After rooftop solar, a business can import fewer kWh while its kVAh imports fall by a different proportion. The effect on the bill depends on the tariff and the site’s reactive-power demand. The answer depends on the meter, tariff category and the way its reactive load behaves during solar hours. Start with the current bill and a daytime meter profile, not a promise that every exported solar unit offsets the same number of billed units.
Direct answer. Solar can lower grid-side power factor because it supplies active power while motors still need reactive power. Under kVAh billing, that changes the relationship between active and apparent imports. MSEDCL applies kVAh billing to HT consumers and LT consumers above 20 kW. DGVCL uses separate PF adjustments in its cited schedule. MPERC rejected the proposed HT kVAh transition for FY 2026-27. Check your category before predicting the bill.
What is the difference between kWh and kVAh on a solar bill?
A kilowatt-hour (kWh) measures active energy, the part that performs work such as turning a motor or running a chiller. A kilovolt-ampere-hour (kVAh) measures apparent energy over time. Apparent power combines active power and reactive power. Reactive power supports the magnetic fields in motors and transformers; it is not an extra solar unit that a panel can simply cancel. The kVAh billing glossary defines the meter terms, and the power-factor glossary explains their ratio.
For a steady load, power factor equals kW divided by kVA. If the load draws 90 kW at a power factor of 0.90, apparent power is 100 kVA. For one hour, that is 90 kWh and approximately 100 kVAh. At a power factor of 0.75, the same 90 kWh of active work corresponds to 120 kVAh. These figures are illustrative, not tariff rates or a prediction for a real meter. Actual monthly meters integrate changing active and reactive flows, and their treatment of leading and lagging reactive energy matters.
A rooftop plant generating 40 kWh during that hour may reduce the meter’s active import from 90 to 50 kWh. It does not follow that the meter records exactly 50 kVAh. If the site’s reactive requirement is unchanged, apparent import stays higher than active import. Conversely, an approved inverter reactive-power mode or correctly controlled capacitor bank may change the result. An EPC should not use a simple kWh export spreadsheet to predict kVAh billing.
Illustrative active load in one hour
Illustrative grid power factor before solar
90 divided by 0.90 for that steady hour
The numbers above are a teaching calculation. They are not drawn from a DISCOM tariff. The governing billing unit and charge must come from the consumer’s current approved schedule. In Maharashtra, the MERC order in Case 75 of 2025, dated 25 March 2026, explains the phased move to kVAh billing. Read that order alongside the bill’s tariff code before using this calculation.
Why can the grid-side power factor appear to fall after solar?
Think of a factory drawing 100 kW of active power and 50 kVAr of reactive power at midday. Its grid-side power factor is about 0.89 because 100 divided by the square root of 100 squared plus 50 squared is about 0.89. Suppose the rooftop plant produces 60 kW of active power. If the site’s reactive draw remains 50 kVAr and the inverter operates at unity power factor, the grid sees 40 kW of active import and 50 kVAr of reactive import. Grid-side power factor is then about 0.62. This is an illustrative steady-hour scenario, not a measured Heaven Green project or a guaranteed bill outcome.
The motors have not necessarily become less efficient. The denominator and numerator at the revenue meter have changed differently. Solar supplies much of the active component, leaving a higher reactive share in the residual grid exchange. This is why a solar installation may reveal a power-factor penalty that was not obvious in the pre-solar bill. The outcome also depends on how the meter treats import, export, leading reactive power and the applicable billing period.
The Three-Register Check keeps the diagnosis grounded: compare active import in kWh, apparent import in kVAh where billed, and reactive energy in kVArh or rkVAh where available. Add the inverter’s generation log and the main meter’s time stamps. If only the monthly bill is available, ask the DISCOM or meter data provider for interval records. A monthly average may hide a short midday problem during low active import.
Do not assume that adding large capacitors always helps. A bank set for pre-solar load may overcorrect when solar output is high and the plant load falls. Some meters count leading reactive energy differently, and switching steps can make the condition intermittent. A qualified electrical engineer should review current-transformer placement, capacitor switching and inverter control before changing any setting. The CEA’s distributed-generation connectivity standards and 2019 amendment set the regulatory engineering context; an individual site still needs its approved interconnection settings.
Verdict. A lower displayed power factor after solar can be a meter-side arithmetic effect, a real compensation problem, or both. The remedy starts with synchronized kW, kVAr and inverter data. A single monthly PF number cannot distinguish those cases.
Which consumers face kVAh billing in Gujarat, Maharashtra and MP?
