Cost-Effective Energy Efficient Building Retrofitting

Materials, Technologies, Optimization and Case Studies

F. Pacheco-Torgal, Claes-Göran Granqvist, Bjørn Peter Jelle, Giuseppe Peter Vanoli, Nicola Bianco, Jarek Kurnitski, F. Pacheco-Torgal, Claes Goeran Granqvist, Bjørn Peter Jelle, Giuseppe Peter Vanoli, Nicola Bianco, Jarek Kurnitski, Claes-Göran Granqvist, Fernando Pacheco-Torgal

• Publisher: Woodhead Publishing
• Year: 2017
• Print ISBN: 9780081011287
• eBook ISBN: 9780081012277
• Topic: Technology & Engineering
• Subtopic: Construction & Architectural Engineering
• Index: Technology & Engineering

Cost-Effective Energy Efficient Building Retrofitting: Materials, Technologies, Optimization and Case Studies provides essential knowledge for civil engineers, architects, and other professionals working in the field of cost-effective energy efficient building retrofitting.The building sector is responsible for high energy consumption and its global demand is expected to grow as each day there are approximately 200, 000 new inhabitants on planet Earth. The majority of electric energy will continue to be generated from the combustion of fossil fuels releasing not only carbon dioxide, but also methane and nitrous oxide. Energy efficiency measures are therefore crucial to reduce greenhouse gas emissions of the building sector.Energy efficient building retrofitting needs to not only be technically feasible, but also economically viable. New building materials and advanced technologies already exist, but the knowledge to integrate all active components is still scarce and far from being widespread among building industry stakeholders.- Emphasizes cost-effective methods for the refurbishment of existing buildings, presenting state-of-the-art technologies- Includes detailed case studies that explain various methods and Net Zero Energy- Explains optimal analysis and prioritization of cost effective strategies

Chapter 1

Introduction to Cost-Effective Energy-Efficient Building Retrofitting

F. Pacheco-Torgal, University of Minho, Guimarães, Portugal

Abstract

This chapter starts with a brief review of the unsustainability of energy production, which is the main responsible for global greenhouse gas (GHG) emissions and also on the importance of energy efficiency to abate global GHG emissions. A short look at building energy efficiency and energy retrofitting within the European building stock and the EU legislation is given. A short analysis of several incentives that are available for financing energy retrofitting in Europe is presented. Social aspects regarding energy retrofitting are reviewed. A book outline is presented.

Keywords

Sustainable development; energy production; GHG; energy efficiency; energy retrofitting

1.1 Sustainable Development and Energy Production

Energy production is the main responsible for global greenhouse gas emissions (GHGs). Oil accounts for 32.8%, coal for 27.2% and natural gas for 20.9% (Hook and Tang, 2013). As the source of two-thirds of global GHG emissions, the energy sector is therefore pivotal in determining whether or not climate change goals are achieved. Climate change is the most important problem faced by the human species, being associated to rise in the sea level, ocean acidification, heavy rain, heat waves and extreme atmospheric events, environmental deterioration and wildlife extinction, health problems, and infrastructure damage (Rockström et al., 2009; Williams et al., 2012; Garcia et al., 2014; IPCC et al., 2014).

Since each day there are now about 200,000 new inhabitants on planet Earth (WHO, 2014) this means that the increase in electricity demand will continue growing (King et al., 2015). It is then no surprise to see that the world net electrical consumption is expect to increase from 20.1 trillion kWh in 2010 to 25.5 trillion kWh by 2020 and 35.2 trillion kWh by 2035 (World Energy Outlook, 2013). Unfortunately only 21% of world electricity generation was from renewable energy in 2011, with a projection for nearly 25% in 2040 (World Energy Outlook, 2013). This means that in the next few decades the majority of electric energy will continue to be generated from the combustion of fossil fuels such as coal, oil, and gas releasing not only carbon dioxide but also methane and nitrous oxide. The World Business Council for Sustainable Development estimates that by 2050 a 4- to 10-fold increase in efficiency will be needed (COM (2011a,b) 571). Energy efficiency is therefore very important in this context because efficiency improvements show the greatest potential of any single strategy to abate global GHG emissions from the energy sector (IEA, 2013). Also energy efficiency is the most cost-effective way to improve competitiveness, as well as create employment (COM (2010) 639; Lund and Hvelplund, 2012). This is especially important in the context of the current global economic crisis.

