This article is the third in a three-part series on America’s energy crisis. See part one: How Energy Made the Modern World; part two: Energy and the Debt Conundrum.

The United States sits on top of the world’s largest supply of natural gas. In the last half-dozen years, the often-demonized oil companies have perfected two technologies that can deliver that clean-burning resource in quantities sufficient to replace imported oil as a transportation fuel. Significantly, natural gas can increase fuel economy, reduce greenhouse gases and do it all for a substantially lower cost per gallon than a gasoline (or diesel) equivalent.

How does this natural-gas revolution work? Since the early 1950s, geologists have known there are massive deposits of natural gas within nearly impenetrable shale formations in several areas of the country, including the Barnett Shale in Texas, the Haynesville Shale in northwestern Louisiana and eastern Texas, the Marcellus Shale along the Appalachian chain in West Virginia, Ohio and Pennsylvania, and the Fayetteville Shale in Arkansas.

Despite their continued demonization by politicians and the press (including conservative Bill O’Reilly on the Fox cable channel), oil companies have been innovating—inventing technologies and techniques to bring that otherwise unrecoverable shale gas to the market.

The first technique is called “horizontal-directional drilling." Based on satellite imagery, ground-penetrating radar studies and other geotechnical-imaging techniques, well locations are chosen above shale formations. Wells are drilled into the shale formation thousands of feet deep, and when the drill reaches a gas- (or oil-) bearing level, it makes a 90-degree turn into the resource-rich area.

Then, the second new production technology is applied: to facilitate the flow rate and create an economically viable production well, the shale is fractured. This is done by injecting pressurized steam and “fracking fluids” down the well. Then, ceramic pellets or sand particles are forced into the fractures to maintain the space necessary for the gas or oil to flow.

Beneficial modifications to fracking technology are being developed rapidly. For example, one methodology adds fibers to the mix of hard, small grains used to hold open the cracks in the shale. The fiber promotes more flow for a longer period of time, improving “conductivity." Another system employs specialized pipe fittings. Much like valves, the pipe fittings, when activated, can crack a vast volume of petroleum-reserve rock. This process also uses about half the water of conventional fracking and requires much less time to complete. As a result, fracking costs, and therefore per-barrel prices, can be reduced. Another new development has eliminated the need for water in the fracking process. It employs liquefied petroleum gas (LPG) as the fracking medium. A mix of LPG gel and sand is pumped deep into the shale formation (often more than a mile underground). The heat at such extreme depths causes the propane gel to heat up and vaporize. The propane, in gaseous form, returns to the surface with the natural gas and is then recaptured and recycled.

As a result of the horizontal-directional drilling, fracking technologies and their continuous improvements, nearly two quadrillion cubic feet of clean-burning, domestic natural gas has become available to the U.S. market. That is the number two followed by fifteen zeroes. How much natural gas is that?

The United States currently consumes twenty-three trillion (i.e., twenty-three followed by twelve zeroes) cubic feet of natural gas per year, using it to generate electricity, manufacture products, and heat businesses and homes. Nearly all of that gas is produced domestically and transported safely, efficiently and economically through underground pipelines. With two quadrillion cubic feet of available supply, the United States has more natural gas than it can use in nearly ninety years at the current rate of consumption.

Currently, only 1.5 percent of the natural gas produced in the United States is used as vehicle fuel. With the new supplies of natural gas, that can change dramatically. New shale-gas supplies can be used to fuel cars, trucks, trains and ships, as well as airplanes. It is easy to visualize natural gas fueling buses or cars. There are natural-gas buses and taxis operating in Washington, D.C., and in many other large cities in the country.

But how can natural gas power trucks and trains and airplanes? It is quite easy. Natural gas can be refined into diesel and jet fuel. In fact, refineries to synthesize diesel from natural gas are already in operation.

