Off-world Power Generation

Given:

earth to moon: 238,900 miles
there are four lagrange points that provide constant sun exposure at predictable locations
l1 to earth/moon: 1 million miles
the sun primarily produces visible light (not microwaves or gamma...)
laser transmission is more efficient than microwave, except where earth's atmosphere interferes
current status: A Gigawatt-range microwave system would require launching 80,000 tons to orbit (prohibitively expensive)
Solar cell efficiency

Basic premise:

<Earth> <- <Earth-orbit satellite> <- <Earth's moon> <- <Earth-Sol Lagrange-point solar array>

Laser transmit antenna in space: 1 meter diameter per GW Receive: Several hundred meters across

Targeting the energy requirement of NYC:

Power is measured in Newton-meters per second or Joules per second or Watts.
3000 trillion BTU in 2016 = 3000 btu / 365 days = 3.4E+11 btu/hr = 1.0036680479e+11 watts = 100 GW
A 10 MW photovoltaic grid connected power plant commissioned at Ramagundam is one of the largest solar power plants with the site receiving a good average solar radiation of 4.97 kW h/m2/day and annual average temperature of about 27.3 degrees centigrade [ info]
The final yield (Y F) of plant ranged from 1.96 to 5.07 h/d, and annual performance ratio (PR) of 86.12%. It has 17.68% CUF with annual energy generation of 15 798.192 MW h/Annum.