There is no safe all-India answer. The three states in this guide do not use the same 2026 billing rule. The table below names the source and date for each state, and it separates an approved tariff from a proposal. A business should match its own licensee and tariff code to the schedule rather than treating a state name as a complete category description.
| State and source | Position as of the cited 2026 order | What a solar buyer should check |
|---|---|---|
| Gujarat, GERC DGVCL tariff order 2581/2025, 25 March 2026 | The cited HTP schedule prices energy per unit and has separate power-factor penalty and rebate clauses; it does not describe a general kVAh switch for these DGVCL consumers. | Read the HTP or LT schedule printed on the bill and check its PF adjustment line. Other Gujarat licensees require their own tariff schedule. |
| Maharashtra, MERC Case 75 of 2025, 25 March 2026, para 4.6 | MERC states that HT kVAh billing began 1 April 2020 and allowed MSEDCL LT consumers above 20 kW to move from 1 April 2025. | Verify the meter, tariff category, kVAh register and any subsequent order applicable to the billing month. |
| Madhya Pradesh, MPERC Petition 140/2025, 26 March 2026, issue 10 and directive 7.3 | MPERC expressly did not approve the DISCOM proposal to introduce HT kVAh billing for FY 2026-27. | Use the current kWh tariff and applicable PF provisions. Treat any kVAh study on the bill as informational unless a later approved order changes the rule. |
This distinction changes the engineering question. A Maharashtra consumer on kVAh billing should model apparent-energy imports. A Gujarat DGVCL HT consumer should model kWh energy charges and the separate PF adjustment in its category. An MP consumer should not be told that a proposed tariff already applies. All three still need a review of reactive load, because poor power factor can influence charges or equipment loading even when the billing unit is kWh.
The DGVCL 2026 HTP schedule shows category-specific PF clauses. This article does not generalise its percentage levels to every Gujarat business, particularly Torrent Power consumers. Similarly, the MERC order describes MSEDCL’s rollout, not every licensed Maharashtra supply area. MPERC’s rejected proposal should not be copied into a sales quote as an active rule.
Tariff check
Ask for the current tariff code, licensee and billing month. A state-level article cannot replace the order that applies to that meter.
Will rooftop solar make a kVAh bill rise or fall?
The total bill can fall even if the ratio between kVAh and kWh gets worse. Solar reduces grid active-energy imports when its output matches the site’s load. A worsening grid-side power factor can partly offset that benefit under kVAh billing. Fixed charges, demand charges, duties and other lines may also remain. These are separate calculations. The high-bill-after-solar guide covers other causes; this article isolates apparent energy and reactive power.
Consider a second hypothetical steady-hour case. Before solar, the site imports 100 kW and 30 kVAr, about 104.4 kVA. After 50 kW of solar active output, the grid imports 50 kW and 30 kVAr, about 58.3 kVA. Apparent import still falls, from 104.4 to 58.3 kVA, even though grid power factor slips from about 0.958 to about 0.857. The fall in power factor does not prove that solar increased apparent energy. It shows why the reduction in apparent energy can be smaller than a buyer expects from kWh alone.
| Hypothetical steady hour | Before solar | After 50 kW solar |
|---|---|---|
| Active grid import | 100 kWh | 50 kWh |
| Reactive grid import | 30 kVArh | 30 kVArh |
| Apparent grid import | About 104.4 kVAh | About 58.3 kVAh |
| Grid-side power factor | About 0.958 | About 0.857 |
Every figure in this table follows from the stated constant-load assumptions and the formula kVA equals the square root of kW squared plus kVAr squared. It is an engineering illustration, not a tariff calculation or a meter forecast. A real bill integrates many intervals, export periods, leading and lagging reactive flows, and the regulator’s metering method. The electricity bill slabs guide explains why energy offsets and bill savings are not identical.
In an actual proposal, request a monthly bill model with two columns: before and after solar. It should retain each charge line that survives installation. Add a sensitivity case for midday low load and high solar output. If the proposed system frequently exports active power while the site still imports reactive power, that deserves explicit review with the meter scheme. A smaller system with strong self-consumption can sometimes be a sounder first step than a larger nameplate chosen from roof area alone.
Mid-article action
Take the last twelve bills and a daytime load profile to the commercial solar proposal page. Ask for kWh, kVAh and PF assumptions to appear on the same model.
- ✓ Grid-side active and reactive energy are modelled.
- ✗ Savings case assumes kWh and kVAh move together.
What should an EPC check before choosing inverter settings?
An inverter can have reactive-power modes such as fixed power factor, voltage-dependent reactive power or a set reactive-power command. That does not mean the EPC can switch them on without review. The approved utility interface, inverter capability at the expected active output, transformer arrangement and protection settings all matter. A request to “fix PF in software” is incomplete until someone identifies where the revenue meter measures the result.
