Solar Tips & Tricks: Frequently asked questions about solar

Author: Darvin Tocmo  Date Posted:11 June 2019 

 

Questions about solar? Over the years, we have compiled our customers’ most frequently asked questions (FAQs) about solar. The perfect place to get started for unbiased information so you can make the best decision.

 

HOW MANY SOLAR PANELS AND WHAT SIZE ARE ENOUGH TO MEET MY POWER NEED REQUIREMENTS?

Each energy consumer has different needs, dependent upon the electric appliances being run. For instance, if you are powering two 27 watt compact fluorescent light bulbs for two hours, you would need to supply 108 watt-hours of energy (2x 27x 2 hours). In Manila, which has yearly average insolation of 5 hours a day, one 32 watts photovoltaic (PV) module is more than adequate (32x 5 hours=160 watt-hours).

To find out how much energy you use, contact us, we would love to help you.

 

WHAT IF THERE IS HARDLY ANY SUNSHINE FOR SEVERAL DAYS?

Most solar electric systems today are connected to the utility lines - allowing you to send energy back to utility grid turning the meter backward, or using power from the utility at times when there is no sunshine including when its dark outside. This connection to the utility grid ensures you will always have power to your home or business.

Different geographic areas provide different amounts of daily sunshine. For instance, the Philippines averages 7 sunshine hours per day and other countries receive about only 5 hours of daily sunshine. More solar panels will increase the amount of power generated when the sun is shining. We at Optimus Energy sizes each system based on your area and also takes into account, shading from trees and other obstructions on your roof or surrounding area for optimal year-round performance.

 

HOW LONG DO SOLAR PANELS NORMALLY LAST?

New solar panels have a manufacturer's warranty of 25 years. With proper care, however, the panels should last many years beyond the warranty. You can expect your solar modules to continue to produce power for 60 years or more.

 

WHAT MAINTENANCE IS REQUIRED FOR A SOLAR ELECTRIC SYSTEM?

Solar electric systems are elegantly simple. Maintenance includes:

  • Occasional checks of the connections between the solar modules and the inverter(s), and to tighten them when applicable.

 

DO SOME SOLAR PANELS GENERATE MORE POWER PER INCH THAN OTHERS?

Some solar panels tends to generate more power per inch than others. For example,

  • Monocrystalline panels have a higher output per square foot than amorphous silicon panels. Traditionally, if square footage was important, monocrystalline solar modules were the best choice due to a higher conversion rate of sunlight to electricity.
  • New amorphous silicon panels absorb three different spectral wavelengths, which translates to up to 30% more real power per watt from the PV module. This is because the amorphous panels produce energy for longer periods each day than monocrystalline panels. This means the panels produce more amp-hours per amp than other technologies.

New and future hybrid designs employ the best of both technologies.

 

HOW CAN I FIND OUT HOW MANY WATTS MY APPLIANCES USE, SUCH AS COMPUTERS AND STEREO ETC.?

There are a few ways to determine how much energy your household appliances use including the following:

  • The easiest way is to look at a monthly utility bill. This has the number of kilowatt-hours consumed during the billed month. From there, a consumer can determine how many average kilowatt-hours were used daily.
  • Additionally, a typical electronic appliance should have an energy rating sticker somewhere on the product.
  • There are devices available including the Kill-A-Watt that can be used to determine the energy usage of a specific appliance.

 

HOW LONG DOES IT TAKE FOR A SOLAR SYSTEM TO PAY FOR ITSELF?

The payback period for a solar system is roughly 5-7 years, based on calculations assuming the cost of energy obtained from the utility grid is 10 cents a kilowatt-hour.

 

IS THE CURRENT TECHNOLOGY MORE ADVANCED THAN A FEW YEARS AGO?

The technology behind PV solar energy is continuously improving. Research on thin film materials, processes and devices are leading to increased module efficiencies while using high-throughput, lower-cost plasma processing. Increased module efficiencies coupled with fast deposition rate technologies implies the cost of PV modules will continue to decline.

 

WHY CHOOSE SOLAR OVER WIND- OR WATER-POWER GENERATION?

Every energy source has its advantages and disadvantages. Wind- and water-power generation may be appropriate in certain situations. However, these technologies are

  • Limited by seasonal variations
  • Have moving parts that require maintenance
  • Generate noise
  • May negatively affect wildlife
     

PV modules, on the other hand, are:

  • Silent
  • Have no moving parts
  • Non-glass panels are covered by a 20-year warranty.

 

WHAT IS THE DIFFERENCE BETWEEN A MICRO-INVERTER AND A CENTRAL INVERTER?

Micro-inverter. A micro-inverter consists of a small box located on the back of or situated very close to a solar panel. Its role is to convert the DC electricity produced by a single solar panel.

Features of a micro-inverter:

  • Ability to use different makes/models of modules in one system, particularly when repairing or updating older systems
  • No need to calculate string lengths – simpler to design systems
  • Increased yield from sites that suffer from overshadowing, as one shadowed module doesn’t drag down a whole string
  • Allows for increased design flexibility, modules can be installed facing different directions - east, west or south - making the most use of your roof space.
  • Lower DC voltage. No need for ~ 600 V DC cabling requiring conduits
  • Panel level monitoring
  • Parallel operation - in rare instances of failure, that single panel will not produce panel while the remaining panels will continue to produce electricity.
  • Panel level MPPT (Maximum Power Point Tracking)
     

String inverters

A string inverter is a type most commonly used in home and commercial solar power systems. It is a box that is often placed near your electric panel. Depending on the size of the installation, there may be more than one string inverter present.

String inverter advantages:

  • Remote system monitoring capabilities
  • Low cost
  • 3 phase variations available
  • Robust
  • High efficiency
  • Allows for high design flexibility

Central inverters

Central inverters are designed for large-scale commercial, industrial, government and field applications – Basically, they are a very large string inverter.