Bidirectional Meter for Solar: How It Works in India

A bidirectional meter, also written bi-directional meter, two-way meter or import-export meter, is an electricity meter with separate registers for the energy you take from the grid and the energy you send back to it. In Indian rooftop solar this is the meter that makes net metering possible. The Central Electricity Authority (CEA) calls it a "Renewable Energy Meter": a meter used for accounting and billing of electricity supplied to and from the consumer.

Every solar buyer asks about it sooner or later, usually at the kitchen table just before they sign. This guide covers the device: what it is, how to read it, which old meters need replacing, the standards behind it, who supplies and pays for it, and what to do if a reading looks wrong. It also gives you the plain-language customer script that goes with each point.

What is a bidirectional meter, and what else is it called?

Customers and DISCOMs use several names for the same job. Use the table to match the words on your proposal, the DISCOM form and the regulation.

Here is the version to use with a customer who has never seen one:

"Your current meter counts in one direction only: units you take from the grid. The new meter counts in both directions. When your panels make more than you use, the extra goes to the grid and the meter counts it separately. The DISCOM then bills you on the difference."

That is the whole idea. Two directions, two tallies, one bill.

How a bidirectional meter measures import and export

Inside a static (electronic) meter there are separate energy registers. One adds up kWh drawn from the grid. The other adds up kWh pushed back into it. The meter senses the direction of power flow at your connection point and puts each unit in the right register.

Old meter vs bidirectional meter

How to read a bidirectional meter

The display scrolls through screens, and the order differs by make and by DISCOM. Whatever the order, you are looking for two cumulative kWh figures: the import register and the export register. The meter's own label or the DISCOM's manual tells you which screen is which. Ask the DISCOM technician to show you at installation rather than guessing.

1. At commissioning, note the import and export readings and take a photo of the display. This is your opening reading.
2. On every billing date, note both again. Subtract the opening figures to get that period's import and export.
3. Compare three numbers: the meter's export register, the export figure on the DISCOM bill, and the export figure in the inverter app. The bill should follow the meter. The inverter app can differ slightly from the meter, so treat the meter as the billing record.

The meter does not show what your panels generate or how much of it you used directly. It only sees what crosses the connection point. Total generation lives on the inverter display or its app. Battery charge level lives on the battery's own monitor.

Which existing meters need to be replaced?

A single-direction meter cannot record export, so it has to go. The CEA metering regulations say that for net metering the Renewable Energy Meter is installed at the consumer meter location, and in the case of existing consumers the consumer meter is replaced with it. The same regulations say all new consumer meters are to be smart meters with a prepayment feature, so many DISCOMs now fit smart meters where they would earlier have fitted a plain net meter.

Two practical consequences for the installer:

• An existing smart meter that records import and export may only need configuration. The DISCOM decides, so ask it rather than assume.
• Never connect export to a meter that has not been approved for it. Export that no register counts earns the customer nothing, so confirm the meter type with the DISCOM before commissioning day.

Under PM Surya Ghar, the MNRE guidelines say the DISCOM provides the net meter, or the consumer may buy it from enlisted meter vendors. In either case the meter is installed after the rooftop work is complete and the DISCOM and consumer sign the metering agreement as per state regulations.

Standards and accuracy class

Three references come up again and again.

The CEA regulations also require every consumer meter to bear the BIS mark. Sources: the CEA (Installation and Operation of Meters) Regulations, 2006, consolidated up to the 2019 amendment and the BIS record for IS 13779. The regulations have been amended since, so check the current text on the CEA site before quoting a clause number in a contract.

Who owns, supplies and pays for the meter?

What the meter costs: one published schedule as an example

There is no national meter price, and we do not quote a universal range. Meter cost depends on phase, load and DISCOM, and some DISCOMs supply the meter to eligible consumers at no separate charge. As one published example, the West Bengal DISCOM (WBSEDCL) lists these import-export meter costs on its solar applicable-charges page (the page carries no date; we read it on 14 October 2026):

Other DISCOMs publish different figures, and other posts on this site give state examples as indicative numbers. The DISCOM's own schedule is the one that counts. For fees by state, see net metering charges in India.

Your customer script: "The DISCOM installs and seals the meter. What you pay for it depends on your DISCOM's schedule and your connection type. We list the figure we have confirmed for your DISCOM in the proposal, so there is no surprise."

Testing, sealing and what to do if the reading looks wrong

Customers rarely doubt the meter until the first bill is higher than expected. Know the ground rules so you can answer calmly.

