Green Buildings and Land use
In the EU, buildings represent about 40% of the final energy consumption and 36% of the total CO2 emissions. This corresponds to the annual unit consumption per m2 for buildings at EU level, which was 220 kWh/m2 in 2009, with a large gap between residential (200 kWh/m2) and non-residential (300 kWh/m2) use. Each EU member state has made national plans regarding energy efficiency requirements for the building sector. As 35% of the buildings in the EU are over 50 years old, special attention should be paid to retrofitting schemes and introducing financial support for energy saving renovations. Urban form and spatial structure is strongly related to resource use. The arrangement of land use directly affects energy consumption primarily in the transport and space heating/cooling sectors.
What actions can increase energy efficiency connected to buildings and land use? How should you communicate? Read about what to consider when choosing actions to increase energy efficiency below.
The construction of new buildings represents between 1-1,5% of the building stock while the removed buildings represent about 0,2-0,5%. Assuming that this trend will continue in the period ahead, the focus needs to be put on renovation of existing buildings in order to achieve substantial impact in terms of energy saving and GHG reduction.
The most efficient way to curb energy consumption in buildings is reducing heat loss by improving the thermal insulation of the building envelope (roof, wall and floor). All traditional insulating materials (as mineral wool), except for a few types of cellular foams, still rely on air embedded in cavities, pores or cells which prevent any convection. These technologies offer a minimum thermal conductivity of about 0.029 W/(m•K) and the thickness of insulating layer ranges from 15 to 20 cm. The emergence of new super-insulation materials (SIM) in the last decade started a new era of insulation technologies.
Another area where energy efficiency could be greatly improved is glazing. The market penetration of high-energy performance glazing products remains low in Europe despite the energy saving potential associated with window refurbishment. Over 85 % of glazed areas in Europe are equipped with inefficient glazing. More than 100 million tons of CO2 could be saved annually if Europe’s building were equipped with energy-efficient glazing.
To reduce energy consumption even further, improving air-tightness significantly increases energy efficiency. However, increased air-tightness can decrease indoor air quality, and therefore, efficient ventilation systems should be used. Mechanical ventilation with heat recovery (MVHR) offers year around, whole home ventilation that will remove condensation and pollutants, improving the indoor air quality, whilst recovering the heat that would otherwise be lost outside. Modern MVHR systems offer heat recovery efficiencies of about 95%. On the cooling side, ventilated cooling is an efficient alternative to traditional air-conditioning systems, where savings over 50% in can be achieved.
Urban planning can support compact built-environment and energy efficient housing orientation and street layout. Urban planning can influence which energy systems should be deployed in new housing areas, e.g. by an energy plan. In the PLEEC WP4 Thematic Report (D4.3) we review how planning can support energy efficient buildings (Chapter 2) and energy efficient transport (Chapter 4).
Contact: Christian Fertner, University of Copenhagen, Denmark
Different thoughts on densification in Eskilstuna and Santiago de Compostela
In the city of Eskilstuna (see WP4 Case Study report on Eskilstuna (D4.2)), a priority area is the densification of housing estates from the 1970s, which were built with vast parking spaces and spaces which are not used today. Densification of those areas can lower the pressure for urban expansion (and urban sprawl) and also make the existing infrastructure more efficiently used. Other cities like Santiago de Compostela are traditionally already very compact. Here the climate-friendly renovation of the historical building stock is the challenge. The WP4 Summary Report (D4.4) outlines spatial planning measures and summarizes the efforts in the six cities.
Targeting people’s behavior is a key aspect in achieving energy savings in the building sector. People make daily decisions affecting energy use at home, at work and leisure time. Some of these decisions have only short term effects on energy use, but many of the bigger decisions (e.g. renovations, new buildings) can curb energy consumption in the long run.
According to research people respond to:
Down-to-earth information and attend for example energy efficiency related training as long as the guidance is practical.
Financial incentives. These can lower the threshold of investing in bigger energy-related renovations. For example, having an incentive to lower the upfront cost of an investment could potentially increase to willingness to make energy efficiency installations.
According to other findings made by the PLEEC project, cities and city planners should:
Integrate energy efficiency in all levels of land-use planning as well as the planning of new buildings.
Involve people already in the planning phase of new buildings and city plans, as this is likely to generate solutions which gain acceptance among the end users.