“Mining” Groundwater in India Reaches New Lows

Water-intensive onions are grown as a cash crop.

Photograph by Lynsey Addario, National Geographic

Mason Inman

for National Geographic News

This story is part of a special National Geographic News series on global water issues.

Nearly a third of India is suffering from chronic water shortages, and making up for it with "the world's largest groundwater mining operation," according to experts.

A band of land stretching across northern India, at the foot of the Himalayan Mountains, is one of the most heavily populated and intensely irrigated regions in the world. The area is chronically short of water. But the region still has a limited supply of it in underground aquifers, according to water resources expert Shama Perveen of Columbia University.

According to a new study by Perveen and her colleagues, Upmanu Lall and Naresh Devineni, some parts of India are using groundwater three times faster than it’s being replenished.

The team's new analysis draws on a 100-year record of daily rainfall in India, reflecting how much water has been available in various parts of the country as its residents endured both droughts and floods.

By estimating water needs over dry spells and across decades, and comparing the estimate with actual rainfall, they found that many areas have been falling chronically short for many years.

The findings, presented this month at an American Geophysical Union meeting in San Francisco, fit with the results from gravity-sensing satellites that have detected the loss of groundwater across the heavily irrigated areas of northern India—with the extraction of water at about 11 billion cubic yards (9 billion cubic meters) of water per year over the past decade. (Read: “NASA Satellites Track Vanishing Groundwater.”)

Local Water Management

Local planners told the researchers they were aware there was a problem with water shortages and stress on the groundwater supply, she said, but they weren't aware of the depth of the problem, Perveen added.

When presented with the results of the study, she said, the officials were "amazed."

The researchers found that some regions receive enough rainfall to supply their needs, as long as they build more reservoirs, ponds, and tanks to store water when supplies are plentiful.

Much of the yearly rain comes during intense monsoon downpours, so storage is needed to help get through the long dry periods of the year.

By analyzing the historical data, day by day, the researchers showed that water stress exists even where the average annual rainfall is apparently enough to cover the average water use.

But the majority of the country’s key food-growing areas would need far more water storage to be able to stop depleting the groundwater, Perveen said.

Water Storing Solutions

A more sustainable solution is to use small ponds, dams, and other ways of storing water locally, a new study suggests.

For about half of the country, their analysis suggests, if people used small-scale "rainwater harvesting"—capturing rain and storing it in tanks and ponds—they would have much of the water they needed, assuming they continued to grow the same types of crops.

(Related: “Lessons From the Field—Rainwater Harvesting in India.”)

By providing detailed information on small areas of the country, the analysis could help policy makers decide how much additional water storage they need to avoid depleting groundwater further, Perveen said.

"India's [water] storage infrastructure is very dismal compared to other countries," she said, because reservoirs there store only about 325 cubic yards (250 cubic meters) per person, compared with 6,500 cubic yards (5,000 cubic meters) per person in China, or 7,800 cubic yards (6,000 cubic meters) in the United States.

"This study points out that India needs to invest in more water storage infrastructure—whether large or small," Perveen said.

(Related: “How to Stem a Global Food Crisis? Store More Water.”)

Crop Insurance

In other parts of India, though, rainwater harvesting alone won't be enough to avoid depleting groundwater further, the study suggests.

So the team is studying how farmers could shift the crops they grow to ones that require less water.

To make a living from agriculture, farmers will have to shift away from water-intensive crops such as rice, sugarcane, and cotton. Or they will have to drastically change their ways of growing these crops to make farming more water-efficient, Perveen said.

"This [kind of] work needs to happen more," said Edward Moran, a water resources expert with the U.S. Geological Survey in Columbia, Missouri.

"The general public needs to be better informed" about looming water shortages, he said, because in many places around the world "we're really not addressing the problem."

Gulf Oil Spill Surprise: Methane Almost Gone

Jars of plankton taken from near the Gulf oil spill show how the water's oxygen—and thus sea life—decreased with time, a sign of increased bacteria.

