Microsoft co-founder Bill Gates would like to talk to you about, of all things, cement. Why?

Gates considers cement to be a great example of something in need of a desperate cleanup to fight climate change.

“It’s over 6% of worldwide [carbon] emissions,” Gates told “Marketplace Morning Report” host David Brancaccio in a recent interview. “And yet, we don’t have a way of doing it that’s clean, that doesn’t cost dramatically more, more than twice the price.”

That extra cost of making “clean” cement is what Gates refers to as the “green premium” in his new book, “How to Avoid a Climate Disaster,” and it will be a huge obstacle to achieving zero carbon emissions.

Economies are unlikely to adopt a cleaner way to produce such a common building block of buildings if they can’t afford it.

“The world is going to keep building buildings just for the basic sheltering needs in the developing countries,” said Gates, who’s also co-chair of the Bill & Melinda Gates Foundation and founder of Breakthrough Energy, a coalition of groups that work toward speeding up the arrival of a sustainable energy system. “And so we can’t ask them to stop doing that, but we need to give them an innovation so that that cement isn’t superexpensive.”

The following is an edited transcript of Gates’ conversation with Brancaccio about his new book and the technological innovations he thinks are needed in the next 30 years.

David Brancaccio: So among the five questions that, apparently, you ask when people talk solutions to climate change, one of them stands out. It’s No. 2 on your list. You ask, what does this do about cement, the construction material? Why is that so important to you?

Bill Gates: People need to understand that there’s lots of sources of emissions. Almost everything around them, you know, plastic, wood, steel. Cement is a great example. It’s over 6% of worldwide emissions. And yet, we don’t have a way of doing it that’s clean, that doesn’t cost dramatically more, more than twice the price. So if people think it’s just passenger cars and electricity, they’re going to miss what we need to do to get to zero.

Cement’s role in climate change

Brancaccio: I mean, it’s the thing about cement — which is a key component of concrete that we build everything out of, it seems — is that it requires lots of energy to heat it up in its manufacturing process. But also, the chemical process that makes cement releases CO2. I mean, it’s a real CO2 thing.

Gates: That’s right. There’s the two sources. Limestone gets heated to pull out the calcium, and that chemically releases CO2. And then if you’re burning, say, natural gas to make that heat, that also creates CO2. And, you know, the world is going to keep building buildings just for the basic sheltering needs in the developing countries. And so we can’t ask them to stop doing that, but we need to give them an innovation so that that cement isn’t superexpensive. And the U.S. has got the innovation power. We need to get our brightest minds, both at the basic [research and development] level and startup company level, working on cement and create demand for any cement that’s starting to lower that extra “green premium.”

Brancaccio: All right, the green premium. You wrestle with this throughout the book. It may be one thing to say, “I have an innovative process that doesn’t use much CO2, and it creates this great building material.” But if it costs a lot of money, I mean, how much is anybody going to actually use?

Gates: That’s right, and particularly if they can say that the U.S. is responsible for all these historical emissions. And so, you know, we’re not going to subsidize countries because that’s trillions of dollars. Unless we can bring these green premiums down by about 95% through innovation, I don’t think we’ll hit the goal of zero by 2050.

Brancaccio: Cement and concrete — we’ve been using that for hundreds of years. Is there actual innovation going on in this space?

Gates: One company looks like they can cut it by 30%, just by reinjecting CO2 into the final product, which is kind of amazing that that works. And there are dozens of other companies that our Breakthrough Energy Ventures group has funded that have different ideas. And if you bring them together and they all work at scale, you could bring that green premium down a lot.

Brancaccio: Well, essentially a carbon sequestration, they call it, by injecting CO2 into the concrete so the slab just permanently holds the CO2?

Gates: Exactly. That’s a Canadian company called CarbonCure, one of the ones doing that. And currently, it’s 10% reduction, but their next generation should get up to 30%. So it’s a start. You know, we need a market, we need people to buy that greener cement, not green cement. And so that we start to scale it up and get the cost down like we did with solar panels.

Toward better batteries

Brancaccio: And when it comes to addressing climate change, we always talk about ways of storing energy — better batteries to store energy when the sun isn’t shining, or the wind isn’t blowing, or if the grid doesn’t need all the power that is on hand. But in the book, Mr. Gates, you seem a little battle-weary on this subject.

Gates: Well, there’s no guarantee that we can make this battery, that would have to be 20 times improved, to store all that electricity. And so to maintain reliability, we may need sources that don’t depend on the weather, like nuclear fusion providing up to a quarter of our energy generation. So during those times with the big cold front over the Midwest, we don’t all freeze to death.

Brancaccio: But you’ve invested a lot of money trying to encourage innovation in batteries, and it hasn’t really revolutionized batteries.

Gates: Well, the battery for the electric car, which is almost within a factor of 2 or 3 of being totally competitive — that, there is progress. That’s a much easier problem than this grid electricity storage, where every battery we’ve ever made couldn’t store a week of U.S. electricity. So there are many approaches. Some of the companies who pursued this failed, but there’s dozens more with good ideas that I’m investing in. And so either we need this big storage miracle or we need some form of nuclear to make sure that it’s green and reliable.

