Why “Free” Solar Isn’t Actually Free!?

The pitch is compelling. Install solar panels on your roof, sell surplus power back to the grid, and watch your electricity bill shrink to near zero. With government subsidies covering up to 40% of installation costs under the PM Surya Ghar Yojana, payback periods of three to five years, and two decades of virtually free energy thereafter, rooftop solar has become one of the most talked-about financial moves in middle-class India. Millions have taken the plunge.

But there is a less comfortable version of this story unfolding in Kerala, and it is coming for every state in India that is serious about solar. The electricity boards are bleeding. The grid is straining. Regulations are being rewritten. And the consumers who went solar first are now in a battle over the terms of the deal they thought they had locked in.

The Hidden Math of Net Metering

To understand the crisis, you need to understand how net metering works, and what it implicitly assumes.

When you install rooftop solar, your panels generate electricity during daylight hours. Your home uses what it needs, and any surplus flows back into the grid. A bidirectional smart meter records both what you export and what you import. At billing time, the two are netted against each other: you pay only for the difference. If you export more than you import over the settlement period, unused credits carry forward, or, in some states, are simply lost at year’s end.

On paper, this is elegantly simple. In practice, it creates a structural problem for the utility company.

Most Indian households, particularly in a state like Kerala, where roughly 80% of power consumption is domestic, use almost no electricity during the middle of the day. They are at work, school, or sleeping through the afternoon heat. Their solar panels, meanwhile, are generating at peak capacity. So the surplus pours into the grid at exactly the moment when demand is lowest and the grid least needs it.

Come evening, these same households return home. Lights come on. Fans, ACs, and appliances start running. Demand spikes, but the sun has set. The solar panels go dark. The households draw heavily from the grid, using the credits they banked during the day.

The problem is that those evening units of electricity are not the same as the midday units the household exported. The utility has to source evening power from expensive sources: inter-state purchases, private generators, or peaking power plants. The credits the household earned were valued at the retail tariff, but the actual cost of supplying evening power is significantly higher. The difference is a loss the utility has to absorb, and eventually pass on to everyone else.

Why Solar Parks Fail in Kerala

Kerala makes this problem uniquely acute. Unlike Rajasthan or Gujarat, where long, flat, sun-drenched days allow both rooftop and utility-scale solar to generate at high capacity for extended hours, Kerala’s geography works against large solar installations. The state is narrow, heavily forested, and receives intense monsoon rainfall for three to four months a year. Large solar parks face land constraints, shading issues, and seasonal generation gaps that make their economics far less attractive than they appear in sunnier states.

What Kerala does have in abundance are rooftops. The Soura program, launched in 2019–20 under the Urja Kerala Mission and predating the national PM Surya Ghar scheme by several years, pioneered a model where KSEB installed panels at its own cost, with households renting out their rooftop and receiving 10% of generation free. It was an ingenious way to build trust, reduce consumer risk, and accelerate adoption. It worked. Kerala now ranks fourth nationally in installed rooftop solar capacity, behind only Gujarat, Maharashtra, and Rajasthan.

But that success has created a paradox. Kerala’s installed rooftop solar capacity has now touched approximately 1,400–1,500 MW. On a sunny afternoon, that capacity floods the grid with power that nobody wants right then. In some areas, voltage levels on distribution lines are spiking dangerously, high enough to damage household appliances. Engineers are warning that KSEB may soon have to physically disconnect solar feeders during peak generation hours simply to protect the grid, which would undercut the confidence of every solar investor in the state.

The Supply vs. Demand Mismatch

The numbers illuminate just how severe the imbalance has become. State data shows that only about 36% of rooftop solar generation in Kerala is actually consumed during daylight hours, when it is produced. The remaining 64% is exported to the grid. Of that exported energy, nearly 45% is drawn back by the same households at night under net metering arrangements.