Ask the EPC for the single-line diagram showing the point of common coupling, the revenue meter, the inverter AC connection, the plant’s capacitor bank and the current transformers that drive its automatic power factor correction (APFC) controller. The controller may react incorrectly if its sensor sits on the wrong side of solar injection. A new inverter operating at unity power factor can expose an old APFC sizing error. An inverter commanded to supply reactive power can reduce active-power headroom under some conditions. These tradeoffs belong in the design note.
The CEA technical standards for distributed-generation connectivity, 2013 as amended in 2019 are a relevant compliance source. They do not substitute for the DISCOM-approved settings at a particular site. Require the EPC to identify the inverter model’s declared reactive capability, permissible setting range and commissioning test. For a technical reading of inverter specifications, the Qbits inverter specifications guide is a sister-site resource; the regulator and the equipment manual remain the authority for a real design.
A baseline test should record at least one representative production shift and a light-load solar hour. Include kW, kVAr, kVA, voltage, power factor and capacitor step status at the meter. After commissioning, repeat the same measurements. If the tariff uses kVAh, compare interval kVAh per unit of activity, not just generation against kWh imports. If the tariff uses PF adjustment, compare the month’s assessed PF and the adjustment line. This is a measurement task, not a setting chosen from a generic checklist.
- Meter location on the single-line drawing
- Baseline interval kW and kVAr
- APFC sensing and step schedule
- Approved inverter Q mode
- PF claim without meter data
- Capacitor size chosen from kW alone
- Inverter mode promised without approval
- Only annual kWh shown in bill model
How do APFC panels and capacitor banks fit with solar?
An APFC panel switches capacitor steps to compensate a site’s changing reactive load. It can help keep grid-side power factor within the range required by the relevant tariff, but only if it is correctly sized and senses the right flow. Solar changes active power at the connection point during the day. The APFC controller may have been tuned when all active power came from the grid. A post-solar commissioning check is therefore part of the electrical design, not an optional maintenance note.
Start with the existing panel’s step sizes, capacitor age and contactor condition. A failed step can leave the factory undercompensated on heavy motor loads. A stuck step can leave it overcompensated when the plant is quiet and solar is exporting. Harmonics from variable-speed drives and other equipment can stress ordinary capacitors and may require a detuned design. Do not add capacitor capacity by taking the pre-solar monthly PF and plugging it into a generic formula. Use a power-quality survey at representative operating points.
A useful sequence is: (1) verify the revenue-meter PF definition; (2) inspect the APFC current-transformer polarity and position; (3) test capacitor steps under load; (4) check inverter Q settings and DISCOM approval; (5) measure again after solar at high and low output; (6) compare the next bill against the baseline model. This sequence narrows the cause before anyone buys equipment. It also makes responsibility clear if the EPC modifies the switchboard or controller wiring.
The power-factor penalty glossary helps decode the separate charge used in some tariffs. A kVAh tariff already reflects apparent energy, so do not assume a separate PF penalty will also apply. Maharashtra’s 25 March 2026 MERC order discusses the method’s built-in PF effect and the rollout history. Gujarat’s 25 March 2026 DGVCL order shows separate PF adjustment clauses for the cited HTP schedule. Different bill mechanics require different post-solar verification.
If the site has multiple transformers or meters, map each capacitor bank to the meter it affects. A healthy APFC panel on one board may not correct the reactive import recorded by another revenue meter. Ask the plant electrician to document manual overrides and maintenance history. This makes the EPC’s proposed interface safer and gives the owner a record for future fault finding.
How Heaven Green Energy helps check kVAh Billing
A bid should name the tariff order and billing category used in its financial model. It should list the baseline meter period, active import, apparent import where relevant, reactive-energy pattern, maximum demand and operating schedule. If the bid has only annual solar kWh and a retail per-unit rate, it cannot show the kVAh or PF effect. That does not mean the plant is unsuitable; it means the proposal has an unresolved bill assumption.
The contract should state who supplies and checks the existing APFC panel, who obtains approval for inverter reactive settings, who tests the post-installation power factor, and what happens if the measured result differs from the model. Define the measurement point and the operating conditions for any acceptance test. A claim about PF at the inverter terminals is not the same as PF at the DISCOM revenue meter. Keep equipment warranties separate from a bill forecast.
Use this Three-Register Check in every quote comparison: active energy, apparent or reactive energy, and the charge actually assessed on the bill. A bid that addresses all three can be compared with a bid that focuses only on kWh. Ask for a second case with lower daytime load, because weekends, maintenance days and seasonal shutdowns change the ratio. Ask for an export case too, especially if the rooftop size approaches the daytime base load.
- Send the EPC three recent bills, a twelve-month bill summary and the tariff code.
