CO₂ Savings Calculator

Why our number is smaller than everyone else’s

Most solar carbon calculators apply a generic emission factor, usually somewhere between 500 and 700 grams of CO₂ per unit. Run a 10 kW Lahore system through one of those and it will tell you the system avoids around nine tonnes a year.
The real figure is about 4.9 tonnes.
The difference is not an error in their arithmetic. It is that Pakistan’s electricity grid is considerably cleaner than the ones those factors describe. In 2025 it emitted about 347 grams of CO₂ per unit generated. India’s grid emitted 670. Bangladesh’s 696. The world average was 458.
Hydro and nuclear are the reason. A substantial share of Pakistan’s electricity comes from sources that emit almost nothing while running, and that pulls the national average down well below its neighbours.
So every unit your panels produce displaces a relatively clean unit – which means the carbon saving per unit is genuinely smaller here than it would be in Delhi or Dhaka. Using their number to describe your system would overstate the saving by roughly ninety per cent.

The grid is getting cleaner, and that shrinks this number

Pakistan’s grid carbon intensity has fallen steadily:

• 2017 – 486 grams CO₂ per unit (KWh)
• 2023 – 401 grams CO₂ per unit (KWh)
• 2024 – 374 grams CO₂ per unit (KWh)
• 2025 – 347 grams CO₂ per unit (KWh)

That is a drop of nearly thirty per cent in eight years, driven by more hydro, more nuclear and more renewables in the mix.
It has an odd consequence for this page. As the grid cleans up, each solar unit displaces less carbon, so the number this calculator produces will keep falling year after year even though nothing about your system has changed.
That is not a problem to be worked around. A shrinking figure here means the thing it measures against is improving, which is the outcome everyone wanted. We update the factor annually and print the year it applies to, rather than quietly leaving an old number in place because it flattered the result.

What the equivalents mean

The calculator gives two comparisons, and they are not equally solid.
Petrol is exact. Burning one litre of petrol releases about 2.31 kilograms of CO₂. That is chemistry the carbon in the fuel has to go somewhere – so when the calculator says your system is worth 2,100 litres of petrol a year, that comparison holds up.
Trees are a rule of thumb. A mature tree is often quoted as absorbing around 21 kilograms of CO₂ a year, but the real figure depends on species, age, climate and how the tree is measured, and it varies by a factor of several. Read the tree number as an illustration to make the scale imaginable, not as a measurement.
We include both because one gives you a solid anchor and the other gives you a picture. Mixing them without saying which is which is how carbon claims become meaningless.

What this does not count

Manufacturing. Making panels, inverters and batteries emits carbon. A solar system typically pays back its manufacturing emissions within the first couple of years of operation and then runs carbon-negative for the remaining twenty-plus — but the calculator above measures avoided grid emissions from day one and does not net off the embodied carbon.
Batteries. If your system includes storage, the manufacturing footprint is considerably larger, and round-trip losses mean some of what you generate never reaches a load.
Grid changes over 25 years. The lifetime figure holds today’s grid intensity constant across the whole period. Given the trend above, that almost certainly overstates the long-run total – the honest direction of the error, and worth stating rather than hiding.
Degradation is included. Panels lose roughly half a percent of output a year, and the 25-year figure allows for it.

Is this the right reason to buy solar?

Worth being straight about it: in Pakistan, the financial case for solar is much stronger than the environmental one.
A 10 kW system in Lahore avoids about five tonnes of CO₂ a year. That is real and it is worth having. But the same system takes a large amount off an electricity bill that has been rising for years, and for most households that is the argument that actually settles the decision.
If carbon is your main motivation, the honest advice is that it is a legitimate reason and the numbers on this page are the ones to use – just use these numbers rather than the inflated ones, because a case built on an overstated figure falls apart when someone checks it.
And if the finances are what convinced you, the carbon saving is a genuine bonus rather than the point. Either way it is the same system.