With energy policy, settling on the best energy source is more important.

An analysis takes a holistic look at America’s eight most important energy sources: natural gas, wind, solar, nuclear, coal, petroleum, geothermal and hydroelectric.

Most analyses look only at one or two factors with each energy source – usually cost. Here is a look at five key factors: reliability, feasibility, technological innovation, environmental and human impact, and cost. A one to 10 score is assigned in each category, averaging them for a letter grade.

The conclusion is that natural gas is the best energy source – and the only one that gets an A. Its reliability and feasibility are high because natural gas plants can be ramped up and down to meet changing demands and are easy to build. At the same time, it gets a high grade for environmental and human impact, with ongoing innovation making natural gas cleaner with every passing year. And natural gas gets the highest grade for cost, because, when all associated costs are factored in, it’s our most affordable energy option.

What about petroleum? While it is reliable, petroleum has lower feasibility and higher costs, with little demand for increased use. It gets a 70%.

As for coal, it gets an 80%. It’s still broadly affordable, reliable and innovative (which lowers its environmental impact). But it’s becoming less feasible, especially because of government policies. Coal produces a smaller share of U.S. Electricity every year, and absent a major shift in policy, that declining trend is all but certain to continue.

What about nuclear? It gets a B+, with a score of 88%. It has the best environment and human impact, since it’s completely clean and is seeing significant technological innovation. It’s also tied for being the most reliable since nuclear plants can run uninterrupted for years at a time. Nuclear energy’s small drawbacks are feasibility and cost. Government policy and regulatory pressure has dramatically increased nuclear energy’s price tag (mostly during construction). With a change in policy, nuclear power could compete with natural gas for the highest grade.

Then there are the four main renewables – hydroelectric, geothermal, wind and solar.

Hydroelectric gets a B-, with 80%. That includes a perfect 10 for reliability since it can generate power on demand. It also gets high marks for cost, innovation and environmental impact. But it’s hard to envision a dramatic expansion in hydroelectric power. The easiest dams to build went up decades ago in the locations where big dams can be located.

As for geothermal, it gets a D+. While clean, it requires unique geographical conditions, making it hard (and expensive) to spread.

Finally, there’s wind and solar. Both get failing grades: 56% and 58%, respectively. While an “F” may surprise some, the grade looks beyond headlines to hard data. Wind and solar get low grades for their environmental and human impact. While the energy they produce is referred to as renewable, they both require massive increases in mineral extraction. Their manufacture also relies on forced labor (such as the Uyghurs in China) and even children (such as slaves in the Congo). They require significant land use, threatening wildlife and huge swaths of nature. Finally they’re inherently unreliable, since the wind isn’t always blowing, nor the sun always shining. As many parts of the U.S. are learning more wind and solar power means more blackouts.

Energy policy should be based on facts, not hopes and dreams. The study shows that the best way to pursue a cleaner future – one that’s economically affordable, reliable and clean – is to double down on natural gas and nuclear.

The worst path is more wind and solar. By choosing energy sources that get failing grades, policymakers are setting America itself up for failure.

Richard Lancaster is a Westfield resident.