Sometimes energy makes headlines, sometimes it doesn’t. But it almost always has important implications for the global economy, the environment, and our day-to-day lives.

Here are ten energy statistics from 2013 that capture some of the most noteworthy trends of the year -- and that will shape the energy world in the years to come.

In the latest update to its analysis on U.S. energy flows, Lawrence Livermore National Laboratory released a report in July showing that despite a slight reduction in total annual consumption, the U.S. still wastes more energy than it uses. The country is just 39 percent energy-efficient.

Take a look at the energy flow diagram below. Of the 95.1 quadrillion British Thermal Units (known as “quads”) of raw energy inputs that flowed into the U.S. economy in 2012, only 37 quads were constructively used at the end of the day (as “energy services”). The other 58.1 quads were, in essence, wasted -- as extraneous heat, noise, and leaks. This waste, summarized in the top right of the flow diagram below, is euphemistically classified as “rejected energy.”

Lawrence Livermore National Laboratory, July 2012

Most of the economy’s energy waste stems from the electricity production sector (because most power plants are relatively inefficient) and the transportation sector (internal-combustion vehicles are relatively inefficient, but they are getting better).

A century ago, utility companies were putting money toward giving away free light bulbs, electric irons, and other appliances to their customers -- to encourage them to boost their energy consumption.

Oh, how times have changed.

Every year, U.S. utilities are now spending more and more on efforts to help their customers reduce energy demand; expenditures in this category have grown 70 percent since 2008. Utilities’ combined budget allocation to “demand-side management” initiatives is currently an $8.3 billion stash of cash, and it's earmarked to improve the efficiency of buildings and appliances, trim peak electric demand, and give consumers the personalized guidance they need to save energy.

The drivers of this energy-lean trend are multidimensional, including: innovative legislation in about 30 states that requires and/or rewards utilities for efficiency investments; consumers’ universal desire and expectation for utilities to offer energy savings advice; and an underlying recognition that it is often cheaper to save a unit of energy than it is to buy or produce it.

Click here for an interactive state-by-state map showing the the economic and environmental potential of U.S. utility investments in residential energy efficiency.

The year 2013 was one of the hottest years ever recorded on Earth. Meteorologists are putting it at the No. 7 spot among all years since modern temperature measurements began in the late 19th century. To date, 2013′s combined global land/ocean average surface temperature has been 1.08°F above the 20th century average.

Down under, Australians sweated through its hottest summer ever and New Zealanders enjoyed their hottest winter ever. Meanwhile, Alaskans gleefully headed for the beach, as their most populous city, Anchorage, blazed through its longest heat wave on record.

The planet’s top ten warmest years on record have all taken place in the past fifteen years -- coinciding with a steady increase in atmospheric greenhouse gas concentrations. The last time the global temperature for any month dipped below the 20th century average was February 1985.

This July, the Big Apple became the Baked Apple.

A sweltering week-long heat wave sent the entire state of New York into air-conditioning mode. And between 3 p.m. and 4 p.m. on Friday, July 19th, the state's quest for comfort made history. The New York Independent System Operator (NYISO) reports that the state’s hourly average electricity demand hit 33,955 megawatts, surpassing a previous record set in 2006.

Peak electricity demand has emerged as one of the modern utility industry’s most important, and most expensive, challenges. To ensure smooth functioning of the electric grid on extreme-temperature days, U.S.-based utility companies budget nearly a billion dollars a year on programs specifically designed to reduce peak demand. These demand-trimming programs are increasingly drawing upon innovative approaches like smartphone apps and large-scale behavioral science.

It seems like Toyota Priuses are everywhere these days, both in and beyond the Whole Foods parking lot. ndeed, sales of hybrids and plug-in electric cars continue to zoom forward in America, where oil still claims 93% of the transportation sector’s energy consumption.

These fuel-efficient vehicles now account for about 4 percent of all vehicles sold in the U.S., up from 3.4 percent last year.

