IEI was commissioned to carry out Measurement & Verification (M&V) activities for a low-income energy efficiency program in Brazil. The program spammed from 2009 to 2010 and is part of the mandatory energy efficiency investments power distribution utilities must implement since 1998. The utility responsible for the program is one of the largest ones.
The M&V comprised the substitution of refrigerators, lamps and “regularization” of the connection into the grid. The utility’s low-income energy efficiency program also focused on information activities and reform of the household internal wiring.
The measurements were done with time-of-use lighting loggers and plug loggers for refrigerators. For the connection regularization, consumptions of monthly billings and measurements on the transformers were carried out.
Incandescent bulbs were replaced by 15 W compact fluorescent lamps and old refrigerators by a one-door, 258 liters, energy efficient refrigerator, whose refrigerant gas is isobutane (R-600a), known as having negligible ozone depletion potential and very low Global Warming Potential (GWP) compared to other common refrigerants (R-22, R-134a). For instance, isobutane’s GWP is 3.3 (3.3 times that of carbon dioxide) and R-22 and R-134a are 1,810 and 1,300 respectively. The regulator obliges that all old refrigerators must be properly decommissioned.
Three case studies were carried out for lamps and refrigerators and one for connection regularization. The total number of measured lamps and refrigerators were 121 and 90 respectively. The energy savings were 77.5% (78.5 kWh per year) and 67.4% (523 kWh per year) for the equivalent model (weighted arithmetic mean of these three case studies) of a lamp and refrigerator respectively.
The reductions of the peak demand were 17.2 W and 122.4 W for an equivalent lamp and refrigerator respectively. The apparently low value for lighting is due to the peak coincidence factor of the equivalent lamp (32%). The peak coincidence factor is low because the operation rate of the equivalent lamp is a weighted arithmetic mean of the operation rate of the most used lamps and the less used lamps.
Concerning the regularization of the consumer’s connection, the energy savings were estimated as 734 kWh per year per household and the peak reduction as 115 W.
The persistence of the energy savings is paramount to the evaluation of energy efficiency programs. All utilities programs consider physical life of an installed measure sufficient to determine persistance. Better understanding of the durability and reliability of energy efficiency are required.
The size of the energy efficiency program
The two-year low-income energy efficiency program replaced more than 480 thousand lamps, 31 thousand refrigerators and 44.9 thousand regularization connections. The annual electricity savings and the reduced peak demand are estimated to be around 88 TWh (88 million kWh) and 17.4 MW, respectively.