China has the dubious distinction of passing the U.S. in terms of total energy usage according to the International Energy Agency. China consumed 2.25 billion tons of oil equivalent last year, about 4% more than the U.S., which burned 2.17 billion tons of oil equivalent. The U.S. had been the globe's biggest overall energy user since the early 1900s.

China overtook the U.S. at an alarming pace. China's total energy consumption was just half that of the U.S. 10 years ago, but since that time, China saw annual double-digit growth rates.

It had been expected to pass the U.S. in 2015, but took the top position earlier due to the global recession that slowed U.S. industrial activity and energy consumption harder and faster than expected.

Huge energy demand also explains why China, which gets most of its electricity from coal, the most polluting of fossil fuels, passed the U.S. in 2007 as the world's largest emitter of carbon dioxide and other greenhouse gases. China is expected to build 1,000 gigawatts of new power-generation capacity over the next 15 years, equivalent to the current total U.S. electric-generation capacity.

The U.S. remains the biggest per capita energy consumer by far, with the average American burning five times as much energy annually as the average Chinese citizen. The U.S. also remains the biggest oil consumer by a wide margin, going through 19 million barrels a day on average. China burns 9.2 million barrels a day. Saudi Arabia, the world's largest crude exporter, now ships more oil to China than to the U.S.

The energy mix for the U.S. and China is very different. Coal accounts for 22% of the U.S. energy consumption, but two-thirds of China's, up from 57% in 2000. This helps explain China's reluctance to join global efforts to reduce carbon dioxide emissions.

The U.S. energy mix is more balanced, although oil dominates with 37% of consumption. Both countries must find ways to become more energy-efficient.

About the Author: Dale Schulz is the President of Schulz Homes, www.schulzhomes.com. He has been building and renovating custom homes in the area since 1987. He is also the President and Founder of Virginia Renewable Energy, which retrofits new and existing homes with renewable energy systems, such as solar PV panels and wind turbines. You may contact him, or send your questions for future columns to dale@schulzhomes.com. His phone number is 540.687.3367. The Schulz Homes office is located at 5 North Hamilton St.