How much energy reaches the earth each day?
Answers
At the upper reaches of our atmosphere, the energy density of solar radiation is approximately 1,368 W/m2 (watts per square meter). At the Earth's surface, the energy density is reduced to approximately 1,000 W/m2 for a surface perpendicular to the Sun's rays at sea level on a clear day.
Each hour 430 quintillion Joules of energy from the sun hits the Earth. That's 430 with 18 zeroes after it!
In a single hour, the amount of power from the sun that strikes the Earth is more than the entire world consumes in an year.
In comparison, the total amount of energy that all humans use in a year is 410 quintillion Joules.
Clearly, we have a source of virtually unlimited (the sun won't die out for another 5 billion years or so) clean energy in the form of solar power — we're just not capturing it.
Renewables — including solar, wind, hydropower, biomass and geothermal — accounted for 13% of the total.
There's a big push for renewables, for obvious reasons. They don't increase our carbon footprint or exacerbate global warming, like burning fossil fuels does.
So if solar is so powerful, why are we still using so little of it?
A large part of the problem boils down to batteries. We haven't developed batteries that can store enough of the energy produced by solar efficiently enough so that it can provide reliable power. Essentially, we need batteries that are good enough to store the incredible amounts of solar energy that are constantly hitting the Earth so we can use it when it's not sunny.
Another issue is our ability to actually capture all of this energy from the sun. Researchers around the world in government labs and at energy companies are developing better solar panels every year, yet the typical array on people's houses today can only convert 14% of the energy it captures into electricity, according to Northwestern University. Lab tests have increased this past 20%, but this performance will likely take years to translate into actual market use.