PARIS—From "clean coal" evangelists to solar power enthusiasts, most experts at the U.N. climate talks here agree that solving climate change means transforming how the world produces and uses energy—and as quickly as possible. Such a transformation would be unprecedented. It would require enormous investments. To help make it happen, the U.S. Department of Energy, which for decades has spent billions of dollars to develop and deploy advanced energy technologies (not always clean), will play a major role in the new "Mission Innovation." The initiative is an effort announced by 20 major countries at the COP 21 negotiations here to significantly accelerate clean-energy improvements.

On December 9, Secretary of Energy Ernest Moniz sat down with Scientific American to explain how innovation and transformation might be sped up to meet the climate challenge, which requires a world without carbon dioxide pollution, soon.

[An edited transcript of the interview follows.]

How do we get to 80 percent cuts in CO2 emissions in 35 years, the Obama administration's long-term goal? And beyond that, to meet a Paris deal that might even require "zero carbon" by then.

Obviously, innovation is going to be central. We're very pleased that our French hosts put innovation on the front burner: having Innovation Day, following Energy Day. And of course, the announcement on the very first day by 20 countries, including Pres. Obama, French Pres. Hollande, India Prime Minister Modi and others, of Mission Innovation. Then the Bill Gates announcement on the parallel Breakthrough Energy Coalition initiative.

There is no question that the world now understands that innovation is the core to meet the INDCs [national climate action plans, known as "intended nationally determined contributions"]. We've had a lot of cost reduction and innovation and deployment increases. That virtuous cycle has put us in a pretty good spot to meet a 10-year horizon, maybe a 15-year horizon. For sure, as we go to the longer time periods and extraordinarily low levels of greenhouse gas emissions being discussed, we're going to have to keep that going.

I just came from a meeting of the Mission Innovation countries. There is a tremendous amount of enthusiasm. The resonance of the Mission Innovation agenda was so great because it largely fits with the directions that so many countries were going in. It's crystallized that—given that a very explicit framework. We are the dog that caught the car. And now we're [laughs] figuring out what to do with the car.

Some people argue that we can meet the goal with the technology we already have, whether it be CO2 capture and storage for fossil fuels and nuclear power or more renewables or all of the above, to use a phrase. Others say we really need a breakthrough. You're on the breakthrough side?

In some sense, the answer is yes. What we're talking about is this cycle of innovation, deployment, cost reduction. They all go hand in hand. We have seen that explicitly in the last six years. Continued cost reduction in clean technologies is going to be important. And new enabling technologies are going to be important. So, for example, with wind and solar, we still are not at the point where we can have a large scale-up of energy storage. We are still not at the stage where we really have incorporated [information technology, like computers and the Internet] extensively into the energy infrastructure in the way we're going to need.

We also have qualitatively new directions to go in. One is the Makani flying wind turbines. Or now the Google X flying wind turbine; it’s so novel that we don't understand exactly how it could have a big, major transformative impact. But it sure looks like it would if it became a widespread technology.

What about carbon capture and storage? You and I have a long history of talking about it. Is it doomed because of cost, even though the emission-reduction projections from so many countries require CCS?

No, it's not doomed. Quite the contrary. We are seeing cost reductions, but those things tend to come by having more projects in place. We have seen six big projects that are in various stages in the U.S., Canada, United Arab Emirates, Saudi Arabia and so on.

The timescale for scale-up in the power sector is probably not tomorrow. It's a little bit longer—but it works. The technology exists. And it's the same story we would have had for solar 10 years ago. You know: "It costs too much. It doesn't have a place." Well, 10 years later the costs are down by an order of magnitude and it has a place.

But it's a lot easier to build a photovoltaic module than a big power plant with CCS.

Well, yes. Whether it's CCS or nuclear power, the bites have to be bigger. But people do lose sight of the fact that 10 years ago, for all those technologies in the clean revolution, the mantra was "they're too expensive." The same was true for LEDs, even though you had a life cycle economic benefit from one LED fixture that cost $30. That was a hell of a big barrier to actually getting the deployment, right?

Well now, with payback periods well under a year, it's suddenly a different ballgame and, as you know, the deployment is going up like crazy. The India story here is fantastic. With their bulk buy of a couple hundred million they are going to be paying one euro, which isn't much more than a dollar, per LED. It's a whole different world.

