Solar panels generate clean, renewable electricity and help to reduce climate-damaging carbon emissions. They are also made of abundant materials, including pure metallurgical silicon and aluminum.
They can also save you money on your energy bills. Depending on your energy costs, available sunlight and electricity usage, solar panels can pay for themselves within a decade or less.
The cost of a residential solar system depends on the number and size of solar panels and the type of inverter that is installed. It is also influenced by state policies and incentives, such as net metering, which provides credits on electric bills for homeowners who produce more energy than they consume.
Typically, the more wattage (power output) a solar panel produces, the more expensive it is. The best way to get a realistic idea of what your solar energy costs will be is to check past electricity bills to estimate your average usage over a 12-month period. Once you know your energy consumption, you can calculate how many solar panels and the associated inverter you’ll need to power your home.
There are two main types of solar panels: monocrystalline and polycrystalline. Monocrystalline panels contain a single solid silicon crystal, which provides more space for electrons to flow and results in higher efficiency and better performance. However, they are also more expensive than polycrystalline panels.
In addition to hard costs, homeowners should consider soft costs, such as permitting, inspections, system monitoring and deposits. These fees can add up to tens of thousands of dollars and can affect your overall return on investment.
If you can afford to pay cash for a solar energy system, that’s the best option. You’ll avoid financing fees and interest rates, and you’ll be able to take advantage of state and local incentives that can greatly reduce the cost. If you cannot afford to pay cash, installers offer a variety of financing options through third-party lenders. These loans can have higher fees and interest rates, so it’s important to carefully compare solar quotes before making a decision.
Energy Efficiency
Solar energy is one of the most abundant natural resources on Earth. The sun produces 173,000 terawatts of energy at any given moment—more than enough to meet all of the world’s energy needs. Capturing this renewable resource with a solar power system and turning it into clean electricity is an effective way to reduce your home’s energy costs and cut your carbon footprint.
The solar panels in a typical solar energy system consist of silicon cells that convert sunlight into usable electricity. The silicon wafers are layered together and coated with silver—the most conductive element on the planet—to intercept electrons and turn them into current. Copper metal conductors and wiring connect the individual cells into a single solar panel, giving them their classic matrix appearance. Finally, an insulative back sheet protects the solar cell from excessive heat and humidity.
The efficiency of a solar panel depends on the type of silicon used. Monocrystalline solar cells are made of one solid crystal and have a higher efficiency, but they’re also more expensive than polycrystalline solar cells. Thin-film solar cells are less efficient than mono and polycrystalline cells but also have a lower price point.
Another factor that impacts the energy efficiency of a solar panel is its location on your roof. Panels should face true south in the Northern Hemisphere and true north in the Southern Hemisphere for optimal performance.
While solar technology has made significant strides over the years, there is a limit to how much more efficient commercially-available solar cells can be. When you hear about efficiency numbers in the 20s or even higher, it’s important to remember that this advanced tech is only available in laboratories and will probably never make its way to commercial production at an agreeable cost.
Efficiency in Cold Weather
The common belief that solar panels aren’t effective in cold climates or during the winter is not true. Although the peak sun hours are shorter in the winter, energy production remains high, compensating for the reduced sunshine. However, a number of factors will impact the amount of electricity that can be produced, including snowfall and ice.
Snow may accumulate on your solar panels, but this is not necessarily a bad thing. Light snowfall doesn’t block sunlight from reaching your solar panels and it can actually help clean them as it melts or slides off. Heavy snow accumulation can, on the other hand, reduce energy output by blocking sunlight from reaching your panels. In these cases, you may want to consider investing in extra-durable solar panels rated for handling the weight of snow and with frames designed to keep it from building up on your roof.
As temperatures decrease, the atoms in your solar panels slow down, increasing their conductivity. This enhanced conductivity translates into greater efficiency in turning sunlight into electricity.
The lower temperature of your solar panels also allows them to more easily absorb sunlight, even in cloudy conditions. This is why solar power systems are increasingly popular in regions that experience frequent snowfall and clouds. However, these solar panels must be installed on a roof that is able to withstand the weight of snow and must be tilted at an angle that can maximize the sun’s exposure to your panel. This is why it’s important to discuss your solar energy options with an experienced and knowledgeable installer. They will be able to recommend the best options for your situation. This includes a battery system that will provide backup power for your home during periods of low sunlight or cloud cover.
Lifespan
Solar panels are an investment that will help reduce your electricity bill for decades. However, they don’t work at 100% for their entire lifespan and will eventually stop working. This is known as degradation. The degradation rate is typically 1% each year. We factor this into our modeling and quote calculations to give you a clear picture of your financial savings.
The most common way your solar panel’s production will decline is through microcracks that form in the silicon. When these cracks appear, it can make it difficult for electrons to get through. Without proper transmission, less energy will go to your inverter and into your home. Solar panel degradation is also caused by thermal cycling – hot and cold weather can cause expansion and contraction of the cells. This can lead to a build-up of moisture, which reduces performance. Finally, the flexing of your solar panels from wind and strong gusts can weaken the connection between the panel and its mounting system.
Fortunately, the degradation rates of most solar panel types are lower than those of conventional electric technologies, and new PV technologies are being developed that will last for 30 years or more. SETO funds research to find materials and designs that can make PV products longer-lasting, more durable, easier to recycle, and less polluting at the end of their useful life.
Once a solar panel has reached the end of its useful life, it becomes solid waste and must be handled according to federal hazardous and solid-waste regulations. Recycling options include thermal decomposition and hydro-metallurgical processes that burn off the adhesives holding the panels to their armatures and break down the solar cells into crystalline silicon, which can then be separated into its components for reuse.
Installation
Solar panels need to be properly installed to operate at peak performance. The first step is to build a metal substructure that will support the panels. This step can take a day or longer. It is wise to rent machinery that can dig trenches and anchor holes in order to speed this up. The next step is to attach the racking rails to the metal structure, which will then secure the solar panels in place. This is another step that should be done by professionals, as the panel connections can be dangerous.
After the solar panels are secured in place, they will need to be wired together according to plan. These connections are made with specialized clamps that have built-in safety features. This step is usually performed by a licensed electrician.
The inverter, which is responsible for converting the direct current (DC) power generated by your solar panels into alternating current (AC) power that can be used by your home appliances, will also need to be connected to the battery bank and home’s circuit breaker box. A monitoring system will also be required to track your energy production.
Finally, any obstructions that may limit the amount of sunlight your solar panels receive will need to be evaluated and possibly removed or trimmed. This is one of the reasons why many people choose to work with a professional solar installation company, rather than trying to do it themselves. Depending on local laws, permits may be needed for the entire process. Once the final inspection is complete and your utility company has given permission to operate, the solar panels can be turned on and begin producing electricity.