When Marty McFly is attempting to time travel to 1885 with the help of the 1955 Doc Brown and the uncovered time machine from the mine, what is used to generate the 1.21 gigawatts of electricity for the flux capacitor? There is no lightning, and they are already out of plutonium.

Where did the power come from?


1 Answer 1


The flux capacitor is powered by Mr. Fusion. You can see it on the back of the DeLorean in the following photograph. We can assume Doc put some appropriate items into it (such as food and other materials like at the end of Back to the Future or beginning of Back to the Future Part II) and they then just need to get the DeLorean up to 88MPH which is done using a locomotive.

Doc: "You mean we're out of gas?"

Marty: "Yeah, no big deal, we got Mr. Fusion, right?"

Doc: "Mr. Fusion powers the time circuits and the flux capacitor. But the internal combustion engine runs on ordinary gasoline; it always has. There's not going to be a gas station around here until some time in the next century. Without gasoline, we can't get the DeLorean up to 88 miles per hour."

Mr. Fusion on the DeLorean

  • Gasoline may not have been around as a product, but I'm sure the Doc could have got some oil and refined it - he probably has enough knowledge to do that.
    – Tim
    Commented Jun 20, 2017 at 20:20
  • 4
    @Tim - He thinks it will take him a month to rebuild the injection manifold; I doubt building a cracking tower would take less time. What he should've known are the adjustments needed to run a combustion engine from 1985 on ethanol.
    – Mazura
    Commented Jun 20, 2017 at 22:17

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