Apr 1 • 1HR 6M

Volts podcast: Audrey Schulman and Zeyneb Magavi on how to replace natural gas with renewable heat

Ground-source heat pump district heating everywhere!

28
15
 
1.0×
0:00
-1:06:07
Open in playerListen on);

Appears in this episode

David Roberts
Episode details
15 comments

In this episode, activists and entrepreneurs Audrey Schulman and Zeyneb Magavi discuss their audacious plan to replace the nation's natural gas distribution infrastructure with a series of networked geothermal heat pumps. Basically, neighborhoods would be heated by warm water rather than natural gas. It would be the most efficient collective heating option available in the world.

Share

Full transcript of Volts podcast featuring Audrey Schulman and Zeyneb Magavi, April 1, 2022

(PDF version)

David Roberts:

As I said in the previous episode, I’m doing a series of podcasts on clever ways to rapidly and substantially reduce demand for oil and gas — if not for the climate, then at least to reduce dependence on Russia.

Today we’re talking about heat. Specifically, we’re talking about the nearly half of US homes that are heated by natural gas, the natural gas utilities that supply it, and what those utilities might be able to do instead of pumping an explosive fossil fuel beneath American streets.

Today’s guests have developed a visionary solution for for America’s sprawling natural gas infrastructure. In short, they want to replace it with “networked geothermal,” water pipes that carry heat harvested from the ground. It’s called the GeoGrid, developed by the HEET (Home Energy Efficiency Team) Coalition, run by Audrey Schulman and Zeyneb Magavi.

Audrey Schulman & Zeyneb Magavi

Schulman is a long-time activist and policy entrepreneur (and novelist!); Magavi is a researcher and guest lecturer at the Harvard School of Public Health (and karate black belt!). Together, they have spent years researching, developing, and evangelizing for the GeoGrid. They have done statewide feasibility studies (in their home state of Massachusetts), hosted design charrettes and community meetings, and had endless consultations with utilities. They have often been ignored or dismissed by the old boys network in the energy world, but they have persisted, and their idea is now being put into place, with extremely promising results.

The technology is not new or untested — many college campuses are heated with ground-source heat pumps — but HEET has got utilities thinking about it in a more systemic way, planning how to build geogrids targeted to best avoid spending on additional natural gas infrastructure.

I’m excited to talk to Schulman and Magavi about why something like geogrids are needed, how they are designed and constructed, and where we might see them being built in coming years.

So without further ado, Audrey Schulman and Zeyneb Magavi, welcome to Volts. Thanks for coming.

Audrey Schulman:  

It's a pleasure to be here. 

Zeyneb Magavi:  

I'm delighted to talk to you.

David Roberts:   

Audrey, I know that for years you have been involved in testing natural gas infrastructure for leaks and have been horrified at what you find. Tell us about why the current natural gas infrastructure situation is unsustainable and reaching a breaking point.

Audrey Schulman:  

Back around 2014 there was a single study that was published in The Boston Globe showing that because the underground pipes are so old and leaky, the amount of gas leaked in Boston alone from the distribution system basically erases the entire state's efficiency goals and work. In Massachusetts, the efficiency program is one of the best in the country, but all the work we're doing is being erased by these very small gas leaks, because gas is such a potent greenhouse gas. 

At HEET, we started mapping those gas leaks using utility-reported data and quickly realized that this is a system we have to get off of. We can triage the system, but it's best to transition now, especially given all of the aging gas infrastructure that's being replaced.

David Roberts:   

We come to this point with natural gas infrastructure a lot – the tension between spending to repair it, spending to build more of it, and then with our other hand saying that we're going to decarbonize. How long do natural gas infrastructure assets typically last? What is the time horizon of these investments?

Audrey Schulman:  

There are pipes still being used in the Boston area that date back to President Lincoln. Some of the infrastructure can last for an enormously long time, but like any old infrastructure, over time it tends to erode somewhat. 

All the cast iron mains were sealed with jute, which is a grass fiber, and most of that grass fiber has dried out over the years. The cast iron mains are leaking natural gas every 12 feet, at every joint. That's a problem.

David Roberts:   

What would be required to repair all those leaks? What is the time and money scale of that investment? Is it being done, or contemplated? Are they being repaired right now?

Audrey Schulman:  

In Massachusetts, there are more than 14,000 gas leaks reported on the books every year. More than that are repaired, but those are the ones that are reported in addition, that are left. 

