Clean Renewable Energy

Install Solar Rooftop with ESCO

Win Win Supply co., ltd. offers turn-key services from

  1. Exploring, designing and consulting: we recommend and propose the most cost-effective plan for our clients. Create 3D model and calculate the info to evaluate performance from PVSyst Program, together with mobilizing financial resource.
  2. Government coordination service: We take care of the documents for permission to install the solar system for you from preparing, sending documents and follow up.
  3. Choose the best equipment: by choosing high efficiency Tier1 solar panel. It is guaranteed electricity production for 25 years (10 years for inverter and 12 years for solar panel warranty). We choose a high-efficiency inverter that can check the power generation online, wherever you are, the power generation is available to check.
  4. Installed by a professional team: We install the solar system by a professional team according to the electrical standards.
  5. After-sale service: We have daily online production tracking with follow-up, inspection and corrective action if the power generation system malfunctions.

How Photovoltaic System Works?

Solar Rooftop is the is a photovoltaic (PV) system that has its electricity-generating solar panels mounted on the rooftop. Solar cells of the solar panels produce electricity in the form of Direct Current (DC). The DC electricity from the panels passes through DC network to an inverter, transforms the direct current into AC power with the inverter and then connects to the electricity distribution system of MEA/PEA.

Main Components of a Solar Energy System

Solar PV Panels

Mounting Structure


Watt Hour Metre

Wiring systems (wires, boxes, cable ducts)

Safety Switch or Circuit Breaker for protection and disconnection of inverter circuit.

PV Surge Protector

What is the difference between On Grid and Off Grid systems?

On-Grid System

On-Grid System is a solar PV system that’s connected to the power distribution system of Metropolitan Electricity Authority (MEA) or the Provincial Electricity Authority (PEA) (Although the power is for your own use, no selling electricity back to the Electricity Authority but if connected to Authority, it is considered On-grid)


  • There is definitely an electrical power to consume even during cloudy days. Because the electricity from the electrical system will flow to supplement the energy from the solar cell that has been lost all the time. If the power output exceeds the demand.
  • You’ll be able to sell electricity back into the system (must have a power purchase agreement with the Electricity Authority first) and
  • Maintenance costs are low because only few machines/equipment are in the system.



  • If there is a power outage, the solar cell power system will also be turned off.
  • The connection to the electrical system must be in accordance with the standards set by the Electricity Authority. And there may be costs to improve the electrical system.

Off-Grid System

Off- Grid System is a solar PV system that’s not connected to the MEA or the PEA. The electricity production is stored in the battery and used when we turn on electrical appliances by the battery capacity (number of batteries) will depend on the amount of energy demand of each place.


  • More saving compared to the case of extending the electricity grid for a long distance.
  • No electricity bill has to be paid to the electricity on a monthly basis, every month.
  • In the case of being in a remote area, the power may fall or go out frequently. Using the off-grid system helps to prevent the electrical system from being damaged by power outages.



  • More expensive than on grid. More machines/equipment system investment.
  • In case there is no sunshine or continuous rain for several days, the energy stored in the battery may run out.

Solar Hybrid

is a newly developed system that combines the advantages of both on-grid and off-grid system, which is, the system is connected to electricity for the sunless period and the battery is used to store the remaining energy produced during the day and also work at night time (similar to a hybrid car that uses engine power and charges the battery while braking).

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Can it be installed on all types of "roofs"?

Can it be installed on all types of "roofs"?

Solar Rooftop can be installed on any type of roof. Whether it is a pair of corrugated tiles, cement tile, or metal sheet because the roof is the part that receives very little strength. Solar panel devices are usually installed on the roof. There will be a load of about 10-13 kg per square meter. However, the engineering team who inspects the area will first check whether the roof is suitable or can support the weight of the solar panels or not. Also need to take into account direction of sunlight obscuring, including the structure of the roof whether it can bear the force or not and how much is the lifespan of the roof.

