Is installing solar panels worth it?

Installing solar panels for businesses in Thailand is highly cost-effective. You can typically save 30-50% on monthly electricity bills with a payback period of 4-7 years. The system lasts 25 years, and after payback, all savings become pure profit.

What is the difference between PPA and EPC?

PPA (Power Purchase Agreement) requires zero upfront investment. The solar company installs and maintains the system on your property, and you simply buy electricity at a discounted rate — saving 10-30% immediately. EPC means you invest in and own the system yourself, yielding greater long-term savings but requiring an initial investment.

How much roof space do I need for solar panels?

On average, 1 kWp of solar panels requires approximately 6-8 square meters of roof space, depending on the roof type. Flat roofs require less space than sloped roofs. CapSolar will survey and design a system suited to your specific roof.

How much carbon does solar energy reduce?

Every 1 kWh of solar electricity produced reduces CO₂ emissions by approximately 0.5 kg. A 100 kWp solar system can reduce carbon emissions by about 60-70 tons per year — equivalent to planting over 3,000 trees.

Solar ROI Calculator

Solar Panel Calculator How Much Will You Save?

Calculate the return on investment from solar panel installation for factories, commercial buildings, and businesses across Thailand
Just enter your monthly electricity bill to instantly see your savings and payback period for both EPC and PPA models

Free — No CostResults in 30 SecondsSuitable for Businesses of All Sizes

Calculate Your Solar ROI

Fill in the details below

Monthly Electricity Bill (THB) *

฿/month

Check your latest PEA/MEA electricity bill

Location / Region

Sunlight levels affect electricity generation

Roof Type

PPA Discount Rate (%)

20%

Percentage discount on electricity bill via PPA model (default 20%)

How Solar Calculation Works — Principles & Formulas

Solar calculation starts from your monthly electricity bill, converts it to energy consumption (kWh), and determines the optimal solar system size. Below are the steps our CapSolar solar calculator uses to estimate your ROI.

1. Calculate electricity consumption

Divide your monthly bill (THB) by the regional average electricity rate (~4.0–4.2 THB/kWh) to get monthly consumption, then multiply by 12 for annual usage.

2. Determine solar system size (kWp)

Commercial solar systems are typically designed to cover 70% of electricity use. This is calculated using average regional peak sun hours (3.8–5.0 hrs/day) multiplied by system efficiency (80%) to determine annual output per kWp.

3. Calculate cost and return on investment (ROI)

Average solar system cost in Thailand is approximately 18,000 THB/kWp (2026), including panels, inverter, mounting structure, and installation. Payback period is calculated by dividing total cost by annual savings — typically 4–7 years.

4. Estimate 25-year profit

Long-term ROI factors in panel degradation (0.5%/year) and rising electricity rates (~3%/year), meaning savings grow over time. Solar systems carry a 25-year warranty, and after payback, all savings become pure profit.

Factors Affecting Solar Calculations in Thailand

Solar calculator results depend on several key factors. Understanding these helps you plan your solar installation more accurately.

Peak sun hours by region

Thailand receives 3.8–5.0 peak sun hours per day depending on the region. The Northeast (Isan) gets the most sunlight (5.0 hrs/day), while the South gets less (3.8 hrs/day) due to higher cloud cover and rainfall. This difference can cause solar output to vary by up to 30% between regions.

Roof type and installation area

Flat roofs (concrete/rooftop) require ~7 sq.m./kWp because tilt-mounting structures are needed. Sloped and tin roofs use 6–6.5 sq.m./kWp. Roof type also affects installation cost — tin roofs are typically ~5% cheaper than flat roofs.

Electricity rates and Ft surcharge

Business electricity rates in Thailand average 4.0–4.2 THB/kWh (including Ft surcharge and tax). The Ft (Float time) charge is a variable component adjusted every 4 months. Higher electricity costs mean greater savings, making solar increasingly worthwhile as rates continue to rise.

Solar panel degradation and maintenance

High-quality (Tier 1) solar panels degrade at only 0.5% per year, meaning after 25 years they still produce 87.5% of original capacity. Cleaning panels every 3–6 months and annual inverter checks help maintain peak performance.

Why Should You Calculate Solar Before Installing?

Calculating your solar potential before installation is a crucial step that helps you make confident decisions, avoid over-investment, and plan your budget accurately.

Size the system to match actual consumption

Calculating solar from your actual monthly bill ensures the system is right-sized — not too large (wasting capital) and not too small (leaving savings on the table). A properly sized system delivers maximum ROI within 4–7 years.

Compare PPA vs EPC before deciding

The solar calculator helps compare two main investment models: PPA requires zero upfront cost with 10–30% immediate savings, while EPC involves self-investment but yields much higher long-term returns. Seeing real numbers makes it easier to choose the model that fits your business.

