Despite its promise as a source of clean energy, there are a number of disadvantages of solar energy that have prevented its widespread use. Solar energy is not always as reliable as other forms of electricity and tends to be expensive to install and maintain. Most experts believe that further technological advances are needed to make solar energy both accessible and practical. However, some governments offer subsidies to offset the price and engineers and scientists continue to work to improve the technology.
The expense of purchasing and installing equipment is one of the main disadvantages of solar energy. Every single panel is not that efficient, it typically converts only 10% to 18% of solar energy into electricity. It often takes 15 to 20 panels to generate enough electricity to power a medium-sized home; the number required varies depending on the amount of electricity required, the amount of sun the house receives, and many other factors. Larger panels that can generate more electricity also cost more.
In addition to the price of the panels themselves, the cost of installation varies greatly depending on the location, the number of panels needed, the location where the panels are installed and other factors. Most estimates, it takes at least six years for the initial costs to be repaid in savings from power generation under the best conditions, and double that time under less ideal conditions.
A disadvantage of solar energy is its lack of consistency and reliability. Solar-powered devices rely on a constant supply of sunlight to generate electricity; as soon as the sun sets, the light stops hitting the solar panels and the power decreases instantly. On cloudy days, there is also less light available to produce electricity. This means that some form of storage technology, usually batteries, or an alternative energy source is always needed to ensure an uninterrupted flow of energy. Some people who use solar energy remain connected to an electricity grid to receive energy when solar energy is not available.
Any obstacle between the sun and the panel can also reduce the amount of energy produced. To function at their best, solar panels must be in a place where they are not shaded by trees or buildings. Sunlight can penetrate about 1 cm of snow to produce energy, but the panels are unlikely to work as efficiently; any additional snow buildup during the winter is likely to prevent them from working a lot.
Damage to panels
Solar panels are susceptible to damage caused by elements, another of the disadvantages of solar energy. Constant bombardment of ultraviolet (UV) rays and other solar radiation often causes the panels themselves to deteriorate, just like any other material left exposed to the sun for long periods of time. There have been improvements in the way they are implemented, however, and their current lifespan is 25-30 years as of 2012. However, blowing dirt and sand can damage the panels, as well as large hail. It may also be possible to cause damage when removing heavy snow and debris if the homeowner is not careful.
Batteries and safety issues
Since it is not possible to produce solar power 24 hours a day, most systems use a deep cycle battery bank to store excess energy to be used at night and on cloudy days. Unfortunately, these batteries can be expensive and have a shorter life than the solar panels themselves. They also present some safety risks and require special handling, depending on the type of battery used. The least expensive and long-lasting, lead-acid batteries, also require maximum maintenance and careful handling, as they can pour acid or explode if not stored properly. The other two most common types, gel and absorber glass mat (AGM), are less dangerous but generally much more expensive.
As an alternative to battery banks, some solar power systems are connected to the power grid. This allows the system to draw energy when needed and, in many cases, to return power to the grid when the solar system produces more than the building needs. One of the disadvantages related to the safety of solar energy systems of this type is ‘isolation’, which occurs when the system continues to generate electricity in power lines that employees of the power company could presume dead. This is a risk of electrocution for employees, although many areas now require solar power systems to include an anti-island component to prevent this from happening.
Addressing the disadvantages of solar energy
Despite the disadvantages, many governments, scientists and activists continue to work on ways to make solar energy cheaper and more efficient. Improvements in battery technology have made it easier to store electricity generated by solar systems, and grid connections allow people to sell energy to their own power companies. Flexible solar panels, although typically less efficient than those made with glass, are less likely to be damaged. Many governments also do their part to encourage the use of solar energy by subsidizing the production of solar panels and offering tax relief to individuals who purchase solar panels for their homes.