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The Philippines Is An Ideal Place For Solar Energy Harvesting

The Philippines Is An Ideal Place For Solar Energy Harvesting

An Overview of How Solar Panels Work

Solar home systems work by harnessing light from the sun — when sunlight strikes the solar panels, they generate electricity.  This electricity coming from the panels is then transformed to a usable power by a device called inverter. This inverter, in turn, feeds electricity to the electrical system of the house where it is connected, which in turn helps power our electrical devices like a refrigerator, air conditioning, etc.  If you want to read further about the technical details on how solar panels work, here is a link that describes it.

Do Solar Panels Still Work On Cloudy or Rainy Days?

Yes, these solar panels still generate electricity although less compared to days when it is clear and sunny.   The amount of power generated by the solar panels varies and it is dependent on the amount of light that hits the panels.   The regular barriers between sunlight and the solar panels are clouds. The type of clouds and their thickness impact the amount of sunlight that can go through the clouds and the lesser the sunlight that reaches the panels, the lesser the electricity it can generate.   

However, even with all that possible cloud cover, the Philippines is still blessed with a lot of sunshine for we are a country located in the tropics where sunshine is plentiful.   Historical data shows that the Philippines blessed with clear sunshine about 48% of the year, the remaining 52% of days are with cloudy or rainy.   

In my experience with the solar panels in my house, during cloudy days, I have seen it generate between 1% ~ 65% of the rated capacity of the system depending on cloud cover (my inverter displays the output in watts every few seconds).  The thinner the clouds, the higher the energy produced. The darker the clouds, the lower the energy produced.

If there is something good about cloudy/rainy days is the fact that we use less electricity to cool ourselves, we may not even need air conditioning in our homes, an electric fan will do (but that is entirely your choice).  So even if there is less power coming from the solar panels, we are using less energy anyway.

So during cloudy days or rainy days, it is possible that you will still get power from the solar panels although much less.  If you will need more power, it automatically starts pulling power from the grid if the solar home systems cannot generate enough power.    There is no simple way to measure this because it varies every second.  


Why Not Store The Energy In Batteries So That There Is Power At Night?

Rechargeable batteries (deep cycle type) are still not practical today as of  June 2018. This is primarily due to their prohibitive cost. According to the Philippine Department of Energy (DOE), the average consumption per capita for the Philippines is 260 kWh per month.  To be able to maintain the current requirement of 260 kWh per month, we would need at least 6 batteries of 12 volts with 200 Ampere hours of capacity each. The total cost for the 6 batteries is ranging at ₱ 140,000 ~ ₱ 180,000 in today’s market.    This cannot run our air conditioning yet. We will have to add the cost of the solar home system on top of this amount to charge the batteries.

The other problem with batteries is they deteriorate as they age.  They can last 3 – 10 years depending on quality. Most manufacturers offer 3 years warranty.

If your house is really far from a distribution utility grid and it is not practical to tap from the grid, then solar home systems plus battery combination is a solution that you can consider.

However, if you are currently connected to the grid, given the cost of batteries today, it is not practical yet.  It is even cheaper to use power from the grid instead of batteries.

There is hope though because the cost of batteries continues to drop so probably in the near future, they reach a level of practicality.

Someday we want to be completely independent of distribution utilities and I’d like to see that day come when we no longer pay a single centavo to power companies.  


What Happens If The Solar Home System Produces More Power Than We Need?

Solar home systems can produce more power than what is needed in our household at about noon if sunlight is ample.  If the power output of the solar home system exceeds the need, this will be exported to the distribution utility company and they will credit our bill for that.  The equivalent amount is deducted from our bill.

To illustrate an example, we have a refrigerator rated at 150 watts running round the clock.  I have a computer and an electric fan running also about 12 hours a day. The combined total of all of these appliances is 240 watts.   

The solar home system can generate 1,000 watts on a clear day at about 10 AM – 2 PM.   In this scenario, the solar home system is producing an excess of 760 watts.

This excess wattage is now our surplus power, which we can now “sell” or export to the distribution utility like Meralco.   This exported power is measured by a specialized bi-directional meter that can read both imported power (from the grid) and exported power (surplus from the solar home system).  If we accumulate a sustained surplus of power, our total export is then credited to our electric bill – meaning Meralco will deduct the equivalent amount from our electric bill.   


If you want to know more about how to use solar for your home, feel free to message me using the contact details below and I will take time to respond.

I would also like to invite you to join the FB Group “Sinag” for updates on how you can also benefit from solar.


We all live on one earth, our home.  Let’s join hands in protecting it.


Thank you for reading.

Galileo Valiente

Facebook Group:  Sinag


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