• Sealing. Consumer meters are sealed by the DISCOM. A broken seal is a conversation with the DISCOM, not something to fix on site.
• Testing. Under the CEA regulations, consumer meters up to 650 volts are tested at site at least once in five years, and a meter is also tested if the consumption pattern changes sharply or the consumer complains about it.
• Check meter on complaint. The 2024 amendment to the Electricity (Rights of Consumers) Rules requires the distribution licensee to install an additional meter within five days of a complaint that the reading does not match actual use. It is used to check consumption for at least three months. Source: PIB, 23 February 2024.
• Accuracy. Consumer meters up to 650 volts must be class 1.0 or better. Compare the meter against your own readings and the bill before you raise a complaint.

If a complaint is not resolved at the DISCOM, the next step is the consumer grievance forum the state has set up. Keep the opening-reading photo and bills together.

Smart meters and time-of-day meters

Smart meters are the direction of travel. The CEA metering regulations say all new consumer meters are to be smart meters with a prepayment feature, and the PM Surya Ghar guidelines ask DISCOMs to install net meters through the smart-metering contractor in areas where smart metering works are already awarded.

Time-of-day (ToD) tariffs change how a unit is priced, not how the meter counts it. The central amendment to the Electricity (Rights of Consumers) Rules announced on 23 June 2023 set these points:

• The tariff during solar hours (an eight-hour block specified by the state regulator) is 10% to 20% less than the normal tariff.
• The tariff during peak hours is 10% to 20% higher.
• ToD applies to commercial and industrial consumers with maximum demand of 10 kW and above from 1 April 2024, and to other consumers except agricultural from 1 April 2025 at the latest. For consumers with smart meters it applies immediately after installation.

Source: PIB, 23 June 2023. Each state regulator sets the actual hours and rates, so quote your own state's tariff order, not a generic multiplier. The meter simply records import and export in each time block.

Net, gross and net billing: what changes on the meter

Under net metering the meter sits where the old consumer meter sat, and the DISCOM bills on import minus export under the state's rules. Under gross metering, the plant's output is metered separately at its own point. Net billing credits export at a rate set by the regulator rather than unit for unit. Which one applies to a customer depends on the state regulation and on the consumer category. The hardware difference is small; the billing difference is large. See net metering vs gross metering and what is net metering for the decision.

How the bill uses the two registers

Billing arithmetic and year-end settlement belong in how the bill and banking work. Here is the one example you need for the meter conversation.

A household imports 200 kWh and exports 80 kWh in a billing cycle. Under unit-for-unit netting, it is billed on 120 kWh. At an illustrative ₹7 per unit that is ₹840 of energy charge. Fixed charges, duty and other levies are extra.

The table below reconciles five typical months. Every row follows the same rules: total use = grid import + solar used directly; net units billed = import minus export (never below zero); the "without solar" bill is total use at the same flat ₹7. These are illustrative numbers with a flat tariff. Real bills use slabs and state rules.

What the Rules say about meter installation timing

The meter is the last gate before export credit starts. The clocks that apply come from the Electricity (Rights of Consumers) Rules, not from a rule of thumb. The February 2024 amendment, per PIB:

• The technical feasibility study is exempt for rooftop systems up to 10 kW. For larger systems the time to complete it was cut from twenty days to fifteen, and if it is not completed in time the approval is deemed given.
• The time for the distribution licensee to commission rooftop solar systems was cut from thirty days to fifteen.
• Distribution system strengthening for rooftop systems up to 5 kW is done by the DISCOM at its own cost.

Real timelines vary by DISCOM and by how complete the file is. We do not publish a typical number of days here. For state examples see net metering application timelines, and for the full process how to apply for net metering.

The 90-second customer script

"Right now your meter counts in one direction: units you take from the grid. After we install solar, the DISCOM fits a meter that counts both directions, in from the grid and out to the grid when your panels make more than you use.

The DISCOM installs and seals the meter. What you pay for it depends on your DISCOM and your connection type, and we show that figure in your proposal.

Every billing cycle the DISCOM reads both numbers and bills you on the difference, as per your state's rules. Fixed charges still apply.

We will photograph the opening readings on commissioning day, so you can check every bill against the meter. Any questions?"

For the residential sales conversation this fits into, see PM Surya Ghar eligibility and how to pitch PM Surya Ghar to customers. For DISCOM-specific meter handling, see the DGVCL, MSEDCL and BESCOM guides. If a customer's net metering file stalls, net metering rejection reasons lists the usual causes.

How Quickest Solar CRM helps with the meter step

Meter questions repeat on every job, so put the answers in your process, not in people's heads.

• Proposal Generator: add a short "how your meter works" note and the confirmed meter charge for the customer's DISCOM to every proposal.
• Pipeline Management: track each job's net metering application, DISCOM inspection and meter installation as separate stages, and record the opening import and export readings against the job.
• WhatsApp Follow-up: send the customer a message when the meter is due, so they are home for the DISCOM visit.

You can see how this looks in a live pipeline in a short demo.

Frequently asked questions