What about nuclear power?

Brancaccio: Now, you address this issue in the book about nuclear power, maybe smaller-scale projects, maybe some underground. You know that those plants can go horribly wrong. I mean, that’s the experience we’ve had with nuclear power in spectacular ways.

Gates: Well, in providing energy we’ve had coal-mining accidents, natural gas pipelines blow up, you know, particulates causing bad health. And yes, nuclear, to get that to be used broadly, we need a completely new generation where it’s inherently safe because there’s no high pressurant. So that fourth-generation, designed-from-scratch nuclear is what a company called TerraPower is working on, and the demo plant that’s been done will prove out whether that can work or not.

Brancaccio: And you have an interest in that. Some of these newer approaches to generating nuclear power require enriched fuel, enriched uranium, and that worries people worried about the fuel getting into the wrong hands around the world.

Gates: That’s right. You always want to make sure that it’s never a source of weapons material. Eventually, you could move away from enriched uranium and just breed in the reactor itself. But, yes, nuclear has lots of challenges, but so does every other path. And because climate change is so important, we need to pursue many paths to make sure we actually get a solution because 30 years is a very short period of time.

Brancaccio: And to be clear, you actually have an interest in a company, TerraPower, that is trying to do work in this area with a new generation of nuclear power.

Bill Gates: That’s right. Because of my interest in climate, I got that going as a potential solution. You know, I don’t know that it will work, or even if it works that the public will accept it. But, you know, along with investing in many storage companies, raising the odds of solving climate is worth taking big risks if it proves out to be super-, supersafe.

The goal is net-zero carbon emissions

Brancaccio: Can I ask why your goal — you make it very clear in the book — why is your goal net zero? I mean, you must have told your people a million times over the years, “The perfect is the enemy of the good.” But you want zero, as in none, nada, zip. Wouldn’t phasing down our carbon dioxide and carbon production be more reasonable than setting success at zero?

Gates: If you don’t mind all the corals dying and Miami Beach [in Florida] disappearing and island countries being underwater and farmers near the equator starving and trying to migrate up to northern latitudes. You know, CO2 stays in the atmosphere for thousands of years. So if you have positive emissions, you’re driving the temperature up on an ongoing basis. And that’s more crop failures, more days humans can’t go outside. It gets pretty extreme, and those natural ecosystems won’t come back.

Brancaccio: You’re saying you don’t have a choice, that zero is just mandatory. We don’t have a choice.

Gates: If you care about not having the sea level rise go up dramatically or losing all these natural ecosystems. I mean, some number of humans can keep moving north. But it’s going kill five times as many people per year by the end of the century as the pandemic is today and cause massive instability. So it’s not a good thing if you don’t bring the numbers down.

Brancaccio: You refer to your journey on this issue of climate change. Because we think of you as a technology guy, we think of you as the philanthropist very focused on global public health. And sometimes this notion of we have to mitigate climate change can mean poorer countries don’t get to have what we have. And that used to worry you more. So you’ve actually evolved on this?

Gates: No, I think that the developing countries deserve to have decent shelter and air conditioning. And that’s why you can’t just reduce consumption all the way to zero. We need a way of making all these physical products, including electricity and aviation fuel, that, even if you make a lot, you multiply by zero and there’s no emissions. And the people who are suffering the most are the poor countries who did nothing to cause this problem. So we also need to invest in adaptation [to climate change], giving them better seeds, better water storage, so that the amount of suffering even in a 2 degrees [Celsius] increase is limited.

On cap-and-trade permit systems

Brancaccio: How do you feel about systems that California has had some success with, “cap and trade” — essentially trading credits between companies that do a better job being cleaner when it comes to carbon and those that will buy them because they’re dirtier?

Gates: Yeah, those systems have value. They don’t solve the whole problem. You’re never going to do anything that has a high green premium because the imputed cost per ton in those systems never gets you working on the hard stuff. And that’s a big message of the book: We have to drive the innovation pipeline to work on the hard stuff. We’ve focused entirely on the easy stuff, which is passenger cars and using solar and wind to generate electricity. And that’s not even a third of the problem.

Brancaccio: And that’s one of the big takeaway points of this book, right? We often think of transportation — if we can figure out how to get cars around without using fossil fuel. But it’s a multilayered challenge, and you come at it from many different directions.

Gates: Right, when you have so many sources, just meeting short-term goals alone won’t get you there. We should be putting dramatically more into the hard stuff, including at the basic R&D level. My Breakthrough Energy Ventures group is funding a lot of new ideas to bring down green premiums, but without government doing more, the innovation pipeline won’t move fast enough.

Brancaccio: Because governments can tolerate big risk on things that might pan out spectacularly or might not?

Gates: Yeah, you see in health innovation the U.S. has been fantastic at driving basic research and that a lot of the companies are created here in the U.S. and great jobs and invent new medicines. And that same cycle of innovation, as people are demanding clean-energy products, the U.S. can take its innovation power and create industries around it. And so we need an increase in R&D.