Energy efficient loads

Common off-grid loads.

An off-grid PV system is sized and designed based upon the loads - appliances and lighting - that will be used with the system and the amount of time that they will function on average. The most commonly uses for an off-grid PV system are for lighting, cell phone charging, radios, televisions, fans and refrigerators. The majority of these types of appliances in the market are conventional, meaning that they are not appropriate for use in off-grid applications. Lighting and appliances that are appropriate for use in an off-grid application are designed to be more efficient. Increasing efficiency does not mean decreased performance as there are cases - like with incandescent and LED bulbs - in which one design simply loses significant amounts of energy as heat or to friction. In addition, energy efficient appliances do not necessarily have to cost more than conventional appliances, but they can have a significant impact on the total cost of the system by reducing the size of the PV source and energy storage system. Energy efficient appliances are available in both alternating current (AC) and direct current (DC), although DC appliances are inherently more efficient as there are no efficiency losses resulting from passing through an inverter.

Finding energy efficient appliances

There are many efficient appliances designed for AC applications. The market for energy efficient DC appliances is evolving rapidly, but it can still be difficult or expensive to find them in many areas.

AC appliances

AC appliances dominate the market; therefore it should be possible to simply survey the equipment available from different providers in any location to find a suitably efficient appliance. There are various organizations that classify products based upon how efficient they are, like Energy Star. These databases can be useful to determine what is truly an efficient appliance or light.

• Energy Star Product finder
• European Union energy efficient product information
• For AC appliances, the internet and markets can be scoured for efficient There are various different agencies that perform product testing and evaluation.

DC appliances

The DC appliance market is growing rapidly address the growing demand from over 1 million people globally that depend upon off-grid DC-only PV systems for their energy needs. These products have achieved incredible leaps in efficiency in recent years with television efficiency increasing 45% from 2014-2017 and best-in-class refrigerators reaching efficiences as high as 9 times that of conventional refrigerators. There are various organizations working to test, evaluate and facilitate the growth of this market.

• Verasol
• Global LEAP Awards - 2017 Buyer’s Guide for Off-Grid Fans and Televisions
• 2019 Global LEAP Awards - Buyer’s Guide for Outstanding Off-Grid Refrigerators