¶ Intro / Opening
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¶ Pioneering Low-Carbon Concrete
So you get to the point that May first has come around and it is time for the moment of truth. I have to imagine this is a pretty tense moment because pouring concrete is something that you very ideally only do once.
Right, once a concrete pour starts, you don't stop it. All the pieces have to fit together. So the the concrete operation itself didn't look all that different from any other concrete operation.
But it was different. Yanni Sippis and his team were building the largest net zero office in Boston, and they were getting ready to pour a low-carbon version of concrete, one that had never been used in the entire history of commercial construction.
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You had a lot of people standing around watching this section of ground floor slab getting put in place. And I think we all recognize the gravity of that moment, you know, based on how much planning had gone into the effort and what the product would mean, not just for our project, but for our planet.
It's hard to understate how big of a deal it is for the construction industry to try a new type of concrete. Specifically, they were using a new type of cement, which is the glue that holds the concrete particles together. It's the stuff the Romans used to build the pantheon.
This is just a totally new way of doing something that's been done for thousands of years, uh, but in a way that's not impactful to the planet. Now there's something incredibly elegant about that.
¶ WS Development's Innovation Catalyst
For centuries, the makeup of cement stayed more or less the same. It wasn't until 1824 when a bricklayer invented Portland cement. that the recipe changed to what we use today. It's incredibly versatile stuff, but making it requires giant coal furnaces. And production of cement now accounts for almost 8% of global emissions.
So there's pressure on the industry to clean up, but with the literal foundations of buildings, bridges, and roads at stake, you can understand why the industry might be slow to change. But Yanni's team wanted to try.
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We weren't doing this to place, you know, twenty yards of concrete. We're we're doing this to show the industry what's possible.
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I'm Laura Pierpoint and this is the Green Blueprint, a show about Architects of the clean energy economy. We've already invented most of the technologies that we need to decarbonize the global economy. But many of these technologies are not yet commercial and they need to get financed and built at scale.
We don't have decades to get them commercialized. We have years. This week I speak to Yanni Sippis, Senior Vice President at WS Development on the first commercial deployment of a low-carbon cement and lessons on finding the right first customer.
If we can embrace the future and if we can create the most interesting, coolest, amazing, forward-looking office building, lab building, retail space, public space, you know, whatever the product is that we're working on, it's a competitor.
advantage for it.
Yanni is senior vice president at the construction company WS Development. He's also from Boston. In his role, he's in charge of redeveloping the city's seaport district. Thirty-three acres of office, residential, and retail space plus parks, a whole neighborhood, really.
I grew up in Boston. I went to school here. I've been doing real estate development in Boston my entire career. And so for a kid who grew up in the city to be able to play some tiny little role in helping to shape its future, that's kind of a boyhood dream.
¶ Securing Buy-In and Key Partnerships
One of the seaport's new buildings is one Boston Wharf Road. It's the city's largest net zero office building, which in this case means that it does have embodied carbon, but it operates with no net emissions. In October twenty twenty three, construction was humming along.
But around that time, Yanni came across an article in MIT Tech Review about a green cement company called Sublime Systems. It said the company made cement with electricity, not fossil fuels, and it had the potential to be completely zero carbon. So he got Sublime's number.
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So your next step is you pick up the phone and you call Sublime. So how did that first conversation go?
I don't think we knew what to expect from that conversation. I know they had no idea what to expect from that conversation because it's it's very unusual that a supplier To a supplier, to a subcontractor, to a general contractor, gets a phone call from an owner, from a real estate developer.
From the perspective of a first-of-a-kind climate tech company like Sublime, it's not just unusual, it's actually incredibly awesome to get interest from the end user of a complex multiple-step supply chain. This is true in commodities like steel and e-fuels because an influential end customer can push the rest of the chain to take a chance on a low-carbon product. It's definitely true here in Cement.
The company that produces the cement is way down on the supply chain.
And definitely is not used to hearing from real estate developers and owners, kind of the the ultimate client at the proverbial top of the food chain. And so it was a just a fascinating conversation. I think uh they they were a little bit taken aback, didn't really know how to react or what to say at first, but I think eventually we got to know each other a little bit and we kind of explained some of our philosophy and why we were so interested.