Photograph by David Liittschwager, National Geographic

Brian Handwerk

for National Geographic News

After months of speculation about what will happen to the Gulf oil spill, it turns out Mother Nature has rolled up her sleeves and dispatched with a lot of the gas released along with it—in just four months.
Surprisingly, practically all of the methane that accompanied nearly five million barrels of oil leaked into the northern Gulf of Mexico (map) has been devoured by giant bacterial blooms, a new study says. Methane, the main component of natural gas, is typically found with oil.
(Read more about how nature is fighting back against the oil spill.)
The Deepwater Horizon oil rig burned and sank last April, and the damaged wellhead on the seafloor below was permanently capped in July.
"We thought it would probably be something on the order of a year or so until the methane disappeared," said study leader David Valentine, a microbial geochemist at the University of California, Santa Barbara. "Instead we found that by mid-September it was completely gone."
Deep, water-dissolved methane was the single most abundant hydrocarbon released during the spill, making up about 20 percent of the flow from the wellhead, Valentine and his team estimated.
However, the discovery doesn't mean that the oil itself is gone. The team found oil nearly everywhere in the deep water—suggesting that oil-water mixing was widespread, and that some ingredients of the oil haven't completely degraded.
(See "Why the Gulf Oil Spill Isn't Going Away.")
Ocean vs. Oil
The Gulf spill's methane release may rival the amount of methane regularly released via deep-ocean hydrothermal vents, oil seeps, and the breakdown of methane-rich gas hydrates in ocean sediments.
(Read more about the Gulf of Mexico's natural seeps.)
Scientists are keeping a close eye on all of Earth's methane sources. That's because warming ocean temperatures are thought to make some parts of the ocean's geology less stable. This could trigger the release of huge amounts of the gas into the ocean and potentially the atmosphere, where it may contribute to global warming.
"The global ocean seafloor contains the largest reservoir of methane, a potent greenhouse gas, and there is evidence that releases of methane from this reservoir have modulated climate in the history of the planet," said study co-author John Kessler, a chemical oceanographer at Texas A&M University.
"Without these bacteria, methane could be released to the atmosphere—and if the release is large enough, it could influence global temperatures."
(Related: "Methane-Munching Microbes Take a Bite Out of Warming.")
But the oil spill—essentially an unprecedented and accidental experiment—offers a piece of good news: The bacterial rapid-response system might be able to significantly curb the effects of even massive natural methane emissions.
"What we found is that for a deep-ocean methane release, the ocean has a capacity to deal with that in pretty rapid order," study leader Valentine said.
Low-Profile Bacterial Bloom
The team studied bacteria concentrations in deep, oil-fouled Gulf of Mexico waters during the spill event and again after the wellhead was sealed.
They found a larger-than-expected presence of methane-eating bacteria, as well as low oxygen levels. Lower oxygen suggests microbial activity because the organisms breathe the gas while they devour methane.
Methane-eating bacteria—discovered only about a decade ago—are distinct from their oil-degrading relatives, which themselves went to work on other oil ingredients.
The newly discovered bacterial bloom isn't as visibly obvious as the vibrantly colored algal blooms often seen in shallower waters, Valentine noted.
"I suspect you wouldn't notice much to look at it, but there was a big change in what happened to the biological community," according to Valentine, whose study was published online January 6 in the journal Science Express.
Bacteria No Guarantee Against Oil
Antje Boetius, a microbiologist at the Max Planck Institute for Marine Microbiology in Bremen, Germany, was impressed with the study.
"We have worked at huge natural methane seeps before, and never found a situation like this with a huge propagation of bacteria in which the methane goes away so quickly—something special [such as warm temperatures] in that event really induced the bacteria to grow tremendously," she said.
But Boetius stresses, as do the study's authors, that caution is needed before assuming these findings can be applied in other places where oil spills may occur.
(See "Exxon Valdez Anniversary: 20 Years Later, Oil Remains.")
"What we've learned from oil spills in general is that the speed with which nature heals itself is very different for different accidents for a number of reasons, including water temperatures," she said.
For example, "bacteria are slowed in colder waters, and the Gulf is a rather warm place compared to locations like the polar regions—which are exactly where we'd expect global warming to have the largest impacts on huge amounts of buried methane.
"Can we deduce from these data where we have an unexpected explosion of bacteria that the same could happen in other very sensitive areas which are much colder? That’s the big question."
Gulf Bacteria Primed For Next Spill?
Now that the spill's methane is mostly cleaned up, the fate of methane-munching bacteria is another intriguing question the team will be watching closely.
"We expect that the [high amount of bacteria] will gradually dissipate, but we don’t really know how the population relaxes back to a baseline level," Valentine said.
Indeed he believes the baseline may be forever changed—and Gulf bacteria could become even more efficient in dealing with future oil spills.
(Also see "3 Future Oil-Spill Fighters: Sponges, Superbugs, and Herders.")
"Sometimes where there is petroleum contamination and a bacterial response, the environment harbors a memory of it. ... It maintains a kind of priming, so that if you contaminate it again, it will react more quickly than it would in a pristine environment."

