|Easy to clean on the ground panel|
In Hawaii, a solar energy system can reduce the cost of a Kilo Watt Hour from 44 cents to about 6 cents. Although solar panels are widely advertised as a way to cut the cost of the monthly electric bill, there is rarely anything said about the need and cost of maintaining the system and keeping the solar panels clean.
Industry reports say lack of solar panel cleanings can cause a loss of up to 25% of the power efficiency. A typical residential installation in Hawaii costs $25,000 to $30,000, so a 15% to 25% drop in power translates to a loss of $3,750 to $6,250. This is in addition to power loss on cloudy and heavy vog days. Panels collect dust, leaves, and other debris and in Hawaii the vog can leave a thick layer of grey volcanic ash. Moisture, bird droppings, and bugs covering the panel are also a problem. Regular cleaning of the surface is the only way to maintain the power generated to maximize the investment and keep the electric bill low.
When solar panels are installed, they are usually positioned where they can perform most efficiently and are not in the shadow of another building, trees, or other obstructions. But, their position on a roof may make it difficult and dangerous to clean and maintain. We used a solar power system at a cabin we owned for about ten years. The solar panel was installed in a rack outside about 5 feet high which made it easy to inspect and clean. Since it was our only source of power we could tell it needed to be cleaned when our power suddenly dimmed. Solar energy systems installed in Hawaii that feed power directly into an electric grid provide no “reminder” to clean the panels when power output lowers.
You can clean the panels yourself which takes time and effort and if the panels are on the roof, could be dangerous. The job requires an investment in tools and cleaning supplies. Cleaning solutions are needed that do the job without harming the roof or garden below. The water used for rinsing cannot be “hard” or it will leave a film of minerals. Telescopic poles with a water feeding system are available for about $1000 and up depending upon the pitch and height of the roof. Other options are to use a professional cleaning service or installing an automated cleaning system, but they add to the yearly cost of the system.
In our case, we have been able to reduce our monthly electric bill to about $100 by using LED lights, LED TV, and LED computers, turning down the water heater, never running the AC, and even minimizing our use of power when cooking. When calculating the benefit of reducing a monthly electric bill with a solar power system, the hidden expense of system maintenance, solar panel cleaning, additional home insurance, and replacement cost for failing or corroded parts should be added to the cost.