Why Sand Battery produces almost ZERO emission during the entire lifetime? 💨 (SAND - Part 3)

In Part 2, I demonstrated how the Sand Battery can

save up to 50–60% on energy costs

in industrial applications and tackle the solar "duck curve" while enhancing grid stability, drawing lessons from events like the Spain blackout on May 2, 2025.

Now, in Part 3, I’ll focus on the almost zero-emission aspect of the Sand Battery, a key pillar of its value proposition in the fight against climate change. We’ll break this down into two sections: first, exploring the zero-carbon-emission operation of the Sand Battery, and second, critically examining the "almost" part, where minimal emissions arise from auxiliary components and construction. Enjoy learning!

1. Zero Carbon Emission Operation: Is It Too Good to Be True?

The Sand Battery boasts a zero-carbon-emission operation throughout its lifetime, a bold claim that might sound too good to be true. But it’s not, let me explain.

Step 1: Charging with Solar Panels

The Sand Battery is designed to be charged using renewable energy sources, primarily solar panels. In Vietnam, where solar capacity is rapidly expanding, factories can harness excess solar energy during peak production hours (e.g., 10 AM–2 PM, as discussed in

Part 2

) to heat the sand block. Solar energy DC generation produces no carbon emissions during operation, ensuring that the charging phase is entirely carbon-free. By integrating with solar systems, the Sand Battery leverages clean energy to store thermal energy, setting a sustainable foundation for its operation 👌🏻

(On a side note, we can absolutely use DC instead of having another AC Inverter. That's topic for another day).

Step 2: Storing Energy with No Carbon Output

Once charged, the Sand Battery stores thermal energy in the sand block with remarkable efficiency (98% charging efficiency). This storage process is passive, it relies on the natural insulating properties of sand and our advanced insulation design to retain heat, with a heat loss of only 5–10% per day. Unlike traditional battery storage systems that may require active cooling or chemical reactions (e.g., lithium-ion batteries), the Sand Battery’s storage mechanism involves no moving parts, no chemical processes, and thus no carbon emissions. The energy is preserved within the sand block without any operational carbon footprint, making this phase truly zero-emission 👌🏻

Step 3: Extracting Heat Using a Lithium Battery-Powered Fan

To extract the stored heat, air is circulated through the Sand Battery using a fan, with an extraction efficiency of 90%. To maintain a zero-carbon operation, we power the fan and associated electronics using a lithium battery, which is charged via solar energy during the day. This ensures that the electricity used for heat extraction produces no carbon emissions during operation. For instance, a relatively small 15kWh lithium battery, recharged daily by solar panels, can run the fan for the 8-hour cycle needed in our fluid bed dryer use case, keeping the extraction process carbon-free. By decoupling the fan’s energy source from the grid and relying on solar-charged batteries, we eliminate operational emissions in this phase as well 👌🏻

So you see, together these 3 steps operates with zero carbon emissions throughout its lifetime, from daily cycles to long-term use. This isn’t too good to be true; it’s a carefully engineered system designed to maximize sustainability, and it's just Science!

2. The "Almost" Part: A Critical Look at Minimal Emissions

While the Sand Battery’s operation is zero-carbon, we’re committed to transparency about the "almost" part. There is minimal emissions arise outside of its operational phase. These emissions stem from two key areas: the manufacturing of the lithium battery used to power the fan and the construction and assembly process of the Sand Battery itself. Let’s examine these critically.

Emissions from Lithium Battery Manufacturing

As noted, we use a lithium battery to power the fan and electronics during heat extraction, ensuring zero operational emissions. However, the production of lithium batteries generates a carbon footprint. Based on industry data, manufacturing a lithium battery emits between 3 kWh and 15 kWh of carbon equivalent per kWh of battery capacity, depending on the energy mix used in production (e.g., fossil-heavy vs. renewable-heavy grids). For our 15 kWh battery, this translates to a one-time emission of 45–225 kg of CO2 equivalent. Over the Sand Battery’s 20-year lifespan, this initial footprint becomes negligible when amortized per year 👌🏻

Emissions from Construction and Assembly

The construction and assembly of the Sand Battery also contribute to its "almost" zero-emission profile. During this phase, we use three-phase electricity to power heavy tools for tasks like welding, cutting, and assembling the sand block container and piping system. In Vietnam, where the grid still relies on a mix of coal and renewables, this electricity usage generates carbon emissions. For a typical 1-ton Sand Battery prototype, assembly might consume ~50–100 kWh of electricity, emitting approximately 25–50 kg of CO2 equivalent (assuming Vietnam’s grid emission factor of 0.5 kg CO2/kWh, trade.gov, 2024). This is a one-time cost, and we’re can minimize it by transitioning to renewable-powered facilities for future production 👌🏻

When combined, these factors over its 20-year lifespan, this equates to just ~100–300 kg CO2 per year, a fraction of the emissions from traditional heating systems (e.g., gas boilers emit ~200 kg CO2 per MWh of heat). This "almost" part is a small price for the Sand Battery’s >95% emission reduction, making it a transformative solution for Vietnam’s industrial sector and globally.

Looking Ahead

The Sand Battery’s "almost" zero-emission profile positions it as a major breakthrough in sustainable Long-Duration Energy Storage.

In Part 4, I’ll share another concrete example on

Water Heating application

👌🏻

Stay tuned!