The gas utilities, in their plan to get rid of the majority of those, want to replace the pipes. There's been a report by the Gas Leaks Allies, which is a coalition here in Massachusetts of researchers and advocates, showing that that replacement over the next 20 years will cost more than $20 billion – which brings it to the size, in terms of economics, of the Big Dig here in Boston where we sunk a major highway artery underneath the entire city. 

From that, we had all these things we wanted – we had the highway underground, we had a beautiful park, we had a way to get out to the airport really quickly. But at the end of this 20-year replacement of gas infrastructure with new fossil fuel infrastructure, which will last an enormously long time and will be paid off by the gas customers over at least 50 years, we don't know if those assets will be used and useful, because we've got a net zero by 2050 emissions mandate here in Massachusetts.

If we're going to be replacing approximately 20 percent of the gas infrastructure for $20 billion, that work will not be completed until around 2040, and then it gets paid off over the following 50 years. That's crazy.

Zeyneb Magavi:  

The leaks are clearly a climate problem – methane, in the first 20 years in the atmosphere, is 84 times more potent than carbon dioxide. Also, some of these older pipes are a safety hazard. 

When we look at this aging infrastructure – and many other cities across the country realize this problem – there are really three ways to fix it. You can triage: repair leaks and attempt to stem the bleeding. You can replace the infrastructure and therefore address the safety as well. The third, which we're trying to move us toward, is transition. Let's not put in last century's infrastructure; let's put in infrastructure for the next century. 

In Massachusetts, triage was the first way that HEET got involved. We figured out a way to identify the largest volume leaks, and since just 7 percent of the leaks were 50 percent of the emissions in our distribution system, we have a program in place now – law and regulation, a couple years in – to find those largest leaks and cut our methane emissions from the distribution pipes in half fast.

David Roberts:   

You could say the process is underway to get Americans off of natural gas, but the way it's proceeding has some equity implications. Why is the current haphazard transition away from natural gas so ethically dubious?

Zeyneb Magavi:  

It's ethically sound to transition off natural gas. Our current plan in many locations is to do it customer by customer with an individual solution: an individual air source heat pump or ground source heat pump. I'm never going to say that's not wonderful. 

However, when it comes down to the fixed costs of a gas system infrastructure, if you pluck customers off throughout the system over time, the fixed cost doesn't disappear. The remaining customers, who are most likely to be those without means to invest in an air source heat pump or ground source heat pump, or without control over their building (like a renter), will face exponentially rising gas prices and heating bills. That is the opposite direction of the way we want to go in terms of energy equity.

David Roberts:   

Before we talk about your idea to cut through this Gordian knot, what's the other plan? Massachusetts has these ambitious decarbonization goals; what is the current thinking for how they transition off of natural gas? Is there any?

Zeyneb Magavi:  

Massachusetts has a Future of Gas planning process in our regulatory system. There are several other states in this process as well. In Massachusetts, it has the fascinating name “20-80.” 

The gas utilities collectively just filed a report on their individual plans for decarbonization to meet the state's goals, and they are a menu of options. There is a lot of effort to project RNG, SNG, and hydrogen as potential justifications for the gas distribution system.

David Roberts:   

RNG is renewable natural gas from biological sources like landfills; SNG is synthetic natural gas. Hydrogen, it's the same thing – just pumping some other gas through the same pipes.

Audrey Schulman:  

That's partly because gas utilities are legally allowed to sell gas and nothing else. If they can't sell the conventional natural gas, they're searching for different gases that might be more appealing to the regulators. 

One of the things we hope to do is to allow them to instead become thermal utilities where they're selling heating and cooling. That would be a way for them to continue their businesses with all their workers, and with the low-income customers and renters who cannot get off the system easily, while meeting our emissions mandates to allow our children and grandchildren a place to live.

David Roberts:   

If you do the math on these other gases, it's not really practical. There's not enough RNG or SNG to cover natural gas. Hydrogen requires different, or at the very least renovated, infrastructure. We're a long way from that. 

It's a weird situation where we're saying we're decarbonizing, we have these fossil fuel utilities whose business model is to sell fossil fuels, and we're asking them ”tell us how you're going to join this transition.” The only honest answer is “well, we're going to slowly shrink and die and not be there anymore.” They can't say that. They have investors, or they just have pride. 

