In 2035, the energy consumption of all the people on our planet is estimated to
ID: 3280921 • Letter: I
Question
In 2035, the energy consumption of all the people on our planet is estimated to be 2.2 x 1014 kWh per year (1 kWh = 1000 J/s * 3600 s = 3,600,000 J). We need to consider how to move to clean renewable energy to meet these demands. One option is solar power. Solar panels convert light energy from the sun into electrical energy. How big an area do we need to cover with solar panels (that are 25% efficient) to meet the energy needs of the world in year 2035? The power from the sun shining on the Earth is 1.2 kW/m2. We would build it in the sunniest place on earth that gets 4000 hours per year of sun. (From your answer for the area, if the solar panels covered an area that was shaped like a square, what would one of the sides of the square measure in length?).
Solar panels aren’t without their problems. You need to keep them clean (which can be challenging in a desert), they are currently expensive to make and the processes used to make them are not very green at the moment.
Explanation / Answer
Power output
Pout=E/t=2.2*1014/4000=5.5*1010KWH
Input power f
Pin=Pout/efficency=5.5*1010/0.25=2.2*1011 KW
Area of solar panels
A=P/I =2.2*1011/1.2
A=1.83*1011 m2
b)
Area of a square
A=L2
Length covered by solar panels
L=sqrt(A)=sqrt(1.83*1011)=4.28*105m or 428.km