on grid
On-Grid Solar Systems
On-Grid Solar Systems
An on-grid system has no battery. It generates during daylight, your building consumes what it needs at that moment, and the surplus goes out through your meter onto the distribution network. At night, or under cloud, you import from the grid as you always did. The meter counts both directions, and you are billed on the difference.
This is the highest-return configuration available to most buildings in Madhya Pradesh, for a simple reason: batteries are the expensive part of a solar system and the part that wears out. Removing them removes roughly a third of the capital cost and the only component with a replacement cycle shorter than the panels.
What net metering is, legally
Net metering in MP is governed by MPERC's RG-39(II) of 2024 as amended. It is a regulation, not a scheme or a concession, and it sets out what you may install and what your DISCOM must do about it.
| Rule | Value |
|---|---|
| Net metering capacity | up to 500 kW |
| Minimum system size | 1 kW |
| Group and virtual net metering | under 100 kW |
| Gross metering | up to 1 MW |
| Capacity ceiling per premises | must not exceed your sanctioned load or contract demand |
| Consumers with pending arrears | not entitled until cleared |
| Cumulative rooftop capacity per distribution transformer | 80% of its rating |
That last row is the one that surprises people. Capacity is allocated distribution-transformer-wise, first-come-first-served, and once the transformer feeding your street reaches 80% of its rating, further connections on it wait. DISCOMs are required to publish available capacity at transformer level on their websites annually. It is also why an approval granted to a neighbour last year says nothing about the queue this year.
Net metering and gross metering are mutually exclusive, and a net-metered prosumer cannot take intra-state open access.
The timelines the DISCOM is bound by
- Up to 10 kW, an application complete in all respects is deemed accepted without any technical feasibility study, and the DISCOM must simultaneously enhance your sanctioned load to match.
- Above that, technical feasibility for rooftop solar must be decided within 15 days — and if nothing is communicated in that window, the application is deemed accepted by operation of the regulation.
- The Letter of Approval issues within 30 days of acknowledgement.
- Once the installation certificate is submitted, the DISCOM has 15 days to sign the agreement, install the bi-directional meter and commission.
- Delay without just cause carries ₹500 per day payable by the licensee to you.
- For systems up to 5 kW, network strengthening costs — including the distribution transformer itself — sit in the DISCOM's revenue requirement and are not charged to the applicant.
You may buy the bi-directional meter yourself to the licensee's specification, though it must be tested and installed by the DISCOM. Under PM Surya Ghar, no meter-testing fee may be charged, and the ₹1,000 processing fee is waived.
How the credits are settled
Your meter is read on your normal billing cycle. The bill must show units injected, units supplied by the DISCOM, net billed units, and the export balance carried in from the previous period and out to the next.
Where export exceeds import in a billing period, the excess carries forward as credited units. Where import exceeds export, you are invoiced after those credits are set off. For time-of-day consumers, export is set off against consumption in the same time block first; surplus beyond that is accounted as though it occurred off-peak.
The settlement period runs from the October billing month to the September billing month of the following year. Unadjusted credit at the end of it is paid out by 15 November, at a rate equal to the lowest tariff discovered in solar or wind bidding in Madhya Pradesh in the preceding financial year. The carried-forward balance then resets to zero.
The practical consequence is that banking a very large surplus is not rewarded at retail rates. A system sized far beyond your own consumption converts expensive retail units into cheap wholesale ones every September. Sizing to consumption, not to roof area, is what makes on-grid work.
Fixed charges do not go away
MPERC was asked, in the FY 2026-27 tariff proceedings, to stop levying fixed charges on units a solar household generates and consumes itself. The Commission declined, and its reasoning is worth quoting in substance: fixed charges recover the cost of maintaining the distribution network, are not linked to energy consumption, and consumers with rooftop solar remain connected to that network and rely on it for backup, for seasonal variation and for net-metering adjustment itself.
Separately, where the tariff schedule computes fixed charges from consumption, the regulation directs that they be computed on units imported from the grid rather than on gross consumption.
So an on-grid system reduces the energy component of your bill, sharply, and leaves a residual. Any projection that shows a bill of zero has either ignored fixed charges or assumed an export credit the settlement rules do not pay.
The interconnection standards
Interconnection must conform to the CEA Technical Standard for Connectivity of Distributed Generation Resources 2013, the CEA Measures relating to Safety and Electric Supply Regulations 2023, and the MP Electricity Grid Code 2021. Three things are mandatory: anti-islanding protection to IEC/IEEE standards, an automatic synchronisation device, and harmonic filtering keeping THD within IEGC/IEEE limits.
Anti-islanding is the one that matters for anyone working on the line. It ensures that when the grid goes down, your inverter stops exporting — which is also why a plain on-grid system gives you no power during an outage, even in bright sunshine. That is not a fault. It is the protection working.
When on-grid is right, and when it is not
It is right when your supply is reasonably reliable, you want the shortest payback available, and outage backup is not the reason you are buying.
It is the wrong choice if you are buying solar because the power keeps failing. An on-grid system will not run your house during a cut. If that is the requirement, a hybrid system with battery backup does both jobs, at higher cost; where there is no usable grid connection at all, an off-grid system is the only configuration that applies.
It is also constrained where your sanctioned load is small relative to the roof you have, or where the transformer feeding you is already near its ceiling — both of which a survey establishes before anything is quoted.