GeoGrid is the first idea I've ever heard that offers some way out of the weird cul de sac that natural gas utilities are stuck in. So what is a GeoGrid and how does it work? What would it look like to take a few blocks of residential area that are currently served by natural gas and replace the natural gas infrastructure with a GeoGrid?

Zeyneb Magavi:  

Initially, you could install this on a single block. It's basically a shared water loop in the gas company right of way with a supply and return loop to each customer building and a closed loop vertical borehole array in, again, the right of way, which is attached to that shared loop and can be accessed as a thermal source and sink.

David Roberts:   

How many vertical feet down do these bore holes go?

Zeyneb Magavi:  

In the geothermal world, these are shallow – 100 to 500 feet, roughly, depending on your energy load and your bedrock, etc. They're just six inches wide. These are little things for the geothermal world. 

Of course, the word geothermal is used for so many different technologies; what we're really talking about is a ground heat exchanger with ground source heat pumps.

David Roberts:   

In the bore holes, a little pipe goes 100-500 feet down into the earth; the water picks up the heat from that depth and carries it back up to the main loop that's going under the street.

Audrey Schulman:  

The temperature of the ground is mostly in the 50s, which is the ideal temperature to keep heat pumps very happy. They work at their greatest efficiency in that range. It's much better than, for instance, air source heat pumps – which are lovely on their own, I don't want to cast aspersions – which have to deal with the difficulty of the air temperature varying so much. When you need them the most is when the temperature of the air is either 100 degrees or 0 degrees, and that's when it's hardest to pull the temperature out that you want in your home or business.

David Roberts:   

The beauty of the shallow Earth is that it is always basically the same temperature.

Zeyneb Magavi:  

It's actually the largest battery we have on Earth, the actual Earth.

David Roberts:   

The loops under the street are carrying water and occasionally dipping down into these bore holes to pick up more heat. Where are the actual heat pumps that extract the heat from the water – in each individual house?

Audrey Schulman:  

Yes, in each unit. That could be homes or businesses. The best possible thing is if you have both homes and businesses on the same loop. For instance, the supermarket might be pulling cold off for all of its fridges and returning the water hotter, and that heat could then go to the homes down the street. Same with an ice rink or a data center, etc.

Zeyneb Magavi:  

With the ground being a constant temperature – it's referred to sometimes as an ambient temperature range – the water in the loop is going to be maintained within a range that is great for the heat pumps in the customer buildings. 

The piece of this infrastructure that's interesting and different is it requires a utility to manage it, especially as you do the next block and the next block and begin to interconnect them. You have a growing thermal grid with the need for a thermal management utility. 

If that temperature in the loop starts to drift out of the design window, the thermal utility can bring a thermal asset or source or sink onto the system. Maybe there's a borehole field that they have off in the spring, and as the temperature rises outside, they bring that asset on. They can turn it on when needed.

David Roberts:   

If I'm a homeowner with my own ground source heat pump, it's a unit in the basement or wherever connected to pipes that run underneath my yard. If I'm on a GeoGrid, from my experiential perspective, it's not that different. I still have the same unit in my basement, it's just connected to pipes that now run beneath the entire block. The pipes are all shared; the ground source heat pumps are in the individual buildings.

Zeyneb Magavi:  

Yes, the utility model. The great part is that the utility pays for all that infrastructure. Ground source heat pumps have been around for a while, but they require a pretty big upfront investment.

David Roberts:   

As far as I know, in terms of individual heating solutions, ground source heat pumps are the most efficient way of heating a house. I can imagine that if your ground source heat pump is drawing from a network of water pipes that's several city blocks, it's even more efficient. 

Zeyneb Magavi:  

We get some exciting efficiency gains by networking. One computer is pretty awesome, but look what happened when we networked computers with the internet – some interesting properties emerged. 

Like Audrey said earlier, if you have mixed use on the same network, you can call it waste thermal recapture, or energy sharing – there are all kinds of ways to name it. You've got a building that's using cooling and rejecting heat into the system, and another building that's using that heat and rejecting cooling. Those two are canceling each other out. You've got synchronous load cancellation.

David Roberts:   

This is not unfamiliar from the talk about how to make distributed electricity grids work better. Everybody's contributing, everybody's consuming, and the more people you have on it, the more balanced the whole thing is.

