These days, most PV installs include system performance monitoring, but this is only half of the monitoring solution necessary to verify that a sound investment decision was made. Often, renewable system owners begin to see lower energy bills and, in turn, increase their energy usage—not always consciously. So, it is also important to measure the energy consumption of a location because it encourages responsible energy usage. A monitoring system that reports on energy production and consumption provides a complete picture of net usage and can lead to greater energy efficiency measures.
An incomplete picture costs time and money. A customer who feels his system is not producing what the installer estimated will place blame on the installer. The installer sends a technician to the site, the system is verified to be producing as expected, and the customer continues to see higher than expected energy bills. Why? Because neither the installer nor the customer has identified the root cause. By monitoring the customer’s consumption it is easy to see when, and if, there has been an increase. It alerts customers that their consumption habits have changed and quantifies the impact that change will have on their energy costs. Monthly utility bills can also indicate changes in habit, but they provide little information about what changes cost the customer and no immediate feedback when the customer attempts to correct the issue.
Customers with commercial buildings benefit the most from consumption monitoring. These customers tend to have higher energy bills, and installing solar PV to offset energy costs is attractive to them. Frequently, commercial customers are charged for their peak demand in addition to energy. Peak demand charges are expensive and difficult to offset with PV because demand spikes do not always occur mid-day when solar is at its peak. A basic utility bill gives no insight into the cause of demand spikes. Real-time consumption monitoring is the best way to capture peak demand occurrences, and it can even be used in conjunction with control systems to flatten demand peaks. When real-time consumption monitoring is used in conjunction with a PV system, customers optimize the value of their efficiency investment.
This tip was contributed by Ed Pantzar, account manager of eGauge Systems.