Solar panels can produce energy even on cloudy days, but they are less efficient. Solar panels work at half efficiency when the sky is overcast and at 5-10 percent efficiency on very overcast days. Normally this isn't a problem for houses in cities or towns because they are still connected to the grid and can use normal electricity as backup power. However, some critics say that using the grid defeats the purpose of having solar.
When solar panels are covered in snow they will not work. This can be a significant drawback for residents in areas that receive a lot of snowfall. Although solar panels can work in cold temperatures because they rely on light and not heat, residents in snowy areas will have to spend time after each snowfall clearing snow off the panels. This presents a substantial challenge as the solar panels are usually located on the roof of a residence.
The cost of $30,000-$40,000 for the panels and the labor is within reach for many families, especially with economic incentives and subsidies available from the federal government. However, as wind power and other alternative energies gain more ground in states like Texas and California, it is possible that solar power will be less cost-efficient in the long run. In addition, critics fear that the subsidies will dry up, leaving most homeowners unable to foot the bill for installation.
Solar panels contain harmful materials like mercury and chromium, which can leak into the groundwater if the panels are not recycled. Because solar panels are designed to last about 25 years, recycling is not yet in place for all of the components of the panels. As of yet, experts are not sure how difficult it will be to recycle the used panels in the future.