StreetLightNews

The Worcester Telegram & Gazette reports that the city council of Fitchburg, Massachusetts plans to eliminate many street lights in an effort to save money. The suggestions so far propose that either one in four street lights be turned off, or the street lights should be turned on at major intersections, and shut off at half of the remaining fixtures. No suggestion related to dimming was allegedly discussed during the meetings.

The benefits of dimming are clear and well-documented. Companies offering solutions in street light management can generate energy savings of 25-40 percent through dimming and more exact burn hours. Such a solution can typically be installed in every pole or simply in the control cabinets, the latter being the most cost-friendly solution. Therefore, dimming would be a great alternative to the suggested solutions in Fitchburg, which in practice would mean that all lights can be left turned on, thus maximizing a high level of safety for the citizens while saving energy and money at the same time.

In a time where a sustainable environment is on top of the agenda, it is crucial that we all have a common understanding of how technology can contribute to a better environment. With street lighting in mind, it is therefore troubling to find that there is still confusion about the benefits of dimming.

In an article brought in The Press on 16 October 2008, the author, a York-resident, expresses his sincere doubts about how dimming can save energy, thus money. He argues that if he turns his dimmer on at home, he will still be charged the same amount as without a dimmer. Several comments follow from different readers trying to explain the correlation between the consumption of kilowatt-hours and dimming, stating that the author is completely wrong.

However, there is some truth in his claim. Provided that he refers to a standard incandescent light bulb with a traditional home-installed dimmer, the savings in his house would be minimal. Such an installation simply cannot be compared to dimmed street lights as these typically use high pressure sodium (HPS) bulbs and a different dimming system. When lowering the voltage on a HPS bulb during off-peak traffic hours for example, the wattage will decrease by 25-40 percent. The point here is, that you cannot compare traditional incandescent light bulbs in your living room with high pressure sodium bulbs used in street lights in terms of dimming.

Japanese company Sharp is now launching a solar-powered streetlight. Combining Sharp’s own solar modules and long-life, white LEDs, the Japanese company presents the environmentally friendly streetlight solution of the 21st century. The unit delivers brightness at the highest level; still the unit does not produce any light pollution, uses no mercury, and emits no ultraviolet light.

Storage batteries charge from sunlight during the day and shines automatically at night. The level of maintenance is minimal as Sharp’s solution only requires replacement once every 10 years.

One of the extra benefits that especially cities in earthquake zones will enjoy is the built-in seismic motion sensor. This feature enables the unit to detect any earthquake measuring five or higher on the Japanese Seismic Intensity Scale. When detected, the unit will turn on full brightness at nighttime hours for at least two days.

Initially, the solution will be available on the Japanese market. In Europe, the European Union applaudes companies who commit to the reudction of light pollution. Thus, the EU GreenLight Programme has been developed to involve public and private organisations in upgrading their lighting systems to reduce light pollution. Well-known B2C companies such as McDonald’s and Nike have been awarded partner status, while international operating B2B companies such as Amplex A/S and Reverberi Enetec are awarded the endorser status.

The town of Lac Megantic is home to Canada’s largest telescope. However, due to population growth and urban sprawl in the surrounding area, conducting research at the observatory was becoming increasingly difficult.
Therefore, an initiative to reduce the sky glow has led to installation of a number of dimming units in streetlight poles. During the hours of 10 pm and 6 am, the streetlight is reduced by up to 65%, saving as much as 50% energy.
The solution, Night-Saver, is controlled via a microchip and is installed in individual poles. Read more about the project in Canada here…

According to Gordon Brown’s clima speech last week, the UK has plans of creating an environmentally sustainable economy. They have passed a law to fight global warming and want to lead the way by becoming the world’s leading green nation.

According to Brown, the government is currently considering whether the targets for CO2 reductions can be increased from 60 to 80%.

Also, the UK strives to achieve the EU target of having 30% of all energy coming from sustainable energy sources in 2020. Additionally, the financial support for sustainable initiatives will be increased significantly.

In Devon and Cornwall, they have already commenced serious preparations for sustanability by launching a project where all street lights will be dimmable. 40% of the region’s CO2 emmissions stem from lighting, and thus lowering the energy consumption here will provide significant CO2 savings. 

The Canadian company, Pure-Tek Earth, has designed a solar powered LED street light where the switch, converter, controller, the wiring and the solar battery fit into a metal box that is mounted on the individual street light pole.
Pure-Tek Earth describes on their website how the solution can save thousands of dollars in electrical costs and save the world from one ton of CO2 emission per light, per year.
There is no mentioning of centralized control of the street lights, so it is unclear whether this is an option. Also, the ROI is not described, perhaps because it is unreasonably long? Equipping every single street light with both solar batteries, controllers, switches, etc. must be rather costly.

In order to increase the safety of night-time driving on UK motorways, and additionally lower CO2 emissions, the Lancashire County Council decided to equip a stretch of motorway M65 with a dimmable lighting system controlled by traffic flow. The system can be dimmed with up to 30%, and is equipped with an intelligent controller and a two-way remote communication facility. Additionally, it offers individual control of luminaires, event reports and constant monitoring functions of the installation.
The project came about when lighting fixtures at a specific stretch of the motorway had to be renewed. The previous installation was controlled by photocells mounted at each feeder pillar, switching the lights on and off through a contactor. The lighting levels were constant throughout the night. The luminaires in the old installation were also emitting excess light beyond the boundaries of the highway, contributing to light pollution in the surrounding area.A replacement plan was implemented in order to link the lighting level to the traffic flow, reduce the power consumption and to monitor possible lamp defects.
Through already existing traffic counters which continuously monitor the amount of cars on the motorway, the lighting levels are adjusted to preset levels depending on the traffic flow.With more than 3,000 cars per hour, the lighting level was kept full on. With 1,500 to 3,000 cars per hour, the lights were dimmed to 75, and with less than 1,500 cars, lights were dimmed to 50%.
The new luminaires allow for ‘soft’ switching when shifting from one level to another, avoiding sudden changes in the lighting levels. Additionally, traffic safety is judged to be increased because dimming, opposed to e.g. turning off every other light as a savings measure, provides protection from a flickering or strobing effect.The completed pilot has shown that not only has the stretch of motorway gained better lighting quality and improved control, CO2 emissions are lowered 274 tons to 129 tons through a combination of the dimming, traffic flow control and the new luminaires. Read more here…

In a pilot project, 16 LED street lights have been installed at Toronto’s Exhibition Place. The city’s mayor, David Miller, states that the initiative is part of an ambitious plan to become the greenest city in North America.
Installing LEDs, he says, is will reduces costs, increase safety and improve the environment. The LEDs were manufactured by Leotek Electronics and supplied by electromega. The price per luminaire, $1,200, is expected to be recouped from savings in electricity consumption and maintenance. For more information on LEDs check out LEDs Magazine.