Factories with solar can add EV charging in 3 configurations: (1) Rooftop Solar + Wall Charger with 4-6 year payback, (2) Solar Carport + Charger with 6-9 year payback, (3) Solar + BESS + DC Fast Charging for 24/7 charging. The critical factor is demand charge, which can increase 26,600-42,000 THB/month without smart load management. BOI A2 category offers 8-year CIT exemption to shorten payback.
Why Factories Are Combining Solar and EV Charging in 2026
Thailand sold 120,301 BEVs in 2025 (+80% YoY), and January 2026 hit a record 48% EV penetration among new registrations. Factory employees increasingly need workplace charging, while many factories are electrifying forklifts and delivery fleets. Solar + EV charging answers both energy cost reduction and fuel savings in one capex decision.
Thailand EV Adoption Acceleration
120,301 BEV sold in 2025 (+80%), 48% penetration in Jan 2026. Industrial fleet procurement of EVs is accelerating.
Employee Workplace Charging Demand
Employees with EVs need to charge during 8-hour shifts. A single shift on a 7 kW AC charger delivers a full charge -- a compelling benefit for talent attraction.
Fleet Electrification
Electric forklifts, delivery trucks, company cars -- all need factory charging. Solar reduces charging cost versus grid-only power.
Stackable BOI Incentives
Solar qualifies for BOI A2 (8-year CIT exemption + machinery duty waiver). EV charger installation has its own BOI promotion window 2026-2027. Both can stack in one project.
ESG / RE100 — Two Goals, One Budget
Solar cuts Scope 2 (electricity), EV fleet cuts Scope 1 (fuel). Combined in one project = dual decarbonization. Addresses CBAM compliance + green supply chain requirements.
3 Configuration Models for Factory Solar + EV Charging
Model 1 — Rooftop Solar + Wall Chargers (Most Common)
Uses existing rooftop solar. Surplus power beyond factory load feeds AC wall chargers (7-22 kW). Lowest capex. Ideal for employee charging -- an 8-hour shift fully charges on 7 kW AC.
Model 2 — Solar Carport + Integrated Chargers
Parking structure with solar panels on top, chargers underneath. 20-75% higher capex per watt than rooftop, but dual function: shade + power. Ideal when rooftop space is full or for new factory builds.
Model 3 — Solar + BESS + DC Fast Charging (Premium)
BESS buffers solar for evening/night charging. DC fast chargers (50-180 kW) for fleet vehicles needing rapid turnaround. Highest capex but enables 24/7 solar-powered charging without grid dependency.
| Feature | Rooftop + Wall | Solar Carport | Solar+BESS+DC |
|---|---|---|---|
| Capex | Lowest | Medium-High | Highest |
| Payback | 4-6 years | 6-9 years | 8-12 years |
| Charging Hours | Daytime (solar hours) | Daytime (solar hours) | 24/7 |
| Best For | Employee charging, day shift | Full rooftop / new builds | 24/7 fleet / logistics hub |
| Extra Space Needed? | No (existing roof) | Existing parking area | Parking + BESS footprint |
Demand Charge Impact — The Hidden Cost Factory Owners Must Calculate
Adding EV chargers to a factory can spike peak demand, significantly increasing demand charges. PEA charges 74.14-210.00 THB/kW-month depending on voltage tier.
Example: Running 4x 50 kW DC Fast Chargers Simultaneously
4 x 50 kW = +200 kW peak demand = up to ~42,000 THB/month extra demand charge (at <12 kV, 210 THB/kW) or ~26,600 THB/month (at 12-24 kV, 132.93 THB/kW)
Factory Solar Battery (BESS)
Sizing Your Factory Solar + EV System
EV Charger Types and Specifications for Factory Use
| Type | Power | Charge Time (60 kWh) | Best For | Approx. Cost (THB) |
|---|---|---|---|---|
| AC Wall Box (Level 2) | 7-22 kW | 3-8 hours | Employee parking, overnight fleet | 25,000-80,000 |
| DC Fast Charger | 50-60 kW | 1-1.5 hours | Fleet turnaround, visitor charging | 500,000-1,200,000 |
| DC Ultra-Fast | 120-180 kW | 20-35 min | Heavy fleet, logistics hub | 1,500,000-3,000,000 |
Thai charging standards: CCS2 (dominant DC) and Type 2 AC (most EVs)
BOI and Government Incentives for Solar + EV Charging
ROI Analysis — When Does Solar + EV Make Financial Sense?
Base Case: 500 kWp Rooftop + 20 AC Chargers
Carport Case: 200 kWp Solar Carport + 10 Chargers
Higher capex but land-neutral (existing parking). Payback 6-9 years including carport structure cost.
Key sensitivity: demand charge impact can add or subtract 1-2 years from payback depending on load management.
5 Steps from Decision to Charging
Energy Audit — Assess load profile, solar capacity, parking layout
Review factory load profile, existing/expandable solar capacity, and parking layout. Identify surplus solar windows for charging.
Charger Selection — Match charger types to use cases
Select charger types based on use cases: AC wall box for employees, DC fast for fleet and visitors. Plan quantity and placement.
Electrical Infrastructure — Panel upgrade, EV circuit, smart metering
Upgrade electrical panel, install dedicated EV circuit, add smart metering for cost allocation and demand charge management.
Solar Integration — Inverter compatibility, EMS for solar priority
Verify inverter supports additional load. Install Energy Management System (EMS) so chargers prioritize solar over grid.
Commissioning — App setup, access control, billing
Set up charger management platform, employee/visitor access control, and service billing system (if applicable).
Ready to Combine Solar + EV Charging at Your Factory?
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