Chapter 1: Hard-core interpretation of Thailand’s electricity market, Ft, TOU, grid connection and Decree No. 805

1.1 What exactly is Ft and why every salesperson must be able to speak it

MEA’s official definition of Ft is very clear: Ft is a variable electricity price item formed based on the automatic price adjustment mechanism, which is used to reflect cost adjustments caused by changes in fuel costs and power purchase costs in addition to the basic electricity price. It is not an 'additional tax', nor is it a concept casually mentioned by an installer, but a real part of Thailand's electricity tariff structure.

The official MEA page further explains that the full name of Ft isFuel Adjustment Cost at the given time, regularly monitored by the energy regulator and reviewed as a 4-month average, usually adjusted in January, May, and September. In other words, changes in Ft will directly affect user bills, and rooftop PV is established precisely because it can hedge part of the electricity purchases that will become more expensive as Ft fluctuates.

PEA’s latest Ft page shows that the current Ft from May to August 2026 is0.1623 THB/Unit. This number by itself does not equal the customer's full electricity price, but it tells us one important thing: the customer's final bill is not static. If a new employee cannot even explain Ft clearly, it will be difficult to explain to customers why photovoltaics does not only look at today's electricity price, but also looks at the power purchase structure in the next few years.

Therefore, the correct expression of the first-line language should be: Thai customers’ electricity bills are not only the basic electricity price, but there is also an Ft item in the bill that is adjusted regularly. The value of rooftop photovoltaics to customers is not only immediate savings, but also locking in part of the future electricity purchase costs that would otherwise be affected by Ft.

1.2 What is TOU and which customers are worthy of TOU?

TOU is Time of Use, which means billing by time period. PEA’s English electricity price manual clearly gives the TOU period:Peak is Monday to Friday 09:00-22:00，Off-Peak is Monday to Friday 22:00-09:00; Saturdays, Sundays and certain legal holidays will be treated as Off-Peak all day. For PV sales, the significance of TOU is to explain why daytime power generation overlaps with high daytime electricity prices, which amplifies system value.

Taking PEA's current English manual as an example, the TOU energy prices for residential and small general services (Schedule 1.2 / 2.2) at voltage levels below 22kV are stated asPeak 5.7982 THB/kWhandOff-Peak 2.6369 THB/kWh, in addition to superimposing Ft and VAT. This structure is very suitable for explaining why the same kilowatt-hour of electricity is more valuable when replaced during the day than at night.

However, not every client should cut their TOU to ‘sound professional’. There are usually two types of customers suitable for discussing TOU: the first type is household customers whose load is obviously high during the day and wants to accurately manage their bills; the second type is small commercial customers whose business hours are concentrated during the day and who intend to do more precise calculations. For ordinary customers who have a stable load but have no preference for the complexity of electricity meters and bills, getting the system right first does not necessarily require forcing a TOU immediately.

Salesmen should avoid two misunderstandings when explaining the TOU: First, they deify the TOU as "if you change it, you will definitely save money"; second, they make the TOU too complicated and make customers lose their willingness to understand. The correct expression is: The value of TOU lies in allowing high-priced electricity during the day to be more clearly replaced by photovoltaics; whether to switch depends on customer load, electricity consumption habits and bill structure, rather than one-size-fits-all.

1.3 Why is it suitable for household/small commercial use: from billing to project screening algorithm

Training cannot just tell newcomers, "Thailand has good lighting, so photovoltaics are installed." This statement has almost no screening value. A more effective expression is: under the condition that the daytime load is obvious and the retail marginal power purchase cost is higher than the long-term LCOE of the system, households and small businesses have natural adaptability.

The first judgment for household projects is not ‘how much can be installed’, but ‘how much can actually be consumed from 09:00-16:00’. For example, if there are people at home during the day, the air conditioner is always on, the swimming pool pump is running, telecommuting, and charging loads are present, the spontaneous self-use rate of such customers is usually more supportive. For small businesses, it depends on whether the business hours coincide with the daytime power generation period, such as clinics, restaurants, stores, B&B front desks, offices, etc.

At the entry stage, a simple screening algorithm can be directly applied: first collect the bills of the past 12 months; then determine the daytime on-site load; then estimate the annual power generation of the candidate system; then calculate the annual savings based on the conservative spontaneous self-use rate range; and finally discuss whether to expand the system and consider energy storage or TOU. Only in this way can project screening be changed from 'feeling good' to 'making informed judgments'.

1.4 Royal Decree No. 805: What was given, do not turn it into a myth

One of the policies most worthy of internal unification in 2026 is Royal Decree No. 805 B.E. 2569. Public interpretations unanimously pointed out that this decree contains two types of incentives that are helpful to the photovoltaic-related market: one is personal income tax relief for residential rooftop photovoltaics; the other is tax incentives for investment in energy-saving equipment and high-efficiency equipment.

