December 2017 will mark the 75th anniversary of worldwide commercial nuclear energy. Nuclear energy has come a long way since Noble Laureate Enrico Fermi and his colleagues achieved the first human generated nuclear fission reaction. Fermi’s pioneering work has resulted in a new, virtually inexhaustible energy source that now provides about one-eighth (about 12 percent) of the world’s electrical power without greenhouse gas emissions. James Hansen, the climate scientist who headed NASA’s Goddard Space Research Institute, has estimated that peaceful nuclear energy has prevented nearly 2 million deaths by reducing global air pollution from fossil fuels.

Today, the U.S. fleet of nearly 100 nuclear power plants generates nearly 20 percent of U.S. electricity. The average capacity factor for U.S. nuclear output — actual electricity produced compared to maximum possible output — was 93 percent in 2015 and provided two-thirds of U.S. carbon-free electricity. America’s nuclear plants safely generate reliable, on-demand, carbon-free electricity with major economic benefits for the communities they serve. Studies show that typical gigawatt nuclear plants generate approximately $470 million in sales of goods and services in their local community and nearly $40 million in total labor income. Each plant also generates $16 million in state and local tax revenue annually.

To meet future energy needs in Utah, small modular reactors (SMRs) using 21st century technology, are under development with a prototype SMR reactor to be built at the Idaho National Laboratory. Power companies in Utah and Idaho recently announced they will jointly build the world’s first SMRs to provide electricity to nine Western states. These reactors will replace about 320 megawatts of electrical output now generated from coal power plants, which may be forced to close under current EPA environmental regulations. Each of possibly 12 modular reactors can generate 50 megawatts of electrical power. SMRs could be a game changer for nuclear power as they may be cheaper and faster to build and site than present reactors. SMRs can be factory built and fully assembled and delivered to the plant site by rail or highway. SMRs require less initial investment and are better able to accommodate variable power demand, making them ideal for meeting the power needs of remote areas. Finally, SMRs may even prove cost competitive with current natural gas generated electricity.

However, despite substantial benefits from nuclear plants, many oppose nuclear energy while demanding control of global warming. They regard the risks of nuclear energy as even greater than climate change. Some also believe that solar and wind power alone can stem the mounting evidence of worldwide climate disruptions from greenhouse gases. Despite mandates requiring use of renewables in 29 states, federal tax credits, and subsidization by non-renewable customers, solar and wind power supply about 6 percent of U.S. electrical power. Obviously, nuclear energy is not the complete answer to world electricity needs. Other energy sources, natural gas and certainly renewables, must all play an important role in balancing the cost of electricity production, demand availability and environmental impacts. Natural gas, produced through fracking, although cleaner than coal, is subject to price and availability fluctuations and concern over the impact of fracking on increased seismic activity.

It required 75 years for nuclear to provide one-eighth of the world’s electrical power, so can intermittent, low capacity wind and solar replace nuclear energy? U.S. renewable energy output in 2015 was 22 percent wind, 7 percent solar, 26 percent hydro and 45 percent biomass combustion and geothermal. Wind and solar contributed, respectively, 4.8 percent and 0.9 percent of U.S. electrical power. World nuclear power plants generated nearly 800 billion kilowatt-hours of electricity in 2015. Can renewables alone replace electrical power needs in the future?

Gary M. Sandquist is a professor emeritus at the University of Utah.