Question

In 2015, the world population was estimated at approximately 8.4 billion people. Also in 2015, the annual per capita gross domestic product (GDP) was approximately $9,350, and approximately 0.38 W-year of energy was expended per dollar of GDP. The world population is projected to be approximately 10 billion by 2050. Assuming the world’s standard of living increases by 1.6% per year and energy efficiency increases by 1% per year, how much power will the world consume by 2050 in TW? How much more efficient will we be in 2050 at using energy compared to 2015? What are these two numbers if energy efficiency increases by 2% per year rather than 1%?

Answer 1

First find the GDP in 2015 and 2050. Note that population was 8.4 billion in 2015 and per capita GDP was $9350. Hence GDP was 9350 x 8.4 billion = $78540 billion or $78.54 trillion. In that manner, energy consumption is 0.38 x $78.54 trillion = 29.85 TW.

In 2050, the per capita GDP will be 9350x(1+1.6%)^(2050-2015) = $16296.39 and so with a population of 10 billion, the GDP will be $16296.39 x 10 billion = $162.96 trillion. Efficiency efficiency increases by 1 percent so we would expend around 0.38 x (1 - 1%)^(2050 - 2015) = 0.267 W per year of $1 or 0.267*$162.96 trillion = 43.51 TW.

Hence the power that the world would consume by 2050 in TW is 43.51 TW. We would have increased the efficieny from 0.38W per year to 0.267 W per year of each dollar of GDP.

Now if the energy efficiency increases by 2% per year rather than 1%, then we would expend around 0.38 x (1 - 2%)^(2050 - 2015) = 0.187 W per year of $1 or 0.187*$162.96 trillion = 30.47 TW. Hence the power that the world would consume by 2050 in TW is now 30.47 TW. We would have increased the efficieny from 0.38 W per year to 0.187 W per year of each dollar of GDP.