Here are cost numbers for the solar power energy project that we know, and that have to be determined.

Low-G, Closed Ecology remanufacturing structure in LEO
See discussion at (url for space habitat).
$ 3  Billion
5 Gigawatts of solar power cells @ 16 Kw/Kg 312,500 Kg
312,500 Kilograms @ $10,000 per Kw to LEOnbsp; $3.125 Billion
Recycled materials plus payload for 4 missions – total 320 metric tons
Includes ion engines and parts for microwave transmitters
This is a rough estimate – actual mass needed to be determined by feasibility study
$2. Billion
Cost of fuel for ion engines to boost solar power cells from LEO to GEO
Fuel costs are 1/7th the cost of chemical engines,
Power to ion engines from solar power panels manufactured in LEO

3.125 Billion / 7
$ 450 Million approx.

Cost of ion fuel for the mass of solar power panels and the microwave transmitter
to GEO from LEO if they mass10 times the solar cells
This is a rough estimate – actual mass needed to be determined by feasibility study

$ 4.5 Billion

Cost of Rectenna land and high power connection to grid $ 1 Billion

Salaries for 10 space workers and $2 million each per year plus $10 million for Earth infrastructure are the only other costs, there is very little cost for re-supply to the remanufacturing center.  There are no fuel costs, nor any hazardous cleanup costs. There will be maintenance costs to be determined.

Since at 5 cents/ Kilowatt hour you will get approx $2 Billion per year in revenues you could re-coup your initial investment in 10 years upon reaching full construction.  The key items will be the actual determination of costs by a feasibility study noting the importance of getting revenue in as short a time as possible.