WS Development didn't know what they would use the cement for yet, but they knew they wanted it. What's in it for you on all of this? Did this come down to real excitement and commitment around greenhouse gas reduction? Is it worth the cost to you to be able to show the world that you're doing something no one else has done yet? Like what was what was the thing at the end of the day with NWS development that was like the reason everyone said yes?
We thought this was just super cool. And it's,
Love that answer.
I mean our ability to say it's cool and then just go do it is also a function of who we are as a company and how we're set up and our decision making process and lots of organizations.
don't necessarily have the ability to just say, wow, that's amazing and try something. And certainly that goes for public and government customers, but it also is true in lots of parts of the private development industry as well. It's also worth pointing out that for us, You know, we're in a very competitive business and Our customers, retail tenants, restaurateurs, tech companies, life science cu companies, you know, they aspire to be in the best buildings, the best neighborhoods.
the kind of physical places that will help them attract and retain the best talent, be most relevant to their customers or their constituents.
The problem was Yanni's team was actually close to finishing construction of one Boston wharf road, but they were so intrigued by Sublime's low-carbon cement technology, they figured there might be a few remaining places to use it.
¶ Economics, Strategy, and Project Timeline
But their window of opportunity was closing.
It was an extremely tight timeline. And in fact, this project, this multi hundred million dollar project was a moving train. And Sublime either had to get on the train at the right at the right uh not even stationed because the train was moving, had to sort of jump on the train along the way, or the train would have kept moving.
But before they could pour any concrete, Sublime WS and its contractors had to deal with a series of hurdles. They had to think through the economics, find the right placements for the concrete, and secure enough cement in time to meet construction deadlines. But first they had to secure buy-in from WS's internal team and the long list of contractors and subcontractors they worked with. As you're having these initial conversations to figure out basically can you work together?
What is happening inside WS development? Like how are you convincing your team to do this? Cause obviously you've got this ethos of experimentation. So does that mean you sort of mention this in a meeting and everyone's like, yes, let's go do this? Or was it more complicated than that to get everyone bought in?
Nobody really knew what to expect at first. This was something completely new. And although we like to think of ourselves as a company and our seaport team as at the forefront of innovation and the built environment. The reality is the design and construction industry generally. Especially in the United States, tends to be pretty reluctant to try new things and to try new materials and products.
So there was a I would say there was a healthy skepticism among the team when this i idea was first raised. Uh it was not something that had ever been used in commercial construction before. Now reenter at that point sublime. They recognized that reluctance. They recognized kind of the ethos and culture of the design and construction industry.
And they recognized early on that in order to gain traction and ultimately be adopted by that industry, uh, they had to do a tremendous amount of legwork in terms of testing and demonstrating that the product could meet the appropriate standards. to satisfy both the designers who were gonna have to specify the product and be comfortable that the product will perform, and construction partners who are gonna have to actually work with the product and put it in place in the field.
And so what we found is that the Sublime team had already done a a really, really robust array of tests. both in the laboratory and in the field, that they had already been socializing the product with the folks who would be their initial customers, so the, you know, the ready mix concrete suppliers. And so they had already laid a foundation. They had already kind of developed a toolkit uh that really helped us very quickly build consensus well, first confidence and then consensus.
around the application or the possibility of application of this product.
¶ Executing the Historic Concrete Pours
They also had a a unique partnership with Boston Sand and Gravel, right? So can you say a bit about how important that partnership was? Had you worked with Boston Sand and Gravel before? What did Sublime and Boston Sand and Gravel do together that kind of helped g give you confidence? Yeah.
Yeah, great, great question. Boston Santa Gravel is a is probably the largest ready mix concrete um provider in Boston. Uh they've provided most of the concrete for our Boston Seaport project over the years. They're a great partner But we as WS almost never intersected with Boston Sand and Gravel as an organization because they were a supplier to a subcontractor to our general contractor. And so we were you know, we're several rungs of the of the supply chain removed.