Assess environmental and ESG impact

Beyond financials, solar calculation shows annual CO₂ reduction — essential data for corporate ESG reporting. It helps your business achieve sustainability targets that customers and investors increasingly demand.

After Solar Calculation — Steps to Real Installation

Once you've used the solar calculator and received initial results, the next step is turning those numbers into reality. CapSolar is ready to help at every stage.

1. Schedule a free roof survey

CapSolar engineers will survey your roof — measuring actual area, checking structural integrity, assessing sun orientation, and identifying electrical connection points — to design a system more precise than online calculations.

2. Get a PPA vs EPC price comparison

CapSolar will prepare quotes for both PPA (zero investment) and EPC (self-investment) models — with equipment details, costs, and ROI calculated from your actual roof data — making your decision straightforward.

3. Installation and start saving

Commercial solar installation typically takes 2–4 weeks. CapSolar handles everything: MEA/PEA permits, panel and inverter installation, monitoring system setup, system testing, and handover. You start saving on electricity immediately after activation.

Solar Panel Types & Technology Used in Calculations

The choice of solar panel type and inverter directly impacts calculation results — power output, cost per kWp, and payback period. CapSolar uses Tier 1 equipment to ensure actual returns match calculated projections.

Monocrystalline Solar Panels

Monocrystalline panels offer 20–22% efficiency — the highest in the market. Ideal for limited roof space requiring maximum output per square meter. They have long lifespans and low degradation rates. CapSolar recommends Mono panels for EPC projects seeking maximum ROI.

Polycrystalline & Bifacial Solar Panels

Polycrystalline panels are 10–15% cheaper with 17–19% efficiency — ideal for factories with ample roof space. Bifacial panels generate electricity from both sides, boosting output by 10–15% — ideal for flat roofs where reflected light contributes additional generation.

Inverters: String vs Micro vs Hybrid

Inverters convert DC electricity from solar panels to AC power used in buildings. String inverters are popular for factories — affordable and easy to maintain. Micro inverters are installed per-panel for higher efficiency but at greater cost. Hybrid inverters support battery backup for businesses needing power resilience.

Thailand Solar Incentives & Policies 2026

Beyond the electricity savings shown in the solar calculator, businesses in Thailand can access government incentives that further boost solar installation returns.

BOI Tax Incentives — 50% Corporate Tax Reduction for Solar

The Board of Investment (BOI) offers a 50% corporate income tax reduction for 3 years for businesses installing solar systems, plus import duty exemption on solar equipment. This significantly reduces total cost and applies to both EPC and PPA models.

Net Metering & VSPP — Sell Excess Power Back to the Grid

Thailand's Net Metering allows solar owners to sell excess electricity back to MEA/PEA at 2.20 THB/kWh. Systems up to 10 MWp can register as VSPP (Very Small Power Producer) to sell power under purchase agreements, further improving calculated solar returns.

Carbon Credits & T-VER — Additional Revenue from Carbon Trading

Solar systems can register under Thailand's T-VER (Thailand Voluntary Emission Reduction) program managed by TGO to earn carbon credits from CO₂ reduction. These credits can be traded at approximately 120–200 THB per ton CO₂, creating additional revenue beyond electricity savings.

Frequently Asked Questions

About solar panel installation for businesses

CapSolar Services

PPA vs Purchase Comparison

Compare solar investment models — which one is more cost-effective for your business?

Compare Now

Check Subsidy Eligibility

Check if your business qualifies for solar subsidies and BOI incentives

Check Eligibility

Factory Solar Guide

Everything factories need to know before installing solar — system size, roof area, ROI

Read Guide

Solar Panel Maintenance Guide

How to clean panels, check inverters, and troubleshoot common issues to maintain power generation efficiency

Read Maintenance Guide

Factory Solar ROI Thailand 2026 (Deep Dive)

5 real sizes 100kW-5MW · 4.0-4.8 yr payback · IRR / NPV / LCOE · shift-based modeling

Read full ROI guide

1 MW factory solar price — 3 BOMs

THB 25-35M installed · Tier-1 / Tier-2 / Tier-3 BOM + hidden costs

View transparent pricing

Thailand Electricity Tariff & FT 2026

Complete 2026 TOU rates, Ft surcharge & demand charges — plus how solar cuts costs

View Tariff Rates

EPC & PPA Services

View our full range of solar installation services — both self-investment (EPC) and PPA models

View Details

Contact CapSolar

Schedule a free site survey and receive a solar proposal tailored to your business

Our Projects

View our completed solar projects — factories, commercial buildings, and government facilities

View Projects

About CapSolar

Learn about CapSolar — Thailand's trusted solar energy experts

Ready to save on electricity with solar?

Free consultation — no obligations

Schedule a Free Site Survey