The business electricity rates of the Provincial Electricity Authority (PEA) and the Metropolitan Electricity Authority (MEA) are identical across every customer type and every voltage tier — from the energy charge for small businesses on the normal tariff at low voltage, where the first tier up to 150 kWh/month is charged at 3.2484 THB/kWh, to demand charges, service charges, minimum charges, and power factor. What actually differs sits in the footnotes at the bottom of the tariff tables instead.
The figures below are the actual energy and demand charges from both utilities' published tariffs, showing that every line matches as stated.
| Rate item, low voltage tier | Figures used identically by both PEA and MEA (low voltage tier) |
|---|---|
| Energy charge, small business, normal tariff, first tier (up to 150 kWh/month) | 3.2484 THB/kWh |
| Energy charge, small business, normal tariff, next tier (up to 400 kWh/month) | 4.2218 THB/kWh |
| Energy charge, small business, normal tariff, beyond 400 kWh/month | 4.4217 THB/kWh |
| Energy charge, medium business, normal tariff | 3.1751 THB/kWh |
| Demand charge, medium business, normal tariff | 221.50 THB/kW |
| TOU energy charge, On Peak, medium business | 4.3297 THB/kWh |
| TOU energy charge, Off Peak, medium business | 2.6369 THB/kWh |
Opening a new branch upcountry: will the electricity rate change from what you're used to?
A business that has operated in Bangkok all along is preparing to open a new branch in another province, and is estimating the new branch's costs before signing the lease. Electricity is a fixed cost always calculated alongside rent and labor, but there is uncertainty over whether moving from the Metropolitan Electricity Authority (MEA) service area into a Provincial Electricity Authority (PEA) service area will change the new branch's electricity cost per unit from what the business is used to.
Are PEA's and MEA's business electricity rates really the same?
Every figure published in the tariff announcements is the same — energy charges, demand charges, service charges, minimum charges, power factor, and TOU periods. For example, the On Peak energy charge for medium businesses on the TOU tariff at low voltage is 4.3297 THB/kWh at both utilities.
The energy charge for small businesses on the normal tariff at low voltage, where the first tier up to 150 kWh/month is charged at 3.2484 THB/kWh, is identical in both utilities' documents. Meanwhile, medium businesses at low voltage on the normal tariff pay an energy charge of 3.1751 THB/kWh and a demand charge of 221.50 THB/kW per month. Neither of these two sets of figures differs between PEA and MEA by even a single digit.
Medium businesses at low voltage that choose the TOU tariff pay an On Peak energy charge of 4.3297 THB/kWh and an Off Peak energy charge of 2.6369 THB/kWh, which are also the same figures at both utilities. Monthly service charges, minimum electricity charges, and power factor charges are likewise written as the same figures in both sets of documents.
The consequence is that a business with branches in both the PEA and MEA service areas does not need to calculate electricity costs separately based on which utility serves it. What actually needs separate calculation is the demand size and voltage tier of each branch.
Why do the two utilities' tariff tables write voltage tiers differently?
The kV boundaries of the voltage tiers differ between the two utilities, but this does not make businesses pay different rates. PEA sets the low-voltage tier below 22 kV, while MEA sets it below 12 kV.
PEA calls the range 22–33 kV the medium-voltage tier, while MEA calls the range 12–24 kV the medium-voltage tier. This difference in the kV figures does not cause businesses receiving power at the same tier to pay different rates.
Type 2 businesses have two voltage tiers — medium and low — while Type 3 to Type 5 businesses have three tiers — high, medium, and low. What makes two businesses pay different rates is the voltage tier according to the tariff table, not which utility's service area they are in. Businesses at the same voltage tier under that utility's tariff table pay the same rate regardless of province.
So what actually differs between PEA and MEA?
The real differences sit in the footnotes at the bottom of the tariff tables, not in the rate figures themselves — such as the legacy-tariff cutoff date, which PEA sets before the Nov 2015 billing cycle and MEA sets before the Oct 2000 billing cycle.
Each footnote affects a different group of businesses. Some apply only to long-established businesses, some apply only to businesses about to switch tariffs, and some apply only to businesses in the residential-rental business. Checking which footnote applies to your own business is what actually reveals whether the rate differs.
Legacy-tariff cutoff date for Type 3 and Type 4
PEA grants the right to stay on the legacy tariff only to businesses that were using electricity before the Nov 2015 billing cycle, while MEA grants this right only to businesses using electricity before the Oct 2000 billing cycle.
All new Type 3 and Type 4 customers are automatically placed on the TOU tariff, with no option for the normal tariff or TOD any longer. The right to stay on the legacy tariff belongs only to businesses that started using electricity before each utility's respective cutoff date. Businesses still on the legacy tariff may choose to move to TOU, but cannot move back afterward.
Cost options when small businesses switch to the TOU tariff
MEA offers small businesses switching to TOU two options: pay a one-time TOU meter charge upfront, or pay an increased monthly service charge instead. PEA sets its own charge conditions without specifying which type of charge it is.
