Solar Transit Lighting Shining in the Cloudy Pacific Northwest

August 10, 2005
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“Our objective is to get more people on mass transit, which we’re convinced is a much more ethical and civic way of getting around,” says Dale Cummings, Transit Planner for King County Metro Transit in Seattle, Washington. “As our oil supplies become more scarce, it will become more important to have good mass transit alternatives.”

Illuminating bus stops increases safety, but installation can be costly and disruptive. Transit authorities across North America are taking a more practical approach: solar-powered bus stop lighting systems.

Shelters Stop the Rain, Catch the Sun

Bus passengers in Oregon, Washington state and Southwest British Columbia are hardly aware that their lighted bus shelters are solar powered. The light-emitting diode (LED) fixtures provide ample illumination for reading a bus schedule. The solar panels and batteries are integrated into the design of the bus stop’s shelter. Ambient light provides a sense of security and deters transients.

King County Metro Transit has been busy this summer installing bus shelters fitted with i-SHELTER solar-powered lighting made by Carmanah Technologies.

“In past Metro surveys, about 85% of riders and non-riders said the security of the nighttime wait for a bus was very important, but only 20% were satisfied with it,” Cummings says. “That report card was the impetus for our lighting program.”

Metro experimented with solar components, but maintenance and failures were a problem. Cummings learned about Carmanah’s products and started investigating them.

“We surveyed people who had been trying out Carmanah’s solar shelter lights, and got very good reports from everybody that was involved with the product and with the company,” says Cummings. “Here’s a company that’s really got their whole system together, which is something we hadn’t found in the past.”

After testing the system through the winter at two downtown shelters, Metro placed an order in June, 2005, for 49 units. Two months later, about 15 of them have already been installed.

“Our natural bent at Metro would be to take advantage of this form of energy. It’s something that we have to do, not only as an organization, but as a society. It’s a direction we have to go,” says Dale Cummings, King County Metro Transit in Seattle. Metro also bought a fleet of hybrid buses last year.

Economics of Solar Transit Lighting

Solar-powered lighting allows Metro to install lighted bus stops without the cost and turmoil of connecting the facility into the electric grid. Instead of requiring trenches and meters, these bus stops are energy independent.

“What drove us to explore this technology is the advantage it has over electrical hardwired sites,” Cummings explains. “It takes quite a capital investment to do all the civil and electrical engineering, get the permits and trench to a site, just to bring power to a bus shelter.”

Metro estimates that the installation cost for solar lights is about 20 to 50 percent less than for the hardwired equivalent. The solar units require very little maintenance and, of course, there is no monthly electric bill. As bus routes change, the self-contained shelters can be relocated more easily. The equipment cost is higher, however: solar lighting systems cost from US$1,500 to $5,000 per bus stop.

Solar outdoor lighting does not always make pure economic sense. If an existing bus shelter or location already has a power hook-up, then the payback period for the solar alternative can exceed the customer’s threshold. Carmanah offers a savings calculator for solar transit lighting online to help customers analyze the economics.

Design and Installation

The lighting manufacturer provides the LED luminaires, photovoltaic charging panels, rechargeable batteries, and proprietary energy management software. Transit authorities provide their own shelter.

Each order involves customizing products to the needs of the buyer. Components are combined and tailored to the design of new or existing shelters. The manufacturer provides installation assistance, but the transit authorities generally install and maintain the shelters and lights themselves.

Bus shelters come in all shapes and sizes, but most share a common component: advertising. As a natural extension, solar-powered LED lighting systems are available for bus shelter ad displays. Despite the seemingly ideal opportunity to tighten partnerships between outdoor advertising companies and transit authorities, the adoption has not been as rapid.

Growing Confidence in Solar

Seattle’s commitment for about 100 units, and the installation of 50 shelter lights by Portland, Oregon’s TriMet transit authority last year, are relatively small orders for Carmanah. Pierce Transit, serving Tacoma, Washington, installed 300 of the company’s bus stop signals and schedule lights. Orange County Transit Authority in California committed to 300 units; Chicago’s PACE has ordered 750. About 90 transit authorities throughout the U.S., Canada, and overseas have installed similar lighting systems from Carmanah in the past few years.

The Northwest’s reputation for gray skies (Seattle gets an average of 96 sunny days a year) would worry any transit planner considering solar. Carmanah asserts its energy management system would allow its lighting systems to work as far north as Anchorage. Reports thus far from cloudy climes have supported the claim.

In our interview on an overcast August day in Seattle, Dale Cummings told me, “What tipped the scales for us was when we learned that they had installed this system in bus shelters in London, where the climate is cloudier than Seattle’s.”

London was Carmanah’s first installation of solar lighted bus stops. Soon afterward (before this summer’s bombings), London reported its bus ridership increased seven percent overall, and 16 percent at night.

The system’s energy management software tracks charging and discharging patterns, and dims lights accordingly to conserve power. This is what allows the system to operate through a string of cloudy days.

“It manages energy-consumption levels by taking into consideration the installation location and any prevailing climatic conditions. It knows what the weather is going to be like and can run at full power for days without sun,” Carmanah’s VP of Corporate Development, Matthew Watson, told the Seattle Times.

That’s much more advanced than twisting wires together between solar components, the approach Metro first tried. Technology developments and widespread acceptance have taken the risk out of using solar in transit applications.

Says Metro’s Dale Cummings, “When someone puts together a product with a good track record, like Carmanah obviously has, it makes it easier for agencies like ours to invest in new technology.”