And frankly, the first time any of us had ever actually met the whole team for Boston Sand and Gravel was in the context of the Sublime Adventure, which I think was is kind of interesting and illustrative in and of itself. But Boston Sand and Gravel is Um simply put, is Sublime's customer. Sublime sells their product to Boston Sand and Gravel. uh which at a batch plant near North Station uh of Austin mixes the cement product, which is the the catalytic component of ready mixed concrete.
with the aggregate, with the admixtures, with the water, in order to create the kind of ready mixed concrete that comes off the the cement uh the concrete truck uh in the field. Um and Sublime again very presciently had been working uh for several years with Boston Sand and Gravel to better understand the ready-mix concrete business.
the the risks that Boston Santa Gravel as their primary customer would be concerned with, some of the technical aspects that they had to be concerned with. And so again, when we made this decision that this was something we wanted to do. that foundation had already been laid, so we weren't starting from scratch.
Okay, so you're working with Sublime, you're talking to them about what they can potentially provide to you. There's gotta be some cost associated with what it is they're ultimately gonna be providing around green cement. So tell me about kind of your initial discussions around that. Um, how did you think about the price premium associated with green cement that you'd be employing in one Boston wharf?
Sure. I I mean the reality in this case is is that the quantities that we were talking about, you know, the building was already under construction, the foundations were already in place, a bunch of the slabs had already been poured. So the quantities that we're talking about here
you know, the product at the time that we used it. And of course it's it's important to point out that the the moment in time or the moment in the the sublime trajectory where we use this product, it really was still sort of handmade in their pilot plant in Somerville. And so it's a it's a pre-scale cost structure. But the reality is the the relatively small amount of product that we were using, it was such a infinitesimally small premium to be paid that it was not at all part of the discussion.
¶ Overcoming Challenges: The Second Pour
Well, and I think it's true generally, right? That when you're thinking about the total cost of construction within a building, you know, a green premium on a different kind of cement. particularly in the future as these costs come down is not necessarily something that's gonna break the bank on these projects. Is that right?
That's right. I mean the the reality is that the premium that we pay for sustainability in terms of uh this building being all electric, uh in terms of the quality of the systems and the nature of the systems that we were already building into the building, uh, makes the cost of the cement, even if it were the entire building. pale in comparison. So the industry has already adjusted to a degree and embraced the notion of paying some degree of premium for sustainability.
And through the lens of, you know, a seven hundred thousand square foot building, some modest premium for green cement or green other types of products, it's not unique to cement, I would say the industry in general has already kind of adjusted to that reality.
¶ Fostering Industry Innovation and Growth
And embrace that reality.
I love that. Well and I really you know, I think this is a trend that hopefully we'll see really accelerate in the coming years because I think
You know, we're seeing this too in for example the carbon dioxide removal markets, where there's a you know a number of companies, particularly around frontier, that are willing to pay upwards of five thousand dollars a ton for CO two. And so recognizing the benefits of going first, of being innovative, of demonstrating what your company can do in all of this and the relative low costs, even at those, you know, really high initial prices, of ultimately incorporating these kinds of
these kinds of products into your systems I think uh hopefully we'll see a lot more of that happening.
Our adoption of this product in our minds hopefully will help accelerate its scaling up. And as a result, you know, the faster it scales up, the faster the cost structure comes into line with with what the industry is is used to on a much larger scale basis.
Okay, so let's go back to the project itself and talk for a second about the timeline because this is also A little bit of kind of like a a crazy a crazy moment for you. You're under construction at one Boston wharf and now you're talking to a startup that as you say has a small pilot production facility, but not exactly the ability to f to fulfill large
cement orders on a rapid basis. So talk a little bit about kind of the timing of what you needed for the project and where Sublime was in that moment and their ability to service contracts.
Sure. Uh one of the most complicated parts of the the sublime discussion once we were past sort of the basic engineering diligence. was this question of well how do we use this product in an impactful way and frankly based on where we were in the project's construction at that time, how much product can Sublime produce in their pilot plant uh in time for it to be used?
And so we iterated a bunch with our design team and their production team, their operations team, and were able to come up with two. places where they could provide enough product for for it to be used in a meaningful, impactful way. And then sort of the two you know, the two uh lines crossed, one in May of twenty twenty four, one in July of two thousand twenty four.
