DFOS Update

We’ve just wrapped up installation of the Distributed Fiber Optic Sensing (DFOS) system across 14 boreholes at Eversource’s geothermal network pilot in Framingham. We’re now in the process of analyzing this high-resolution data.The fibers, installed deep in the boreholes, act like thermometers stretched through the subsurface—recording temperature data every meter along their length. This allows us to observe what’s happening underground in far greater detail than standard monitoring systems, which typically only record water temperature at the surface. With DFOS we can better understand how heat is stored and dissipated into the ground, how those conditions vary with depth, and system performance changes over time.

This project is a collaboration between HEET, as part of the LeGUp project, and the Soga Research Group at the University of California Berkeley—experts in the science and applications of DFOS technology. Our goal is to integrate these measurements into our subsurface and system models to optimize the Framingham system performance and improve future thermal network designs and operations.

This work wouldn’t be possible without the collaboration and support of Eversource, RH White, Celsius, Berkel, Midwest Geo, and Senecal Electric. To each of these partners—thank you for helping us lay the foundation for smarter, data-driven thermal infrastructure. We’re also looking ahead to the Franklin Field geothermal network pilot, led by National Grid, where we will be installing a DFOS system as well.

As we continue to collect and interpret data, we will be publishing our findings and making this information available through the GeoDataBank. Stay tuned for more updates as the data begins to reveal the underground stories we couldn’t see before. 

‍