Since there is almost an unlimited supply of free solar energy to our planet why is it not the primary source of generated electricity?

Plants use only 0.2% of solar energy on average. Man has been pushing the envelop on increasing this utility as light from sun comes in a huge spectrum, each holding a portion of the total solar power (power = energy in a unit of time) that Earth receives.

On average, one meter square of Earth's surface receives equivalent of 1400 watts during day. This will translate into around 700 watts per sq. m as we receive no solar power during night.

Current solar power cells translate up to 23% of solar power into electric energy but the small ones you put on your rooftop usually have an efficiency of just 15%-18%. High tech solar cells such as the ones on satellites have efficiency of up to 50%.

Solar power costs around 5 times the current rate you pay to your utility company. That's the real hindrance in its adoption.

It is the primary source of all our energy.

Only nuclear power did not have its origins in the capture of solar energy.

Wind and hydroelectric are both created by the sun making differential heating.

Coal, wood etc are created by solar energy being captured by plants.

So solar energy capture has always been our primary source.

But the benefit of coal ( or oil) is that it is concentrated in one spot. Because it has been pre stored we can use it at any time of the day or night or of the year. Not just when it is currently available.

As it has been laid down over millenia we can use far more energy than is currently available and we can do so with minimal climatic consequences.

If we were able to absorb large amounts of energy from the sun directly then the other effects that it currently performs would diminish.

So there would be alterations to wind, rain, thermal gradients etc.

And these may be far more deleterious to life on earth then merely burning the coal.

Mostly it is difficult to manage. Despite your statement; sources such as wind or sloar, are limited. There are factors like best location, and seasonal changes. Then there is cost, since they would need the supporting cables bringing the power to the grid already in use. At best the alternate sources simply can not produce the amount of electric consumed by other methods.

I would like to see it used more myself, it is and under developed and cleaner source. But realistically it would help; not replace.

I think we could use solar energy from yrs but marketing.politics.economics.corruption stopped this.

It is very difficult to get 250W/m² using reasonably priced solar cells. I have never heard of 1400W/m². More like 1kw/m² from the sun. You need batteries and an inverter to convert to 110VAC. Cloudy days notably reduce output. Solar energy requires batteries and inverters (not cheap). It costs about 20,000 bucks to get off the grid. Solar is great for heating water and green houses but for refrigerators and A/C it isn't that grand

Solar Power Design Manual : http://solarpower.duebq.com/?tkv