The project itself was actually completed in September of 2024, so this is right at the tail end of the of the overall construction project. And so we made a decision to put Sublime right at the front door of the building. So that everybody who walks into and out of one Boston Wharf Road through the beautiful public space that exists at the ground floor of that building will be stepping on sublime cement.
The second installation is in a public sidewalk right outside the building. So we have a one-third mile-long linear park. uh designed by James Corner Field Operations, the same uh landscape firm that did the Highline in New York. Um ours is called Harbor Way. And so if you're walking on Harbor Way and you cross Congress Street, you will step on a sidewalk made of sublime cement.
Okay, so tell us about the moment that you decided to press Go as a company. How exciting did that feel? What was it like? Or was there even a single moment?
No, th there was definitely a moment when when all the stars aligned. Uh the data was was good. The design and construction team had signed off. We identified the location. Uh Sublime had confirmed that they'd be able to deliver the product. And this was a relatively short time before we actually were making the installation, just because They were the ones who who were uh on the hot seat to to produce enough product uh in a timely manner for us.
And so it came together a couple of weeks before the the placement. And I think we all sort of just looked around uh uh around the room at one of our weekly job meetings and said, Okay, we're gonna give this a shot. We're gonna try it out. It's gonna be really neat. And we had our first placement at the beginning of May uh two thousand twenty four. By that point everybody was lined up. We had the plan in place.
Uh we knew where it was gonna be, we had the logistics plan done in terms of where the trucks were gonna come in, how the concrete product was gonna get to the place where it uh would ultimately lie. You know, all the legwork had been done and We were all just sort of holding our breath, waiting to see how this was all gonna go.
We'll hear how it all went down after the break.
¶ The Path to Global Zero-Carbon Cement
So Yanni's team had done their due diligence on Sublime. They'd secured the buy-in from contractors up and down the supply chain. They'd pick their two places to use the cement, and Sublime had sprinted to produce enough cement to deliver in time to meet the construction deadline. They were getting close to their first concrete pour, the moment you heard at the top of the show, but there was still a lot that could go wrong.
I'm curious to know if you're at all like me. I love to catastrophize. Did you like have moments where you were sitting there thinking through everything that could go wrong and what this might look like if it does?
Absolutely.
What what are some of the things that could go wrong here?
Sure. I mean look, if if you're gonna innovate, you have to be ready to fail. I mean, that's sort of that's sort of foundational to the culture. And In the very worst case scenario, we place the stuff and then a month later it starts to crack or it goes to pieces or it, you know, turns purple or something, and we have to chip it out and replace it with normal ready mixed concrete. And in this instance Um you know, we're not talking about an entire
portion of a building. We're not talking about an entire floor of a building. We're talking about a very prominent, but you know, somewhat uh small area of the building. If that was the worst that happened, we're fine with that. And that was a that was definitely a scenario that we discussed.
Um and it was a choice that we made and uh we were certainly prepared to to bear the consequences if the product failed, but we also had a very high degree of confidence because of all the testing that had been done that the product was not gonna fail.
Okay, so you get to the point that May first has come around and it is time for the moment of truth. How did it go?
The good news is the Sublime product worked and handled just like normal ready mixed concrete did. Um, except that you had a lot of people standing around watching and taking videos and documenting and smiling and, you know, really enjoying um watching this section of ground floor slab getting put in place.
And I think we all recognize the gravity of that moment, you know, based on how much planning had gone into into the effort and what what the product would mean, not just for our project, but for our planet.
And so you mentioned before that standard practice is you take samples, right, of this particular concrete pour and then you're gonna be testing them. So what was it like to hold your breath over the period of time that you were doing those tests?
Yeah, great, great question. We had we took a bunch of samples and then held our breath to see really it's the seven day break that's the first indication of whether this stuff is working or not. And um, you know, lo and behold, the seven day breaks all came out great. And then over time, you know, what we found is that the product was performing extremely well. And in fact,
the the strength curve kind of kept going. And that gave us a a whole lot of confidence in how this product is going to perform long term as well.
Okay, so your confidence is going up and up, and now you're approaching a second concrete pour date and you hit a bit of a snag in the form of one of this podcast's favorite bugaboos, which is the weather. So can you tell us a bit about what happened in July?
