BGE Taps into an Earth Friendly Energy Source Proposing a Networked Geothermal System Pilot

BALTIMORE (August 8, 2025) - BGE has developed and proposed a networked geothermal system pilot project, filed recently with the Maryland Public Service Commission (PSC). The pilot proposal is aligned with the Working for Accessible Renewable Maryland Thermal Heat ("WARMTH") Act passed by the Maryland General Assembly in 2024.

"Networked geothermal systems represent a powerful solution for decarbonizing the building sector while delivering broad public benefits," said Sonya Harbaugh, director of Strategy at BGE. "These systems reduce overall energy consumption, lower the demand on the energy grid on the hottest or coldest days, and are resilient in severe weather. This is yet another method BGE is utilizing to meet Maryland's ambitious climate goals while continuing to provide reliable and safe energy to our customers."

The proposed pilot would deploy networked geothermal systems in two locations: Baltimore City and Howard County. The Baltimore City location consists of residential multi-family housing and one of Coppin State University's dormitory buildings and is expected to result in reducing emissions by 100,000 pounds of carbon dioxide equivalent annually as compared to electrification via air source heat pump. The Howard County location consists of residential multi-family housing, two community centers, and an ice rink owned by the Columbia Association and is expected to reduce emissions by 110,000 pounds of carbon dioxide equivalent annually as compared to electrification via air source heat pump.

What is networked geothermal?

Geothermal energy is an innovative and sustainable approach to heating and cooling. Geothermal heat pumps use energy from deep in the earth to heat and cool customers' homes. Throughout the year, outdoor temperatures change but temperatures in the ground remain stable. Geothermal heat pumps take advantage of the Earth's consistent temperature by transferring heat from one place to another through water-based piping. In the winter, the earth is warmer than the outside air, so it aids in heating your home. In the summer, the earth is cooler than the outside air, so it aids in cooling your home. Transferring heat from the earth does not use natural gas or large amounts of electricity to heat your home like many traditional furnaces.

Networked geothermal systems connect multiple buildings that are individually equipped with electric-powered ground source heat pumps (GSHP). The networking of different buildings allows for additional heat to be injected into the system, increasing efficiency of the entire system.

The four primary components of the networked geothermal system are:

• Borefield: A series of vertical geothermal wells (or "bores") drilled to depths of 500 feet or more into bedrock, where temperatures remain stable around 55 degrees Fahrenheit.

• Pump House: This facility houses the mechanical systems, including pumps that maintain fluid circulation throughout the network.

• Ambient Loop: An underground, closed-loop piping system that connects the borefield, pump house, and customer buildings, distributing the temperature-stabilized fluid.

• Ground Source Heat Pump (GSHP): Installed within each participating building, these devices use the 55 degrees Fahrenheit fluid to provide space heating and cooling by adjusting the temperature to meet indoor comfort needs.

Geothermal systems contain a variety of benefits including:

• Energy efficiency: Geothermal systems have up to a 500% efficiency rating, meaning they transfer far more energy than it takes to power the equipment.

• Comfort: Geothermal systems are whisper-quiet and provide better air quality.

• Environmentally friendly: Geothermal systems result in up to 62% lower emissions compared to traditional HVAC.

• Aesthetically pleasing: Ground loops are buried underground, and the geothermal heat pump is kept indoors, so no outdoor unit is required.

• Low maintenance: Ground source heat pumps have a 20- to 25-year lifespan and require low maintenance.

• Employment opportunities: This project will stimulate local job creation in a high-potential, emerging industry while supporting a transition to clean energy.

Recent advancements and policy support have enabled utilities to pilot community-scale implementations across the United States, such as the Eversource Framingham project in Massachusetts.

To learn more about geothermal systems and BGE's pilot program, visit BGE.com. More information, resources, and initiatives related to geothermal energy can be found on the U.S. Department of Energy's website.