Energy

Investments in efficiency are most cost-effective when electricity prices are highest. Smart meters are helping economists better estimate when electricity is needed to meet consumer demand.

The issue: Imagine: It’s a hot August evening, people are returning home from work and switching on their air conditioners. Electricity demand spikes.

Efforts to limit climate change generally focus on reducing carbon dioxide emissions caused by burning fossil fuels. However, another byproduct of fossil fuel combustion is black carbon, a major component of soot. Sources include diesel truck and car engines as well as wood fires, kilns, and stoves. Particles of black carbon in the atmosphere absorb sunlight and can have significant effects on the temperature, as do ozone, methane and other chemicals.

Which American state has the most earthquakes? If you guessed Alaska or California, you might have been right — years ago. These days, the title goes to Oklahoma, where research links the oil and gas industry to the quakes.

According to a Congressional Research Service report, “U.S. Energy: Overview and Key Statistics,” in 2010 renewable sources contributed 8 quadrillion BTUs of energy, which constitutes 11% of U.S. production and 8.2% of consumption.

According to a 2012 report from the Congressional Research Service, “U.S. Energy: Overview and Key Statistics,” petroleum accounts for 40% of all U.S. energy consumption. As of 2010, petroleum was predominantly used for transportation (70.5%), followed by industrial (22.9%), residential (5.7%) and electricity generation (0.9%) uses.

According to a 2012 report from the Congressional Research Service, “U.S. Energy: Overview and Key Statistics,” energy consumption in the U.S. nearly tripled from 1950 to 2011. Over the same period, however, electricity consumption grew even faster, rising from 334 billion to 4,120 billion kilowatt hours — an increase of 1,134%.