Fixed price vs discount electricity plan comes down to one question: do you expect the regulated tariff to go up or down during your contract? A fixed-price plan charges the same rate per kWh for the whole contract, so it wins when the SP Group tariff rises. A discount-off-tariff plan charges the tariff minus a percentage, so it moves every quarter and wins when the tariff falls or stays steady. Nobody knows the tariff path in advance, so the useful approach is to price both under a few scenarios.
Below, we do that for a household using 360 kWh a month, close to the recent average for an HDB 4-room flat.
The short version: In our illustration, a 15%-off-tariff plan cost less than a 27-cent fixed plan when the tariff held steady or fell, and more when it rose back to the July to September 2026 level. The fixed plan’s cost never changed. Choose based on how much bill certainty matters to you, then check the deposit, termination charge and contract length.
How We Compared Fixed Price vs Discount Electricity Plans
The Open Electricity Market (OEM) site describes the two standard plan types:
- Fixed price: “a constant rate” per kWh for the contract duration.
- Discount off the regulated tariff: a fixed percentage off the prevailing regulated tariff for the contract duration.
Our assumptions (illustration only, not a guarantee):
- Usage of 360 kWh a month (4,320 kWh a year). SP Group’s data put the average HDB 4-room household at 369 kWh in July 2026.
- A hypothetical fixed price of 27.00 cents/kWh including GST.
- A hypothetical discount of 15% off the tariff.
- A 12-month contract and three tariff paths, each held flat for the year so the maths stays simple.
These are not quotes from any retailer. Real plans differ; check current offers on the official comparison tool.
Three Tariff Scenarios, Worked Out
The three tariff paths use real recent levels as reference points: 31.16 cents/kWh is SP Group’s Q4 2026 household tariff with GST, and 34.78 cents was the Q3 2026 level.
| Scenario (tariff with GST) | SP tariff, yearly | Fixed 27.00 cents, yearly | 15% off tariff, yearly |
|---|---|---|---|
| Steady at 31.16 cents | S$1,346 | $1,166 | $1,144 |
| Rising to 34.78 cents | $1,502 | $1,166 | $1,277 |
| Falling to 27.00 cents | $1,166 | $1,166 | $991 |
What the table shows:
- Both retailer plans beat the SP tariff in the steady and rising scenarios. In the falling scenario, the fixed plan only matches it.
- The discount plan’s cost swings by $286 between the best and worst scenario. The fixed plan’s cost does not move.
- Break-even: the discount plan costs the same as the 27-cent fixed plan when the tariff is about 31.76 cents (27.00 divided by 0.85). Above that, fixed wins; below it, the discount wins.
What Recent Tariffs Tell You, and What They Do Not
The SP tariff moves with energy costs. It rose 17.0% for July to September 2026 and fell 10.4% for October to December 2026. In its 30 September 2026 release, SP Group said global fuel prices had risen since September and tariffs are expected to increase for the following quarter.
That is a short-term signal, not a forecast for a 12 or 24-month contract. Past quarters show the tariff can move several cents in either direction within a year. If a $100 to $150 swing in your yearly bill would strain your budget, the certainty of a fixed price has value of its own.
Our Q4 2026 tariff news has the latest figures.
The Costs That Can Change the Answer
A few cents per kWh is not the whole comparison. Check each plan’s fact sheet for:
- Security deposit. OEM says a retailer should not collect more than twice your average monthly bill; some ask for none. A deposit earns you nothing while the retailer holds it.
- Early termination charge. Not standardised. If you might move house or want to leave when the tariff drops, this matters.
- Contract length. Standard plans on the official comparison tool run 6, 12 or 24 months. A longer fixed price gives longer certainty, and a longer exposure if tariffs fall.
- Non-standard terms. OEM notes some non-standard plans have rates that are not all-inclusive or can change during the contract.
- Renewal. Contracts auto-renew. From 19 June 2026, the renewed rate must be lower than the regulated tariff at renewal, and you can leave within 60 days of an auto-renewal without a termination fee.
Who Each Plan Type Does Not Suit
- A fixed-price plan may not suit someone likely to move within the contract, or someone who would be frustrated paying above the tariff if prices fall.
- A discount plan may not suit a household on a tight budget that needs predictable monthly bills, since the rate changes every quarter.
- Staying on the SP tariff may suit anyone who does not want to track contract end dates or deposits. It has no contract and no minimum period. Our Open Electricity Market explainer covers that option.
What To Do Next
- Average your monthly kWh over the last few SP Services bills, and use that figure, not ours.
- On compare.openelectricitymarket.sg, pick one fixed and one discount plan of the same length and work out the yearly cost at the current tariff and at a tariff three cents higher and lower.
- Read the fact sheet for the deposit and termination charge before signing.
- Put your chosen plan’s monthly cost into our monthly budget planner, and look at our year-end household money audit for other bills worth reviewing.