In part thanks to the burgeoning popularity of hybrids and all-electric models, August 2013 marked a record-breaking month in the U.S. for the average fuel economy of new vehicles sold -- clocking in at 24.9 miles per gallon. This figure has increased 20 percent since five years ago, and is set to ratchet up further in the next few years in alignment with new federal standards.

Energy demand growth in the Asia-Pacific region continues to be brisk, especially when compared to the rest of the world. The Asian Development Bank projects that Asia’s thirst for energy will grow by 2.1 percent per year through 2035, exceeding the global average rate of 1.5 percent and far outpacing the 0.5 percent annual demand growth expected in industrialized countries. In twenty years, Asia will account for more than half of the world’s energy consumption.

But Asia’s energy appetite may yet be curbed if the region plays its energy efficiency cards right. Many nations in the area are pursuing bold policy and technology targets that are poised to make a serious dent in demand growth. And sustained investments in energy productivity like these can be stunningly effective. For example, one astonishing result of America’s energy efficiency efforts over the past four decades is that the country, believe it or not, uses less oil now than it did in 1973.

Utilities around the world continue to undergo an infrastructural transformation that is changing the way customers and energy companies interact with energy data.

The number of smart meters in the U.S. has grown more than sixfold during the last six years. There are now more than 46 million smart meters installed nationwide, enabling real-time communication of energy data between customers and their service providers.

Ready for another billion-scale statistic about the rapid rise of smart meters? Worldwide, the installed base of smart meters will triple from 313 million in 2013 to nearly 1.1 billion within ten years, according to a November report from Navigant Research.

You may remember the 2013 Super Bowl for the 34-minute blackout that shrouded the playing field in New Orleans’ Superdome. But here’s another energy-related fact that you should keep in mind about America’s most-watched television event: the Super Bowl reduces home energy use.

In January, Opower’s Outlier blog examined game-time energy consumption data (from Super Bowl XLVI) across a large-scale sample of 145,000 U.S. households in multiple regions -- finding that residential electricity usage decisively tumbles to an average of 5 percent below normal during the event.

Why do homes use significantly less electricity during the Super Bowl? We surmise it’s a combination of two factors: first, everyone is glued to the TV, so they aren’t using any other appliances; and second, many viewers “TV-Pool” -- that is, they watch the game at the houses of friends and family.

It was another shining year for solar energy.

After a near record-breaking third quarter, the solar industry is on pace to have installed a total of 4,300 megawatts of electric capacity for this year alone. In other words, this year’s volume of solar additions are approximately equivalent to all the solar capacity installed between the beginning of time and the end of 2011.

While solar electric generating capacity has grown more than twentyfold since the year 2000, it still only accounts for 0.3 percent of annual U.S. electricity generation. That fraction could expand substantially in the coming years as utility companies deepen their large-scale solar investments and tens of thousands of households install photovoltaic panels on their rooftops each year.

The electricity you’ve been using to charge your iPhone may be coming from Russian nuclear weapons.

This October, in a fascinating intersection of international diplomacy and energy affairs, a top U.S. State Department official told a UN Committee that a 1993 disarmament agreement between Russia and the U.S. -- known as the “Megatons-to-Megawatts” deal -- has cumulatively converted 500 metric tons of bomb-grade uranium from Russian warheads into low-enriched uranium fuel that has been used by “nearly all U.S. nuclear power plants.”

Since the first shipment of Russian low-enriched uranium arrived on U.S. soil in 1995, it’s estimated that half of all U.S. nuclear electricity production has been fueled via the Megatons program. The program officially comes to a close this month, but an analogous smaller agreement has been signed to extend the Russia-U.S. uranium exchange within a market-price framework.

We can only hope that an equally amazing number will emerge in 2014 -- one that we can use to conclude this same list next year. Given how fast the energy world is changing and the scale of innovation taking place within it, we’re optimistic.

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Barry Fischer is the head writer at Opower, where he manages the Opower Outlier blog.

This piece was originally published at Opower's Outlier blog and was reprinted with permission. Follow @OpowerOutlier on Twitter.