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Photograph courtesy of Uni-Solar

Facts about Solar PV

  1. What is PV?
  2. The alternative energy technologies of PV or photovoltaic systems use semiconductor technology to convert solar energy (sunlight) into electricity.

  3. What components are required for a photovoltaic (PV) system?
  4. The system consists of an array of solar modules (panels), bracket support system, a charge controller, a possible battery bank system (if not grid connected), a DC (direct current) load centre, a fuse or breaker system, an inverter, a possible optional generator (for cloudy days or nights) and an AC load centre.

  5. Why use PV?
  6. The overall reasons for using PV are the dwindling traditional resource base, the rising cost of traditional energy resources and preservation of the environment.

    We can summarize the specific advantages of using PV as opposed to the conventional energy sources as follows:

    1. The environment - PV systems generate no waste products and create no pollution.
    2. Cost - In many cases, the advantages of PV systems offset their relatively high initial cost.
    3. Modularity - PV systems can be designed for easy expansion as the demand for power increases in future years.
    4. Site Access - There could be considerable savings in labour and logistics costs because a well-designed PV system can operate unattended and requires minimum maintenance periodically.
    5. Maintenance - PV systems require less maintenance than other energy alternatives.
    6. Supply - Solar energy is delivered free whereas supplying conventional fuel and storing it on site can be much more expensive than the fuel itself.
    7. Durability - Most PV modules available at the present time are designed to last over 20 years with little degradation.

    The effectiveness of a PV system depends upon the proper design and size appropriate for the particular site in question.

  7. Is my house suitable for a PV system?
  8. The irradiation intensity varies from one area to another. However, in most areas of the country it is possible to make a PV purchase justifiable and to pay for itself over time. In principle, PV systems can be installed anywhere where there is sufficient light. A most advantageous location would be with southern exposure and with about a 30 degree angle. A variation to southwest or southeast between 25 and 60 degrees will reduce your energy output minimally. It is important that there should be no shading because of trees, close buildings, antennas, or chimneys etc., as they would reduce the effectiveness of the energy output.

  9. What should be the size of a well-designed PV system?
  10. The size of a solar system should not only be measured by one's own hydro needs but also by the size of the roof area and your pocket book. A PV system with a 1 Kwp (kilowatt peak) requires approximately 10 m2 of roof area. With this measurement we could plan a costing and payback structure for you.

  11. How much energy should I expect from a PV system?
  12. As a rule of thumb, in our area we can expect an energy yield of approximately 850 Kwh (kilowatt hour) to 1000 Kwh per Kwp (kilowatt peak) installed output of the system per year. A 2 Kwp photovoltaic system with a 20m2 will produce approximately 1600 to 1800 Kwh of solar electricity per year.

  13. What kind of installation is available?
  14. Photovoltaic systems can be installed on almost any roof structure. With a flare for architecture in mind, these PV panels will enhance the look of the building and may increase its value. As a choice of installation, there are: a) the freestanding option, b) facade installation and c) the roof mounting installation that can be considered. The architectural view considered so as to enhance the look and make it aesthetically pleasing. The installation of the whole PV system would take about 3 days.

  15. How long do PV systems last?
  16. Some manufacturers of PV systems claim a life expectancy for their panels of 40 years. Since this technology, however, has not been around for that long, we cannot substantiate this claim. Most reputable firms give a guarantee of 15-25 years. This is a more reasonable expectation. Since there are no moving parts, the PV module will last a long time, depending upon the quality of installation. On average, every 10 years, the inverter or charging system may have to be replaced. There are no batteries to replace if the system is on the grid.

  17. How much maintenance is required?
  18. PV systems require much less maintenance than conventional power generators. The amount and type of maintenance directly affects the performance and lifetime of a system. The best and in the long run, the least costly kind of maintenance is preventive maintenance. The PV system should be checked several times a year on a regular basis (i.e. 4 times a year is recommended). The type of things to check are the features that are likely to experience failures, such as fuses, switches and connections. Documentation of the system and logs of system checks should be kept on hand. Also, dirt and dust on top of solar modules should be removed as well as any bird droppings or fallen leaves in order that the system can perform at its best.

  19. How and where to obtain systems and components reasonably?
  20. The best advice is to be an educated consumer. Know what you want to accomplish. We will be happy to design a system for you or to quote you on your system requirements. You can email us here.

  21. System Availability?
  22. System availability represents the percentage of time that a power system is capable of meeting load requirements. The number of hours the system is available, divided by 8,760 hours, gives the annual system availability. What lowers the availability of any energy system are failures of the system and maintenance time. For a PV system, the variability of the system's source, i.e. sunlight and radiation, is an added factor of uncertainty for the system availability. The most likely time for periods of unavailability occurs when the solar resource is at a minimum, such as in winter.

    Photograph courtesy of Uni-Solar

    It should be kept in mind that there are few single energy sources such coal fired or nuclear or hydropower generators that achieve even 90 % availability. Many PV systems exceed this standard even when maintenance, component reliability and solar variability are taken into account.