A prison in the US could save more than $33,000 (£21,120) for being more efficient.
The Eastern Oregon Correctional Institution (EOCI) have installed LED lights which could conserve around 518,000KWh per year.
The EOCI received $70,000 ($44,800) from nonprofit organisation the Energy Trust of Oregon to install the energy efficient lighting inside the 103-year old building.
A prison spokesman said: “We’re trying to be more sustainability conscious. A lot of it goes to the simple things we do every day.”