Audrey Schulman:  

The bigger the system, the better, because then it can be sized for stochastic load. Instead of adding up the aggregated sum of all the total peak hour use, you can figure out statistically: what's the chance that in 1,000 buildings, every one of them is going to be asking for all of the peak heat or cooling at the same moment? It's zero, or very close to zero. Then you can just decrease the infrastructure needed in all of those buildings.

David Roberts:   

Once you have ground source heat pumps and several city blocks of networked pipes, is there any temperature extreme that they couldn't handle? Would there be need for any of these units to have backup sources of heating or cooling?

Zeyneb Magavi:  

No. The beauty of an interconnected system is, if you're anxious about it for whatever reason, you can put the backup on the loop in one location. But there isn't a need. 

In fact, a cold climate heat pump for a new design building is absolutely doable. For a lot of our old New England building infrastructure, you have to do a lot of work on the building to get it to the point where it's reasonable. Obviously, you always want to do energy efficiency, but if you have a unique building, you can cover the load with this.

David Roberts:   

So the applicability of this is not restricted by climate. You could do this anywhere.

Zeyneb Magavi: 

Absolutely.

David Roberts:   

District heating systems are very common in Europe. Can you say a quick word about how this is different from those?

Audrey Schulman:  

In district systems, generally there's one central plant that is generating. If we're talking geothermal, there's one really deep borehole generating the heat you want. 

What we're doing instead is distributing the boreholes everywhere in the right of way of the street. One plus about that is that there's nobody at the end of the line who's going to get the last dregs of heating or cooling. It's everywhere. 

Zeyneb Magavi:  

That makes it more resilient. But I want to clarify, and this is where that word “geothermal” gets messy – that district system with a deep borehole is getting direct-use hot water from the earth, not capturing stored solar energy of our near bedrock. 

There are some great installs all around the world. In Europe, they've got a naming system for their district energy systems – first generation, second generation, third generation, fourth generation. Interestingly, some folks in Europe have now been evolving toward a fifth generation, which starts to take on the distributed heat pump ambient loop characteristics that we're proposing here as well. 

David Roberts:   

In a district heating system, you'd have one main source of heat, and then the network distributes the heat. In your system, you have way more sources. Intuitively, people might look at that and say it seems like it would be cheaper to dig one big hole than a bunch of holes. How should we think about the cost of this? It sounds expensive, but what do I know?

Zeyneb Magavi:  

The first part of that is that there isn't always an easy one-big-hole direct-use hot water source. It is location-dependent. 

The second part of it is that if you do that direct hot water source, you're pumping hot water around in a district; you’re not doing an ambient loop that is also simultaneously providing cooling and heating. You don't get as easily that energy sharing or simultaneous load cancellation, and that's a significant loss in terms of the overall system's energy efficiency.

Audrey Schulman:  

I think of the US as the Saudi Arabia of energy waste. Through this system, we can reuse that energy waste so that we're each reducing waste.

David Roberts:   

I did a post a while back on Amazon reusing the heat from one of their data centers in downtown Seattle to heat nearby buildings. Getting rid of waste heat is one of the big costs for data centers. They spend a lot of money building systems that vent enormous amounts of heat into the atmosphere.

Zeyneb Magavi:  

We don't pay much attention to all the waste thermal in our environments. There's actually a cool London heat map that tried to map all that waste heat from data centers and other sources. 

By building a thermal network, a GeoGrid, we basically create a thermal market. If there is a heating need in that region, that data center, instead of having to pay to dispose of its heat, can actually get paid for their heat.

David Roberts:   

I found the physical characteristic of these systems really intriguing. They're like Legos; they're quite modular. You can do this at the smallest scale, like an individual city block. Talk a little bit about what advantages you can get from modularity, in terms of how to approach where to build them.

Audrey Schulman:  

We vision the gas infrastructure as a giant tree spread out across the state, or whatever territory it is. What we want to do is replace the distal ends of that infrastructure – graft the GeoGrid onto that tree in modular bits, interconnecting over time. We give the gas utilities time to become thermal management utilities, where they're moving the wasted thermal energy from one site to the other, learning how to balance it, getting the customers used to this concept, so that we can all buy in and the system can be de-risked as we decarbonize the entire system over time.

Zeyneb Magavi:  

I want to acknowledge that that idea of the gas system as a tree actually came directly from a tree physiologist, Dr. Nathan Phillips at Boston University, who imagined the gas system as a tree and attempted to think of how we were going to prune the tree.