This means KSEB is effectively functioning as a free battery for solar prosumers, absorbing surplus midday power it does not need, then returning equivalent units in the evening when it must buy expensive power to do so. The financial consequence is stark: in 2024–25 alone, this mismatch produced losses exceeding ₹500 crore. That figure was added to the bills of all electricity consumers in the state as an additional 19 paise per unit.

KSEB has projected that if large rooftop systems, those above 3 kW, continue to grow at current rates without battery storage, the cost impact could reach 39 paise per unit by 2034–35. That is a meaningful increase on already-rising electricity tariffs, and it is being paid by the 1.4 crore consumers who do not have solar panels, effectively subsidising the 2 lakh who do.

The structural irony is sharp: solar energy was supposed to make electricity cheaper and cleaner for everyone. Instead, in its current form, it is making it more expensive for those who cannot afford to install it.

Physical Infrastructure and Grid Overloading

The financial losses are only part of the problem. The physical grid was not designed for millions of small generators feeding power back in from thousands of dispersed rooftops.

Traditional electricity networks were built for one-directional flow: from large power plants down through high-tension transmission lines, into substations, and finally to homes and businesses. Bidirectional power flows, where households simultaneously act as both generators and consumers depending on the time of day, require a different kind of grid: one with smarter controls, upgraded transformers, and better monitoring at the feeder level.

India’s distribution network, particularly in older residential areas, largely lacks these capabilities. When too much solar power flows backward through a distribution transformer that was designed for forward flow, voltage rises. If the voltage rises too high, equipment trips. Grid engineers must intervene manually or the system risks cascading failures. The more rooftop solar that connects to a distribution feeder, the more precarious this balance becomes — especially at noon on a clear day when every panel in a neighbourhood is generating simultaneously.

Tariffs, Smart Meters, and Changing Rules

KSEB has responded to these pressures by pushing for significant reforms in the regulatory framework. The Kerala State Electricity Regulatory Commission (KSERC) drafted its Renewable Energy and Related Matters Regulations, 2025, proposing major changes to how solar prosumers are compensated and how they interact with the grid.

The core proposals include: capping net metering eligibility for new connections at 3 kW (systems above this threshold would move to a less generous “net billing” or “gross metering” arrangement), settling banked energy credits on a monthly rather than annual basis, and requiring smart meters for all solar connections.

The shift from net metering to net billing is significant. Under net metering, every unit you export is credited at the same rate as the retail tariff you pay to import. Under net billing, exported units are credited at a separately determined export tariff, typically lower than the retail rate, often closer to the wholesale cost of power. For large-system owners who were counting on high net metering credits to justify their investment, this represents a meaningful reduction in returns.

Smart meters are a related reform. Traditional meters are passive recording devices. Smart meters allow real-time monitoring, time-of-day pricing, and remote management by the utility. Under time-of-day tariffs, the value of electricity is priced differently depending on when it flows, midday surplus solar becomes worth less, evening peak power becomes more expensive. For the grid, this creates incentives for better consumption behaviour. For the prosumer, it changes the economics of a rooftop system in ways that were not necessarily anticipated at installation.

The Battery Storage Mandate

The most contested element of the proposed regulations is the battery storage mandate. KSEB’s draft framework proposed that rooftop systems above 3 kW should be required to install battery storage, capturing surplus midday generation for later use rather than dumping it onto the grid.

The technical logic is sound. If households store their midday surplus and discharge it in the evening, the mismatch between solar supply and grid demand largely dissolves. The utility no longer functions as an involuntary battery. The grid stabilises. Everyone benefits.

The economic logic is considerably more complicated. Battery storage remains expensive. A home battery system capable of storing several kilowatt-hours adds a significant upfront cost to an already substantial solar installation. For households that installed large solar systems specifically to maximise net metering credits, being required to add batteries retroactively or having the future terms of their arrangement substantially altered, represents a broken expectation.

