Startup Uses Supercritical CO2 to Power Data Centers
▼ Summary
– American Supercritical has launched with $8 million in funding to retrofit data center gas turbines using liquid carbon dioxide for improved efficiency.
– The company aims to replace inefficient simple-cycle turbines by utilizing supercritical CO2 to capture waste heat and generate additional electricity without extra emissions.
– Current simple-cycle turbines convert only about 35 percent of energy to electricity, whereas combined-cycle plants achieve 60 to 65 percent efficiency.
– This technology allows for the creation of miniature combined-cycle systems that significantly reduce water usage compared to traditional steam-based methods.
– The initiative addresses the environmental impact of massive data centers, such as an Amazon facility in Texas permitted to emit over 33 million tons of greenhouse gases annually.
American Supercritical has emerged from stealth mode, securing $8 million in funding to address the energy efficiency crisis facing modern data centers. The startup aims to retrofit existing gas turbines with technology that leverages liquid carbon dioxide, allowing facilities to generate more power without increasing their carbon footprint. While these gas-fired units will continue to produce emissions, the new system significantly boosts output per unit of fuel consumed.
“We want to start with gas turbines but eventually expand beyond that,” says cofounder Simon Shuham.
Most large-scale power generation in the United States utilizes a combined-cycle process. This method employs multiple heat engines: initial turbines burn compressed air and natural gas to create electricity, while a secondary engine captures hot exhaust to produce steam for additional energy. This approach typically achieves an efficiency rate of 60 to 65 percent. However, many data centers have historically chosen simple-cycle turbines instead. These smaller units exclude the steam component, resulting in lower efficiency where only about 35 percent of the input energy is converted into electricity. The remaining energy escapes as waste heat, which carries significant greenhouse gases.
The environmental impact of this inefficiency is substantial. For example, a massive Amazon data center power plant in Texas, equipped solely with simple-cycle turbines, is permitted to release over 33 million tons of greenhouse gases annually. This volume exceeds the yearly emissions of several small nations, highlighting the urgent need for cleaner operational models in the sector.
American Supercritical’s founders argue that supercritical CO2 technology is ideally suited for these smaller, inefficient turbines. Carbon dioxide enters a supercritical state when pressurized and heated to specific temperatures. In this phase, it possesses the density of a liquid while retaining the flow properties of a gas. This unique state allows for highly efficient energy transfer through compact equipment.
By attaching American Supercritical’s units to existing turbines, the company harnesses the hot exhaust that would otherwise be wasted. Instead of using this heat to boil water, the pressurized CO2 transfers the thermal energy directly to generate additional electricity. This process creates no extra emissions.
“We’re essentially building miniature combined-cycle plants,” says Shuham.
A critical advantage of this technology is its minimal water requirement. Data centers have faced intense scrutiny regarding their water consumption, particularly for cooling purposes. The supercritical CO2 system operates within a closed-loop mechanism, meaning the fluid does not need to be refilled or replenished. Cofounder Matthew Carlson, who spent over a decade researching supercritical CO2 applications, compares the circulation of the gas to modern refrigeration systems that use CO2 for cooling.
The company intends to launch a 10-megawatt unit as its first product. According to internal calculations, integrating supercritical CO2 technology can boost turbine efficiency by up to 50 percent. This improvement comes without any increase in greenhouse gas emissions or water usage, offering a scalable solution for the rapidly growing demand for data center power.
(Source: Wired)