From the 2026 public interpretations of BDO, BizWings, Nation Thailand, etc., several points that must be mastered at the training level can be summarized. First, the residential part isActual expenses incurred, upper limit 200,000 THBPersonal income tax exemption; second, the rooftop system must be grid-connected and successfully connected to the MEA or PEA power grid; third, the discount does not automatically arrive upon installation, but is related to the customer's tax entity, filing year, completed grid connection, documents and qualifications.

The same type of public interpretation also mentioned that there is a 50% tax deduction/interpretation caliber that can be understood as a total 150% pre-tax deduction effect for investments in high-efficiency and energy-saving machinery and equipment by enterprises or specific entities. However, this part is more suitable for small commercial and industrial and commercial scenarios, and must be submitted to tax consultants for approval, and is not suitable for front-line sales to make deterministic commitments on their own.

Therefore, the real value of Decree 805 to sales is not to ‘quote a rebate figure’, but to let customers know: within the policy window of 2026-2028, the Thai government has indeed given more friendly tax treatment to investment in residential grid-connected rooftop photovoltaic and energy-saving equipment. But whether it can be used, how to use it, and how much it can be used depends on the customer's own application qualifications and information closure.

1.5 Industrial and commercial/enterprise tax incentives: What exactly is the 1.5 times deduction, and what is its relationship with “enterprises installing photovoltaics”

This is the most easily misunderstood section of the first chapter and the most worthy of correction. According to the official press release and new law page of the Thai Revenue Authority in 2026, in addition to personal income tax exemptions for residential rooftop photovoltaics, Decree 805 also introducesEfficient machinery, equipment and energy-saving materialstax measures. The official press release clearly states: Eligible individuals (income categories 40(5)-(8)) and companies/partnerships can apply for1.5 timesDeduction of investment expenses can be understood as deducting an amount equivalent to the actual investment on the basis of normal costs/depreciation.50%income tax exemption effect.

But the boundaries must be clarified: the official statement is "high-efficiency machinery, equipment and energy-saving materials", and it does not directly read "150% tax deduction for all industrial and commercial photovoltaic projects" in one sentence. Therefore, the correct expression for corporate customers should be:If the project involves energy-saving equipment, machinery or materials that meet the DEDE/EGAT 5-star energy efficiency label certification and meet the regulations of the tax bureau, the logic of 1.5 times investment deduction or 50% additional income tax reduction may be applied; the specific scope of application needs to be further determined based on the nature of the equipment, invoice, operational status and tax entity.

what does that mean? This means that commercial and industrial sales cannot mix residential solar tax breaks and business energy-saving equipment deductions into the same policy. Nor can we simply say, ‘Enterprises can get 150% tax deduction as long as they install photovoltaics’. The mature training caliber should be: There are more attractive energy-saving investment tax policies for industrial and commercial customers, but it must be confirmed whether the equipment belongs to the officially recognized category, whether it has obtained the corresponding energy efficiency label, whether it meets the e-Tax Invoice, whether it is new equipment, whether it has been put into operation, and whether it conflicts with existing preferential treatment such as BOI/EEC.

From a business perspective, the value of this policy to small commercial and industrial and commercial projects is not necessarily reflected in the ‘immediate commitment to how much tax customers can save’, but in the fact that you can upgrade the project from simple electricity bill savings to a comprehensive management issue of ‘energy-saving investment + possible tax optimization’. This will significantly improve your professionalism when communicating with your boss, financial director, and accountant.

1.6 Grid connection and electricity sales: What can be discussed and what cannot be discussed

The grid connection and electricity sales of rooftop photovoltaics in Thailand have long been subject to regulatory frameworks such as ERC, MEA, and PEA. A summary of ERC rules and official forms compiled by Asia Pacific Energy Portal shows that if you want to sell electricity and conduct system interconnection, applicants need to submit an application for electricity sales and system interconnection to the corresponding MEA or PEA in their location, and meet access and security requirements.

The training must clearly distinguish between 'grid-connected systems' and 'must sell a large amount of electricity to make money'. Grid-connected means that the system establishes a legal connection with the public power grid and meets safety, metering and procedure requirements; it does not mean that customers will definitely gain great benefits from external power transmission. For household and small commercial projects, the core value is still self-use.

The correct words of new employees to customers should be: Grid connection is an important part of the project's compliance operation, and it is also the prerequisite for some policy qualifications and delivery arrangements; but whether there is any delivery revenue, the amount of revenue, and the procedures must be confirmed based on the project location, current rules, and actual approval standards. It cannot be summarized with a general statement "you can sell electricity."