What Is Solar Phak Prachachon 2026? — and Why Factories Need C&I Instead
Solar Phak Prachachon 2026 is a residential rooftop excess-electricity buy-back program approved by the National Energy Policy Committee (NEPC) on 29 April 2026 — a 2.20 THB/unit buy-back rate, a 500 MW national cap, ≤5 kW per meter, and a 10-year term. It is a program for HOMES, not factories or C&I businesses. This page summarises the program facts, compares it with factory solar, and explains which model a plant should use instead.
Quick Answer — What Is Solar Phak Prachachon, and Does It Apply to Factories?
Solar Phak Prachachon 2026 is a program that buys back the EXCESS electricity from residential rooftops under a Net Billing scheme: a 2.20 THB/unit buy-back rate, a 500 MW national cap, an install limit of 5 kW per meter, and a 10-year term. It was approved by the National Energy Policy Committee (NEPC) on 29 April 2026; the Energy Regulatory Commission (ERC) is to issue the rules by June 2026, with registration expected to open around June–July 2026 (confirm with PEA/MEA). The program is for RESIDENTIAL homes only — factories and C&I businesses cannot use it, because the 5 kW cap is far too small and selling excess at 2.20 THB is worth far less than self-consumption. Factories should use self-consumption or a Direct PPA instead.
Solar Phak Prachachon 2026 — Program Facts at a Glance
- Buy-back rate (excess)
- 2.20 THB/unit (Net Billing)
- National program cap
- Up to 500 MW
- Install cap per meter
- Up to 5 kW/meter
- Contract term
- 10 years
- Approved by / status
- NEPC approved 29 Apr 2026 · ERC rules by Jun 2026 · registration expected Jun–Jul 2026
Note: this program is for RESIDENTIAL homes only and buys back EXCESS units under Net Billing (not a Net Metering unit-for-unit offset). The registration date is an expectation — confirm with PEA/MEA.
1. What the Program Is (The Facts)
Solar Phak Prachachon 2026 is a policy that lets homeowners install rooftop solar for self-use and sell the leftover EXCESS into the utility grid at a 2.20 THB/unit buy-back rate under a Net Billing scheme — meaning buying and selling are priced separately (you buy grid power at the normal rate and sell excess at 2.20 THB), NOT a Net Metering unit-for-unit offset. Each meter may install up to 5 kW, and the whole program is capped at 500 MW, on a 10-year term. The decision came from the National Energy Policy Committee (NEPC) meeting on 29 April 2026; the Energy Regulatory Commission (ERC) is then to issue the rules and procedures by June 2026, with the utilities (PEA/MEA) expected to open registration around June–July 2026. (Figures and timing reflect official reporting as of June 2026 — check the latest with PEA/MEA before deciding.)
2. Comparison: Solar Phak Prachachon vs Factory Solar (C&I)
These two models are built for different users, different sizes, and a different "source of value." The table below summarises the key differences:
| Solar Phak Prachachon | Factory Solar (C&I) | |
|---|---|---|
| Who is eligible | Residential homes (home meter) | Factories / businesses / commercial buildings |
| System size | Up to 5 kW/meter | Sized to real load — often hundreds of kW to several MW |
| Main source of value | Selling excess at 2.20 THB/unit | Self-consumption — offsetting the ~4–5.5 THB/unit you'd otherwise pay |
| Mechanism | Net Billing (buy/sell priced separately) | Self-consumption / Direct PPA / Net Billing on excess |
| Term / investment model | 10-yr buy-back contract; homeowner self-funds | Self-invest (EPC) or zero-capex (Direct PPA, 15–25 yrs) |
| Best fit for | Homes with low daytime use and excess to sell | Factories with high daytime load wanting to cut their bill |
3. Why Factories Can't — or Shouldn't — Use This Program
There are two main reasons. First, the 5 kW cap is far too small: a typical factory has a daytime load from tens of kW to several MW, so a 5 kW system covers only a sliver of demand and can't meaningfully cut a factory bill. Second, the value math: this program pays just 2.20 THB/unit for the EXCESS you sell into the grid, but a factory pays roughly 4–5.5 THB/unit for the power it buys from the grid (energy TOU + demand charge + Ft + VAT). So every unit a factory generates and consumes itself (self-consumption) is worth the ~4–5.5 THB it avoids paying — more than double the 2.20 THB you'd get for selling excess. A factory should therefore design its system to self-consume as much as possible rather than to export — a completely different goal and design from the residential program. (This is an economic explanation, not investment advice.)
4. So What Should a Factory Use Instead?
For factories and C&I businesses there are two main routes. The first is self-investment (EPC): install a system sized to your real load for self-consumption, with payback coming from the electricity you save. The second is a Direct PPA: a developer funds and installs the system for free, and the factory pays only for the power it actually uses at a rate below the grid, over a 15–25-year contract (zero upfront capex). Both focus primarily on self-consumption, and where there is surplus, some cases can still sell excess under Net Billing. A good starting point is to read your daytime usage off your bill, then size the system and estimate the savings — use the tools below.
Read: Direct PPA for factories (zero capex, fixed rate)How Much Can Your Factory Save — Start with Your Bill
Whether factory solar pays off depends on your daytime load and your current electricity cost — not the residential buy-back rate. The fastest start is to take your latest bill and estimate system size and savings with the solar ROI calculator, then decide between self-investment (EPC) and a Direct PPA.
About the Author
This article is prepared by Frank Lee, Founder of CapSolar, which has delivered 80+ MWp of commercial & industrial solar across 150+ projects for 100+ clients. We help factories pick the solar model that fits their real load and budget (self-consumption / EPC / Direct PPA) — not a residential buy-back program.
Reviewed by: CapSolar Research Team | Updated: Jun 2026
Frequently Asked Questions
Sources
- National Energy Policy Committee (NEPC) resolution, meeting 1/2026 on 29 Apr 2026 — approving the residential rooftop excess buy-back (Solar Phak Prachachon) at 2.20 THB/unit, 500 MW cap, ≤5 kW/meter, 10-year term (official reporting, Jun 2026).
- Energy Regulatory Commission (ERC / กกพ.) — issuing the program rules and procedures (due by Jun 2026); PEA/MEA handle registration (expected Jun–Jul 2026 — confirm with the utilities).
- CapSolar knowledge pages — Net Metering / Net Billing Thailand and Direct PPA for factories, explaining buy/sell mechanisms and C&I solar models.
Your Factory Isn't in the Residential Program — but It Can Still Cut Its Bill
CapSolar has delivered 80+ MWp of commercial solar across 150+ projects. We analyse your bill, estimate system size and savings, and pick the right model (self-consumption / EPC / Direct PPA) — free consultation.