In China’s Icy North, Outfitting Buildings to Save Energy

Harbin, in China's northeast, plays up its "Ice City" reputation with its annual Harbin International Ice and Snow Festival, where ice sculptures were on display January 4. But in its real buildings, officials are making renovations that they predict will increase energy efficiency by 50 percent.

Photograph by David Gray, Reuters

Te-Ping Chen in Harbin, China

For National Geographic News

Published January 7, 2011

This story is part of a special series that explores energy issues. For more, visit The Great Energy Challenge.

Jin-Xing Ma's apartment has a new hat, and a five-layered coat. Standing in her living room, her trim frame ensconced in a purple sweater, Ma is effusive about her home's new wardrobe.

Here in the China’s northeast, where winter temperatures plummet to -40ºF (-42º C), cities are getting serious about giving old, drafty buildings a face-lift. Last year, Harbin (map) spent $1.1 million to retrofit 21 million square feet (2 million square meters) of residential buildings—adding five new layers of wall insulation, as well as better windows and roofing that tenants like Ma affectionately describe as the building's new "winter clothes."

“Before, the temperature in this room was 12 degrees [Celsius, or 53ºF]. Now it’s 18 degrees [Celsius, or 64ºF],” said Ma, 76, surveying the apartment with pleasure. For Ma, who runs a small Chinese medicine shop with her husband out of their front room, the change has meant fewer chilly days for both herself and her customers.

The Challenge to Keep Warm

Beijing’s snarled traffic and the smokestacks smoldering over the Pearl River Delta may be the most iconic images of China’s environmental woes.

(Related: “On China’s Roads (And Rails), a Move Toward Greener Transit”)

But these days, policymakers are increasingly turning their attention to the buildings of China’s industrial northeast, as well. This is the country’s frigid rust belt, where cold fronts roll in directly from Siberia’s frozen tundra to the north, and residences need to be heated six months out of the year.

After all, in the developed world, fully 40 percent of carbon dioxide emissions come from heating, cooling, and powering buildings. Already in China, nearly 30 percent of the country’s energy is absorbed by its building sector—a figure that has tripled within three decades, and growing.

(Related: “The Carbon Bathtub”)

In 2006, as part of the country’s most recent five-year plan, China pledged to reduce overall energy intensity by 20 percent. It’s an ambitious goal, one that local officials were scrambling to meet by the end of 2010—shuttering factories and even briefly powering down hospitals in a last-ditch scramble to reach their quotas.

But if China does hit its 20 percent target, it won’t be thanks to improvements to the building sector, said Mark Levine, head of the China Energy Group at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory. “Efforts in this area have been terrible,” said Levine. National subsidies, he noted, have been too slim to inspire much effort at the municipal level, where cities have typically used the funds to install meters instead of embarking on more costly retrofits.