The design of this GeoGrid, even at the block level, with that ambient bidirectional loop, allows us not just to have an incremental growth model, allowing that gas-to-GeoGrid infrastructure evolution; it also allows us to be really agile in response to a changing climate or changing energy use intensities on your block or in your city by adding and subtracting sinks or sources in an incremental way over time.

David Roberts:   

So you start building these out at the edge of the tree, at the tips – pruning the tree back, getting people used to it, learning how these things work, and then you slowly work your way down all the way to the trunk until the whole tree is replaced.

Zeyneb Magavi:  

We acknowledge there are some industrial gas users who we don't have an electrification solution for. Think glass smelter. For those gas customers, that is an appropriate use of the more expensive and smaller supply RNG, for example, or a green hydrogen.

David Roberts:   

How much of the natural gas infrastructure would you have to keep in place, if you pruned your way down to only those customers needing natural gas?

Zeyneb Magavi:  

It's not clear that you would necessarily keep the infrastructure in place. That would be locationally dependent. If you have a large cluster of such industrial use, that would make sense; if you have one or two you would do onsite, I assume. We haven’t figured that out. We need to build some interesting models and map this out.

Audrey Schulman:  

There would also be some places where, because of the hydrogeology or whatever, a site would not be financially viable for the GeoGrid. In those cases, there would be air source heat pumps installed instead. 

For gas utilities, we believe this might even increase their business model, because there might be a lot of towns where they can't get a gas pipeline out there because nobody wants a gas transmission pipeline cutting through their neighborhood. Instead, they wouldn't need the gas; they could just build the system there and use the ground under their feet to provide the temperature that they need.

David Roberts:   

Say I want to do this on a particular block. What are the requirements? What's the order of operations? Do I first have to get every building in that block to be willing to stop using natural gas? What is the homeowners’ or building owners’ role in this, and how capable are they of stopping it all if they decide to be difficult?

Zeyneb Magavi:  

That's a critical question. Partly, we have to do the experiment. However, I have some good news for this one.

One of the first installations going in in Massachusetts was gas-utility led. The gas salespeople for the utility were retrained to sell this GeoGrid network. They went out and knocked on doors and attempted to sign up customers. The report is that they had some of the best sales days of their lives, got a dramatically higher uptake, and within two days had more customers than they needed. They had an incredibly positive response. And it was a very blue-collar community.

Audrey Schulman:  

The gas utility, Eversource, first requested permission from the state regulators to be able to install this demonstration installation and got approved to do so. National Grid, which is the other large gas utility here in Massachusetts, did the same, and they were also approved. It's amazing that these gas utilities are both trying out a method forward to decarbonize the system. 

Our hope is, since we've had several economic briefs and analyses on it, that in the end, the cost for heating and cooling will be lower for the customers. We cannot state that for sure – the regulators have to make that decision – but three different economic analyses have shown that it is likely to reduce the customer energy bill as well as to provide cooling. That's two big wins.

Zeyneb Magavi:  

I don't know if we answered your earlier question, which was whether you have to convince everyone on the street in order to move forward.

David Roberts:   

It seems like an all or nothing thing – you're yanking out infrastructure on one block and replacing it with another. You can't do a hybrid of two infrastructures, can you?

Zeyneb Magavi:  

No. That would be foolish. You would then have that fixed infrastructure cost and the need for operations maintenance. 

There's a real difference between these initial installations and demonstrations that are de-risking the process for everyone, and what you would actually do in the full transition.

If we legally redefine a gas utility as a thermal utility, they have permission to move forward with this business model and make it an equivalent service. You have an obligation to serve your customers. This is simply a thermal service upgrade; we are going from outdated 1800s thermal to modern thermal. The costs go down, you get better health benefits, and bonus, it happens to be good for the climate. 

I imagine you'd have salespeople go out in the future, knock on doors, put up flyers, say “your street is targeted for a thermal upgrade, we will be providing a heat pump, we'd like to assess your pipe coming into your house” or something like that.

David Roberts:   

I'm imagining the one cranky boomer at the end of the street who loves the character of his natural gas stove. If one homeowner says no, do they thereby veto an entire block? 

Audrey Schulman:  

With all the health impact information that seems to be coming out these days around indoor combustion, it seems unlikely for them to want natural gas anymore. But if they do, it would cost them several hundred dollars a year, if not more, to stay on the gas system and use that one gas stove. Economically, they'll probably go to a propane tank that they keep for that one person on the street.