With oil prices having risen above $100 per barrel and natural-gas prices having fallen to generational lows (below $2.50 per MCF), the ratio of oil price to natural-gas price now stands at a forty-year high. The economics of converting cheap natural gas into highly valued diesel fuel for trucks or into scarce jet fuel are compelling. No subsidies are needed to build that industry, and no food is consumed in the process.

How much imported oil actually can be replaced with domestically produced natural gas? According to the Department of Energy’s Energy Information Administration (EIA), 6000 cubic feet of natural gas has the same energy content as a 42-gallon barrel of oil or of the gasoline or diesel fuels produced from that barrel of oil. Second, what volume of natural gas would be needed to offset the 12 million barrels of oil the United States imports each day? That figure can be determined by multiplying 12 million barrels by 6,000 cubic feet per barrel. That yields 72 billion cubic feet of natural gas. So seventy-two billion cubic feet of natural gas would be needed each day to replace the fuel now being refined from imported oil to power roughly 60 percent of the U.S. fleet of cars, trucks, busses, trains, planes and ships. How much natural gas is that in a year? Multiply 72 billion cubic feet per day times 365 days per year. The result is 26.2 trillion cubic feet of natural gas. Although that figure sounds large, the reserves of domestic natural gas are in the range of 2 quadrillion cubic feet. So how many years’ supply of natural gas is that? Before we do more math, we must recall that the United States already uses 23 trillion cubic feet of natural gas annually. Therefore, in order to fuel the transportation requirements now being met by imported oil, as well as to continue providing the natural-gas-fired electric power we already consume, we must add 26.2 trillion and 23 trillion. That sum is nearly 50 trillion cubic feet. If we divide the 2 quadrillion cubic feet of reserves by 50 trillion cubic feet per year, we find that the reserves would last forty years.

Without importing another drop of oil, the United States could operate the 60 percent of its transportation fleet now powered by imported oil, as well as continue to use natural gas for its current uses, for forty years. That gives America forty years for new technology to improve the efficiency and reliability of alternative-motive power, such as hydrogen fuel cells and electric batteries. That gives the country forty years to scale up economic production of infinitely renewable synthetic oil from algae and other biological sources. (That solution entails converting sunlight, brackish water and carbon dioxide from the ambient air into “green crude” via engineered algae. That green crude can be refined into gasoline, diesel and jet fuel usable in existing car, truck and jet engines.)

At the current price of oil, about $100 per barrel, the United States is sending more than a billion dollars every day—or more than $400 billion dollars a year—to foreign oil suppliers. At the current import rate and price, over forty years, $16 trillion (in 2012 dollars) will to be sent to foreign oil suppliers. That sum is more than the official, outstanding national debt.

That $16 trillion figure does not take into account the nearly certain probability that oil prices will rise as supplies grow more scarce and demand continues to rise. Remember, there are two giant and rapidly growing economies, India and China, that used relatively little oil as recently as ten years ago. The more than 2.3 billion Chinese and Indians are increasing their oil consumption at annual rates in excess of 5 percent. That exponential growth rate means that Indian and Chinese oil consumption will double in just fourteen years.

But the U.S. natural-gas reserves mean that the United States will not have to compete with India and China for oil. It will not be forced to pay ever-higher prices for scarcer and scarcer oil. Indeed, the $16 trillion that otherwise would have been sent to foreign oil suppliers will stay home. Those dollars will circulate in the U.S. economy, creating millions of high-paying industrial jobs in drilling, engineering, pipeline construction and refining. Those jobs will create enough earning power that employees will be able to improve their living standards, increasing their purchases of goods and services such as houses, cars, furniture, appliances, electronics, health care and education.

The economic benefits of that $16 trillion would multiply as the economic pie grows. It would be a real “stimulus package," not another government program to take from one unpopular group to give to a more favored constituency. Unemployment and welfare payments would be reduced. Tax revenues would increase. Deficit reduction would be possible. The dollar could be saved. The stock market would rise as corporate profits increased in a sustainable way. Retirement plans would be rebuilt. The standard of living for all Americans would improve. Societal rifts would diminish. America’s strength would be rebuilt.