Net Billing in Pakistan: Recalculating a Rooftop Solar Business Case

Pakistan's move from net metering to net billing on 9 February 2026 did not just lower a number. It changed the shape of the calculation. A rooftop business case that used to need one price now needs two, and most models circulating in the market have not caught up. The background to the rule change is in net metering in Pakistan.

This article is a method, not a price list. It does not assert a current tariff, export rate or payback period, because those are site-specific and reviewable. What it does is show you where the numbers go, so you can tell a sound proposal from a stale one.

One roof, two prices

Under the repealed framework, generation had a single effective value. A unit exported at noon cancelled a unit imported at night, so both were worth your retail tariff and it barely mattered when you used your own output.

Under net billing that collapses into two separate questions:

• A unit you consume on site avoids a purchase at your applicable consumer tariff — including fuel adjustments, quarterly adjustments, surcharges and taxes, which for many consumers are a substantial share of the bill.
• A unit you export earns the national average energy purchase price.

So the return on a system is no longer a function of how much it generates. It is a function of how much it generates *and* when, measured against when you actually use electricity.

The three numbers your proposal must contain

Ask any installer for these explicitly. A proposal that cannot supply them has not done the work.

1. Estimated annual generation, with assumptions. Irradiance figure, system losses, expected soiling, shading, and degradation over the warranty period. A generation number with no assumption set attached is marketing. The mechanics of that decline are in solar panel degradation and lifespan.

2. Estimated self-consumption share. What proportion of that generation your site will use as it is produced. This is now the most important single input, and it is the one most often left unstated. It should be derived from your actual consumption pattern, not a national average.

3. The two prices, each dated. Your effective import tariff from a recent bill, and the export rate applying on your application date, with the date recorded. If a bidder quotes an export rate without saying when they last checked it, that is the question to press.

From those three, the structure of the calculation is simply: generation multiplied by self-consumption share, valued at your import tariff; plus the remainder, valued at the export rate. Everything else — finance cost, maintenance, inverter replacement — sits on top of that base.

Why sizing changed direction

Under net metering, a larger array was close to strictly better: surplus carried the same value as consumption, so overbuilding cost you capital but rarely wasted output.

Under net billing, every unit you export rather than consume is monetised at the lower price. Past a certain point, additional capacity earns the export rate alone — and whether that clears the cost of the extra panels is a real question rather than an assumption.

The practical consequences for a Pakistani buyer:

• Size to daytime load first. The array that covers what you actually use while the sun is up is the part of the system doing the heaviest lifting.
• Move what you can into daylight. Pumping, washing, pre-cooling, batch production, irrigation. Shifting load raises self-consumption without adding hardware — the cheapest return available. Agricultural users in particular should read solar tube wells in Pakistan.
• Match the technology to the pattern. A commercial site running through the working day is close to the ideal case; we cover that in commercial and industrial solar in Pakistan.
• Be honest about evening-weighted demand. A household empty until 7pm cannot self-consume much of a midday peak, whatever the array size.

Where storage does and does not help

Storage raises self-consumption by moving generation into the hours you actually use it. Under net billing that is worth more than it used to be, because the gap between the consumption value and the export value is what storage captures.

That does not make it automatic. A battery adds capital cost, has round-trip losses, and has its own replacement cycle — the mechanics are in battery degradation and cycle life. It earns its place where the arithmetic of your own pattern says so, and not otherwise.

Treat backup and savings as two separate purposes. A system bought for continuity during outages is being judged on a different test from one bought to lower a bill, and conflating them is how buyers end up disappointed with equipment that is working exactly as designed. We separate those cases in solar battery backup in Pakistan.

A warning for existing net metering holders

If you hold an agreement executed under the repealed 2015 regulations, you retain the old rate and mechanism until that agreement's term expires. That is a genuinely valuable position.

It is also conditional. The protection is forfeited where the generation facility is materially modified in a way that changes its maximum electrical output. Adding capacity to a grandfathered system is therefore a regulatory decision before it is a technical one, and the downside is asymmetric: the additional generation is unlikely to be worth losing the old rate across your entire installation.

Get your distribution company's written position before you commit. An installer's verbal reassurance carries no weight in a billing dispute.

How to read a payback claim

Most disappointing solar outcomes trace to a business case nobody stress-tested. Three questions do most of the work:

• Which regulations does this model assume? If the answer is net metering, the model is describing a framework repealed in February 2026.
• What self-consumption share does it assume, and why that number? If it cannot be justified from your consumption pattern, the payback figure resting on it is decorative.
• What happens if the export rate falls further? The rate is an average purchase price under periodic review. A case that only works at today's figure is carrying a risk the buyer has not been told about.

A proposal that survives those three questions is one you can act on. Our full procurement framework is in comparing solar quotations in Pakistan, and the prior question of whether to proceed at all is in is solar worth it in Pakistan.

Get the determination, not the brochure

Export rates, tariff determinations and settlement rules move faster than most buyers can track, and each one changes the maths on a system you may be about to buy.

• Follow our continuing Pakistan energy coverage for determinations as they land.
• Browse the solar energy desk for sizing, equipment and project economics.
• Subscribe to The Energy Edit — free, independent reporting, start here.

Are you an installer who states scope, assumptions and dates plainly? Explore partnership with Arcnex Energy.