Introduction of Solar PV System
Solar PV systems can be classified into three types:
1) On-grid systems
2) Off-grid systems and
3) Hybrid systems.
Now we introduce you on-grid systems.
As their name suggests, on-grid systems are systems that are “on the grid” or connected to the grid. On-grid systems are also called grid-tie systems or grid-tied systems or grid-paralleled systems.
The figure above shows a typical on-grid system. It has three main components:
- Solar PV modules: The solar PV modules generate DC electricity, as explained in the previous two articles: Introduction to Solar PV and An In-Depth Look at Solar PV.
- On-grid inverter: The on-grid inverter, also called grid-tie inverter or grid-tied inverter, converts the DC electricity generated by solar PV modules into AC. Before feeding it into the grid, it “synchronises” it with the grid. In other words, it ensures that the AC signal that it generates is “in-phase” with the grid. Yet another way of saying this is that the AC signal it generates is at the same point in the cycle as the AC signal in the grid. (Refer to the description of alternating current in the article War of Currents.)
- Meters: There are three meters in the system:
- Sell-back meter: The sell-back meter, also called the “export” meter, measures the amount of energy generated by the on-grid inverter and fed or “exported” to the grid. This is always less than the amount of electricity generated by the PV modules by an amount equal to the various losses in the system: PV module mismatch losses, resistive losses in the cables, inversion losses in the inverter.
- Purchase meter: The purchase meter, also called the “import” meter, measures the amount of energy purchased or “imported” from the grid.
- Net meter: The net meter measures the net energy imported from the grid by calculating the difference of the imported and exported energy. If the net energy is positive, it means that the consumer consumed or imported more than he generated or exported, and therefore has to pay money to the distribution company as per the applicable rate. If the net energy is negative, it means that the consumer generated or exported more than he consumed or imported, and therefore the distribution company has to pay him as per the agreed rate for excess generation.
Although they are not visible in the figure, some other components called Balance of System components, or BoS components in short, are also part of the system. They are:
- Mounting structures: These are used to mount the solar PV modules on the roof or the ground, depending upon whether the system is a rooftop or ground-mounted system.
- AJBs: AJBs (short for Array Junction Boxes), also called SCBs (short for String Combiner Boxes) or PV Combiner Boxes, combine the output of several strings into one as their name suggests. This is required if the number of PV “strings” (i.e. a string of PV modules connected in series) is more than the number of inputs that the grid-tie inverter has. AJBs are available in various configurations: 2:1, 4:1, 8:1, or 16:1, and in general, they can be made in any configuration that one desires. Besides combining the output of multiple strings, they can, and in most cases do, perform one other important function: string monitoring. Before combining the output of several strings, they monitor the current in that string. Doing this is important to figure out where the problem lies in case the system is not generating as much it should. If the current in one string is less than those in other strings, you know that there is a problem in that string; in all probability, one of the PV modules in that string is malfunctioning or is shaded.
- Cables: Cables are required to connect the strings of PV modules to the AJBs and the output of the AJBs to the grid-tie inverter; the cables to connect the PV modules to each other are already provided at the back of the modules.
- Earthling: The earthling system is needed to “ground” the system, which literally means connecting the system ground to the actual ground.
- SPDs: SPDs, short for Surge Protection Devices, are required to protect the system from surges which typically arise due to lightning. It is very important to have a good SPD; we want the system to last a long time, i.e. 25 years, and in that long a timespan, it can experience surges on multiple occasions and will get damaged without the proper protection.
Different Schemes to choose
Net- metering system:
The Customer generates electricity using solar panels installed on their houses/premises it is connected to the grid through net metering system. The consumer has to pay only for the NET amount of electricity that he/she has consumed. In this system, if that particular customer’s production exceeds consumption, he/she can bring forward the balance and consume it in the months to come. No fee will be paid for the excess electricity produced. The customer will be given the choice of using the balance electricity within a 10 year period.
If the generated units of electricity from the solar panels fixed on their houses/premises are greater than the amount that is consumed, the customer will be paid Rs. 22.00 per unit during the first 07 years and from the 08th year he will be paid Rs. 15.50 per unit. If the consumption is greater than he generated, the consumer has to pay that existing electricity tariff for the excess electricity consumed.