David Roberts:   

So this is not like electricity transmission lines, where one intransigent landowner or homeowner can stop the whole thing. Or at least you think there's a way around that.

Zeyneb Magavi:  

There is a way around it. As long as our laws and regulations permit it, we can accommodate the individual choice even as we do what's best for the utility scale, cost, and safety. 

David Roberts:   

Is this compelling to natural gas utilities? You've talked at least two into building test sites, so they must be at least open to it. Can you pitch them and say “you will be making at least as much money for your investors as you were before,” or is this going to be a shrunken business in some way? 

Zeyneb Magavi:  

At HEET, we try to do our best to blame the system and not the human beings within the system. To that end, working with the system we have, it turns out that the higher infrastructure cost of the GeoGrid going in, in comparison to a new gas pipe going in, actually means that you have a larger asset acquisition opportunity for the gas utility that's now a thermal utility. And, like Audrey said, a business model expansion not just into cooling, but also into areas of gas capacity constraint. As far as business models go, this looks like a real growth model for the gas utility.

Audrey Schulman:  

Gas utilities don't get paid by how much gas they sell. The profit comes from capital expenditures: when they install new infrastructure, buy new trucks, make a new facility. This is a way for them to do more capital expenditures while potentially reducing the customer cost and providing that cooling too.

David Roberts:   

You say it is more expensive to put one of these in place for a given block than it would be to put in place natural gas infrastructure. What is the delta there? Is that a big difference?

Zeyneb Magavi:  

In the technical and economic feasibility study that Buro Happold did for Massachusetts, we got results that showed about a 1.6, so 60 percent more. The beauty of it is, you've got this higher infrastructure investment, but because the customer bill no longer includes the cost of gas, even though you're paying an increase in the cost of infrastructure, all of the economic predictions show the feasibility of the total customer bill actually being lower. You've got this economic benefit to the utilities and an economic benefit to the customer in a “steel for fuel”-like model, like coal to wind.

David Roberts:   

Familiar story in clean energy: higher upfront costs, but you are eliminating fuel costs. If you're a utility transitioning from operational and fuel costs to fixed costs of infrastructure, that's better for you. Those are the costs you care about.

Audrey Schulman:  

You also get more revenue all the way through the year, because you're not doing just gas sales during the winter. Now you're having revenue through the summer, too, as you provide cooling.

David Roberts:   

If one of these Massachusetts natural gas utilities wants to do a GeoGrid over their whole territory, would you need any public subsidy to get started, or do they have the resources to start doing this incrementally and pay for it themselves?

Zeyneb Magavi:  

They have the financing model. In fact, here in Massachusetts, there is a whole program for gas system replacement which can be redirected to replacing the aging gas pipe with GeoGrid. The funding structure would remain fundamentally the same. 

The customer building transition is really the biggest barrier to overcome in so many forms of electrification. My hope is with this approach, not only are we doing it in a systematic street-by-street way, but the infrastructure can be considered to include the heat pump, and the meter would go on the other side of the heat pump, covering the cost of the heat pump with utility financing. It makes technical or engineering sense, because the last thing you want on this infrastructure is a whole bunch of individually sized heat pumps.

David Roberts:   

How bespoke is it at an individual building level? The pipe coming up is pretty standard; is it just the size of the ground source heat pump that differs between buildings? 

Zeyneb Magavi:  

If you've got a standard residence, it's pretty plug-and-play as long as you're not dealing with one of those antique steam systems in the distribution. It's great for a forced hot air distribution or a forced hot water distribution. 

When you get to a larger-scale building or a commercial building, you may want an array of heat pumps. You might want the option of having one heating and one cooling simultaneously, like so many of our buildings do. 

I'm sure that once they've done a couple thousand buildings, there will be some clear patterns. Operations is what utilities are good at.

David Roberts:   

Has anyone built a GeoGrid as you envision it out in the world yet?

Audrey Schulman:  

There's one in Colorado Mesa University, which has interconnected Lego block components that over time have built a GeoGrid, with borehole fields as opposed to being in the right of way of the street. 

The GeoGrid is what's called an architectural innovation; it’s known components rearranged in a slightly different way. In this case, the boreholes are as close as every 20 feet in the street and its ambient temperature etc., and done by the gas utility. That way you get a gas utility’s financing, its customers, its right of way in the street, its workers, everything to move the decarbonization method forward at a much greater speed and scale that we so desperately need. 

