Lighting

Lighting is the most commonly use for an off-grid PV system. Choosing the right type of lighting is not only important to ensuring that a system functions properly, but also to making sure that whoever is using the system is happy as the type of lighting, brightness and color can have a dramatic impact on a peron's experience using the system. The only appropriate type of lighting for us in an off-grid PV system is light-emitting diode (LED) lighting as it is far more efficient and durable than its predecessors - incandescent (traditional bulbs) and compact flourescent lamps (CFL). LED bulbs cost slightly more than these other two options initially, but are cheaper when their longer life cycle is considered, not to mention the importance their reduced consumption contributes to reducing overall PV source and energy storage system size. Reductions in the cost of LED lighting, as much as reductions in the cost of PV modules, has contributed to increasing accessibility of PV systems for people in rural areas that lack electricity.

Lighting comparison

LED lighting is the right choice for off-grid applications, but it is important to distinguish between the different designs to ensure that no one mistakening uses one of the alternatives and to help advance the important role that efficiency plays in PV system design.

Output

Higher energy consumption for a particular lighting design (LED, CFL, incandescent) will translate into improve light output, but a 40W incandescent bulb will put out less actual light than a 10W LED lightbulb. This is because the LED bulb can more efficiently turn energy into light than an incandescent bulb which loses a significant amount of energy in the form of heat.

Lifespan

In terms of lifespan, LED are far superior to the competition:

• LED: 25,000-35,000 hours
• CFL: 10,000-15,000 hours
• Incandescent: 750-1,500 hours