The purpose of adding solar to a building is to save money and the environment. By including an upgrade to LED lighting in conjunction with the solar system, you save so much electricity you can install a smaller solar system in order to offset your electricity usage.
The synergism of this combination is such that the cost for the LED upgrade is less than the amount saved on the size of the solar system. In other words, a solar system with the cost of all new LED lighting included is less than the cost of a larger solar system that would be required to offset your usage with your existing fluorescent, HID or incandescent lighting.
An accounting way to look at this is with paybacks, or Return on Investment (ROI). The payback on an LED lighting upgrade in PG&E territory is between 1 and 2 years, depending on many factors such as type of fixtures and how long they operate every day. The payback on a solar system in PG&E territory is between 2.5 and 3.5 years, again depending on the size of the system, and where it is installed. Carports add shaded parking, but also cost to a solar system without increasing efficiency, so they lengthen the payback, reducing the ROI. Because an LED upgrade has a faster payback than a solar system, it is clear that when combined with a solar system, the overall cost is reduced, the payback is reduced, and the ROI is increased.
LED lighting has other benefits that are harder to quantify than strictly measuring the electricity savings. There are many reports about improving health, morale, safety, quality and productivity with better, brighter LED lights. That is why states and nations are literally eliminating other forms of lighting in new construction. LED lights are now coming with built in controls for dimming, occupancy sensing, changing color and dimming based on ambient light (daylight harvesting). These features further enhance the other benefits, helping to optimize the lighting portion of the working environment. Because LED lights generate almost no heat, and almost all of their light is generated in the visible spectrum, they are getting very close to optimally generating light from electricity. There is not going to be an invention that will come along making them obsolete other than incremental improvements to lifespan or controls.
A solar system added to a commercial building makes vast improvements right away. The power generated on site by the solar system has a perfect power factor. This means your motors are fed their voltage and amperage in phase, minimizing the heat created with power with a poor power factor. (The ballast transformers in fluorescent lights degrade the power factor of your building also, which is another benefit of combining LED and solar.) Cooler motors last longer and run more efficiently, which directly translates into electricity savings.
If the solar system is mounted on the roof, it will shade the roof, reducing the heat load the building imports, thereby reducing the air conditioning load or interior temperature. It will also make your roofing last longer, but since it doesn’t cover every square foot of your roof, this effect must be taken on a case by case basis and should not be exaggerated. If the solar system is mounted on carports, called solar support structures, it will create shaded parking for employees and customers. Solar support structures do not keep out the rain, because the water drips between the panels, but it does help a little when battling a storm. LED lights under these canopies with occupancy sensors and photocells create a safe, light environment with a minimal expense in installation costs and operation.
Another benefit of installing LED light fixtures when planning a solar installation, is that the solar system is smaller and will require less roof space, fewer carports, less ground and all of this will reduce the price incrementally.
Whenever two upgrades enhance each other, their use is synergistic and they should always be considered together when one is planned. Once the paybacks of LED light fixtures became less than the constantly dropping payback of a solar system, specifying them together became something that every company providing either one should be doing. There may be reasons for installing LED fixtures without a solar system, but there is literally no reason to install a solar system without first installing LED lighting and taking the savings in electricity into account when designing the solar system.
CitiGreen Inc. is the forward thinking company that is driven to reduce your electric bill with your best interests in mind.