I'll throw in, because it's an important point: HEET does not take any funding from gas utilities or from industry. We are a nonprofit climate solutions incubator. We just try to figure out the best ways forward that do systems change in hopes that we can make the future better for our children and grandchildren.

David Roberts:   

You're not trying to get rich selling GeoGrids.

Audrey Schulman:  

If so, we're doing a really bad job.

Zeyneb Magavi:  

As we were trying to figure out what to do to evolve gas utilities, I designed the GeoGrid idea; we drew it out on paper, thought “basic thermodynamics and physics says this should work.” We put out a feasibility study RFP, and on the webinar for that RFP, we were stunned with the scale of people that showed up across the world. There was the guy who drilled the Chinese Olympic Stadium. The geothermal ground source heat pump world got word. 

It was on that call for our RFP in 2018 that we met the folks that built Colorado Mesa. Cary Smith was the engineer who designed that, coming up with the idea 10 years before we did. Being an innovative geothermal engineer, he actually knew how to put it in the ground, and had the most beautiful data showing how incredibly it worked. 

That was the best gift ever, and we continue to work with him today. In fact, we're hoping to come up with a pretty awesome case study sometime this year.

David Roberts:   

What's the status of GeoGrids proper, the gas-to-GeoGrid transition pathway?

Zeyneb Magavi:  

In 2019, we released the Buro Happold feasibility study; in less than a year, Eversource Gas filed with our Department of Public Utility a request to demonstrate this. It took a year, but they got permission, and that's the gas utility that's installing in Framingham, Mass. They've got a great video up, you should check it out on the website. 

A little after that, National Grid Gas filed in Massachusetts and requested four demonstration projects. They just got permission in December and are moving forward, hoping to get the first and maybe second one in the ground next year. 

In addition, because there are a lot of states where gas utilities are seeing the writing on the wall of climate legislation, we have talked to more than 14 gas utilities across the country and in Canada, and some of them are moving forward with feasibility studies right now. 

In Philadelphia there was a process of looking at decarbonization pathways for the largest municipal gas utility, PGW, and the most popular one in some of the hearings was to demonstrate the GeoGrid, which they are moving forward with.

David Roberts:   

To my ear, it sounds like a win-win-win for the natural gas utilities. Primarily, they get to survive. They could do something that people wouldn't hate and condemn them for constantly. More spending on infrastructure means better profits for their investors, more jobs for their people, a stable long-term future for them as a business concern. Have any of them come up with problems that strike you as legitimate, or reasons for doubt?

Audrey Schulman:  

Gas utilities have always done innovation. They've gone from being primarily lighting companies in the beginning when there were gasworks, to heating as electric light bulbs came in, to going from manufactured or “town gas” where it was made from gasification of coal, to natural gas, to fracking – they've always innovated all the way along. This is a new potential way for them to innovate, to meet this future of a lower-emitting or non-emitting country or world. 

But they haven't heard of the idea yet. We've talked to as many gas utilities as we can, but they're large organizations. They have to get the regulators to agree to do it. It takes a long time and a lot of people fretting about it. The more we can get the idea out, the more people can think on it, the more demonstration installations that we can have gas utilities do, and the more it will de-risk the concept for all, including the customers.

Zeyneb Magavi:  

Gas utilities are by nature a risk-averse business, and we actually want them to stay that way. They are piping an explosive gas around. A utility is not structured for innovation necessarily;  it's a process. 

I keep trying to find the major flaw that I haven't seen yet, because I'm that way. It seems you can put one of these anywhere; the question is, is it cost effective? If you're on a sandbar, do you have the thermal transfer that makes it make any sense? 

David Roberts:   

I wonder how much soil composition makes a difference.

Zeyneb Magavi:  

And there's a threshold for the density of customers; if you've got a mile between houses … 

David Roberts:   

Do we know enough to know what that density threshold is? 

Zeyneb Magavi:  

With the Massachusetts feasibility study, it came out looking like it matched pretty well to the existing gas utility’s threshold. A gas utility doesn't go into rural America and pipe gas. The cost of the infrastructure to the ratio of customer distance seems to match pretty well so far. But there's so much research needed in the entire thermal space.

David Roberts:   

You can imagine something that would have been unthinkable not that long ago: the interests of natural gas producers and producing states drifting out of alignment with the interests of natural gas utilities. You can see them splitting.