Sure. So the sidewalk pour an outdoor pour and it was a very, very hot day. And just by way of background, um when concrete cures, uh it's an exothermic reaction that generates a lot of heat. And you really don't want to have concrete get too hot as it cures because it'll crack, it'll fail, it'll spall, uh, and you have to chip it out and start over. So we're you know, we're pretty good in the industry at at
figuring out how to deal with um hot weather placements of normal ready mixed concrete. We add ice to the mix. There are other admixtures that we can add to the mix uh to keep the concrete temperature down and the uh uh the exothermic reaction under control. We really didn't know what to expect.
with the Sublime product. We didn't know whether it was gonna respond the same way. And so we sort of stood around that morning and said, Okay, it's gonna be really hot. What should we do? Is there anything different we should try? And the team, the Sublime team suggested that we just treat it like any other ready mixed concrete, you know, in a hot weather pour, which is exactly what we did. Nobody knew how it was gonna work.
Uh nobody knew how the how workable the concrete was gonna be, whether it would set up too fast, too slow, whether it would crack very quickly, but we treated it just like normal ready mixed concrete on a hot day, um and everything worked out great.
And when will you know that the placement has been fully successful? I know that one of the things you're tracking right now is the freeze thaw cycle, which we're so familiar with in Boston.
So the interior placement is certainly performing uh very well. The outside placement on the sidewalk, um, we are gonna watch very closely over time. You know, concrete in Boston and sidewalks is subject to a freeze-thaw cycle year after year. It's subject to uh corrosive agents like salt and other de-icing uh agents.
year after year. And, you know, the industry has figured out how to make very durable sidewalks. There are plenty of thirty, forty, fifty year old sidewalks all over the city of Boston that are performing great. We're definitely gonna watch the sublime pour carefully over time to understand how it performs. So far so good. We're halfway through the winter and it's been more focused on freeze than thaw. Um but it's something we're gonna learn from over time.
I love this. So what do you think this has meant to Sublime as a company? Uh I I would imagine that they've got folks coming through all the time to check out the real installed version of their cement.
Yeah, our our hope is that this helps them a lot and and as a result helps the product gain um you know more traction across our industry, not just in Boston, but locally, nationally, globally, of course. Um and so that's, you know, a big part of the reason that we did this was to help the the the company and the product.
um proliferate. And yeah, it's been great over the just over the past few months. Sublime has had a number of prospective customers, a couple of prospective investors, you know, through the project and to meet with us and interview us about our experience. And uh you know, that's every bit as much part of our commitment and aspiration as putting the product in place in the first place.
What are some of the lessons for other building owners and real estate developers who want to be as innovative as as you are? Uh, what can you tell us about the decision-making process, the number of decision makers? The ways in which you've infused this culture of innovation and experimentation, what are some of the things that other companies could do to start to run in these directions?
No, it's a it's an excellent question. Uh there are a couple of different topics here. Number one is just the nature of the organization and the culture of the organization. Um there are lots of businesses, real estate development being one of them, where innovation and trying new things is dangerous.
In the sense that, you know, whether you're building single family homes or retail centers or office buildings, you know, very often around the country, around the world, um there's a bit of a of a of a formula and there's a sense of, well look, if we build it this way, we know it's gonna work. Uh because that's what the market has always told us. And there's nothing wrong with that per se.
Um but you know very often there there are organizations that come along that say, well, that's great. That's the typical prototype. That's how it's been done, you know, for a long time, and that's proven. But maybe we can do better by trying something new, by innovating.
And I this isn't to say that that's, you know, better than uh uh you know a more traditional approach. It's just different. It's a different business model, but certainly having an organizational culture that treats innovation and entrepreneurship um in a way that's celebrated and embraced is really important because inevitably
Um, you know, whether this is coming from a uh the most junior assistant project manager, uh, you know, or someone like me that oversees, you know, the a big project or the CEO of a company. one has to have a comfort zone bringing forward a new idea like
You know, someone has to feel safe saying to his or her peers, managers, mentors, investors, hey, let's try something different. You know, this has never been done before, but we think it could be really cool. And that's a that's just an organizational uh culture uh sort of principle. Um and some organizations value that, some organizations don't. And again, it's not right or wrong. But for entrepreneurs in in this space and in in building systems and you know building materials and climate.
