Solar Generation Calculator

Around 4 units a day averaged over the year in north India — roughly 1,350 to 1,650 units per kWp per year depending on the site. Summer days run well above the average and December-January fog and winter sun run below it, which is why annual figures are the honest way to plan, not one good May afternoon.

Cooler panels are indeed more efficient, but winter sun is lower, days are shorter and north-India fog can wipe out whole mornings. The irradiance loss far outweighs the temperature gain, so December generation is typically the year's lowest even though panel efficiency is at its best.

Soiling is the big one — dust costs several percent even with monthly cleaning, more near Delhi NCR. Then shading (even a parapet line at 4 pm), inverter clipping if the DC-AC ratio is aggressive, cable losses, downtime nobody noticed, and module degradation of roughly half a percent a year after the first-year step. A generation guarantee in your EPC contract is how you make these someone's problem.

It is a fair planning band for a well-designed, unshaded plant in Punjab, Haryana, Delhi NCR or western UP. A real proposal replaces it with a simulation using satellite irradiance data for your coordinates, your actual roof orientation and tilt, and a measured shading survey — that number is what a lender will accept, and it is the one we quote against.