An environmental group found that the Sony and Microsoft's next-gen video game consoles consume large amounts of energy, even when the devices are in standby mode.

According to a report by the Natural Resources Defense Council, the PlayStation 4 and Xbox One use up at least twice as much energy per year than the two companies' previous consoles -- the Xbox 360 and PlayStation 3 -- did.

The report cited the next-gen consoles' newest features as the reason why the two are energy hogs. It also found that the Nintendo Wii U, the third most popular video game console, is an "energy sipper," USA Today reported.

The Xbox One uses 15 watts of continuous power, even while it is in standby mode, because the voice command feature is always on so the user can turn the device on without pressing a button. During sleep mode the PS4 still uses eight watts of power so the controllers can charge.

A desktop computer uses less than two watts of power only while in standby mode. Operating an Xbox One would cost five times more than the Wii U in terms of average lifetime energy.

Pierre Delforge, director of high-tech energy efficiency for the NRDC, said the increase in power usage doesn't only affect the user's utility bills but it increases the carbon pollution at power plants.

"This adds up to several power plants of electricity," Delforge said. He added, "We don't have a problem with people playing games. But the problem is the amount of energy used when not playing a game."

According to the study's findings, on average, the new consoles also use more energy when videos are playing than when games are being played. Media players including Apple TV, Amazon Fire TV or Google Chromecast require 30 to 45 times less power to stream movies than the two consoles.

Gamers switching from the Sony and Microsoft's earlier consoles to the next-gen models would increase their energy usage by 10 billion kilowatt-hours annually. When compared to its predecessor, the Wii U not only has better graphics and faster processing, it actually consumes eight percent less energy, according to USA Today.

Delforge said the next-gen consoles are an improvement from the group's 2008 study that found that the consoles didn't have automatic power-down features. However, the voice command and video streaming capabilities have offset the improvements.