But there have been a few notable exceptions, including Harbin, the largest city and capital of Heilongjiang province, with a population of nearly 10 million, a place often known as “Ice City.” Officials in Harbin project that the retrofitting drive of 2010 will increase energy efficiency in affected areas by 50 percent. Other cities also have embarked on efforts to make buildings more energy efficient, like Qingdao (map) in the eastern Shandong province and Lanzhou (map), capital of Gansu province in the northwest. And across China, there has been one improvement that officials are quick to note: compliance with existing building codes has increased to at least 98 percent, according to government figure.

Still, such progress might not “necessarily result in energy savings, because living standards are increasing as well,” said Ping Yowargana, Beijing-based energy analyst with Azure International. China is adding new buildings at a clip of 22 billion new square feet (2 billion new square meters) a year—which means more concrete being poured, more steel being manufactured, and additional mass consumption of energy. At the same time, residents these days expect more air conditioning, lighting, and heat than ever before. Accordingly, even a building at code today can still use energy in excess of its leaky, poorly insulated predecessors.

Then there’s the fact that China’s heating sector is riddled with inefficiencies, including pricing systems that create no incentive to conserve. For example, Ma pays a flat sum of 200 renminbi ($30) per year to supply her heat—a fee charged according to the size of her residence, not her energy use. Which is why Ma won’t be turning down the thermostat anytime soon.

“It’s warm and cozy inside now,” she said. “The government takes good care of us.”

A Need for Deeper Change

Heating price reform—already under way in certain regions—and better funding for retrofitting efforts will likely be a priority in the next five-year plan, said Levine. What’s less clear, he said, is whether China’s central planners can effectively push the country beyond the heavy, energy-intensive industry that’s propelled it forward. “They have to make structural change in the economy,” he said. “And so far, that hasn’t happened.”

Back in Harbin, some residents continue to eye retrofitting programs with suspicion. Although the effort was government-financed, a number of Ma’s neighbors complain bitterly that the construction was slapdash, and that the material won’t weather the years well. Meanwhile in Shanghai, after a blaze took 58 lives in a building undergoing renovations, sparking local furor, all other retrofitting projects were temporarily halted.

“Right now, the government wants to complete goals faster, Chinese-style. There are big targets,” said Ruidong Jin, building energy efficiency expert with the Natural Resources Defense Council. China’s national energy efficiency goals are ambitious, he says, and municipalities just focus on keeping pace.

“There’s not much time to talk to people and make them understand,” said Jin. “Local governments have to keep moving, faster.”

(Related: “Missing the Chance for Big Energy Savings”

Te-Ping Chen is a writer based in Sichuan, China.

(See photos of China, including the Harbin Ice Festival, submitted to National Geographic by users like you.)

Pictures: Mount Etna Erupts Overnight

 

Etna Aflame

Photograph by Antonio Parrinello, Reuters

<>Streams of lava light up Mount Etna during a two-hour eruption on Tuesday night—the peak of the Italianvolcano's fiery week (Mount Etna map).


Towering nearly 11,000 feet (3,350 meters) over the island of Sicily, Europe's tallest and most active volcano began trembling Tuesday afternoon, seismologists told the OurAmazingPlanet news site. Wednesday and Thursday saw flames and ash flung hundreds of yards into the sky, closing down area airports.

 

 

 

Scientists Make Dozens of Storms in the Abu Dhabi Desert?

Camels and trucks travel on a main desert road in Abu Dhabi while rain descends in the background.

Photograph by James Davis Photography, Alamy

Brian Handwerk

for National Geographic News

Published January 18, 2011

This story is part of a special National Geographic News series on global water issues.
In arid lands, the ability to create freshwater out of thin air would be priceless.

Now a Swiss company, Meteo Systems, is poised to earn a pretty penny in Abu Dhabi with a controversial weather modification system said to be responsible for dozens of rain showers in the desert last summer.

The claim is difficult to verify but certainly has raised a storm of skepticism among many leading weather modification experts.

