The complete conversion of deuterium nuclear fuel releases an energy content of 250 x 1015 joules per metric ton of deuterium. The quantity of deuterium in the world’s oceans is estimated at 4.6 x 10^13 metric tons. Deuterium present in seawater will yield around 5 x 1011 TW-year of energy. In the year 2011 the entire planet consumed around 16 TW-years of energy, which means that the energy content of the deuterium in seawater would be enough for 31 billion years of energy supply.
To give all 10 billion people expected to live on the planet in 2050 the level of energy prosperity we in the developed world are used to, a continuous average use of power of 6 kilowatts per person as is typical in Europe, we would need to generate 60 terawatts as a planet—the equivalent of 900 million barrels of oil per day.
In view of the enormous amount of deuterium available, it is important that we learn to use the D-D fusion reaction in the long term, and Thorium Ignited PACER Fusion is the most practical form of fusion today that is capable of economically supplying large Gigawatt levels of power safely without requiring decades of additional development.
The time since the earth first formed = 4.54 billion years.
The time until the sun burns out = 5 billion years.
The deuterium in the sea is capable of completely powering planet earth at a level of 60 Terawatts for 8.33 billion years (longer than the earth has existed or the sun will burn)