results from this study.