Getting paid for the amount of electricity generated using the solar panels fixed on their houses/premises. Unlike net metering method there is no linkage in-between the electricity consumption of the customer and the electricity generation. The customer has to pay for the electricity consumed according to the existing tariff. Electricity Board will pay for the total amount of electricity he generates.
REASONS TO CHOOSE SOLAR ENERGY
- LOWER YOUR POWER BILL
We all know that dreaded feeling that comes when you see your power bill in the mail. How much will it cost? Have you budgeted enough?
Having the right solar electricity system on your roof eases this tension. Here at Sunmade we work with your unique wants and needs to ensure your solar energy system is both within your budget and designed to maximize your savings.
You’ve seen the reports, unfortunately the cost of power is only going one way and that’s up.
- GENERATE YOUR OWN ELECTRICITY
Energy from the sun beams down on your home every day; even in winter and on overcast days.
When you have solar PV panels on your roof, you harness this power and generate electricity that you can use in your home.
Surplus power is fed back into the grid and depending on your utility you’ll be credited for the power you provide. When you don’t have solar PV panels, the limitless power of the sun is lost on your home.
- IMPROVE THE ENVIRONMENT
Installing solar PV panels on your roof is one of the easiest and most practical ways of contributing to a sustainable future.
Though most of us would love to be rallying in the world’s rain-forests or scouting the ocean for illegal poachers, it’s not something we’d usually get around to!
Starting on your own home is a fantastic way to show that you care about reducing your carbon footprint. In fact, installing a small 1 kW solar electricity system prevents the release of an incredible 1.5 tonnes of carbon every year.
- IT’S NOT AS EXPENSIVE AS YOU MAY THINK
The cost of producing and installing solar power systems has dropped dramatically when compared with systems from just ten years ago. A highly competitive market and enormous global demand continues to drive prices down and it’s no wonder that the industry is experiencing a boom in Sri lanka.
Plus, there are still plenty of generous government incentives such as STCs and Feed-in Tariffs, which add up to thousands of dollars saved over the lifetime of your system.
Sunmade has a range of solar energy systems available to suit almost any budget. A chat with our friendly team is the best way to decide which is best for you.
- SOLAR ENERGY IS A LONG TERM INVESTMENT
Your solar system will start saving you money the moment it’s switched on, but the benefits of solar power run well into the future.
Indeed, the longer you have your system, the more benefits you enjoy. Most solar systems pay themselves off in less than five years, and they add value to your home.
Plus, for complete piece of mind, our solar panel suppliers all offer 25 year limited power warranties along with industry-competitive guarantees on parts and workmanship. This means that your solar system is set to save you money and support the environment in both the short and long-term.
Most importantly, Sunmade prides itself on exceptional after-sales service. We’re dedicated to our customers long after their initial purchase and offer quick turnaround on solar servicing, maintenance and repairs.
- ROOM TO MOVE
Sunmade gives you the option of expanding your current solar electricity system in the future. We understand that circumstances change and your energy requirements can increase.
That’s why we offer a range of expandable systems which have the potential to grow with your needs.
- INCREASE THE VALUE OF YOUR HOME
As more Srilankans see the value in solar PV panels, getting a quality system installed on your property adds instant desirability and value.
- SOLAR POWER IS NO LONGER NICHE
By 2025, it is expected that more than a million homes will be fitted with solar PV panels. This number is set to increase rapidly over the next five years and definitely goes to show that solar power is no longer niche.
- SRI LANKA LIGHTS THE WAY
Contrary to popular belief, solar PV panels are not powered by the heat of the sun, rather they rely on sunlight. This means that you do not have to worry if you live in an area where average temperatures are not high. In fact, extremely hot days will often hinder your solar panel’s performance, not enhance it.
Your solar PV panels will happily convert sunlight into electricity on cloudy days and do not require heat.
When you call Sunmade, we ensure that your panels are installed in the best possible position, away from shade and in direct sunlight for the longest part of the day.