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
Here are the 3 main components in a solar system:
- Photovoltaic (PV) Panels
- Solar Inverter
- 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:
- These photons hit electrons lose in a photovoltaic cell.
- The loose electron will move towards the N-Type side of the cell and the hole will move towards the P-Type side.
- 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
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:
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.
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.
The solar energy system is relatively simple. There are no moving parts or maintenance to be worried about.
Good and easy to understand article. I am considering installing Solar Energy System for my house. My monthly bill around RM 600 to RM700. What would be a typical up-front cost and long term maintenance cost for a monthly breakeven?
I know you may have left the industry but any estimate figure will really help. Thanks in advance.
Hi CK, thanks for writing in.
The cheapest solar system can offset around RM250 of electricity bills each month & would cost at least RM20k++.
To offset your RM600 to RM700 bill entirely, you’re looking at a system that costs around RM40k (I’m quoting, please shop around).
ROI, we’re looking at around 10 years. After that, free electricity. Long term, solar is a financial win. But many people are impatient.
In terms of maintenance, there’s nothing to do, except if you live in a dusty area that will cover the glass, then you’ll need to hire someone to go up there and wipe the dust off your panels. But for most Malaysians, this wouldn’t be a problem.
Usually, the contractor will sell insurance together with your panels. It’s dirt cheap starting at RM150+ a year, and it covers a lot of accidental damages. I’d take the insurance personally.
The panels last around 25 years. The weakest point in the system is the inverter (insurance does not cover inverters), so get a quote from your contractor, on how much a replacement will cost you so you can financially prepare yourself in the worst case.
Hope this helps!