“As far as I’m concerned I don’t believe these claims,” said Roelof Bruintjes, who heads the National Center for Atmospheric Research’s international weather modification programs. “There’s no scientific basis for this; the physics doesn’t support it.”

(Related: “Planes Create Weird Clouds—And Snow, Rain Fall Out.”)

While typical weather modification efforts—which began in the mid-20th century and continue in nations from the United States to China—make use of natural clouds and attempt to “seed” them to produce precipitation, Meteo Systems purports to create the clouds themselves.

Their system uses arrays of 33-foot (10-meter) electric towers that produce negatively charged ions, according to the company. These ions bind with tiny solid and liquid particles, supercharging the particles’ ability to form clouds and precipitation.

Joseph Golden, a weather modification expert who once chaired the now-defunct Atmospheric Modification Program at the National Oceanic and Atmospheric Administration (NOAA), also has serious doubts that the technique could work.

“This method is inherently incapable of producing clouds out of thin air,” Golden said.

(Related: “China’s Rain-Free Olympics Plan Met With Skepticism.”)

A Long History of Ionization

The Technical University of Munich’s Peter Wilderer, winner of the 2003 Stockholm Water Prize, said people have been attempting ionization techniques for decades.

"The ionization technology was first mentioned in 1890 by [Nikola] Tesla. In 1946 General Electric executed some field trials under the leadership of [Bernard] Vonnegut [brother of novelist Kurt Vonnegut]. Later the technology was used for military purposes in the former Soviet Union."

Wilder added that reviews of radar images suggested to him that ionization could possibly have some effect, under proper meteorological conditions. Despite press reports to the contrary, he has never personally witnessed any rainfall events produced by Meteo Systems.

Show Me the Data

NOAA’s Golden is interested in hearing much more from the scientists trying to make it rain in the desert.

“I put out a challenge to any of those that are involved in this project and making these claims. Show me the data,” he said.

There may be little chance of such transparency in the near-term, however, as Meteo Systems is closely guarding the secrets of the potentially valuable technology the company has dubbed “WEATHERTEC.”

Meteo Systems did not respond to calls and emails from National Geographic News.

The directors of the Max Planck Institute for Meteorology, who have been erroneously linked to the project via media reports, released a statement expressing “distress” that the scientific organization had been associated in any way with the work of Meteo Systems. They added that rainstorms were part of unusual weather patterns in the Middle East last summer.

“Our institute has no connection whatsoever to this work, nor have we been privy to the underlying evidence that the company is using to support its claims,” the statement said.

“We also note that many people have a financial stake in seeing these claims being credibly reported by the media, and that to the extent rain showers in the region were unusual this summer, they accompanied rather unusual weather patterns over the broader region, which certainly had nothing to do with the very localized experiments in Abu Dhabi. One only needs to be reminded of the terrible flooding over neighboring Pakistan.”

Playing God

NCAR’s Bruintjes noted that the UN-based World Meteorological Organization’s expert team on weather modification research met in Abu Dhabi in March 2010, and issued a report on the state of the science that cautioned against just this type of technology.

“The energy involved in weather systems is so large that it is impossible to create cloud systems that rain,” the WMO report read. “Weather modification technologies that claim to achieve such large-scale or dramatic effects do not have sound scientific basis (e.g. hail cannons, ionization methods) and should be treated with suspicion.”

Golden said people who are simply desperate to fool Mother Nature often pay for modification techniques that are unproven at best, including the hail cannons mentioned in the WMO report. “Farmers invest thousands of dollars in those cannons to suppress hail even though the scientific evidence is that they don’t work,” he said.

Bruintjes put his point bluntly: “The rotation of the Earth, the energy of the sun, and moisture from the oceans cause these things. None of us can change that, and it’s actually good that none of us can change that because we’d likely make a mess of it.”

