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How Do Solar Panels Work?

Learn how solar power systems work in NZ

Ever wonder how solar panels are able to convert the sun’s UV rays into electricity? Read on to find out more about this green sustainable technology.

With the need for control of the negative climate change, many people and organisations are adopting green energy. Green energy is energy generated in an environmentally friendly way. Burning of fossil fuels or coal to produce energy, or what is commonly known as thermal energy, has been proven to be hazardous due to the air pollution caused from fume emission.

Green energy on the other hand involves use of geothermal plants, wind turbines, hydropower plants and use of solar panels. These energy generation methods are environmentally friendly and cheap to run. This has seen some countries like New Zealand adopt these power sources greatly with positive climate change in mind. However, some of these plants require massive capital to establish. For instance, turbines used in geothermal plants, hydro-plants and wind turbines are very expensive. Use of solar panels is the only cheap power generation method as far as the establishment capital is concerned.

Solar panels are readily available in NZ from installers in Auckland and Wellington like Solarworx. You can get a free quote or more information on why you should go solar.

How do solar panels generate power?

Solar panels convert sun rays into electricity. Sun rays are a spectrum of light moving at different frequencies. The main frequency that is applied by the solar panels is the ultraviolet [UV] rays. The solar panel is capable of converting these rays into direct current [DC]. This is electric current that flows in one direction from the positive terminal to the negative one.

For solar panels to make this conversion, they use photovoltaic (PV) cells. These are made using compounds of carbon or silicon. They react with the UV rays and get their electrons energised. Flow of electrons from the negative terminal (cathode) to the positive one (anode) is what causes a flow of current from the anode to the cathode. What does this mean? The electrons have a negative electric charge. Therefore, their flow in one direction can be considered as an apparent flow of positive charge in the opposite direction. It is the rate of flow of these charges that is called electric current.

One photovoltaic cell produces very little current. They therefore have to be arranged in an array so as to generate reasonable power. These arrays are what make up the solar panel. These arrays can either be arranged in series or parallel depending on whether it’s the current or voltage that needs enhancing. Voltage is the potential or `force` that drives the current from the anode to the cathode. If it’s the voltage that needs enhancing, the array is arranged in series and if it’s the current, parallel. Arrangement of the cells in series involves connection the negative terminal of one cell to the positive terminal of the second cell, the negative terminal of the second to the positive terminal of a third cell and so on. This means the electron from the negative terminal of the first cell has to flow through all the other cells in the array before reaching the positive terminal of the cell.

Arrangement of cells in parallel on the other hand means arranging the cells such that all their positive terminals are connected together and the same for their negative terminals.

To achieve the best performance and precision, integration of both arrangements is used, a hybrid system.

How is the power deployed?

Now once the desired voltage and current is achieved the power can then be connected to the consumer’s load or appliances. The power generated however is not stable (or `uniform`) as desired. This is because the intensity and irradiance of the UV rays is usually not constant. During the night it reduces close to zero. To help control this issue a battery or battery bank, in case of large scale solar plants, is used. The battery is charged and from it the consumer’s load can access the appropriate power. The batteries have ratings which should closely correspond to the solar panel’s output power. The solar panel’s power output- as mentioned earlier- fluctuates. It is therefore necessary to use a charge controller to help ensure the battery is not damaged by the panel’s unstable output.

With the batteries charged it might seem that everything is set. It is not. Most appliances’ power inputs are designed for alternating current (AC) or the electric current from the grid. As the name suggests, the current flow keeps on switching directions between the positive and the negative terminals at frequencies of 50 or 60 times per second (50Hz or 60Hz).

It goes without saying that there is a need to convert the solar panels and battery’s DC to AC. This is done using a device called an inverter. The inverter is fed with DC power, say 48VDC at 5A and outputs approximately 240VAC at 1A. With the 240V one can run ordinary appliances as if using the grid mains electricity.

And from the sun rays we can now see how solar panels work to produce AC power.

Contact the friendly Solarworx Team today for a free no obligation quote.