What Is Wheeling — Understand in 40 Seconds
Wheeling is delivering electricity from a private generator to an end-user over the utility's transmission/distribution grid, paying a "wheeling charge" to the network owner. It lets a factory buy renewable power from an off-site source even when its own roof isn't enough. Doing so requires Third-Party Access (TPA) rights — which in Thailand are still at a pilot/sandbox stage under ERC (กกพ.) oversight.
Wheeling = buy green power elsewhere + deliver over the grid + pay a wheeling charge → needs TPA rights (Thailand still in pilot phase)
Many Thai factories have filled their roof with solar yet still don't cover all their demand — especially night-time load, or high-consumption plants with limited roof. The next question is "how do I bring renewable power from somewhere else to my factory?" The structural answer is wheeling: a green generator (say a solar farm or wind project in another province) feeds power into the grid, and your factory draws the same quantity out of the grid at its own end, paying a wheeling charge for using the network. What makes this "not yet simple" in Thailand is that Third-Party Access — the right for a third party to use the grid — is still opened only in a limited, pilot form, not a fully liberalized market as in some countries.
Note: the legal status and rules for TPA/wheeling in Thailand are evolving continuously. This page is a principles-level overview — before committing to a real project, verify the latest ERC announcements and pilot-project status.
Where Third-Party Access (TPA) Stands in Thailand Today
In short: "partially open, but still in a pilot phase — not a fully open right." The ERC laid down a Third-Party Access framework guideline around 2022, and the government later approved a pilot policy to allow renewable-power trading via Direct PPAs over the grid (TPA), initially targeted at large electricity users such as data centers. The ERC is now drafting and consulting on the detailed rules (a TPA Code / Direct PPA regulation). So it is best understood as "not yet anyone-can-wheel-immediately," but a pathway being laid down step by step. Interested factories should watch which user groups the next phase opens to, and on what terms.
TPA status snapshot (principles-level — verify the latest with the ERC)
- An ERC TPA framework exists, plus a pilot policy for Direct PPAs over the grid
- Early phase focuses on large users (e.g. data centers) — limited eligibility/quota
- Detailed rules (TPA Code / Direct PPA regulation) still in consultation/drafting
- Not yet a fully liberalized market — watch which phase/terms open to each group
The TPA-status overview above is a principles-level snapshot for 2026 and may change — please confirm the latest ERC announcements and pilot-project status before planning.
The Wheeling Charge — How the Cost Builds Up
The wheeling charge is the fee paid to the network owner (e.g. EGAT/PEA/MEA) for using the transmission and distribution grid to move electricity from the generator to your factory. It typically covers the cost of using the transmission system, the distribution system, and various ancillary services. The key thing to understand is that your "total delivered price" is not just the energy price you negotiate with the generator — it is a stack of several components, as in the table below. The actual figure for each component depends on ERC-set rates and your contract terms, so request a case-specific assessment for your factory rather than relying on any off-the-shelf number.
| Component | What it is |
|---|---|
| Negotiated energy price | The per-unit price agreed with the green generator (negotiable, often below the full grid tariff for large loads) |
| + Wheeling charge | Fee for using the utility's transmission/distribution network, at ERC-set rates |
| + Ancillary services & other fees | E.g. balancing services, related fees, taxes, etc. (per the applicable rules) |
| = Total delivered price | The sum of the above — compare against the full grid tariff to see if it pencils out. Actual figures depend on the contract and the latest ERC rates |
This page does not state a fixed THB/kWh wheeling rate, because the methodology is still being developed/updated by the ERC — rely on the latest ERC announcements and a case-specific assessment for actual figures.
Physical PPA vs Virtual PPA (VPPA) — What's the Difference
When buying green power across locations, you'll meet two main forms: physical (real electricity delivered) and virtual (a financial contract). The difference isn't merely technical — it changes whether you get actual electricity at your factory or just a financial outcome plus a certificate, and each fits a different situation.
Physical PPA (real delivery)
Electricity from the generator is physically delivered to your factory over the grid (requires wheeling + TPA). You get both the power and the right to claim renewable energy (with the certificate). Best when physical grid delivery is feasible and the wheeling charge pencils out.
Virtual PPA / VPPA (financial)
A VPPA is a financial contract-for-difference (CfD) paired with the transfer of renewable certificates (REC/I-REC) — no physical electrons reach your factory. You still buy grid power as usual, but you "hedge the price" and receive certificates to use in reporting. Best when physical wheeling is impractical or not yet open to you.
Note: Thailand runs a Virtual PPA pilot under the ERC sandbox, and EGAT is the domestic I-REC issuer. For a VPPA to count toward RE100 it depends on properly transferring and retiring the certificates, not just on having the financial contract — verify the pilot status and current criteria before planning.
Where Wheeling/VPPA Fits in the RE100 Decision
Wheeling and VPPA are not a single path you must pick — they are one layer in your road to RE100. The most cost-effective order usually starts with the roof (cheapest), then considers cross-grid mechanisms for what the roof can't cover. See the full picture of every option on the RE100 hub, and go deeper on each mechanism in the dedicated pages below.
RE100 hub — start here
The overview of all 4 paths (rooftop → Direct PPA → UGT2 → IREC) with a decision tree. Wheeling/VPPA is the mechanism that makes a Direct PPA actually reach you.
RE100 — 4 green-power pathsDirect PPA — factory guide
The buyer's guide to negotiating power directly from a private generator — wheeling is how that PPA's power is delivered across the grid to your plant.
Direct PPA factory guideUGT2 — the utility route
If wheeling/Direct PPA is too complex, UGT2 is the shortcut through the MEA/PEA utility — no negotiation and no wheeling to manage yourself.
UGT2 — utility green tariffI-REC — close the paper gap
A VPPA usually comes paired with an I-REC transfer. Understand how the certificate works and how to use it correctly for RE100 here.
What is an I-RECIs It the Right Route for Your Factory? — A Checklist
Wheeling/VPPA suits some factories very well but not all. Run through the short checklist below — if you answer "yes" to several, this route is worth considering. But first, always maximize the roof, because it's usually cheaper and faster.
Let CapSolar Help Map Your Factory's Green-Power Route
CapSolar designs and installs factory rooftop solar, backed by 80+ MWp / 150+ projects in Thailand, 100+ clients, and 85,000+ tons of CO₂ avoided. We help you start by maximizing the roof, then assess whether the remainder is best topped up with a Direct PPA/wheeling, UGT2, or a VPPA/I-REC for your factory. Not sure where to start? Let us assess your roof and remaining power demand for free.
Plan Your Factory's Green-Power Route — Start a Free Assessment
Consult CapSolar experts for free — we analyze your roof and the most cost-effective green-power options, including when wheeling/VPPA fits you.