How Much Hydrogen is Needed at What Cost to Save the Planet? To replace 100 million barrels of oil per day equivalent requires an investment of USD17 trillion, spent over 30 years from 2020 to 2050 or at an average rate of USD567 billion annually. (For comparison purposes, the total US defense budget in 2018 was USD618 billion) It follows that saving the planet won’t be cheap, but spending the money is better as an alternative to not having a livable planet. The report notes that this level of spending is lower than the USD25 trillion investment otherwise required to maintain such fossil fuels flows in future decades, and contrasts with a USD70 trillion investment for a similarly sized renewables-to-fuels strategy.