Coupled with renewable sources of energy like wind and solar, nuclear power can help us transition to a zero-emission future, a new study reports. Especially in countries with geographies less suited to these renewable sources, nuclear energy could play a key role in helping us finally get rid of our polluting fossil fuel industry.

We’re all excited about renewable energy — well, fossil fuel companies are understandably less happy about it, but in general, it’s excellent news. But renewable energy isn’t perfect; it has gaps where it doesn’t provide energy, and the infrastructure isn’t quite here yet.

“Renewable energy sources like wind and solar are great for reducing carbon-emissions,” says Lei Duan, from Carnegie’s Department of Global Ecology, and author of a new study analyzing this. “However, the wind and sun have natural variation in their availability from day to day, as well as across geographic regions, and this creates complications for total emissions reduction.”

So we need something to help fill in the gaps, at least until renewables have matured enough to take over. In today’s world, this unfortunately means either coal, gas, or oil. But there’s another way, the authors of a new study argue: by using nuclear.

Nuclear energy has a very bad rep, and many fear it based on what happened at Chernobyl and Fukushima — but this reputation is very undeserved. Study after study has shown that nuclear energy is one of the most reliable and safe sources of energy. In fact, nuclear energy is responsible for 99.8% fewer deaths than brown coal; 99.7% fewer than coal; 99.6% fewer than oil; and 97.5% fewer than gas. Most of these fossil fuel deaths come from pollution.

In terms of both safety and emissions, nuclear energy is on par with renewables, and it would be a good complement to renewables as well. Previous estimates have suggested that in many parts of the world, renewables could account for 80% of energy production within the decade — the new study suggests that the remaining 20% should come from nuclear.

“To nail down that last 10 or 20 percent of decarbonization, we need to have more tools in our toolbox, and not just wind and solar,” explained Ken Caldeira, also one of the study authors.

To assess the potential of nuclear power to address this need, Duan, Caldera, and other colleagues looked at the wind and solar potential for energy in 42 countries. They found that some countries, like the US, have great potential of implementing new sources of solar and wind energy. For these countries, nuclear power would only be needed as a complement to get over the last remaining hurdles of decarbonization. But in countries with less potential (like Brazil, for instance), nuclear power could play a more important role, accelerating the energy system’s decarbonization.

Furthermore, the team notes, nuclear energy can be cost-competitive with other types of energy, and can even promote wind and solar by storing energy.

“In our model, in moderate decarbonization scenarios, solar and wind can provide less costly electricity when competing against nuclear at near-current US Energy Information Administration cost levels,” the study reads. “In contrast, in deeply decarbonized systems (for example, beyond ~80% emissions reduction) and in the absence of low-cost grid-flexibility mechanisms, nuclear can be competitive with solar and wind. High-quality wind resources can make it difficult for nuclear to compete. Thermal heat storage coupled to nuclear power can, in some cases, promote wind and solar.”

All in all, nuclear energy seems to be the missing puzzle piece in our plans to decarbonize energy production. While often feared, nuclear energy is a safe and reliable alternative and a great complement to renewable energy.

“Our analysis looked at the cheapest way to eliminate carbon dioxide emissions assuming today’s prices. We found that at today’s price, nuclear is the cheapest way to eliminate all electricity-system carbon emissions nearly everywhere,” Caldeira concludes. “However, if energy storage technologies became very cheap, then wind and solar could potentially be the least-cost path to a zero-emission electricity system.”

The study was published in Nature Energy.