HEET’s gas-to-geo pathway —based on single-pipe, ambient-temperature geothermal networks— is a practical, efficient, and exciting technology evolution that allows utilities to modernize delivery of home heating and cooling. This ultra-efficient approach will improve safety, health, reliability, and costs for all.

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Which gas, and what’s in it?

We’re talking about the natural gas that’s piped into buildings for heating and cooking.

Natural gas is over 90% methane, which has 84-86 times the global warming impact of CO2 in its first twenty years in the atmosphere. This means reducing methane emissions is a fast and powerful tool for slowing climate change.

Natural gas is hazardous stuff.

For one thing, it’s highly explosive. In Massachusetts, we know that all too well from the 2018 Merrimack Valley disaster.

In 2015, HEET began investigating the composition of natural gas (apart from methane) and found that it contains trace amounts of volatile organic compounds, which impact air quality and may be a hazard to human health, depending on exposure.

Millions of households depend on gas utilities for low-cost energy.

A just transition must not increase energy bills. With more than a quarter of gas customers in Massachusetts paying low-income rates today, raising monthly energy costs will cause widespread difficulties for the most vulnerable. 

So how can we get off gas without increasing energy bills?

By using the abundant geothermal energy that sits just beneath our feet! It’s safe, efficient, affordable, renewable, local, and always available.

In 2017, HEET proposed that instead of installing gas pipes, utilities could install geothermal networks, using ground-source heat pumps to deliver heating and cooling to homes and businesses.

Thus the gas-to-geo transition was born.

Ground-source heat pumps have been in use for decades and have a strong domestic supply chain. Because they use no fuel—and run on just a modest amount of electricity—they cut carbon emissions substantially (over 60% in Massachusetts compared to gas heating systems). As electricity generation moves to renewables, emissions from geothermal networks will fall to zero.

Utility-scale geothermal networks leverage the utilities’ right-of-way in the street along with their capital financing, existing workforce, and customer base. Installation and building retrofit costs could be paid for up front by the utilities and spread across the entire customer base over many years, making it accessible and affordable for everyone.

Is it efficient?

Yes! In fact, geothermal networks are the most efficient form of heating and cooling out there—they have been recorded to be six times more efficient than the most efficient gas furnace on the market today.

What does a geothermal network look like?

This short video illustrates it beautifully!

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What it’s not

Geothermal networks do not go to a depth where the Earth’s temperature reaches hundreds of degrees. Instead, they stay in the shallow bedrock, where the sun’s warmth over millennia has warmed the ground to the average annual air temperature for the area.  

Wouldn’t this gas-to-geo transition be expensive?

Ground-source heat pumps are already less expensive than heating with gas. A study by the Applied Economics Clinic shows that geothermal networks outcompete all other forms of heating in terms of monthly energy bills—both today and in the future. 

Up-front infrastructure costs are high by some measures—but not compared to the alternative. In Massachusetts, we’re projected to spend $42 billion replacing aging gas pipes—more than the Big Dig! And those costs will get passed on to gas customers. That’s an enormous amount of money for a system that will have to be almost entirely retired by 2050, when the state has committed to net zero emissions. 

Instead, we think it’s wiser to invest our infrastructure dollars in a system that will last beyond 2050, have the potential to provide the lowest monthly costs for households, and also help protect the planet for future generations.

Are geothermal systems new?

Not at all. Ground-source heat pumps have been in use since the late 1940s. A growing number of college campuses are installing geothermal networks of varying designs to make their campuses truly carbon neutral (as opposed to just buying carbon offsets). And private developments, such as Whisper Valley in Texas and Mattamy Homes in Toronto, have recognized the long-term financial benefits of geothermal networks. 

What IS new is gas utilities installing these networks in our communities as a way to decarbonize our buildings.

Are the utilities on board with this?

Increasingly yes! HEET helped establish a national coalition of gas utilities—now more than 26 companies—that is meeting regularly to explore the potential of geothermal networks. Together they represent more than half of all the gas customers in the U.S.

In Massachusetts, Eversource and National Grid are installing the first gas utility geothermal networks. New York and Colorado have passed laws requiring gas utilities to build geothermal networks—and more laws, feasibility studies, and installations are moving forward across the country. 

Is it scalable?

Yes! The engineering firm Buro Happold found that geothermal networks could provide 100% of the heating and cooling for a significant portion of the gas system in Massachusetts, and other states hold similar promise.

Can I sign up for geothermal service on my street?

Not yet…but you can add your address to HEET’s Want Geo map. The more people who show their support, the faster legislators and utilities will adopt these systems—which means billions of dollars not spent replacing our aging gas infrastructure and burning more fossil fuel!

If you have questions…

We love curiosity! We invite you to learn more on the Gas-to-Geo Wiki and subscribe to HEET’s newsletter to stay informed about this exciting transition.

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