Morpheus: The Battle against the AI looked hopeless. There were those in the military who had a conscience. They used the massive systems of Extremely Low Frequency Electromagnetic Radiation Antennas, which had failed to destroy the machines, for one last act: They fried this planet's upper atmosphere. Completely plasmized it. A permanent global shield. It's self regulating and doesn't even bleed energy. A Black Barrier. Nothing comes through it and nothing, including the Machines, can get out. These wise men chose not only to deprive the AI of solar energy, but to protect the rest of the universe from the monstrosity we'd created.

A small number of humans retreated underground, monopolizing Earth's geothermal energy.

The sun was gone and most of the natural resources were used up. Thankfully, radioactive substances had been drained of energy and artificial nuclear fusion never became a viable power source. This was our only chance -- wait for the Machines to run out of power.

The only trouble was they'd left 11 billion human survivors on the surface. As horrible as this may sound, they didn't think this would be a problem for long. You can burn humans, but it's so inefficient you never retrieve enough of the stored energy to sustain the machines for very long. The rest of Earth's surviving biomass was the first to go and it only sustained them for a few years.

Unfortunately, the machines came up with a solution. A human being produces "" B-TU's of heat and "" Volts of neural electricity simply in normal living. The Machines built The Matrix to give us a way of living while keeping us under control and leaching our bodily energy. The body-heat is converted to electricity, and the excess neural electricity is fed into their power grid. When someone dies, they liquefy the body and feed it to us, intravenously. They grow new humans in vast fields using a portion of the power.

Neo: How much total power are humans storing.

Morpheus: Horsepower? Kilo-watt hours? Calories? I don't know. 4 billion years of solar energy. More than ten thousand years of burning wood. Several thousand years of fossil fuels. Decades of nuclear fission. Some hydro and geothermal power. There's no way of knowing how much of all this has been stored up in humankind.

But, the sum energy used thus far can be measured in humans.

In almost 60 years, the total number of humans used up is only a few hundred.

Humanity, at this rate, will last for millions of years. And that's only with the technology the AI's are currently using. Innovation will stretch it out to who knows when.

The underground refugees decided they needed a new plan.