LIFE-DIADEME stems from the need to greatly reduce the GHG emissions in the public sector. This can only be achieved by providing novel high performance and smart solutions.
The lighting industry is undergoing a radical transformation, driven by rapid progress in semiconductors technologies as well as changing societal needs towards sustainability. Luminaires essentially consist of lamps and ballasts, while additional devices, e.g. timers, computer vision, sensors or adaptive dimming devices might also be added.
According to “EuP Lot Study on Street Lighting” and the “EU Lamp Companies Federation” the most predominantly used lamps in street lighting are high-intensity discharge lamps (HID), metal halide (MH) and high-pressure sodium (HPS) lamps in particular. However, Reg. (EC) No 245/20098 requires less efficient HID lamps will be phased out in the following years: HPM lamps (E27, E40 and PGZ12 base) and retrofit/plug-in HPS lamps (E27, E40 and PGZ12 base) are banned from 04/2015, while MH lamps not meeting minimum requirements (E27, E40 and PGZ12 base) shall be phased out from 04/2017.
LED (light emitting diodes) lamps are a more recent type of lamp that currently appear very promising for street lighting applications in terms of energy efficiency, and are expected to replace future luminaires. LED lamps can be rapidly turned on and regulated (other lamps might require 5min. to achieve full luminance) The directional nature of LEDs generally makes LED luminaires more efficient and can in principle direct the light very precisely to where it is required. Table B2-3 shows a comparison of the performance of current lighting technologies. Smart and sensors technologies provide are expected to provide additional efficiency and additional performances (e.g. traffic sensing).
Smart street lighting
In the last decade, we has seen a sharp development of efficient, “smarter”, safe and sustainable lighting solutions. EU standards (CEN13201) define the maximum dimming level and when it can be applied e.g. 25% dimming when the traffic is reduced of 50% and 50% dimming when traffic is reduced by 75%.
The core element for intelligent street lighting is seamless dimming of the lamp depending on specific environmental conditions such as wet or dry ground, snow, traffic density and streets complexity. Fig. B2-4 shows an example of statistical data flow in a smart street lighting system (Italian standard UNI11248), whilst B2-5 shows an example of smart street lighting layout.
SOA public lighting systems are LTM by REVE (it includes, luminance traffic and meteorological sensors and primitive adaptive real-time adjustments), E-Street, and ENLIGHT systems (EU funded), and TVILIGHT (city of Nijmegen, Norway). They mainly consist of the components shown in Table B2-4.
In principle, there are two different approaches to regulate luminous lighting flux: i) a central regulated controller, which only allows to set the same lighting level to all the lamps connected to the plant at the same time; ii) a point-to-point regulation, where each lighting point can be regulated with a varying dimming profile, thanks to a more sophisticated communication and mapping system. SOA systems, depending on the local legislation or application (e.g. parks, public or street lighting), are not always in compliance with the EN13201 standard. Such a standard, for safety reasons, do not allow 100% dimming, but only a minimum luminance value as a function of the street class.Recently, it has been shown it is possible to greatly reduce the energy consumption with respect to the traditional non-LED lighting points by about 60%. However, the maximum energy saving depends more on the dimming profile used (number of dimmed hours per night). Moreover, such solutions are based on preprogrammed dimming cycles. The traffic flow is estimated statistically, and the a schedule dimming program is set, possibly taking into account not only the time of the night, but as well the day of the week and the period of the year. Importantly, such technologies are characterised by technological limitations shown in Table B2-5. The most innovative system appears to be TVILIGHT. This system approach the energy savings problem switching off the light and on occurrence (when safety is taken into account), but it is not yet able to evaluate traffic. On the other side, the speed of the vehicles must be the driver for the switching on of lights.
The higher is the speed, the higher should be the lighted street in front of the driver. TVILIGHT does not consider these hazardous conditions.
For such a reason pre-programmed solutions are adopted in street lighting and are considered the SOA in terms of performance and cost-efficiency, whilst real-time adaptive systems are only used for other public or private purposes (small parks and gardens).
Transferability and replicability. Today most of the EU street lights are not dimmed, even if the CEN13201 allows dimming for energy conservation purposes:
Many municipalities are reluctant to accept dimming technologies, because of safety and security concerns. Also, SOA technologies are “blind”, i.e. they dim light even if traffic or meteorological conditions are not ideal for dimming.
Dimming a traditional source can be very expensive, and each lamp needs to be dimmed individually. The incremental cost of dimming can be higher of the cost of the luminaire.
In some cases, the type of electric installation (e.g. mixed circuits, old ones) make the investment relatively high and not profitable.
The novel LIFE-DIADEME point-to-point system will consist of a cost-efficient integrated system (payback of the order of 8 years on LED lamps as compared to 30 years of most technologically advanced solution on the market, i.e. LTM), which combines highly accurate sensors network, and it is able achieve accurate and in-real-time dimming, and monitor environmental data in entire cities, thanks to a network of cost-efficient sensors and a dedicated software tool. LIFE- DIADEME evaluates traffic and regulate the minimum luminance to the value able to guarantee safety for drivers and pedestrian.
The project pilot will demonstrate an innovative adaptive dimming solution that will overcome the aforementioned shortcomings (including replicability and transferability aspects), and it will provide:
– A distributed and uniquely integrated, compact and durable smart sensing solution able to monitor in real-time, noise (accuracy ±5% of the maximum range), air quality (20% accuracy
– 1 sensor per 20 lighting points) and traffic conditions (10% accuracy).
Additional 30% energy saving with respect to the state-of-the-art pre-programmed solutions, at least 10% if we theoretically considered a LTM system (REVE), which cannot be applied to street
lighting, as explained above.
Lower maintenance (10%) as compared to the state-of-the-art, in compliance with WEEEs directives.
A cost-efficient solutions with a large potential for replicability, transfer and mainstream adoption, and additional important societal and environmental benefits brought by sensing technologies (see form B2).
Transferability and replicability. The novel solution is cost-efficient and durable (20 years life span) and allows to optimise lighting in all possible situations (meteorological, street and surface conditions), overcoming “blindness” issues.
Fig. B2.10 shows a draft layout of the LIFE-DIADEME system. The system has been currently tested and validated at the laboratory level (TRL 5) and it will be constituted by the integrated prototype components.