VOA常速英语:Better Street Lighting Lowers Carbon Emission

A United Nations panel on climate change says global warming is causing extreme weather all over the world and is calling on governments to come up with new ideas to curb gas emissions. Since much of the air pollution comes from coal-fired power plants, scientists in Denmark are trying to lower their nation's energy needs with new types of smart streetlights.
 
Our increasingly industrialized world needs huge amounts of electrical energy, but our power plants still rely mostly on technology introduced as early as the 19th century - coal-powered plants, hydroelectric dams or somewhat newer nuclear energy, all of which have their own shortcomings.
 
Renewable sources, such as solar plants and wind turbines, have just started making inroads in lowering harmful emissions, while safer fusion-based nuclear plants are believed to be many decades off.
 
But scientists say we can slow down global warming by lowering energy demands for street lights.
 
These common features of the world's urban areas require a lot of electricity.
 
The U.S. Energy Information Administration estimates that in 2012, lighting for buildings, streets and highways in the U.S. used about 274 billion kilowatt hours.
 
In a bid to make Copenhagen the world’s first carbon-neutral city by 2025, scientists in the Danish capital are testing a variety of new street lighting technologies.
 
Kim Brostrom is the chief technical officer at the Danish Outdoor Lighting Lab.
 
“We have installed nine kilometers of streets, we have 280 masts placed here, we have 50 different solutions, we have 10 different management systems, and we have a lot of different sensors and things out in the open area," said Brostrom.
 
Chief science officer Jakob Andersen says the lights can be managed individually from a tablet computer or a smart phone.
 
“You can monitor the run time, the efficacy, the lumen output or the power consumption, and then we do real time measurements on the lux levels on the street level," said Andersen.
 
The main goal is to lower energy consumption when the light is not needed. So the lamp brightens up only when it senses an approaching pedestrian, cyclist or vehicle. Some of them even have a backup wind generator or a solar cell.
 
Scientists say installing the smart lights city-wide could save up to 85 percent of the current budget for illuminating the Copenhagen streets.