Bi-level lighting offers huge savings potential for buildings across B.C.
Sometimes, even the experts are surprised.
When BC Hydro's technology innovation group decided to test a new approach to lighting stairwells and corridors, they expected to find some savings. After all, we're accustomed to lighting these spaces around the clock — yet they are used only a fraction of the time.
The project tested "bi-level lighting" — lighting that is set to go on (or increase brightness) when occupancy is detected, and turn off (or reduce brightness) after occupancy ceases.
"There was concern in the past that the technology you need for bi-level lighting wasn't reliable, and that was a perceived safety issue," says Irfan Rehmanji, technology innovation manager with BC Hydro. "One of the things we wanted to test is whether that was a valid concern."
Motion sensors boost energy savings
Four sites were tested: an office tower, a large hotel, a hospital, and a school. Each facility installed sensors and light fixtures that communicated as a network.
The tests were limited to just 10 lighting fixtures in corridors and two stairwells at each site. When unoccupied, the light was reduced to 10% of the lighting normally required by the building code during occupancy.
The project, supported by Power Smart engineering, had four objectives:
- Demonstrate the reliability and controllability of bi-level lighting products;
- Evaluate the validity of perceived safety barriers;
- Measure energy saving potential;
- Understand the applicability in different market sectors.
Stairwells, corridors seldom need full lighting
When the test period was complete, Rehmanji says his team was surprised by what it found. In the office tower and hotel, stairwells and corridors were actually unoccupied — despite being fully lit — a whopping 97-99% of the time.
"There were huge savings," he says. "We didn't expect the unoccupied time periods to be as great as we saw, especially in office towers."
The stairwells in schools and hospitals saw more traffic, but the project demonstrated that the lighting could still be switched off 40-69% of the time.
Overall, even the limited installation of bi-level lighting in the four test locations yielded enough energy savings to power 20 B.C. households per year (approximately $18,000 per year in electricity costs).
Rehmanji says if bi-level lighting was applied to even 75% of the commercial building stock in the province, the total potential savings could be between 260 and 520 Gigawatt-hours per year — or enough electricity for 23,000-47,000 homes.
"Everybody realized there was some potential for conservation, but they didn't realize how big," he says.
Optimize savings with quick shutdown and total shut-off
Rehmanji says the project proved that sensor technology is reliable. Since that means the lights are always on when people are present, it also demonstrated that energy efficiency in low-traffic areas doesn't have to compromise safety.
Bi-level lighting technology can be set to turn completely off when there is no one present — or to simply go dim. The electricity savings depend on how low the light turns down, and how soon it shuts off after a person has exited the space. Optimizing the settings for quick shutdown and total shutoff is what yields the highest potential savings.
Meanwhile, there was another positive outcome of the test project. "The participants had no issues, they had no complaints," he says. "They didn't have any of their customers report any issues, which is what we wanted to hear."
Available bi-level lighting incentives
To find out more about Implementation Funding, contact your BC Hydro Key Account Manager, or call 1 866 522 4713.