Saving energy in a retail chain

Monitoring of energy consumption of retail store network. The mother company pays all operating costs, including the energy/utility bills. In the light of increasing energy prices, the customer started to look for ways of reducing the energy costs.

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Issue description:

The only central overview of energy consumption at individual stores was provided by the supplier's invoices. Therefore, it was first necessary to find a way to accurately measure the consumption, down to the level of individual stores and even their different areas (sales floor, offices, warehouse, air-conditioning, water and gas consumption). The next step was to analyze the data gathered during the operation of all stores.

This analysis will help to identify stores with overly high energy consumption as well as ways of saving energy. In addition, the data will be normalized to determine the usual consumption figures per square meter of a store. Based on these figures, stores with higher consumption will be motivated to reduce it, or remodeled in order to save, for instance, on heating or lighting.

Solutions	Benefits	Solution image
At some branches, it was necessary to install newer electricity, water or gas meters equipped with the M-Bus interface. For the measurements, a HWg-PWR device was used. This device uses the M-Bus interface to link to external electricity, water and other meters. One HWg-PWR can be connected to a maximum of 3 or 12 or 25 M-Bus meters. Individual energy meters are third-party products. It is often possible to use those already installed at the customer's premises. The HWg-PWR unit connects to a LAN. It provides a Web interface, and supports displaying charts, SNMP and Modbus/TCP output, data logging, e-mail and SMS alerts, and much more. Measured data can be checked by the store management (online via the unit's web interface), and in addition, data from all units are centrally collected at the headquarters using the HWg-PDMS application and exported directly to MS Excel for further analysis. Technical description Gas, electricity and heat meters are usually easily accessible at the store premises. There can be a central water meter only located outside of the store premises; in such a case, a supplementary water meter for the store can be installed. A central overview can be obtained for instance with the HWg-PDMS software for Windows, or with a suitable NMS/SCADA software package. Energy meters with pulse (S0) output can be connected to a M-Bus converter.	Thanks to the ability to analyze consumption values and patterns for individual branches, first problem spots were identified after just a few weeks of operation -- for example, branches that did not turn off the lights at nights, branches with unsuitable or improperly used heating, and branches where savings could be achieved by replacing certain appliances. Instances of water wasting, mainly due to running toilets, were also identified. Obtained data helped to establish energy consumption benchmarks, set rules for the use of electrical appliances, and draft guidelines for staff. Thanks to the ability to analyze the consumption in individual parts of a branch, the branch management could be given clear information where energy was being wasted and what could be done to prevent it. Thanks to precise measurements and a thorough data analysis, the consumption of energy and utilities was reduced by 18% in the first year alone. More savings are expected after some further optimizations. This was more than the customer had expected in their project rentability calculations. It had also helped that staff were informed that the consumption was being monitored, and in addition were incentivized to take concrete steps to reduce utility costs.

Devices

Standalone Monitoring

HWg-PWR3/12/25

Saving energy in a retail chain

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Technical description

Devices