By Rob Hull on June 14, 2010
Solar panels have been around for sixty years and, with development ever increasing on the functionality of them, are seen as one of the future sources of alternative energy for businesses and households.
They are an active solar power meaning they harvest sunlight and actively convert it into energy. The panels are made up of solar cells, or photovoltaic cells, arranged in grid-like patterns which collect sunlight during the daytime and convert it into electricity or heat water.
What are solar panels made from?
Solar panels are traditionally made from crystalline silicon and gallium arsenide which is produced only for photovoltaic cells. However, there are now also types of panel made by depositing amorphous silicon alloy in a continuous roll-to-roll process. As a result, amorphous silicon solar cells are created which can be used in panels that are more durable, efficient and thinner than crystalline versions.
Solar water heating panels, also known as collectors, are made up of either evacuated glass tubes or flat plate collectors encasing metal tubing. These panels look very different to photovoltaic panels and can provide your household with the majority of its annual hot water requirements.
How do solar panels work?
Solar panels collect solar radiation from the sun and converts that energy into electricity. The solar cells within the panel function in a similar way to that of semiconductors – they utilize a large-area p-n junction diode. When the cells are exposed to sunlight the p-n junction diodes convert the energy from sunlight into usable energy.
The energy generated from photons hitting the surface of the solar panel knock electrons out of their orbit and releases them. The electric fields in the solar cells pull these free electrons in a directional current to the metal contacts in the solar cell which can generate electricity. So the more high quality solar cells in a panel, the more electrical output the solar panel can produce.
How much power do solar panels produce?
The efficiency of a solar panel, and the resulting energy it produces, is dependent on many climate, geographic and weather-related factors. Arid climates are ideal for solar panels, and they will produce more energy when exposed to direct sunlight in clear skies. But the power a solar panel can achieve and the power it delivers are two very different matters.
There are ways of working out how much power a solar panel could produce. If a panel is rated at, for example, 180W it will perform up to that level in the brightest sun light which would generate 1,000 watts per square metre. However, unless you live directly on the equator, your solar panel is not going to be subject to that much sunlight. The easiest way to work it out is finding out the number of ‘peak sun hours’ your location receives each day with a peak sun hour being one hour of 1,000 watts per square metre of sunlight. Once you’ve found this out you can multiply the watt rating of the solar panel by the number of peak sun hours of your location. Be aware that sun hours will vary by season with the lowest being in the winter.
What are the advantages of solar panels?
The primary advantage of solar panels is that they are a renewable energy source so there is no danger of depleting the reserves. It’s also non-polluting and causes no harm to the atmosphere. But what consumers will benefit from directly is the fact it’s a free energy source. And solar cells require very little maintenance as they are non-moving parts and can last a lifetime.
What are the disadvantages of solar panels?
Solar panels aren’t a cheap technology to purchase and have installers fit. But the savings incurred by having one implemented into your home will cover the cost of the collectors and fitting over time. And government grants are available to encourage you to fit renewable energy sources for your home.