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• Energy consumption reduces sby 91.1% in 2030, by applying major renovation and PV. • Heavy renovation inside residential buildings proved to be more effective in reducing the energy consumption; • The implementation of the mobility scenarios will lead to a reduction by 2030 of 33.26% of energy. One of the major objectives of the European Union by 2030 is to reduce energy consumption at the building level. Aware of this fact, the main goal of this study is to propose some strategies more adapted to the temperate climate aiming to modernize the existing residential districts towards zero energy and low carbon emissions by 2030. A total of 454,994 dwellings (terraced houses; semi-detached houses; detached houses and apartments) were investigated for this purpose. These are spread over 5 provinces in the Walloon region in Belgium and grouped into 5 types of the neighbourhood (isolated rural, peripheral rural, peri -urban, suburban and in urban neighbourhoods). The technique of reducing energy consumption in the buildings studied in this research is centred on the implementation of scenarios related to climate, renovation, transport and renewable energy. In addition, several energy optimization models are being tested for this purpose. The results showed that the objective "near-zero energy neighbourhood" can be achieved in temperate zones. In fact, current energy consumption is reduced up to 91% by simultaneously applying a heavy renovation of residential buildings, renewable energy and green mobility. By applying the heavy renovation (100%) on these residence buildings, the heating energy decreases from 230.6 to 23.7 kWh/m2 in the terraced houses; from 239.7 to 24.6 kWh/m2 in the semi-detached house; and, from 202.1 to 20.8 kWh/m2 in the detached house. [ABSTRACT FROM AUTHOR]

• Heavy retrofit allows to reduce up to 95 % of CO 2 concentration emission. • Over 70 % of the total carbon emissions worldwide is produce by the developed countries. • Embodied carbon represents the 27.9 % of total CO 2 produce during operational phase. The building sector has become a major source of worldwide carbon emissions and energy consumption because of rapid population growth and a continuous environmental strain caused by humanity. A lack of consistent data on life-cycle carbon emissions and energy demand at the neighbourhood level has made it difficult to understand the origins of climate change at this scale. A sensitivity analysis brought clarity concerning the extent of environmental impacts on future climate evolution. From this perspective, the authors aimed to evaluate, analyse, compare, and provides recommendations to reduce carbon emissions, as well as the energy required by three types of neighbourhoods (urban, rural, and sustainable) located in and adapted to all countries worldwide. The most important parameters affecting carbon emission and energy consumption were analysed, including the energy mix of countries, local building materials and climate, technological solutions utilised, daily mobility, and occupied spaces. The results indicated that the highest levels of carbon dioxide emissions were produced by countries with prosperous economies, such as China, the United States, India, Germany, and Poland, because of high concentrations of coal in their energy mixes. Modernising cities through the construction of new eco-districts and increasing the use of new techniques for substantial renovations of outdated buildings worldwide could mitigate the amount of greenhouse gases emitted by neighbourhoods 53–97 % by 2050. Moreover, by combining substantial building renovations with the installation of photovoltaic panels on roofs, the objective of 'zero carbon' at the neighbourhood level could be achievable by 2050 in rural neighbourhoods. Radical changes in the judicious choice of construction materials and use of green energy production represent targeted opportunities to resolve the future climate dilemma. [ABSTRACT FROM AUTHOR]

The European Union (EU) aims to establish a guideline that requires all new buildings to comply with nearly zero-energy buildings (NZEB) by 2030. This decision involves new technologies based on concepts that meet international standards. This research aims to review the literature on 'net zero-energy building' and analyses the possibility of applying this research on nine statistically representative neighbourhoods of the building stock'in Belgium, depending on the built density. All the areas, grouped into four categories (urban, peri-urban, suburban, and rural neighbourhoods), were used for current energy consumption analysis and to evaluate prospective scenarios based on four major challenges, namely climate change, building renovations, photovoltaic panels, and sustainable mobility. In addition, a new approach combining several scenarios to further improve energy needs at the neighbourhood scale is also highlighted. The nine different types of neighbourhoods studied are commonly found in different countries across the EU. The average reduction in energy consumption of neighbourhoods (buildings + daily mobility) in 2040 (compared to reference year 2012) will likely reach 5.69% attributable to a 20% reduction in distances travelled, 6.48% to climate change, 12.95% to the current annual buildings renovation rate, 18.76%–100% electric cars, 22.26% for doubling the current buildings renovation rate, 31.62% and 63.25% to a light or heavy renovation of the entire building stock, respectively. Moreover, installing 20 m2 of solar panels on the rooftops of each residential building would produce renewable energy equivalent to 6.53% of the current global energy consumption. Finally, the results show that more than 90% of current energy consumption can be reduced at the neighbourhood scale (buildings + daily mobility) by combining a heavy renovation of all the buildings, electric vehicles, and photovoltaic panels. This scenario allows reaching the 'nearly zero-energy' target at the neighbourhood scale. • The 90% of energy consumption can be reduced by combining a heavy renovation, electric vehicles, and photovoltaic panels. • Photovoltaic panel yield is higher in rural than urban neighbourhoods. • Electric vehicles reduce up to 20% of energy consumption in neighbourhoods. [ABSTRACT FROM AUTHOR]

Aware of the strong population growth expected in the coming years in cities, it is imperative to evaluate the impact of this new concentration on the environment, health and power consumption. Life Cycle Assessment (LCA) is the most appropriate method to quantify these different impacts. The aim of this study is to carry out the Life Cycle Analysis (LCA) in two sustainable and old neighbourhoods located in Belgium, while comparing different environmental impacts; but also, to determine the most important source of environmental change at the neighbourhood scale. This study begins with a strong review on LCA in residence buildings and neighbourhoods since 1996 up to 2018.Then followed by the assessment and comparison of the climate variation in six different periods (past, current, 2020,2050,2080 and 2100).In the same line, three scenarios (A2, B1 and A1B)were associated to several models of the Intergovernmental Panel on Climate Change (IPCC). We have combined three simulation tools, such as ALCYONE, COMFIE-PLEIADES and nova-EQUER. The main results showed the twelve environmental impacts studied in this research that does not always evolve in the same way. Indeed, it was noticed that the CO2 emissions were up to 36.6% higher in an old neighbourhood than in a sustainable one; while the energy demand was estimated at 62.6% and 37.4% in an old and a sustainable one, respectively. Good planning of the public space will play an important role to reduce in average up to 15% the eutrophication in both neighbourhoods. Globally, the renovation of residential buildings is very important, indeed, it allows mitigate in average up to 30% of environment impacts in both neighbourhoods. • The first research on LCA in old and sustainable neighbourhoods is showed. • Eleven of the environment impacts were more important in the old neighbourhood. • The exploitation phase showed the highest GHG emissions and energy consumption. • The renovation of buildings mitigate up to 30% of impacts in both neighbourhoods. • The CO 2 emissions were up to 36.6% higher in an old neighbourhood. [ABSTRACT FROM AUTHOR]