The answer first: the Ft charge is not a tax, not a penalty and not a service fee. It is the fuel cost difference
Your electricity bill is not a single number. It is several parts added together.
The structure is: total = energy charge, plus service charge, plus the Ft charge, with 7 per cent value added tax applied to the whole.
The energy charge is the units you actually used multiplied by the base tariff rate.
The base tariff reflects the expenditure of the three electricity organisations: the Electricity Generating Authority of Thailand, the Metropolitan Electricity Authority and the Provincial Electricity Authority.
The Ft charge is the variable component, added to or subtracted from the base tariff, reflecting fuel and energy costs that have moved away from the assumptions built into that base.
So when you use the same amount every month and the bill still moves, what moved is usually not your consumption. It is Ft.
This article covers why the mechanism exists, who sets it, how often it changes, how to read your own bill, and what you can and cannot control.
Why the mechanism exists
Think of a restaurant that has printed a price for fried rice.
Ingredient costs move every month, but reprinting the menu every month is impractical.
One answer is to price from an assumed cost and then add or subtract a difference periodically when the real cost diverges from the assumption.
Electricity works the same way.
The base tariff is calculated from a set of assumptions: fuel prices, the fuel mix used for generation, and power purchase costs.
When reality differs from those assumptions, for instance when natural gas prices rise or the exchange rate moves, that difference becomes the Ft charge.
The advantage is that the whole base tariff structure does not have to be rebuilt every time costs shift.
The disadvantage is that consumers feel the bill change with no explanation, when the explanation exists but is not printed on the bill.
Who sets it, and how often
Ft is revised once every four months, by the subcommittee governing the automatic tariff adjustment formula, under the supervision of the Energy Regulatory Commission.
So there are three reviews a year, each covering four months.
What is useful to a homeowner is that the coming period's Ft is usually announced in advance, which means you can know ahead of time which way the next four months will go.
Anybody budgeting annually can genuinely use that, especially a household deciding about air conditioning or solar.
What this article will not do is print an Ft figure, because it changes every four months and a number correct today will be wrong within months.
Take the current period's rate from the Energy Regulatory Commission's announcements or from your local electricity authority's website.
Reading your own bill
Take out your most recent bill and find these four parts.
- Units used, which is this month's meter reading minus last month's.
- The energy charge, units multiplied by the base tariff structure.
- The Ft charge, units multiplied by that period's Ft rate.
- The service charge and value added tax.
The fastest way to understand your own bill is to keep six months of them and build a two-column table: units, and total.
Same units and a moving total means Ft or the tariff structure.
Moving units means your own household's behaviour, and that is the part you control.
Plenty of people blame Ft when their consumption has clearly risen, which is blaming the wrong thing and fixes nothing.
What you control and what you do not
Not yours to control: the Ft rate and the base tariff structure, which are set at policy level and reflect national fuel costs.
Yours to control: the number of units you use, which multiplies everything else on the bill.
An important consequence: when Ft rises, the effect on a heavy-consuming household is always larger than on a light one, because it multiplies by units.
Which means a period of high Ft is exactly when reducing consumption pays best, and when investment in insulation or efficient appliances repays fastest.
What to do before anything else is find out where the units are going, which is measured as described in which appliance uses the most electricity and how to measure it.
Common misunderstandings
Ft is a tax. It is not. It is part of the electricity charge, and value added tax is applied afterwards to the total.
Ft is a flat amount per household. It is not. It multiplies by units used, so heavier users pay more of it.
Ft only goes up. Not true. It can be positive or negative, because it is a difference from the base. In a period where fuel costs run below the assumption, it can be negative.
A bigger meter makes the bill bigger. Not true. Bills are charged on units used, not on meter size.
Using electricity at night is always cheaper. Not for an ordinary household, because time-based rates have to be applied for and are not suitable for every house.
If the bill moves unusually, in what order
One, compare units first, not the amount, because the amount has two variables in it.
Two, if units rose, find what rose: a new appliance, a change in how many people are home, or hotter weather making air conditioners work harder.
Three, if units are unchanged and the amount rose, compare that period's Ft rate with the previous one, which usually explains almost all of it.
Four, if units rose sharply with no explanation, suspect leakage or the meter, and ask the electricity authority to check.
That last point matters, because a house with an electrical fault shows units rising steadily with no behavioural cause.
Frequently asked questions
What is the Ft charge?
The variable electricity charge, added to or subtracted from the base tariff, reflecting fuel and energy costs that have diverged from the assumptions used to set that base.
How often does it change, and who sets it?
Every four months, by the subcommittee governing the automatic tariff adjustment formula under the supervision of the Energy Regulatory Commission.
Is it a tax?
No. It is part of the electricity charge, and 7 per cent value added tax is applied afterwards to the total.
Can Ft be negative?
Yes, because it is a difference from the base tariff. In a period where fuel costs run below the assumption, it can be negative.
Same usage, higher bill. Why?
If units really are unchanged, it is usually that period's Ft rate. Always compare units first rather than the amount.
Do heavy users feel Ft more?
Yes, because it multiplies by units. Which also means a high-Ft period is when reducing consumption pays best.
Where do I find the current rate?
From the Energy Regulatory Commission's announcements or your local electricity authority's website, because the figure changes every four months.
Units keep rising with no explanation. What now?
Suspect leakage or the meter and ask the authority to check, because a house with a fault shows units rising steadily without any behavioural cause.
In short
- The total is energy charge plus service charge plus Ft, then value added tax.
- Ft is the fuel cost difference from the assumptions in the base tariff.
- It is revised every four months under the Energy Regulatory Commission.
- It can be positive or negative. It does not only go up.
- It multiplies by units, so heavy users feel it more.
- When the bill moves, compare units first, not the amount.
- Units are yours to control. The rate is a policy matter.
- Units rising steadily with no cause means asking the authority to check.