Energy savings related to waste in night lighting is back in the news.
Mayors complain about the huge costs of public lighting and threaten to cut essential services to deal with it (school heating, school bus services, etc.), but the possibilities for savings are enormous. In fact, Italy produces a luminous flux of exterior nocturnal lighting which is three times, per inhabitant, that of Germany. It just means shedding light on what the Germans are doing could save two-thirds of energy costs.
If the plans of Enrico Bondi and Carlo Cottarelli to review public spending on night lighting had been implemented, today the “expensive bill” would be much less onerous for municipalities, which would have saved several billion euros over the years.
Consumption for public lighting alone has been around 6,000 GWh (6 TWh) of electricity per year for more than 10 years (the drop in 2020 is not structural). It corresponds to almost 2% of national electricity consumption. For public lighting it is obviously not possible to take advantage of the photovoltaic contribution, so most sources of electricity production for night lighting are fossil sources. More than one billion cubic meters of methane are needed to produce 6 TWh of electricity. This does not take into account all the outdoor night lighting of individuals (eg courtyards and car parks for artisanal and industrial production activities).
The carbon footprint of night lighting worldwide is 200 billion kg of CO2 each year, which corresponds to more than 0.5% of global emissions. This without taking into account the CO2 emitted produce, install, efficiently maintain and recycle all infrastructure related to each lighting fixture (eg excavations, laying of cables, steel poles, concrete, etc.).
The European Parliament for Biodiversity Strategy calls on the Commission to “set an ambitious target for reducing the use of artificial outdoor lighting by 2030”.
According to the most comprehensive and recent studies, road and crime safety does not change by reducing lighting levels, by turning off street lights in the middle of the night, or by turning off street lights all night . There is possible evidence that too bright light compromises safety.
Thousands of French municipalities partially or completely turn off public lighting, generally at 11 p.m., while France has a large availability of electricity of nuclear origin, energy that the transalpine obviously prefer to sell to us.
Almost all local energy conservation and light pollution laws require you to dim the lights no later than midnight and turn off the lights of the monuments (except the very rare fully armored ones).
The big advantage of LED technology compared to sodium lamps, it consists of the possibility of reducing the flow as much and as desired. It has not been used to date.
The LEDs that have the least impact on the nighttime environment are those that contain little or no blue light, such as LEDs with a color temperature similar to sodium lamps.
All that being said the possible savings, both economic and energy, are enormous:
– By lowering the light to the levels of Germany, we would go from 6 to 2 TWh;
– By turning off half of the night hours, like thousands of French municipalities, we would go to 1 TWh;
– By adequately exploiting the obligation provided by many regional laws not to exceed the minimum levels authorized by the technical standards, we can light our streets in a more uniform way, so as not to have over-lit areas and other which, on the contrary, seem dark and for this often generate protests from citizens (the UNI11248/2016 standard foresees how to lower the lighting categories, so that most streets can be illuminated at 0.5 cd/m2 or 0 .3 cd/m2);
– Similar savings can be made in the private sector.
The economic costs are not only those of the bills, but also those necessary to install the new systems and keep them efficient over the decades, as well as to dispose of them at the end of their life. Even more expensive, but difficult to quantify financially, they are the costs linked to the loss of biodiversity (eg pollinating insects), often irrecoverable or the consequences on our health due to excessive exposure to artificial light. Dimming and turning off lights not only saves money, but also improves the environment, preserves biodiversity for future generations and reduces CO2 emissions.