What is Solar Energy & How Does it Work to Power Your Home?

I had the opportunity to work briefly for a solar energy company that installs solar panels for residential homes and commercial buildings in Malaysia.

During my short tenure, I quickly learned all there is to know about solar energy in Malaysia and I’ll be sharing with you what I know in these series of articles.

What is Solar Energy?

Solar energy is electricity harnessed and converted from the sun. This process is also called photovoltaic (PV).

Here’s why Solar Energy has a bright future, especially in Malaysia:

  • Out of all the other renewable energy, solar is one of the cheapest.
  • Converting energy from the sun has no negative side effects on the environment.
  • It’s easy to install on an individual level.
  • It’s modular. Meaning you can add the capacity of your system at a later time.
  • Malaysia is a tropical country with sunlight all year round.

To understand how solar energy systems works, let’s break down the 3 main components of a solar energy system:

The 3 Main Components of a Solar Energy System

Simplified diagram for Solar Energy System. Source.

Here are the 3 main components in a solar system:

  1. Photovoltaic (PV) Panels
  2. Solar Inverter
  3. Net Energy Metering (NEM) meter

Now let’s see how they all work individually and together to for a solar energy system:

How Photovoltaic (PV) Solar Panels Work

This part get’s a little technical but let me explain it in layman’s term.

Electric current is flowing electrons. So by this logic, to generate current, you need to get some electrons flowing.

Here’s how PV modules uses sunlight to make this happen:

A solar PV panel is made out of 2 layers of silicone. The sunnyside is modified to be negatively charged (or N-Type), and the bottom side to be positively charged (P-Type).

Light is a flow of tiny particles called photons. When sunlight hits the Solar PV panel (from the top of the above picture), here’s what happens:

  1. These photons hit electrons lose in a photovoltaic cell.
  2. The loose electron will move towards the N-Type side of the cell and the hole will move towards the P-Type side.
  3. By connecting an external wire to complete a circuit creates a pathway for the electrons to flow to fill the holes on the other side, thus completing an electrical circuit and generating electricity.

Types of Solar PV Panels

A typical solar PV panel. Source.

As of today, a typical Solar PV panel dimension is 2m tall, and 1m wide with an area of 2 sqm. There are 2 types of popular Solar PV panels:

  • Monocrystalline (better efficiency, 450 W capacity but expensive)
  • Polycrystalline (lower efficiency, 350 W capacity but cheaper)

What is a Solar Inverter

The electricity generated from the Solar PV panels is in the form of Direct Current (DC). Which is not the same as the electricity supplied to your home, which is in the form of Alternating Current (AC).

An inverter is an electrical device that converts Direct Current (from the PV panel) to Alternating Current. Here’s how one looks like:

An example of a Solar Inverter

What is Net Energy Metering (NEM)?

Net Energy Metering (NEM) is a government scheme for Solar Energy System Users. Here’s how the system works:

Whatever electricity that is generated from the solar PV will be used by the property first. Any excess energy (if any) will be exported back into the grid.

When You Consume More Energy Than Your PV is Generating

If you consume more than what your solar PV is generating (like at night), you will be importing energy from the TNB power grid as usual.

When Your PV Generates More Energy Than What You’re Consuming

On the flipside, if you consume less energy than what your solar PV generates, what’ll happen to the excess energy?

Example: If your entire family goes on vacation for a long period of time and your usage is less than what you are generating, the excess energy generated from the solar PV will be exported back into the power grid.

The excess energy will offset your imported energy on a 1 to 1 basis.

  • Since you export more than you import, you’ll pay nothing to TNB.
  • The excess exported energy will be carried forward and offset your next billing for a maximum carry forward of 24 months.

Now how does TNB measure your import and export of energy? That’s why an additional meter is needed:

The Additional NEM Meter

The solar energy system will consist of an additional meter (NEM meter) that will calculate the total import and export of energy.

The NEM meter looks almost identical to a normal TNB meter

In your TNB bill at the end of the month, you’ll be able to see the net total import and export of energy.

i.e, if you export 1 kWh, it will offset against 1 kWh consumed from the grid, resulting in a lower (or RM 0) electricity bill.

Summary

The solar energy system is relatively simple. There are no moving parts or maintenance to be worried about.

Helmi Hasan

Hi, I'm Helmi Hasan, the founder, and writer for the personal finance blog, Balkoni Hijau. Read more in the 'About Me' page or follow me on Twitter.

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