Kenya Steps Ahead Into Solar Future

Photo courtesy of World Bank, IFC and Lighting Africa

 

For Africa’s poorest families, lighting is often the most expensive item in their budget, typically accounting for 10–15 percent of total household income. The energy poor in Africa spend about US$17 billion a year on fuel-based lighting sources.  To put the full energy sector in perspective, independent estimates place worldwide spending on fuel-based lighting in developing countries at $38 billion.
Beyond household use, commercial use of fuel-based lighting can have even more acute economic impacts. Fishermen on Lake Victoria in Kenya, for example, often spend half their income for the kerosene they use to fish at night. Yet, while consuming a large share of scarce income, fuel-based lighting provides little in return. Fuel-based lamps, such as kerosene lamps, are costly, inefficient, and provide poor lighting. The smoke they emit causes respiratory and eye problems, while the flames from kerosene lamps are responsible for thousands of severe burns among children every year, along with untold numbers of devastating house fires.
But many African countries are making strides to put fuel-based power behind them. Kenya, for example, as I discuss in an article this week posted on InterPVNet, has one of the largest and most dynamic per capita solar PV markets among developing countries, with over 300,000 households having installed solar PV systems since the mid-1980s. Since 2000, annual sales for these systems have regularly topped 15 percent, and they account for roughly 75 percent of all solar equipment sales in the country.  In addition, exciting and rapid developments in off-grid lighting with highly efficient long-lasting light emitting diodes (LED) lamps are also changing the set of options in formerly neglected markets.
The rapid spread of this off-grid green energy solution in a low-income country is all the more remarkable as it is propelled by unsubsidized market demand. With Kenya’s electricity grid largely dependent on expensive hydropower, only 5.2 percent of rural households use electricity, and most of these are relatively well-to-do.
Solar is a comparatively low-cost alternative, especially for families whose poverty puts grid-based electricity out of reach. Manufacturers and importers have noted the business opportunity and are coming up with products that they say will fill the gap. They are focusing on affordability, the green agenda, and renewability of power sources.
With Kenya’s government having set 2017 as a deadline for the country to make significant advances in green in power generation, the stage is set for the solar PV sector to deliver household systems to a national market that is intended to be able to absorb a million of them a year, according to the International Finance Corporation. An education campaign has also been launched to encourage people living in rural Kenya to adopt solar lighting.
Dubbed “Zonga Mble na Solar” (Stay ahead with solar), the campaign targets 13.5 million people, both households and small businesses, in rural Kenya. It shows how by switching from fuel- based lighting to modern, solar lighting rural people can improve their health, increase their savings—households typically spend about 10% of their income on kerosene— and benefit from better lighting and more productive time in their homes, schools and businesses.
“The main argument for people to switch from kerosene lamps to solar light is an improvement in their children’s health and education: the solar portable lights emit no fumes, and provide better illumination for studying. Longer producing hours for businesses is another winning argument,” says Nana Asamoah Manu, Country Officer for Lighting Africa, which is supporting the campaign.
The campaign, which runs to end of 2011, is staging road shows in market towns, to generate consumers’ interests in the solar portable lights that passed Lighting Africa quality tests. The road shows are attracting crowds of 300-500 people every evening, and are packed with product demonstrations, fun quiz, dance shows and a chance to try the solar lights. “People are enthusiastic,” says Nana, “but the major obstacle is the relatively high upfront cost of solar lights. Many families can afford to spend 20 to 50 shillings a day on kerosene, but are struggling to find 2000 shillings for a solar lamp.”
Lighting Africa, a joint IFC and World Bank program, is working with microfinance institutions to secure loans for rural households and businesses willing to buy solar lamps. The program is also exploring light rental schemes as another option. The program is implemented in partnership with the Energy Sector Management Assistance Program (ESMAP), among others.
Daniel Kammen’s posts appear here and on the Development in a Changing Climate blog at the World Bank, where he is chief technical specialist for renewable energy and energy efficiency. He is an adviser to National Geographic’s Great Energy Challenge initiative.

 

Tough Road to Getting LED Lights on the Streets

Ann Arbor, Michigan has been a leader in converting streetlights to LEDs, but the city has had to work out some kinks along the way.

