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• Examination of a typical classroom in Greece and its installed power for an artificial lighting profile from 1970 until today (type and number of luminaires, installed power per classroom, consumed annual energy kWh/m2). • Calculation of potential energy savings for customizing installed power LED with AC and DC supply aiming for the illuminance target values from the European Norm 12464–1, 2011. • Measurements of dimming curves of LED luminaires with AC and DC supply (consumed energy versus lighting output) and measurements of power of typical photosensors. • Estimated energy savings, CO 2 reduction and cost optimal analysis due to various scenarios (different luminaire technologies and daylight harvesting techniques). • Calculation of the final energy consumption for potential power supply from renewable energy sources using DC LED luminaires and photosensors. The energy consumption for the artificial lighting in school buildings is one of the main consumers of electricity. In Greece, there is a large number of school buildings with quite old lighting systems using luminaires with T8 and sometimes T12 fluorescent lamps and degradated translucent diffusers. Due to the economic crisis, the public sector failed to invest in LEDs and although daylight is adequate during the year, the adoption of control technology is rather slow. The paper, using a typical classroom of a Greek public school, examines a number of lighting technologies (with AC and DC supply) together with two daylight harvesting systems. The first one uses one stand-alone photosensor per luminaire while the second one sensor per control zone, in an effort to calculate energy savings and light adequacy. The dimming curves of the DC LEDs were measured along with the installed power of the photosensors. The results show that the existing 90.5 kWh p /m2 of annual lighting primary energy consumption can be reduced to 0.55 kWh p /m2. The maximum annual reduction of CO 2 emissions was 32.44 kgr/m2 for classroom areas, which is translated to 201929 tn for the whole country. It is evident that the path to Zero Energy School Buildings goes through the mandatory use of daylight controls. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Highlights • The weighted average values of thermal energy consumption (oil and natural gas) for space heating, as of 2011, of the complete stock of buildings in Greece used as primary residences (insulated or not, single-dwellings or apartments), is estimated to 60.9 up to 130.1 KWh·m−2·year−1. • The mean actual thermal energy consumption for space heating of residential buildings is much lower than that evaluated based on HDHs or the method of Hellenic Building Energy Performance Regulation (REPB), according to European Directive 31/2010. • The implementation of the Hellenic regulation for building energy performance (REPB) imposed the improvement of thermal protection of the building envelope and the performance of the electrical and mechanical systems. • Applying the REPB minimum requirements on thermal protection reduce the space heating loads of residential buildings in all climate zones by 63% to 70%. The compliance of existing residential buildings to the minimum requirements of the REPB could result to about 24.4 TWh of savings in space heating energy annually. • The benefits of any National Regulation on Building Energy Performance should be examined on the basis of expected lower actual energy consumption. Abstract This paper presents the energy, the technical and the environmental characteristics of residential buildings in Greece, as well as their potential for energy conservation, based on their actual energy consumption data. The technical characteristics of residential buildings related to their energy performance (insulation, type of openings, system for space heating and cooling, etc.), the actual energy use (kWh.m−2.year−1) and the environmental factors (kgCO₂.m−2.year−1) related to energy consumption, are some of the parameters of this survey. The average annual specific energy consumption of residential buildings in Greece was 112 kWh·m−2·year−1 in 2014, the 6th lower consumption among the 28 European member states (EU-28) in which the average residential building energy consumption is of about 158.8 kWh·m−2·year−1. The potential of space heating energy conservation for Greek residential buildings was estimated, based on (i) the 2011 heating energy consumption data and (ii) the percentages of space heating energy conservation, calculated by analysing 144 different types of residential buildings, having various geometric and technical characteristics, such as the A/V ratio (envelope area to volume of building), the heating degree hours (HDHs) and various occupancy profiles. The resulting average actual energy consumption is much lower than that calculated using Heating Degree Hours (HDHs) or the method of Hellenic Building Energy Performance Regulation (REPB). Almost 45% of these buildings were built before 1980, without any thermal insulation or double glazing. The compliance of these buildings to the minimum requirements of the REPB (related to thermal insulation and the efficiency of their electromechanical systems), could result to about 24.4 TWh of savings in space heating energy annually, i.e. to about 32–175 kWh·m−2·year−1, depending on the climate zone that corresponds to 8.5–46.2 kgCO₂·m−2·year−1 reduction. [ABSTRACT FROM AUTHOR]

