City Energy Efficiency
In the framework of climate change mitigation programs, energy efficiency is essential and drives the demand for specific services that indicate energy losses and potential savings.
Within the DECUMANUS project, EUROSENSE developed products that enable to detect heat loss from building roofs (+-30% of all energy losses for a standard house) and excessive lighting (night-time lights). These products can be used by city planners as policy support for large-scale retrofitting campaigns but also to alert in a direct way their citizens to the today’s needs and benefits of saving energy.
The basic products are based only on satellite data while the premium products require the acquisition of specific data, such as aerial data. The broader resolution of the basic products makes them useful for analyses at a neighborhood scale (several building blocks) and for inter-city comparisons. On the other hand, the high-resolution premium products provide enough details to detect and moreover to identify energy losses at a building and a street light scale. The differences between Basic and Premium Services make their use complementary.
Furthermore, EUROSENSE developed a Premium Service that evaluates the photovoltaic potential of each building. This service uses high resolution terrain data and a solar model to identify suitable areas for the installation of solar panels and to evaluate potential electricity yield.
>> Heat loss (50 cm resolution)
>> Light emission: ISS data (10-50 m resolution)
>> Light emission: aerial data (15 cm resolution)
>> Photovoltaic potential (50 cm resolution)
>> Heat loss (750 m resolution)
>> Light emission (375 m resolution)
User feedback and usability
With the Basic Service, city planners are able to locate neighbourhoods with anomalously high energy losses from building roofs. The service allows them to detect city light spots at a neighbourhood scale, and to monitor light emission over time. By doing so, the service can be used as evidence-based policy support for large-scale retrofitting campaigns across the city.
With the Premium Service, city planners can launch campaigns among their citizens to encourage the improvement of their roof insulation and the installation of solar panels. Each citizen is able to verify the quality of their roof insulation on a map, as well as the suitable areas for the installation of solar panels and the corresponding potential electricity yield. Moreover, the service can be used by the city planners to make an overall evaluation of the street lighting network. The luminance values are compared to European standards to detect over-exposed areas and thus potential areas for energy savings.
Example Premium/Local Products:
During a night flight, a light sensitive camera acquires aerial imagery while luminance data are collected on the ground. It enables to calculate absolute values of luminance (Cd/m²). By comparing these values with luminance standards, over-exposed areas and thus areas for potential energy savings are detected. The high resolution of the product (15 cm) enables to make very detailed diagnoses (at a street light scale). A cheaper alternative to the use of aerial data is the use of ISS night-time photographs but the broader resolution (10-50 m) does not allow the same level of analyses.
Over-exposure map, Antwerp (2016)
Aerial thermography measures heat radiations coming from the Earth surface and the objects on the Earth surface. Specific meteorological conditions and the collection of in situ data in parallel with the aerial data acquisition, enable to map heat losses through the roofs (+-30% of all energy losses for a standard house). With support of an interpretation key, any inhabitant is able to verify the quality of their roof insulation. Furthermore, the data can be used to detect leaks in district heating. The high resolution of the product (25 cm) allows very detailed diagnoses.
Aerial thermographic map, Antwerp (2016)
The photovoltaic potential products quantify the suitability of a building roof for installing solar panels, the expected annual electricity yield and the corresponding CO2 savings. The map is based on a geometric model which calculates, for each grid pixel, the solar irradiance. The model takes into account the daily and annual cycles of solar angle, the average monthly climatological conditions at the location (cloudiness) and the shadows casted by neighboring objects such as trees and adjacent buildings.
Solar insolation (left), suitability areas for the installation of solar panels (middle) and expected annual electricity yield by building (right) in Helsinki (2015)
Example Basic/Strategic Products:
The product detects city light spots at a neighborhood scale (several building blocks). Suomi-NPP data (satellite) are used and combined with land cover data. The monthly cloud free composites of the Suomi-NPP data enable to repeat easily the exercise and to monitor light emission overtime. In this way, the product can be used as evidence-based policy support for retrofitting campaigns. The product enables also comparison between cities, in terms for example of light emission per inhabitant.
Multi-temporal light emission monitoring, Madrid (2014-2015)
The product detects neighbourhoods with anomalously high energy losses (hot spots). It is based on night-time satellite acquisitions during cold, cloud-free and snow-free conditions (Landsat 8 and Suomi-NPP data). By combining these data with land cover data, it is possible to isolate the signal from the buildings and create a map with relative heat loss values from building envelopes.
Satellite-based thermographic map, Milan (2013)