Space Based Solar Power (SBSP) is an economical way of delivering power to remote locations or areas isolated by war.
To deliver power to a certain places in Iraq and Afghanistan it costs well over $1USD/kWh, not mention the loss of human life.
The pentagon is seriously considering SBSP as a viable way to deliver power to not only these locations, but other places of humanitarian interest.
The technology to deliver and deploy SBSP payloads (for it will take many deployments) already exist. Improvements will undoubtedly be made, and with the hopeful completion of
NASA's Ares V cargo launch vehicle SBSP will be economical for the rest of us. (under 20cents(USD)/kWh.)
As for the microwave radiation concern, it is not as scary as commonly depicted. (Can anyone recall the tale of the discovery of microwave radiation as a cooking tool--something to do with a Snickers bar melting in a pocket? [Who the heck carries a Snickers bar in their pocket?]) If the size of the receiving antenna is increased, the power of the transmitted signal may be decreased on a W/m scale. With a transmitter that can 'dither' the signal over a rather wide swath one can abate errors associated with tracking, solar anomalies and human error.
Military applications, however, are not
quite as concerned with stray microwave beams.
Do not forget that SBSP is exposed to the sun for 24 hours--no interruptions!
On another note the Japanese are working on developing devices that may convert solar energy to transmittable energy in upwards of 40% efficiency by converting
solar power to laser.