written 2 March, 2025
published 9 March, 2025
Living systems store energy for long term survival. They gather energy from the environment when it is available, use what they can in the moment, and store the excess to live until they can gather more energy.
Energy from the breakdown of food is stored internally as various carbohydrates, proteins, or fats, allowing life to survive in situations with extreme variations in available environmental energy. Every life form on Earth synthesizes adenosine triphosphate (ATP) as the primary energy carrier for use in living cells, demonstrating the unity of life. This stored energy carrier powers the essential cellular processes when released.
Animals collect and store food externally to achieve the same ends. For example, bees produce and store honey from collected seasonal plant nectar, which nourishes the whole hive throughout the year. Humans began wide scale food storage with the shift from hunter gatherer to agriculture. Improving food preservation, creating greater storage life, has defined human "progress". The relatively recent advent of refrigeration massively expanded the quantity of food preserved, but with the added cost of increased energy consumption, primarily electricity.
The first commercial electrical system was established in 1880. Until fairly recently, all electricity consumed was produced "just in time", because once electricity has been generated, it must be used immediately. Production has thus been designed to follow the varying load, and economic growth has been constrained by the amount of electricity able to be produce in any given moment. Despite that extreme limitation, electricity has transformed our entire economy, even though humanity stores relatively little of the energy we consume each day.
For the last several centuries, most of our energy has been generated from fossil fuels, sunlight transformed by living organisms, and then geologically sequestered for millions of years. Our consumption has increased to the point where all the cheapest, easily available fossil fuels have been burned, and the waste from this combustion is relentlessly changing the environment to conditions never before encountered by humans, risking economic collapse, possibly even human extinction. This is the real push for the shift to renewables, not a hoax or a fashion statement, but the constraints of a finite energy source on a finite planet.
However, as critics have pointed out, renewable energy is intermittent, not steady state. It must be collected when available, not manufactured. Like life forms before us, we need to develop energy storage at a scale that can support our needs, if we expect to survive much longer with the lifestyle we now take for granted. Even if we reduce our consumption, acknowledging our real needs take much less energy than our current profligate culture, there are three cycles that must be addressed: day/night, summer/winter, and year-to-year.
Battery technology has made amazing advances in just the last few decades. Consider the impact of battery powered hand tools, cell phones, and computers. Even at grid scale, new and larger batteries are being installed each month, with declining costs and improved chemistries. Electric vehicles, despite the best efforts of the current president, are becoming mainstream, and will replace fossil fuels the same way cars replaced horses. Even if the US is tries to be obsolete on the planet, the rest of the world is moving forward.
Batteries are a good solution for the day/night cycle. They already help store midday solar peaks for evening power usage. An EV can last for days between charges. However, while a long range EV might have as much as 100 kilowatt hours of storage capacity, the City of Ukiah consumes 300 megawatt hours each day, 3,000 times as much. And that is just 1/5 of the power consumed in Mendocino county each day. While grid scale batteries this large are being built, they are not viable for dealing with the summer/winter cycle, especially not at grid scale.
A solar array output can vary from almost nothing on a grey winter day to more than 10 times as much on a sunny summer day. Large hydroelectric dams have similar variability, ranging from flooding in the spring to droughts in the fall. The challenge is to be able to capture all this energy when it if freely available, and store it for usage throughout the year.
This must be existing technologies that have already been demonstrated to work, energetically efficient, scalable to the quantities needed, with stable storage for months or years, and economically affordable. Fortunately, candidates do exist.
