To estimate the required space to place a roof-top power plant, for each 1 Kw of solar power plant you need to have 100 square feet shade free area, preferably direct sunlight facing south, east / west orientation. E.g. if you need have a 3kw solar power plant, you may need to estimate the required space 3kw x 100 sqft = 300 sqft.

The subsidy program cost for the standard power plant is estimated based on the concrete flat roof. Other than the flat roof cost may verify depend on the site conditions. If the consumer roof is not flat roof, the consumer is responsible for the additional structural cost. Usually if the roof is covered by roofing sheet these are the additional work need to carry out, e.g. need to construct roof-access, need to fabricate a ladder, on the top of the sheet need build a walk- way, for the sun light direction a frame has to fabricate to place solar panel.