How does a PM-KUSUM solar pump compare cost wise over the years to running a diesel pump?

The core economic case for a PM-KUSUM solar pump against diesel is that you pay a one time farmer share, often part funded by loan, and after that the running fuel cost drops close to zero, while a diesel pump keeps burning fuel every single time you irrigate, year after year. Diesel cost is a recurring drain that rises with fuel prices, whereas the sun is free, so over the life of the system the cumulative diesel you would have spent typically dwarfs the upfront solar share, which is why many farmers find solar pays back within a few years if the pump is well sized and well used. Maintenance during the warranty period is largely covered, and there is no electricity bill on a standalone pump. The caveats that decide whether the maths works for you are honest sizing and usage. If you oversize the pump, your share and any loan go up for no extra benefit, and if you barely irrigate, the savings accrue slowly. A solar pump also only runs in daylight, so it suits farmers who can shift irrigation to daytime, ideally paired with drip to use the water efficiently. So compared to diesel the long run cost strongly favours solar for a regularly used, correctly sized pump, but the actual payback depends on your diesel spend, your share amount, and how much you irrigate. Confirm your benchmark cost and farmer share on the PM-KUSUM portal so you can compare it against your own diesel spending.