Q: What is On-Grid Solar PV System?
A: An On-Grid or Grid-Tied Solar PV System is connected in parallel to the public grid. During daytime, DC electricity generated by the solar panels are converted to AC electricity by the Grid-tied inverters and this AC electricity is either used immediately or sold off to the electric company. In the evening, no energy is generated by the system.
With an On-Grid Solar PV System, an establishment would be able to save on his electricity bills since a part of its electricity demand during daytime can be supplied by the on-grid solar PV system.
Q: What is Off Grid (Stand Alone) PV System?
A: An Off-Grid Solar PV System is a system that generates electricity thru the use of solar photovoltaic (PV) panels. The system includes a battery system which stores the energy generated by the solar panels and a charge controller that regulate the charging of the battery by the solar panels, preventing over-charging which may lead to shortened battery life or possibly battery damage. To utilize the power that was stored in the battery, a battery inverter is connected to the battery to convert DC energy to AC energy. You can now plug your common AC appliances (i.e. 220V appliances) to the battery inverter to make use of the energy stored on the battery. Even during night time, you could still use your appliances, as long as there is enough energy stored in the batteries.
This system is called “off-grid” because it is independent from the public grid (i.e. Meralco, electric cooperatives). These systems are most ideal in areas where there is no electricity – islands, remote villages, etc.
Off-grid Solar PV Systems are typically more expensive than On-Grid Solar PV Systems because of the batteries.
Q: How much maintenance do you need for a solar PV system?
A: Solar panels require very little maintenance. Depending on the location, periodic cleaning of the solar panels may be needed. But in some cases, cleaning of solar panels is not necessary. Solar panels are typically installed with a tilt of 10 to 15 degrees (in the Philippines). With this tilt, dusts/dirt that may have accumulated on the surface would be washed away when it rains.
Q: Where could I install solar panels?
A: The basic rule is that solar panels should be installed in an area where the panels would be directly exposed under the sun from sunrise to sunset. The solar panels should not be shaded by any object at any time of the day. In this way, the electricity-generation capability of the solar panels is maximized.
Q: Will a solar panel produce electricity on a cloudy day?
A: Yes, a solar panel could still generate electricity even on a cloudy day. However, electricity produced is not as high as when the panels are under bright sunlight.
Q: How durable are the solar panels?
A: Solar modules are designed to last for several years. It is constructed with strong aluminum frames and high strength tempered glass designed to withstand moderate hailstorms.
Q: How long does it take to install a solar PV system?
A: Installation would actually depend on the complexity and difficulty in the installation location. A 2-kilowatt PV system, for example, could be completed in 1 to 3 days.
Q: Would I still have power even during power failure/blackout?
A: Your on-grid solar PV system would not operate during power failure/blackout. This is one safety feature – called Anti-Islanding feature – required by electric distribution companies to avoid powering up electric lines even during power outages.
However, Off-Grid Solar PV Systems would still work even during power outages since these are independent and not connected to the grid.
Q: What is Net-Metering?
A: If you have an On – Grid Solar PV System in your establishment, there may be occasions when the energy produced by the on-grid system would be more than the establishment’s energy consumption at certain periods of the day. This may especially be true in residential homes where there is minimal consumption during the day. Also if you have an on-grid installation in your office/shop and you don’t have operation during weekends, most probably, you would have excess energy production from your on-grid system.
This is where the net-metering program would come in. Net-metering is a service to an electrical consumer who has an on-grid solar PV system, under which the energy generated by that consumer is delivered to the distribution company. This energy exported to the grid shall then be credited to the consumer, the price of which would be based according to the blended generation cost for the month.