A new report from the World Economic Forum’s Global Future Council on Energy seeks to assess the signs of whether there will be a gradual or a rapid “energy transition.” In other words, will global economies switch from fossil fuels to renewable energies slowly or all at once? The report takes for granted that the world will transition to using renewable energies—mainly solar and wind—by the middle of this century. However, the report omits a crucial piece of technological development from its forecast: batteries. The few times batteries are mentioned, they are generally referred to as “storage,” because batteries are essentially just storage containers for electricity or power. The report draws conclusion like, “Even as penetration [of renewable power] rises, technologies such as storage and demand response are likely to make higher levels of penetration cheaper.” This is serious flaw with the conclusions and forecasts because we do not yet have that technology to make better and cheaper batteries, and we don’t know when or if we will. Solar and wind offer the promise of a plentiful, clean power. Yet, we still need to improve the efficiency of their power production, and we need to find a way to effectively store the power they produce. The wind does not always blow, and the sun does not always shine. If and when we find the ability to store the excess power created by wind and solar (and hydro and nuclear and anything else), we will be well on our way to much cleaner energy production. Right now our batteries cannot store that kind of power over the long term, regularly recharge, and last for years. Someday, someone will invent the new generation of batteries that will revolutionize energy use. When they do, the transition to renewable energy will surely be rapid. This breakthrough could be as close as a few years away. Or perhaps it won’t come for decades. However, making assumptions about the speed at which global economies can transition away from fossil fuels without a revolution in battery technology is just wishful thinking. Investment and innovation in battery and energy storage technology is still needed before we can transition away from fossil fuels. I’m an energy historian writing about how governments and energy businesses interact globally. My work looks at how policy, wars, diplomacy, the stock market, oil pricing, and innovation impact the future of energy. I am the president of Transversal Consulting, a firm that provides consulting on energy and geopolitics to a range of industries. I am also a Senior Fellow at the Atlantic Council. My book, Saudi, Inc., (Pegasus Books, 2018) covers the history and policy of Aramco and Saudi Arabia.