Photovoltaic (PV) power system is a technology for producing electricity from renewable resources that is rapidly expanding thanks to its capability to save conventional fossil fuels and to decrease the emissions of greenhouse gases. However, as more attention is being focused globally on the development of building-integrated PV systems, the technical, the economic as well as the environmental assessment of these systems is crucial to ascertain their viability. The purpose of this paper is to present an economic and environmental analysis of relatively small rooftop PV-grid-interconnected energy systems of 2–10 kW p rated power, located in Athens, Greece. The techno-economic feasibility of the PV systems is conducted employing the computerized renewable energy technologies assessment tool ‘RETScreen’. The energy and environmental assessment of the systems is carried out employing SimaPro 7.1 software, which is a standard Life Cycle Assessment tool. The results of the economic analysis indicate that with the current prices, investment in PV-grid-interconnected systems with power capacity higher than 5 kW p is in general viable. However, an increase in energy sale prices and/or cost reductions in the production of PV systems are crucial for the successful development of small-scale residential size PV systems in the country. The environmental analysis reveals that the PV systems with higher rated power perform worse as far as the environmental impact is concerned. The critical phase of the life cycle of PV systems is the module manufacturing process, which is characterized by high electricity consumption, representing most of the environmental impact. Nevertheless, it is further shown that the application of PV technology presents important environmental benefits compared to conventional energy production systems. [ABSTRACT FROM AUTHOR]

Residential buildings in Greece account for about 79% of the exclusive-use building stock and consume about a quarter of the total final energy consumption, with space heating and domestic hot water being the main energy end-uses. About 58% of the dwellings were constructed before the 80 s and the adoption of the first thermal insulation regulation. This paper presents the results from the Hellenic pilot action within EPISCOPE. The overall approach and analysis are based on the national TABULA residential building typology for single- and multi-family houses in order to estimate heating energy performance and savings. The work exploits Census and statistical data for defining the Hellenic building stock and empirical adaptation factors to make more realistic estimates from normative calculations. The analysis is supported by a detailed data disaggregation in terms of the number of dwellings and floor areas, based on envelope thermal characteristics, heat production units, energy carriers, use of renewables etc. The calculation results are adapted for the building types and then projected to the building stock. Numerous scenarios for different modernization rates are assessed for identifying the most promising refurbishment strategies in space heating and DHW for reaching the 2020 and 2030 national CO 2 emission targets. [ABSTRACT FROM AUTHOR]

This paper aims at implementing appropriate methodological approaches for a preliminary assessment of fuel poverty in Greece and analyzing in quantitative terms the potential impact of fuel poverty on public health. As regards the assessment of fuel poverty in Greece, both subjective and objective approaches have been implemented, utilizing primary data from existing surveys undertaken by National Statistical Authority, while the health impacts attributed to fuel poverty were quantified through statistical analysis. The implementation of objective approaches showed that around 20–25% of Greek households were in fuel poverty in 2013, while with subjective measures this percentage reaches to 29.5%, twice as in 2010. Furthermore, the regression models developed showed that the increased levels of fuel poverty observed after 2010 have had significant negative impacts on public health. Specifically, 1–2.7% of deaths recorded annually in Greece as well as the 2.7–7.4% of cardiovascular diseases and the 3.1–8.5% of respiratory infections treated by the Greek hospitals are attributed to fuel poverty. Taking into consideration that more than 60% of Greek households do not have adequate insulation, the development of ambitious energy saving programs for residential buildings could build synergies between climate change mitigation and fuel poverty alleviation. [ABSTRACT FROM AUTHOR]