Audrey Schulman:  

We hope it doesn't happen. A lot of the people who have expertise with fracking, for instance, would be extraordinarily useful in installing this infrastructure to do diagonal drilling and drilling underneath the streets so we don't disturb any of the preexisting infrastructure. It is potentially a really interesting match. 

Cary Smith came from a gas and oil background; during the 1980s, when there was a gas emergency, he moved to geo. The expertise is somewhat fungible from one to the other.

David Roberts:   

If we imagine GeoGrids scaling up – so instead of a block or a couple of blocks, we’re talking about a whole town, or a whole city – what do you imagine could come from scale? Are there learning curves where we could make it cheaper? Are there emergent effects once you get a bigger network? What do you see happening as this grows?

Zeyneb Magavi:  

I believe there are going to be efficiency increases up until a certain point, and ease of optimization for the thermal management utility. I also am excited that once we get to that kind of scale, we start to have opportunities to do thermal storage – not just adding a thermal storage site, but also, the entire system becomes a form of energy storage because the bedrock is allowing us to do asynchronous energy sharing over a seasonal basis. And the piece of building decarbonization we've really got to grapple with is that seasonal energy storage challenge.

David Roberts:   

We're talking about basically using the shallow Earth as a giant thermal battery.

Audrey Schulman:  

For instance, if you have some wind turbines that primarily work more in the middle of the night when the wind is stronger, but nobody's using electricity, you can take that extra electricity and dump it into the shared loop of water, adjusting for the temperature. If your shared loop is running a little bit cold, you take the wind energy, dump it in, and heat up the shared loop, or vice versa. 

The system, as it scales, will also increase jobs. There's going to be a lot of work needed in terms of retrofits in buildings and installing the system. It'll allow the gas workers who currently operate and maintain the system to continue in their trade with the good jobs that they have. 

It'll improve health for people, not only because the indoor air will be better from a lack of combustion, but also the outdoor air will have fewer emissions and excess deaths from that. 

David Roberts:

Perhaps fewer explosions as well. 

Audrey Schulman:

Yes. Here in Massachusetts, we have that horrible experience with the Merrimack Valley gas disaster. 

In addition, we will be doing electrification of the buildings by gas utilities and reducing the peak electric impact from that, because the system is so much more efficient during peak times than air source heat pumps. It's a better future that we can have at a lower cost for the customers.

David Roberts:   

You're not only sharing thermal energy around a network, you're also integrating the thermal network with the electricity network, and they're all becoming one big network.

Zeyneb Magavi:  

We can have different ownership models; that's another conversation. But yeah, you can have synergistic support and resilience between a thermal grid and an electric grid. And a ground source heat pump is currently the most efficient form of electrification, but a networked ground source heat pump goes a few steps further, and some of the initial sites are showing a system COP of 6 or more.

David Roberts:   

Air source heat pumps go up to what, 3 at the highest?

Zeyneb Magavi:  

Two to four. There are multiple studies out there.

David Roberts:   

As far as we know, is there a way of heating buildings of any kind that's more efficient than this? 

Audrey Schulman:  

The only more efficient thing is to just turn off the heating or cooling entirely.

Zeyneb Magavi:  

That higher efficiency means that as we shift from the chemical energy storage of fossil fuels for our winter peaks, and our electric grid starts to carry that, instead of switching from a summer peak to a massive winter peak with a COP of 1, 2, 3, 4, if we go higher, we can lower that winter peak and not have to build as much wind and solar renewable energy to cover our electrification of buildings.

Audrey Schulman:  

Which allows us to go faster and for less cost.

David Roberts:   

That's an amazing world that you envision, and it's so exciting that you've been pushing this long enough now that it's starting to get taken up. I hope we can have the two of you back on in a couple of years when we have some GeoGrids in the ground to look at and assess. It will be so interesting to see how this evolves. Thank you for doing all the work to get this large stone rolling.

Audrey Schulman:  

We are thrilled. The Massachusetts legislature has put $5 million toward a GeoGrid research team, so they will be looking at the normalized data and making that data public, doing best practices etc., and figuring out what the scaled-up impacts will be. We hope from that to de-risk the system for everybody and make it so that we can all figure out how to use this system in the best possible ways.

David Roberts:   

Awesome. This is fun. I love what you're doing.

Zeyneb Magavi:  

Thank you. It was fun talking about it. We'll keep going and let you know where we get to.

Audrey Schulman:  

Thanks so much. Bye.