Assume a climate crisis.

"We have the tools—the technologies, the resources, the economic models—to deliver cost-effective climate solutions at scale," testified K.C. Golden of the U.S.-based NGO Climate Solutions before the Senate Public Works Committee in July 2013. Friends of the Earth issued a similar statement in September: "We have the technology we need [to address climate change] and we know what needs to happen. We just need to get politicians to do it." Tove Maria Ryding, coordinator for climate policy at Greenpeace International, sounded the same note last year: "We have all the technology we need to solve the [climate] problem while creating new green jobs."

The implication is that humanity could deploy a suite of currently available zero-carbon energy production technologies and energy efficiency improvements to avert the impending climate catastrophe. And the idea has been around for a while. Back in 2008, Al Gore urged America "to commit to producing 100 percent of our electricity from renewable energy and truly clean carbon-free sources within 10 years," a goal that he pronounced "achievable, affordable and transformative." His plan was possible, he explained, because the price of the technologies needed to produce no-carbon electricity—solar, wind, and geothermal—were falling dramatically.

As it happens, America did not take up the former vice president's challenge. In 2012, solar, geothermal, and wind energy generated 0.11, 0.41, and 3.46 percent respectively of electric power in the United States.

Was Gore right five years ago? And are the folks at Greenpeace, Friends of the Earth, and Climate Solutions right now that the no-carbon energy technologies needed to replace fossil fuels are readily available and ready to go?

Not really, concludes a new report, "Challenging the Clean Energy Deployment Consensus," by the D.C.-based Information Technology and Innovation Foundation (ITIF). Such plans, the study argues, "are akin to attempting large-scale moon colonization using Apollo-age spacecraft technology." Such a feat may be technically feasible, but only at vast expense.

Would you rather drive a 1913 Model T Ford or a 2013 Ford Fiesta? They both cost about the same amount of money in inflation-adjusted dollars. The ITIF analysts think the advocates of immediately deploying current zero-carbon energy production technologies are essentially arguing that we should all drive Model T Fords now.

To get some idea of what would be involved in "repowering" America using only the currently available zero-carbon technologies, let's delve into one of the more ambitious of the studies that the ITIF folks criticize. In a 2011 paper, the Stanford engineer Mark Jacobson and the University of California–Davis transportation researcher Mark Delucchi calculated what it would take to produce all the energy (not just electric power generation) to fuel the United States using zero-carbon sources by 2030. They conclude that this would require 590,000 5-megawatt wind turbines, 110,000 wave devices, 830 geothermal plants, 140 new hydroelectric dams, 7,600 tidal turbines, 265 million roof-top solar photovoltaic systems, 6,200 300-megawatt solar photovoltaic power plants, and 7,600 300-megawatt concentrated solar power plants.

Let's adjust those figures to take into account the fact that we currently use 40 percent of primary energy to generate electricity. Making the heroic assumption that Americans will consume no more electricity in 2030 than they do today, what would it take to "repower" the country's 1,000-gigawatt electric generation sector entirely in zero-carbon renewable energy sources? Keep in mind that the total asset value of the entire U.S. electrical system, including generation, distribution, and transmission, amounted to $800 billion in 2003.

Well, first we would have to install 15,000 new wind turbines, 155 solar photovoltaic, and 190 concentrated solar power plants each year. In 2012, the U.S. wind industry installed a record 13 gigawatts of rated generating capacity; construction of 15,000 5-megawatt turbines annually for the next 16 years entails a five-fold jump in the installation rate. Building 13 gigawatts cost $25 billion, which implies an increase to $125 billion annually, reaching a total cost over the next 16 years of $2 trillion. And that's just for wind power.

The world's largest solar photovoltaic plant has just come online in Arizona at Agua Caliente. That facility, rated at 250 megwatts of generation capacity, cost $1.8 billion to build. Achieving the zero-carbon repowering goal implies constructing 155 of these each year for the next 16 years. The costs would amount to roughly $280 billion annually, for a total of $4.5 trillion. The U.S. is also home to the world's largest concentrated solar power plant at Ivanpah, California. That 372-megawatt plant cost $2.2 billion to build that implies spending of about $440 billion annually for 190 such plants, adding up over 16 years to roughly $7 trillion.

That's just to build enough rated zero-carbon generation capacity to replace what we have now. As the ITIF study makes clear, most renewable power sources are highly variable in their production. The deploy-now crowd hopes that somebody will invent some way to store electricity so that it could make up for shortfalls when the sun doesn't shine or the wind fails to blow.

A 2013 study analyzed by the ITIF researchers cleverly solves this renewable energy storage problem by oversizing—that is by building two to three times more generating capacity than would be necessary if they could operate near their rated capacity all of the time. This suggests that at the low end of this estimate would raise the estimated costs in the repowering scenario by 2030 to $4 trillion for wind generation and to more than $23 trillion the total solar portion.

But my calculations assume that costs for constructing zero-carbon energy sources do not fall over the next 16 years. The price of the Model T Ford fell from $550 ($13,000 in 2013 dollars) to $260 ($3,500 in 2013 dollars) by its last year of production in 1927. Assuming that the costs of installing current versions of zero-carbon energy production technologies fell as much immediately, the total costs for would still amount to roughly $7 trillion by 2030.

The ITIF analysis alternatively adds up all of the costs in the Jacobson/Delucchi paper to estimate that weaning Americans off of fossil fuels entirely by 2030 would add up to a more modest total of $13 trillion, i.e., 5 percent of each year's GDP over the next 16 years. The upshot is that this repowering would cost each American household an additional $5,664 per year until 2030.

Are Americans really willing to shell out that much cash for zero-carbon energy? The ITIF report observes that a 2011 poll found that Americans were willing to pay just under $10 per month ($120 per year) more for electricity generated by renewable sources. In addition, half of Americans can choose to pay about 10 percent more to purchase electricity generated from renewable sources, but only 1 percent actually do so.

These calculations are just for the United States. Somewhere around 1.3 billion people around the world still do not have access to electricity. Taking the Jacobson and Delucchi figures for the world, the total cost to completely eliminate fossil fuels by 2030 would amount to $100 trillion, i.e., eight percent of global annual GDP. The global cost per household per year would amount to $3,571. The nearly three billion people who live on less than $2,000 per year simply cannot pay the prices needed to deploy current versions of renewable power technologies.

The ITIF researchers conclude, "The key to mitigating climate change is to make clean energy cheap enough to replace conventional energy without mandates, subsidies, or carbon taxes." That's entirely correct. But how to do that? Chiefly they advocate boosting federally-funded energy research and development from $5 billion to $15 billion per year in search of technological breakthroughs aiming to achieve dramatic cost reductions.

That overstates the efficacy federal energy R&D. But it does make a lot more sense than trying to force everybody into the equivalent of a Model T Ford.