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What is the main source of energy at Earth's Surface Please helP!?

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From the sound of your question you are asking about natural energy sources rather than man-made ones such as nuclear power, or the burning of fossil fuel.
If so, the main energy source of the planet is heat from the sun. At the radius of the earth's orbit, the solar power flux is 1.35kW/m^2. On the surface of the earth it is considerably less, mainly because half of the time (on average) any point on the surface is turned away from the sun (night-time). Other effects are the spreading of the energy over a greater area because of the latitude of the location, and of course, the effect of the weather !!
The mean solar power flux on the surface of the earth is 50-350 watts/sqm (averaged over day and night) (~130W/m^2 in the UK)
By comparison, geothermal power (power coming from the interior of the earth) is only 0.06 W/m^2 (0.2% of the solar power flux).
If your question is about alternative energy sources you might be interested in wind power. Calculating this in terms of power per unit area of the earth's surface could be tricky, but you can take a useful short-cut. Wind power is driven by the sun, so it cannot exceed half of the free-space solar energy flux, or 0.675W/m^2 - this would theoretically be available if all of the power received by the earth from the sun were to be converted into wind power ! (Half because half of the earth's surface is in shade at any time). However, between 30 and 40% of the solar power is re-radiated by the earth, so you must bring this down to something like 250W/m^2 maximum. Of course, even if this amount of wind power were produced, only a tiny fraction of it could be harvested.
The practical usefulness of wind turbines depends on their being located in particularly windy places where wind power is naturally concentrated.

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atomic power plants

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The Sun.

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