To hear environmentalists tell it, the United States and our big power plants are symbols of profligate, destructive energy use.

As Ralph Nader told me, "This country, because it was blessed with huge amounts of oil, gas and coal, is the most wasteful user of energy." The Sierra Club’s Ann Mesnikoff says our coal plants should be much more efficient, and calls nuclear power a "dirty" technology.

But is our world-leading economy really so inefficient and wasteful? Are U.S. energy sources really so destructive to the environment? To answer these questions, it’s worth looking at some other economies that don’t have our massive energy infrastructure.

Consider the African nation of Tanzania. You might call these folks the kings of conservation. They consume a tiny fraction of our kilowatt appetite. They also have an infant mortality rate more than 10 times higher than ours, they die about 25 years earlier than we do on average, and their per capita GDP amounts to a few hundred dollars a year, compared to $35,000 in the United States.

Tanzania produces no crude oil, no nuclear power, and burns very little coal - and yet … this is one unhealthy environment. That’s why the Tanzanian government is trying to develop U.S.-style power production in a country where most of the energy comes from burning wood.

Peter Huber is co-author of the Huber Mills Digital Power Report and a former engineering professor at MIT. According to Huber, our big power plants are very kind to the environment when you consider the alternatives.

Says Huber: "Per unit of energy used, our large advanced fossil fuel and nuclear plants are way more frugal with the environment than what has been called, ‘the carbohydrate economy," when you’re trying to grow your fuel the way you grow corn and then harvest it whether from the rainforest or from corn fields…that takes huge amounts of land, it’s very inefficient and it displaces a whole lot of nature."

Huber says that if environmentalists really want to preserve wilderness areas like the Amazon rainforest, they should "transition the South American farmer from an economy that depends on burning down the rainforest to the kinds of energy sources we in fact use in North America today."

So while a modern American power plant may represent a wasteful burning of natural resources to some people, it actually produces a lot of energy with a very small footprint on the landscape. And for the amount of energy produced, a U.S. plant emits less carbon dioxide (Carbon dioxide – the main culprit in greenhouse gas emissions) than a guy burning trees in Tanzania or Brazil.

So why aren’t environmentalists embracing Big Energy? They fear the possibility of man-made global warming and the risks of nuclear power. So the environmentally correct solution is zero-emission wind and solar power. But just like farming for fuel, these alternatives would require huge amounts of land to deliver the juice we need to run our $10 trillion economy. According to Huber, that means clear-cutting huge tracts of land to make room for solar panels and windmills.

Says Huber, "To power New York City, you’d need most of upstate New York. People can argue about the numbers but these things are very low power density fuels. The sun doesn’t fry you to a crisp when you step outside. It sort of warms you a little bit. Wind doesn’t send you hurtling into space. It ruffles your hair.

That means there isn’t that much energy in it. You dig down a mile or so under the ocean and get out a barrel of oil, that’s a very concentrated form of energy. You want to match that with real estate, it’s a lot of real estate."

Could alternative energy sources become more competitive with more government research dollars? Well, the track record is not encouraging. Energy Secretary Spencer Abraham recently told Fox News, "Over the last 20 years in the Department of Energy, we’ve invested almost $6 billion in current dollar terms in solar, wind and geothermal energy research. Today, we find that combined, those three sources of energy supply less than one percent of all the energy we generate in the country. We believe those areas have had enough research."

The actor Robert Redford has criticized Abraham’s "drill, dig and burn" approach to energy production, but it may turn out be kinder to the environment than the "clear-cut, chop and collect" approach tied to wind and solar power.

James Freeman is the host of Power Politics, appearing at 9 p.m. ET tonight and 11 p.m. ET Sunday on the Fox News Channel.