How does solar energy harm the environment?

Answer 1

One negative impact of solar energy is in land use. Another impact is an increased dependence on less efficient, fossil fuel powered peak electric generating equipment. There are also concerns about toxic chemicals which may be used in solar cells and batteries for solar cells.

Most solar installations will likely be on top of buildings or in lawns, so the land use issue is minor.

The concern over "toxic" elements is significantly over-hyped. These elements come from the ground, which is the same place your food is grown in, and your water is drawn from. In fact, before RoHS, most electronic devices contained less biologically active lead and Mercury than a can of tomatoes, and were consumed considerably less often than those tomatoes. While lead in gasoline and paint, and mercury use in gold mining were harmful, the current toxic metals concerns are more anti-industry than pro-health driven.

The increased fossil fuel use seems contradictory to solar energy use, but the most efficient fossil fuel plants are the gigantic ones, and they cannot be started and stopped on a whim. They rely on a nearly constant power draw to operate properly. When energy use exceeds their capacity, peaker plants are activated, which use natural gas turbines to power smaller generators. These small generators provide a buffer for temporary high loads, and while the large generators at the main plant are brought on line or taken off line, a process which can take days.

If solar power becomes wide spread, more of these peaker plants will become necessary, as the power demands will fluctuate considerably from sunny and cool to cloudy and hot days, swings which can occur far faster than the startup and shutdown times of the larger, more efficient plants.

There are some buffering technologies which can store renewable energy and help alleviate the dependence on those peaker plants. The first is a hydroelectric storage plant, which fills its reservoir when power is plentiful, and empties the reservoir when power is needed but there are limited locations at which to build such things. Another technology is a vacuum encased flywheel. This is an extremely heavy flywheel which is spun upwards of 10,000 rpm in an evacuated chamber, and can hold a considerable amount of kinetic energy. The storage density may be higher than a battery bank.

Requiring large battery storage at the point of use may also alleviate some of the variability associated with solar power.