Installation Restrictions

The installation area should not be shaded.

Not suitable for roof structures that cannot support the weight of equipment or very old structures.

Not suitable for galvanized roofs or double corrugated roofs that are about 10 years old or more.

Permissions Required For Installing Solar Rooftop System

Permits & Licensing

Building Modification Permit / Building Modification Notification (Aor 1)

License for Energy Industry Operation

Mini Code of Practice (Mini CoP) checklist

Regulated Energy Production License (Por Kor 2)

Factory Operation License (Ror Ngor 4)

Notify for Exemption of Power Generation License : this step is for solar PV rooftop systems smaller than 1,000 kVA.

Power Generation License: PV systems with an installed capacity of ≥1,000 kVA must apply for a Power Generation License with ERC. System sizes <1,000 kVA are exempted from these licenses.

Request for Grid Connection: If the project is in Bangkok, Nonthaburi, and Samut Prakarn, the request must be submitted to Metropolitan Electricity Authority (MEA). If the project is in other provinces, the request is to be submitted to Provincial Electricity Authority (PEA).


Permits and Licensing Stage

Different permits and licenses are required depending on the installed capacity of the system (DC capacity).


License/Permit < 200 kWp 200 – 1,000 kWp

>1,000 kWp


Building Modification Permit / Building Modification Notification (Aor 1)





Mini Code of Practice (Mini CoP) checklist





Regulated Energy Production License (Por Kor 2)




Factory Operation License (Ror Ngor 4)



Notify for Exemption of Power Generation License




Power Generation License




Performance Guarantee

3-year warranty on system power output of 80% of the Produced Energy calculated by Program PVSys.

Guarantees the efficiency of solar panels at least 84.80% (Linear Performance Output) for 25 years.

Component Warranty

PV Module 12 years

Inverter System 10 years

Monitoring System 5 years

Mounting System 10 years

Maintenance Services

Solar panel cleaning service

Check the operation through the monitoring system.

Report of the generated energy, system performance and system operating status records.

Test and analyze various electrical result ​​in the system

Prepare performance reports

What is TOU?

Time of Use Rate - TOU

Time of Use Rate – TOU

Since October 1, 2000, the government has announced new tariff structure and has set the TOU electricity tariff to have more Off Peak, which is added on Saturdays and public holidays (except compensatory holidays) all day.

New Rate: Electricity rates depending on the usage period are divided into 2 periods:

– On Peak from Monday – Friday / time: 09.00-22.00
– Off Peak from Monday – Friday / time: 22.00-09.00
and Saturday – Sunday, public holidays (excluding substitute holidays) all day

* Peak is the period when electricity prices are high because the country has a high demand for electricity. Electricity must supply all kinds of fuel both high and low in electricity generation to be sufficient to meet the demand during this period.

* Off-Peak is the period when the electricity price is low because the country has a low demand for electricity. Power plants can choose to use lower-cost fuel to generate electricity, thus lowering the cost of electricity during the off-peak period than during the peak period.

How to benefit from TOU?

TOU rates can save electricity costs. When there is good and appropriate management of electricity usage, for example:

  1. Avoid using the device or machinery that causes the peak demand for electricity during On Peak (09.00-22.00) to reduce the demand charge
  2. In case the business has 2 shifts, consider postponing the production process for 1 shift to be in the Off-Peak period (22.00-09.00 hrs.) in order to reduce the demand for electricity during the On Peak period where the energy charge (Energy Charge) Off Peak is 55% cheaper than On-Peak.
  3. Work on Saturdays, Sundays and public holidays to the fullest instead of normal working days. No need to pay for electricity and electric power on these days. It is 65% cheaper than normal days during On-Peak.

In addition, entrepreneurs should take into account adoption of technology to save energy, suitable to be used in tandem to increase the efficiency of electricity use


Source [TH]: Electricity Division. ทำอย่างไรให้ได้ประโยชน์จากค่าไฟฟ้าแบบ TOU. [online]. 2002.