How to stop wasting clean energy | Tommi Eronen | TEDxLinz

The speaker emphasizes the critical role of heating and cooling for human survival, noting that extreme temperatures are becoming increasingly dangerous globally. Exposure to wet bulb temperatures of 35°C or more can be fatal within hours, even for healthy individuals, as the body can no longer cool itself. This issue is exacerbated by rising CO2 levels in the atmosphere, a reality that disproportionately affects the world's poorest populations. This grim outlook serves as a strong motivation for the speaker and their team to combat climate change. Currently, about 40% of energy-related greenhouse gas emissions come from heating. While clean electricity from wind turbines and solar panels is available, it often arrives at inconvenient times—wind is strong at night, and sun shines at noon when many homes are empty. This leads to energy waste, with turbines and panels being turned off because the grid cannot absorb the excess power. The core issue, therefore, is not energy production but energy storage. The speaker, Tommy, along with co-founder Marco, has dedicated 14 years to addressing this storage problem. Their journey began at Tumbra University of Technology, driven by a question about the viability of 100% heating self-sufficiency in Finland using large energy storage. Initially considering large water tanks, they realized that future clean energy storage would primarily involve electrical energy. With electricity, much higher temperatures can be achieved in storage, increasing the heat's value, which is crucial for industries needing clean steam. This realization led them to seek a cheap, inert, readily available material for energy storage, something so common it's often overlooked: sand. This marked the birth of the "sand battery" concept. After deciding to found a company, they began building physical test rigs to validate their computer models. A small demo at the speaker's grandparents' cottage showed only a 3% deviation from simulations, encouraging further development. They progressively built larger units: a 20-times larger unit in Dumbre, then a 20-times larger pilot plant, a 100-ton commercial system in Kanga, and finally, a 2,000-ton system in Bordon. The continuous effort to build the world's largest sand batteries is driven by the principle that larger heat storage offers better efficiency due to an improved surface-to-volume ratio, reducing heat losses. This approach also achieves economies of scale, maximizing their positive climate impact with finite resources. The sand battery operates by converting excess grid electricity into heat using resistors within a closed air loop, which then indirectly heats the sand. When energy is needed, the process is reversed, producing heat via a heat exchanger or steam with a steam generator. The sand battery is considered a valuable innovation because it is simple and reliable, with few moving parts. It's affordable, avoiding rare materials or complex components, and most importantly, it may have the lowest life cycle assessment emissions of any battery, a critical factor for terawatt-hour scale deployment. The speaker envisions a future where burning fossil fuels for heating is an exception, not the rule. Cities would utilize underground sand batteries to store excess wind and solar power, factories would run on stored heat, and even small communities would have sand batteries for resilience against price spikes or grid failures. The speaker believes that clean energy is already here, and choosing to waste it is choosing pollution. He concludes that crazy ideas, combined with patience and hard work, are the catalysts for change.