Here are a few tidbits and figures compiled from various sources that I hope will put the world energy supply and demand balance in perspective.

On any given day, jet airplanes travel 41 million miles while burning 76 million gallons of jet fuel, cargo ships travel 3 million miles while burning 300 million gallons of oil.

In a year the United States will use more than 7 billion barrels of oil and 6 billion tons of coal.

All forms of global energy usage amount to a staggering 15 trillion watts, the equivalent of 150 billion 100-watt light bulbs burning 24 hours per day, seven days per week, every day of the year.

Fossil fuels supply 80 percent of the world’s energy: 35 percent is from oil, 25 percent from coal and 20 percent from natural gas. The rest comes from a mix of other sources: nuclear, hydroelectric and a tiny fraction from solar, wind and geothermal.

Everything we do involves energy and demand rises as population grows. At the current rate of growth, we will need 50 percent more energy by 2050, when the global population will have grown to 9 billion. And that does not take into account a likely increase in the rate of usage outside the United States.

Power usage varies markedly by culture. Americans on the average use 11 kilowatts, the equivalent of 110 100-watt bulbs. Europe uses half of that, 55 bulbs; Asia uses 16 bulbs; Africa, eight bulbs. Estimates are that it would take the resources of 5.4 planet Earths to sustain the entire world at current U.S. levels.

Everything we eat and everything we use requires energy to produce and distribute — even things that we take for granted such as food, the glass and china for table settings and leather shoes. Energy is invisible in the product.

On the supply side, remote locations that were written off a decade ago now produce oil, but at higher cost.

The Athabasca tar sands in Northeastern Canada contain 7 trillion gallons of oil, second only to Saudi Arabia in total reservoir size. It accounts for 20 percent of U.S. imports. The sand is gooey, thick and heavy and requires that many tons of material be moved and proc­essed rather than being pumped as liquid.

With reserves dwindling it is getting more expensive to extract oil even from current sources.

When we began using oil 100 years ago, it cost one barrel to extract 100 barrels. Now the same one barrel will extract only 20 barrels in Saudi Arabia and five barrels of tar sands.

When oil costs more than it is worth, it will be the end of the oil age. No one knows exactly when this will happen, but it will happen and it is a sure thing that the price of oil will rise as the supply diminishes.

To have 70 percent of our energy produced by solar, wind and nuclear by 2050 would require that we construct 1,600 square feet of photovoltaic cells per second, one large wind turbine every three minutes and one nuclear power plant every week.

That is a daunting challenge.

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Richard Brill is a professor of science at Honolulu Community College. Reach him via email at rickb@hcc.hawaii.edu.