Finding those organizations that have a culture of innovation and entrepreneurship and celebrating the bringing forward of new ideas and the trying of new things, those are the kinds of marriages that are gonna work best. And the you know the sublime example is a is a terrific illustration of that.
How important do you think it is that WS development is private, locally owned, family owned? You know, do you think this is possible in the context of a big public company?
It's certainly possible anywhere, but it definitely helps a lot that we're a relatively small company. We're privately owned. You know, it's a very flat organization. Uh the decision making uh process here is very integrated. very uh engaged across different levels of the organization. And so it's very easy for us to be entrepreneurial and to be nimble and to try new things without having to check with
you know, somebody across the country or around the world or um, you know, the public markets, uh, for example, we have a lot of ability to be entrepreneurial just because of the way we're set up. Um, but that doesn't give us a monopoly. on innovation or entrepreneurship. It just makes it a little bit easier for us to be nimble and flexible and and try new things like this.
Yeah, I love that. Well, so talk a little bit about what Sublime did right and what kind of lessons there are for other companies that are like Sublime in their scaling journeys and are looking to partner with big companies, get real demonstrations under their belts. Are there certain things that really stand out to you as really critical to the story that Sublime did that could illustrate what to do for other companies?
Sublime did a lot of things right. First of all, they started with a really incredible idea and technology. Like let's be clear about this. Um they have discovered something really extraordinary. And so that was the first thing they did right.
But what they did with that And I think this speaks to the s sort of the humility of that organization and the the humble nature of the concrete industry is they understood very clearly where they stood in the supply chain and what the risks and barriers would be. to the adoption of their product by what they I think assumed would be their customer, which is the ReadyMix concrete industry.
Very risk averse, very set in their ways, um, not a great history of innovation or entrepreneurship or trying new things, um, you know, for all for for valid reasons. And so they set about very early on taking this incredible new product, this incredible new idea they had developed, um, and coming up with the the data and the technical uh foundations that would be necessary.
to convince their very conservative, very set in their ways primary customers that this product was something worth looking at and and worth buying and w was not unacceptably risky.
So Yanni, let's talk a little bit about the trajectory here for Sublime. You're talking about world-scale revolution in ultimately decarbonizing cement production. What is it gonna take to get there? And what do you think this project is gonna mean for Sublime? And for zero carbon cement in that picture.
Sure. Well our hope is that this demonstration project illustrates to the construction and development industries. the power of the possible. We hope it helps illustrate the availability of Sublime's product. We hope it helps illustrate the impact the product can have on our planet.
And ultimately we hope It helps Sublime accelerate their trajectory and attract more, um attract more folks in our uh business to be saying to their teams, hey, we want to try this, not just on a demonstration project basis, but on a project-wide basis. and have it become rapidly adopted across the entire construction and development.
And as I as I mentioned earlier, a big part of that responsibility rests with Sublime, which now has under construction there for a scale up facility in Holyoke, Massachusetts that will, you know, be able to produce tens of thousands of tons a year, not dozens of tons a year at the way their pilot plant does currently.
And ultimately it's that prototype of larger plant that can be replicated into megaton type facilities, the way we have very large cement uh manufacturing facilities around the the globe today. and help to really accelerate the trajectory of the of the production capacity. And that's ultimately what will help.
make the product more available, lower the unit cost so it competes head to head directly with normal Portland cement and help get this stuff into every construction project around the world.
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Yanni Sippis is the Senior Vice President for WS Development Seaport and Fenway Development. The Green Blueprint is produced by Latitude Media in partnership with Trellis Climate. The show is hosted by me, Lara Pierpoint. Our producers are Aaron Hardick and Daniel Waldorf. Ann Bailey is our senior editor. Sean Marquand is our technical director. Stephen Lacey is our executive editor. If you'd like to suggest topics or guests for the show, send an email to editors at latitudemedia.com.
You can listen to the green blueprint at latitudemedia.com or subscribe wherever you can. And if you have a fellow client, this show, send them a link. This is the Green Blueprint, a show about the architects of the clean energy economy.