The Sun powers (almost) everything
Posted May 22, 2008on:
When we talk about Solar Power, we are really talking about direct solar power. Using the sun’s heat to heat our homes or light to produce electricity. When you think about it, the Sun actually powers almost everything we do either directly or indirectly.
With the exception of Nuclear energy, all of our energy comes from the Sun. All of the oil, gas, and coal we burn is carbon based energy that was converted by photosynthesis and stored in short hydrocarbon chains, ready to be broken down by combustion and combined with Oxygen to form water vapor, CO2 and heat.
The bond between Carbon and Oxygen is so strong that a lot of energy is given off during the chemical reaction (combustion) when the atoms combine to form CO2. Conversely, to break the CO2 molecule back into Carbon and Oxygen requires a lot of energy. That is where the sun comes in.
Our Sun is about 93,000,000 million miles away. It takes light leaving the sun 8.31 seconds to reach Earth. The Sun’s diameter is about 870,000 miles, compared to Earth which is about 7,900 miles. The rate of the Sun’s energy striking Earth is called insolation. The average rate of insolation on the surface of the Earth is 250 watts per square meter. This takes into consideration the North and South poles, inclement weather and night time periods. When the sun is shining, the average insolation for any given location is about 1,000 watts per square meter.
Here is a little perspective. Currently, we (the human race) consume 15 TW (terawatts, one terawatt equals 1,000,000,000,000 watts) of power at any given moment. The energy from the Sun striking the Earth is 89,000 TW.
There are, of course, a few details. We cannot cover the entire surface of the Earth with solar collectors.
- Water covers 70 percent of our planet. Which means that 30 percent of the energy from the sun strikes land areas. 89,000 TW x 0.30 = 26,700 TW available.
- Mountainous terrain (too difficult to build on) covers about 10 percent of the land area, that leaves 90 percent available for use, or 26,700 TW x 0.90 = 24,030 TW
- Roughly 9 percent of the land area is Antarctica, which is uninhabited. 24,030 TW x 0.91 = 21,867.3 TW available for use.
- Lets assume that roughly 5 percent of the remaining land area would be able to be developed into solar power installations (includes roof top installations). 21,867.3 TW x 0.05= 1,093.4 TW
Then there is the matter of conversion efficiency.
- Currently Photovoltaic efficiencies (technologies actually in production) are at most 16 percent. 1,093.4 TW x 0.16 = 175 TW
There are 175 TW of practical solar power available for our use. This gives us more than enough room to grow. Additionally, some of the solar power that strikes the oceans and other water areas. This energy creates wind, evaporates water and generates waves. It is currently being used for wind turbines, hydro power and so on. There is also a big push to develop wave and tidal power. These applications would further enhance the amount energy we directly use from the Sun.
The long and the short of it; there is plenty of energy for everyone provided we use our technology to develop that potential and stop trying to blow each other up.