Do you think the U.S. can build more nuclear power plants or even prevent old ones from closing down early?

Those are two different stories. We need to think about some different timescales and what the real issues are. I use 2030 as a kind of dividing line, because the Clean Power Plan has a 2030 horizon. The typical INDC is in that ballpark, too (ours is 2025).

It doesn't take a lot of arithmetic to figure out that 2030 is the beginning of a big wave of retirements of nuclear power plants. What's going to be the capital planning of utilities starting in the 2025 timeframe going forward, and will that include new nuclear?

The immediate issue is sustaining existing nuclear. A big part of that story is going to be how states structure their implementation for the Clean Power Plan. That could provide incentives for sustaining those nuclear plants.

The second issue relates to the 2025–2030 timescale. One option is advanced light-water reactors. We obviously have four such reactors under construction in the U.S. More than that are under construction in China. But we still don't have a solid answer to the question: How is this going to perform on cost and schedule?

Another question is what will small modular reactor technology look like? NuScale [Power] is on schedule to submit its design certification application to the Nuclear Regulatory Commission next year. That puts it on a pathway where we could see a bunch of the initial plants deployed and operating in the first half of the next decade.

This technology looks very, very interesting from the safety point of view. It's much more modular. But again I don't think anyone can say that we really understand the cost until we actually see it done. And not just the first one but some number where we can get an idea of the true cost.

Then, for the longer term, there's the question: Are we going to get some additional technologies on the table beyond light-water reactors?

Although those are the issues to be resolved for different time periods, I want to emphasize that you’ve got to work on all of them now [laughs]. You don't have a new option for 2040 if you just wait around until 2040 to start developing it.

I know you don't want to "debate the undebatable," as you've said, but how can remaining doubts about climate change be overcome in the U.S.?

Why do you think there are doubts?

Because people like members of Congress say they have doubts.

Those are some statements made by a narrow slice of the population.

It happens to be an important and powerful slice of the population.

Look, I think public opinion is clearly evolving to understand and support the idea that we need to act on climate change. We are seeing all kinds of constituencies—military, religious leaders, businesses, labor—all saying, "We gotta act, and guys, it's probably better if we could just get some certainty about where we're going now."

I just don't believe the noise in the system will be sustainable much longer. It's just time that we don't debate what's not debatable, since you raised that from the dead, and just get down to the business of what's the scope, the scale, the pace at which we address it? That's a legitimate discussion.

What's coming out in Paris is important. Obviously, we still have a few days to go in terms of some very important negotiations around transparency, and more ambition with renewed commitments. But I don't want to lose sight of the fact that when almost every country in the world has come forward with an INDC, with various levels of reductions of greenhouse gas emissions, that's kind of a "Hello?!" A big message that the world has moved past the idea of whether [there is climate change] to how to try and resolve the issues.

In the U.S. we will move forward. That's why it's very important to emphasize the innovation agenda—for the U.S. and now for 19 other countries, Mission Innovation as well as the parallel investor initiative led by Bill Gates. I think is going to be a very big deal.

And frankly I think that the innovation agenda, which of course has multiple objectives, does have support. The reality is we have felt, and CEOs have felt—like the American Energy Innovation Council, for example—that we are significantly underinvesting in energy research and development.

So I think the innovation agenda—pursuing climate-risk mitigation, pursuing energy security (not just for us but for everyone), satisfying our social responsibilities to help two billion people get some semblance of appropriate energy services—that's all wrapped up in this innovation agenda.

The 20 countries come from almost every continent. They are countries at very different levels of development. They are countries with very different energy situations. Germany and Saudi Arabia would be a good set of bookends, for example. It's East–West, it's North–South. I think it just shows the real resonance in this innovation focus.

So, having been involved with the Iran nuclear agreement and now observed climate change negotiations, which is harder?

There's no point comparing. [interviewer laughs] They were both multipolar. There are more poles here than there were there but…. As you know, I'm not part of the detailed negotiating here.

Yes, but you have a window into that that the rest of us don't enjoy.

Well, yeah…

I'm sure you talk with Secretary of State John Kerry and maybe lead negotiator Todd Stern.

Oh, I've heard of them. [interviewer laughs] But my principal function here is to advance this innovation agenda as part of the solution.