- Share interval meter data, production shift hours and the existing APFC drawing.
- Request a pre-solar and post-solar model for kWh, kVAh or PF adjustment, and demand.
- Have the EPC identify the inverter Q mode, approval path and commissioning tests.
- Put the accepted assumptions, exclusions and meter location into the signed scope.
The commercial solar page is the proposal route for a business. A large factory can also use the industrial solar page. Heaven Green’s proposal should be assessed against the same written meter and tariff questions as any other EPC’s proposal. A reader should be able to ask for these documents before deciding to proceed.
The service routes for a site-specific review are:
- Commercial solar for a business bill and rooftop proposal.
- Industrial solar for a larger factory connection and protection review.
How can a business check the first three bills after commissioning?
Keep the pre-solar bills and the signed proposal model. On the first post-solar bill, confirm the tariff code, meter number and billing unit. Compare imported kWh and, if billed, imported kVAh. Record the PF shown, reactive-energy register if present, energy charge, demand charge, PF adjustment, duties and export credit separately. A single total-bill comparison can be distorted by production changes, weather and billing days.
For each month, compare like with like. Divide energy by production output or another stable activity measure if available. Note plant shutdowns, new equipment and abnormal inverter outages. If kVAh per unit of output rises while active grid kWh falls, look at reactive import and APFC step logs. If only the PF adjustment line worsens, verify its calculation against the current tariff. If the bill seems inconsistent with the meter display, request the interval data and register definitions from the DISCOM.
Do not immediately alter the inverter or capacitor controller. Unapproved reactive-power changes can affect voltage, protection and the approved interconnection scheme. An electrical engineer should review the measured condition with the EPC and plant electrician. Keep the revised settings, approval record and test results with the as-built drawing. The diagnosing low solar generation guide helps separate a generation fault from a billing issue.
The decision is practical: if the active-energy benefit remains strong and the reactive issue is small, correct the control and monitoring plan without redesigning the entire plant. If reactive imports dominate during long low-load periods, revisit the solar size, APFC design and approved inverter capability. If the site is in MP, first verify whether a later MPERC order has changed the March 2026 position. Under the 26 March 2026 MPERC tariff order, the proposed HT kVAh change was not approved for FY 2026-27.
For a bill review and plant proposal, start at commercial solar. Bring the tariff code, recent bills, interval data and APFC drawing. A factory with a larger HT connection can use industrial solar. Those inputs let the EPC model the bill you actually pay instead of applying a generic per-unit saving to every solar kilowatt-hour.
Frequently asked questions
Does solar always increase a kVAh bill?
No. Solar can reduce apparent-energy imports even when grid-side PF falls. In the article’s illustrative steady-hour example, active import halves while apparent import also falls, just by a different proportion. A real monthly bill depends on the load shape, reactive flow, meter logic, tariff and export settlement. Compare synchronized meter data and charge lines rather than treating a lower displayed PF as proof that the total bill rose.
Is Gujarat using kVAh billing for all HT solar consumers?
No such blanket conclusion follows from the cited 25 March 2026 GERC DGVCL order. Its HTP schedules show energy charges with separate power-factor adjustments. Gujarat has multiple licensees and tariff categories, so the consumer must check the specific schedule and bill. A proposal should not copy the Maharashtra kVAh framework into a DGVCL or Torrent Power bill without a current order showing that it applies.
Did MPERC approve kVAh billing for HT consumers in 2026?
No. MPERC’s retail supply tariff order dated 26 March 2026 says it did not approve the DISCOM proposal for FY 2026-27 because the required awareness and impact assessment work was incomplete. That is a dated position, not a claim about every future billing year. An MP business should check for a later order before relying on a kVAh forecast.
Can an inverter fix poor power factor after solar?
Some inverters have reactive-power control modes, but a mode should be selected only after reviewing the equipment capability, meter location, utility approval and plant load. Inverter control may share capacity with active output. It may also interact with an existing APFC panel. Ask the EPC and a qualified electrical engineer to document and test the proposed setting at the revenue meter.
Should the APFC panel be replaced when solar is installed?
Not automatically. First inspect capacitor health, controller logic, current-transformer placement and step response under representative loads. A healthy panel may need control changes; a failed bank may need repair. Adding capacity without a power-quality survey can overcorrect at light load. The post-solar test should measure both lagging and leading reactive behaviour if the meter records them.
Which documents should I send before requesting a commercial solar proposal?
Send the current tariff code and twelve months of bills, interval meter data if available, a single-line diagram, APFC details, production hours and any planned load change. Ask the EPC for separate kWh, kVAh or PF-adjustment, demand and export assumptions. The proposal should name the applicable order and measurement point, then specify how the electrical settings will be approved and tested.