This difference affects small businesses considering a move to TOU. MEA offers the option of paying a higher monthly service charge instead of paying for the meter upfront, while businesses in PEA's area should check the charge conditions directly with the local utility before deciding to switch.
Downsizing from Type 3 or Type 4 back to Type 2: which rate applies?
For a business whose demand has fallen below the small-business threshold for 12 consecutive months, PEA additionally requires that the following month must still be below the threshold before allowing the downgrade to Type 2.1 or 2.2. MEA, on the other hand, reclassifies the business into Type 2, rate 2.1, in the very next month.
This difference affects businesses that scale down production or close part of a factory, causing demand to fall below the medium-business threshold. Businesses in PEA's area can be downgraded to Type 2.1 or 2.2, while businesses in MEA's area return only to the single normal Type 2 tariff.
Type 5 hotels and residential-rental businesses: how to compare without mistakes
The Type 5 rate figures are identical between the two utilities, but the sub-code numbers 5.1 and 5.2 have swapped meanings. PEA uses 5.1 for the TOU tariff, while MEA uses 5.1 for the normal tariff.
Hotels and residential-rental businesses are all placed on the TOU tariff in principle under Type 5. Those that have not yet installed a TOU meter are charged a non-TOU rate temporarily only. When comparing bills across the two utilities' areas, look at the tariff type — TOU or normal — rather than the sub-code number attached. The same sub-code number under Type 5 represents a different tariff type at each utility.
Which row of the tariff table does your business fall into?
The rate row a business must pay is determined by demand size and voltage tier according to the tariff table, not by which utility provides service. A business whose highest 15-minute average demand is below 30 kW is classified as a small business, while a business whose highest 15-minute average demand is 1,000 kW or above is classified as a large business.
These three criteria determine the rate row the same way in every province. PEA's and MEA's tariff announcements use the same set of size thresholds. Businesses that want to know which row they fall into can check the following three points.
The business's demand size
A business whose highest 15-minute average demand is below 30 kW is classified as a small business. A business with demand from 30 kW up to but not reaching the large-business threshold of 1,000 kW, and whose average usage over the preceding 3 months does not exceed 250,000 kWh/month, is classified as a medium business.
A business whose highest 15-minute average demand reaches 1,000 kW or above, or whose average usage over the preceding 3 months exceeds 250,000 kWh/month, is automatically classified as a large business. This size determines whether the business pays the demand charge under the medium-business or large-business rate, which differ in the announced figures but are always the same between PEA and MEA.
Voltage tier according to the tariff table
The voltage tier according to the tariff table is another factor determining the rate row. PEA calls the range 22–33 kV the medium-voltage tier, while MEA calls the range 12–24 kV the medium-voltage tier.
Businesses at the low-voltage tier — below 22 kV in PEA's area or below 12 kV in MEA's area — pay the same low-voltage tier rate, even though the kV figures used to draw the line differ. The result the business pays does not change with these differing kV figures.
On the normal or legacy TOD tariff, or already moved to TOU
A business that started using electricity before the cutoff date still retains the right to stay on the normal or legacy TOD tariff. PEA uses a cutoff before the Nov 2015 billing cycle, while MEA uses a cutoff before the Oct 2000 billing cycle.
A business that started using electricity after the cutoff date is automatically placed on the TOU tariff, and an existing business that has moved to TOU cannot move back to the legacy tariff. Knowing where a business falls on these three points allows for a more accurate estimate of a new branch's electricity bill than simply looking at which utility serves that area.
Service area determines which utility serves you, not the price
MEA's service area covers Bangkok, Nonthaburi, and Samut Prakan. Every other province is served by PEA.
Moving a branch across these two service areas changes which agency to contact for an electricity connection, but does not change the rate row that applies. The rate row is determined by demand size, voltage tier, and the tariff type in use. A business opening a new branch in another province can estimate electricity costs from these three points directly, without worrying that being outside MEA's area means paying more or less.
How does this relate to whether solar is worthwhile?
The value per unit that rooftop solar helps save depends on the day and time electricity is generated, not on whether the business is in PEA's or MEA's area. Small businesses at low voltage on the TOU tariff pay an On Peak energy charge of 5.7982 THB/kWh and an Off Peak energy charge of 2.6369 THB/kWh.
The difference between these two rates is the value rooftop solar helps save per unit of electricity actually generated during daytime on working days. A business that uses a lot of electricity during the day on Monday through Friday benefits fully from this difference, while a business closed on weekends will not capture the full value of electricity generated during Off Peak hours.
This set of On Peak and Off Peak rate figures is the same in both PEA's and MEA's areas. Assessing whether solar is worthwhile therefore does not require separate calculations by utility, but rather by each branch's actual electricity usage pattern. A business wanting to know how worthwhile solar is for its own branch can check the main deciding factors at Is rooftop solar worth it? What determines the answer