Photograph by Tom Drew

By Josie Garthwaite

For National Geographic News

Published January 20, 2011

This story is part of a special series that explores energy issues. For more, visit The Great Energy Challenge.

Power plants may not spring to mind during an evening stroll on a well-lit block, or when an overhead lamp burnout darkens a treacherous bend in the road. But power plants indeed provide much of the world's nightly abundance of electric light, usually by burning fossil fuel and adding greenhouse gases to the atmosphere along with the glow. And cash-strapped cities foot the bill.

According to the Clinton Climate Initiative, street lighting accounts for a staggering 159 terawatt hours of electricity use worldwide each year. That's more than the annual output of three dozen 500-megawatt power plants. And although street lighting accounts for less than one percent of all electricity use in the United States (it's about 1.3 percent in the European Union), this comes at a hefty cost for cities. In some areas, street lights command upwards of 60 percent of municipal electricity spending.

So in tough economic times, municipalities have begun to pull the plug on inefficient lamps in favor of long-lasting, highly efficient light-emitting diode (LED) technology. In the United States, many of these projects have been supported by economic stimulus block grants for energy efficiency and conservation projects.

(Related: "On Edison Bulb’s Anniversary, a Lighting Breakthrough.")

According to the U.S. Department of Energy, LEDs could help communities save more than $750 million per year in energy costs, while also offering benefits like more uniform light distribution. Around the world, LEDs are lighting streets from Torraca, Italy, to Toronto, Canada, and from Tianjin, China, to Sydney, Australia. Yet, in the big picture, the Clinton Climate Initiative report notes "negligible" adoption of new lighting technologies by cities. When cities do seek to cut energy costs by converting old streetlights—many of which are non-metered and owned by the local utility—they often encounter a rocky road ahead.

Not Just Screwing in a New Light Bulb

LED streetlights cost more up front than incumbent high-pressure sodium, mercury vapor, and metal halide lights. Partly because the technology is changing quickly, long-term performance in real-world installations is also unproven. "There are a lot of unknowns in terms of maintenance," said Ed Henderson, who runs a system of 200,000 streetlights in southeast Michigan as manager of community lighting for utility DTE Energy.

Whereas replacing a traditional streetlight in DTE’s network is typically as simple as unscrewing a dead bulb and screwing in a new one, said Henderson, LEDs can come in a variety of packages, and they're changing all the time. "Like cell phones and flat screen TVs, there's an obsolescence factor," he said. "When we put an asset up there, we want it to be up there a long, long time." The more "one-off" or specialty installations, the more difficult maintenance becomes for a utility managing streetlights on a large scale, he said.

Yet reduced costs for energy and, crucially, maintenance over the working life of LED streetlights (as long as 10 years for some models) mean they can "pay for themselves" in seven years or less, depending on factors like wattage, electricity rates, and labor costs. "As long as the warranty is longer than the payback," said Andrew Brix, energy programs manager for Ann Arbor, Michigan (map), which expects a four- to five-year payback on LED streetlights with a seven-year warranty, "I'm happy."

Ann Arbor has worked to iron out the kinks of LED streetlight installations over the past few years. Back in 2007, the city drew national attention with plans to become the first U.S. city to convert all of its downtown streetlights to LED technology. Replacing 120-watt bulbs with 56-watt LEDs that were expected to last a decade instead of only two years, the project was projected to shrink the city's public lighting energy use by half, cut maintenance costs by about $85,000 per year and save another $15,000 in annual electricity costs, according to Ann Arbor’s estimates at the time.

Two years later, however, DTE was still billing Ann Arbor at the old rates—as though the LED streetlights were using as much energy as their less efficient predecessors. Since the lights weren't (and aren't) metered, charges were based on estimates, which in turn were based on the older technology.

Similar issues halted an LED streetlight project in nearby Jackson, Michigan, last year. Having determined that installing LED lights will not cut electricity bills until the local utility, Consumers Energy, develops a new rate, City Engineer Jon Dowling said Jackson has for the time being dropped plans to pursue the technology.

