(From Land Art) According to the US Department of Energy (Energy Information Administration), the world consumption of energy in all of its forms (barrels of petroleum, cubic meters of natural gas, watts of hydro power, etc.) is projected to reach 678 quadrillion Btu (or 715 exajoules) by 2030 – a 44% increase over 2008 levels (levels for 1980 were 283 quadrillion Btu and we stand at around 500 quadrillion Btu today in 2009).
I wonder what surface area would be required and what type of infrastructural investment would be required to supply that amount of power by using only solar panels. To create fuel that can be used in vehicles and equipment I am assuming that some of the electricity generated would be used to create hydrogen. We should all start wondering about these things since we will have really no other choice* by the turn of the next century.
So to find this out we start with the big number 678,000,000,000,000,000 Btu.
Converting this to KW•h [1 Btu = .0002931 kW•h (kilowatt hours)] makes 198,721,800,000,000 kW•h (199,721 TW•h). This is for an entire year. As a comparison, the average household uses approximately 18,000 kW•h per year (1/11 billion of the total world usage).
We can figure a capacity of .2KW per SM of land (an efficiency of 20% of the 1000 watts that strikes the surface in each SM of land).
So now we know the capacity of each square meter and what our goal is. We have our capacity in KW so in order to figure out how much area we’ll need, we have to multiply it by the number of hours that we can expect each of those square meters of photovoltaic panel to be outputting the .2KW capacity (kilowatts x hours = kW•h).
Using 70% as the average sunshine days per year (large parts of the world like upper Africa and the Arabian peninsula see 90-95% – so this number is more than fair), we can say that there will be 250 sun days per year at 8 hours of daylight on average. That’s 2,000 hours per year of direct sunlight.
Therefore, we can multiply each square meter by 2,000 to arrive at a yearly kW•h capacity per square meter of 400 kW•h.