This is where the political battle has been fiercest. Opposition politicians have accused the government of designing the regulations to benefit battery manufacturers at the expense of ordinary consumers. Solar vendor associations called a “Solar Bandh” across Kerala. Over 1,600 organisations and experts participated in public hearings, which had to be extended beyond their original schedule. Prosumer groups alleged that KSEB was using the financial loss argument to suppress solar adoption in order to protect its existing high-cost power purchase agreements with private suppliers, agreements that rooftop solar was directly threatening by reducing daytime demand.

KSEB dismissed these allegations as “baseless propaganda” and maintained that without timely reforms, grid instability and financial losses would harm the majority of non-solar consumers.

Cost Impact and Payback Periods

For anyone considering rooftop solar today, in Kerala or elsewhere, these regulatory shifts materially change the investment calculation.

Under the current net metering regime, a well-sized residential system can deliver payback in three to five years and generate near-free electricity for the remaining lifespan of the panels (typically 20–25 years). Under a regime with lower export tariffs, monthly credit settlement, and a mandatory battery requirement for larger systems, payback periods could extend to six to eight years or beyond, depending on the specifics of each state’s new policy.

The critical variable is how aggressively states move from net metering to net billing. States that shift to gross metering, where all solar generation is exported at a fixed, low feed-in tariff regardless of self-consumption, create the least favourable economics for rooftop solar. Research by IEEFA and JMK Research found that under gross metering, export credits of ₹2–4 per kWh are often below the cost at which private developers sign power purchase agreements, making the economics of rooftop solar commercially untenable for larger consumers.

For small residential systems below 3 kW, which the draft Kerala regulations explicitly protect, the economics remain broadly favourable, particularly where government subsidies apply. For larger systems that were sized to maximise credits and minimise bills, the calculus is shifting in ways that demand careful attention.

Legal Battles and What Comes Next

The regulatory confrontation has already moved into the courts. The Domestic On-Grid Solar Power Prosumers Forum filed a petition in the Kerala High Court challenging the new KSERC regulations, alleging among other things that the regulatory commission had been captured by KSEB, noting that its members were largely former KSEB officials or politically connected individuals. The High Court stayed the implementation of the new regulations in November 2025, pending full hearing.

The stay provides temporary relief to prosumers but does not resolve the underlying structural tensions. The KSERC’s 2020 net metering regulations were already set to expire, and the new framework for 2025–2029 cannot be indefinitely delayed. Some form of revised policy will eventually take effect, and the broad direction, toward lower export credits, battery mandates for larger systems, and smarter metering, is unlikely to reverse.

The Kerala situation is also, as one analyst noted, a preview of what Pakistan’s solar sector is experiencing and what every Indian state with serious solar ambitions will face. Rajasthan paired its large-scale solar expansion with transmission upgrades and early battery integration. Gujarat’s 2025 policy framework has begun incorporating similar lessons. For states that are earlier in the solar adoption curve, the Kerala experience is a cautionary map of what not to delay.

The Honest Investment Case for Solar

None of this means rooftop solar is a bad investment. For most households, it remains one of the most compelling financial decisions available, particularly for smaller systems in states with clear net metering policies, strong sunlight, and stable regulatory frameworks.

What the Kerala crisis clarifies is that the “free solar” narrative has always rested on an implicit subsidy, one paid not by the government or the panel manufacturer, but by the millions of electricity consumers who cannot afford solar. Net metering in its purest form uses the grid as a free battery, a service that has real costs that were, for a long time, invisible to the individual prosumer.

As rooftop solar scales from a niche to a mass phenomenon, that invisibility is no longer sustainable. The grid has to be paid for. The engineering challenge of integrating millions of small generators has to be addressed. And the rules under which solar investors made their decisions will, inevitably, evolve.

Going solar in 2026 means understanding not just the panel cost and the subsidy, but the regulatory trajectory of your state, how long the current net metering rules are guaranteed, what the proposed changes are, and whether the economics still work if the terms shift. The sun is still free. Everything else is a policy decision.