In Washington, D.C., by contrast, where a $1 million grant from the economic stimulus program, the American Recovery and Reinvestment Act, will support installation of LEDs for more than 1,000 streetlights this year, the District's streetlight utility bills are based on the bulb's wattage. So according to John Lisle, spokesperson for the District Department of Transportation, D.C.'s selection of a 73-watt LED light to replace a 150-watt high-pressure sodium light, for example, will cut both energy use and costs by about 50 percent.

Low-Wattage Sticker Shock for Power Companies

Further complicating matters for ambitious LED streetlight supporters is the fact that many streetlights in U.S. cities (5,000 of Ann Arbor's 7,000 lamps, for example), are owned by the local utility, while the municipality pays for the electricity and operating costs. Because most utilities bring in money based on the amount of energy they sell, changing over to more efficient lamps would therefore reduce the utility's revenue.

This is where a policy known among energy and efficiency wonks as "decoupling" comes into play. In California and at least 12 other U.S. states, regulations have decoupled utility profits from electricity sales, creating a mechanism for utilities to make up for some of the revenue they would lose as electricity sales decline, and in some cases offering incentives for efficiency programs. California utility Pacific Gas & Electric offers rebates for LED installations and has established rates for different lamp types, a move that trade publication LEDs Magazine hailed in 2009 as "an example for utilities across North America."

(Related from National Geographic: "The 21st Century Grid")

In Michigan, the state utility regulator ultimately directed all Michigan utilities to put together a rate for LEDs. Today DTE Energy charges Ann Arbor rates based on the LED streetlights' expected energy use, under a larger category for experimental lighting technology. The utility credited the city for the lower energy use retroactive to the installation, and today Brix says the city has saved about $200,000 as a result of the downtown streetlight installation, combined with the first few months of additional LED streetlight projects throughout the city. "Getting billed properly for city-owned streetlights is important, but only accounts for one-fifth of the savings," said Brix. The rest comes from reduced maintenance costs.

Out of 7,000 streetlight fixtures citywide, Ann Arbor has about 1,400 LEDs, saving an estimated 350,000 kilowatt-hours per year—about equivalent to the amount of electricity used by 50 average Ann Arbor homes, according to Brix. Out of the 200,000 streetlights that DTE owns and operates throughout southeastern Michigan, about 1,000 use LEDs, said Henderson, noting a goal to bring that up to 4,000-8,000 (2-4 percent).

Back in 2007, the city approached DTE and said, "Hey, we want to do LEDs," Brix recalls. The utility "came back and said they needed to get their own hands-on experience with what was, at the time, still a pretty new technology," he said. "What has changed since then is that the industry is maturing and we have more standards and specifications we can rely on now, so that going forward we won't have to do those tests."

Much larger LED streetlight installations are in the works. San Francisco, California, for example, issued a request for proposals late last year to replace 18,500 high-pressure sodium "cobra-head" streetlights owned and maintained by the city and county. Looking to go beyond the basic benefits of greater efficiency and longer life, San Francisco envisions a wireless monitoring and control system being integrated into dimmable LED luminaires.

Henderson sees the capability for controls and dimming as an exciting part of the future of LED streetlights. Regarding late night and early morning dimming, he said, "Other parts of the world do that for energy savings," offering Paris as an example. "If people can get comfortable with that," electricity needs could be further reduced, and the LEDs would last even longer, he said.

For now, Ann Arbor still spends about $1.5 million annually on streetlights. Brix considers it "a big ask" to propose a new technology for utility-owned streetlights that would save the city money. "They need to be comfortable with it," he said. By the end of 2011, Brix said Ann Arbor expects to double its streetlight energy savings by installing 500 LED fixtures as replacements for high-wattage streetlights. And with a goal to bring streetlight costs below $1 million per year, said Brix, "we're just going to keep plugging away, putting in LEDs as soon as we've got the funding."