To tackle climate change, the European Union (EU) has agreed on ambitious goals. In the long term (until 2050), the EU has set a goal of reducing by 80–95% its GHG emissions compared with the 1990 emissions level. In the short term (until 2020), GHG emissions in the EU have to be reduced by 20% compared with the 1990 level. Also, energy consumption from renewable resources should be increased by 20% and energy savings of 20% should be achieved (COM (2008) 30). Since the EU has succeeded in cutting its GHG emissions by 18%, between 1990 and 2012, this means that the EU is on track to meet its 2020 GHG emissions target. Unfortunately the same cannot be said concerning the target related to renewable energy or about the energy savings (EU, 2014). As a consequence and according to the latest figures of Eurostat (2015) the annual energy consumption in EU28 (gross inland consumption) is still around 1666 million tonnes of oil equivalent (Mtoe) which basically is the same value of the annual energy consumption of EU28 in 1990 and far from the 371 Mtoe planned savings, being that a substantial amount of that consumption (53%) corresponds to energy imports. This not only constitutes a very important amount of European financial resources of more than 1 billion euro per day, but also raises serious concerns concerning the security of the EU energy supply because almost 70% of EU imports came from just two partners, one being Russia, whose disputes with transit countries have threatened to disrupt supplies in recent years. That is why the recent Communication on the European Energy Security Strategy (COM (2014) 330) among other measures emphasizes the need for a sped-up building energy efficiency and energy-retrofitting rate.

1.2 Building Energy Efficiency and Energy Retrofitting

The building sector is responsible for a high energy consumption and its global demand is expected to grow in the next few decades. Between 2010 and 2050, global heating and cooling needs are expected to increase by 79% in residential buildings (Fig. 1.1A) and 84% in commercial buildings (Fig. 1.1B). These projections are based on a 115% increase in the number of households and on a floor space increase of 94% (Ürge-Vorsatz et al., 2015). Energy efficiency measures are therefore crucial to reduce GHG emissions of the building sector. Recent estimates (Ürge-Vorsatz and Novikova, 2008; UNFCCC, 2013) state that energy efficiency concerning building heating and cooling needs could allow a reduction between 2 and 3.2 GtCO₂e per year in 2020. Other estimates mentioned a potential reduction of around 5.4–6.7 GtCO₂e per year in 2030 (UNEP, 2013).

Figure 1.1 Trends in the different drivers of energy consumption in (A) residential and (B) commercial buildings in the world, 1980–2050. Reprinted from Ürge-Vorsatz, D., Cabeza, L., Serrano, S., Barreneche, C., Petrichenko, K., 2015. Heating and cooling energy trends and drivers in buildings. Renew. Sustain. Energy Rev. 41, 85–98. Copyright 2015, with permission from Elsevier.

Since buildings are responsible for 38% of the EU’s total CO₂ emissions, higher energy efficiency in new and existing buildings is key for the EU climate and energy strategy (COM (2011a,b) 885/2; JCR, 2015). Residential buildings account for 75% of the total building stock in the EU27 and energy in dwellings is mainly consumed by space heating (68.4%) and the remaining share respects to lighting and appliances (14.1%), hot water production (13.6%) with a minor 3.8% used for cooking (De Boeck et al., 2015). Therefore, in order to achieve such reductions the implementation of building codes associated with a high energy performance must be seen as a top priority.

Over the first decade of the 21st century, several high energy-performance building concepts have been proposed, from low-energy building through passive building and zero-energy building to positive-energy building and even autonomous building (Thiers and Peuportier, 2012). Some authors (Adhikari et al., 2012) use ZEB to mean “net zero-energy buildings” and NZEB to mean “nearly zero-energy buildings.” “Net” refers to a balance between energy taken from and supplied back to the energy grids over a period of time. Therefore, Net ZEB refers to buildings with a zero balance, and the NZEB concept applies to buildings with a negative balance. Rules and definitions for near-zero energy buildings or even zero-energy buildings are still subject to discussion at the international level (Dall’O’ et al., 2013).

The European Energy Performance of Buildings Directive 2002/91/EC (EPBD) was recast in the form of the 2010/31/EU by the European Parliament on May 19, 2010.

If there are no delays in its implementation, this directive could provide the EU with up to 65 Mtoe savings in the buildings sector by 2020 (EU, 2014). One of the new aspects of the EPBD is the introduction of the concept of NZEB. Of all the new aspects set out by the new directive this one seems to be the one with most difficult enforcement by member states. The article 9 of the European Directive establishes that, by December 31, 2020, all new constructions have to be nearly zero-energy buildings; for new public buildings, the deadline is even sooner, i.e., the end of 2018.

Also the EPBD recast (article 4.1; recital 14) obliges Member States to “assure that minimum energy performance requirements for buildings or building units are set with a view to achieving cost optimal levels”. The cost-optimal methodology introduces, for the very first time, the prerequisite to consider the global lifetime costs of buildings to shape their future energy-performance requirements. However, EU regulation and guidelines provide to member states a very large degree of flexibility when selecting the input data for the calculation. Flexibility is also provided for the selection of reference buildings (which represent the typical and average building stock in a certain member state), optional discount, energy cost, equipment and packages, maintenance and labor costs, primary energy factors, and estimated economic lifecycle (BPIE, 2013). Both concepts (cost effectiveness and cost optimality) are related, but still different, the latter being a special case of the first. They are based on comparing the costs and (priced) savings of introducing a particular level of minimum energy-performance requirements for buildings. In general, a measure or package of measures is cost effective when the cost of implementation is lower than the value of the benefits that result over the expected life of the measure (BPIE, 2013). Still some authors (Becchio et al., 2015) mention that nearly zero solutions are far from matching cost-optimal solutions. This is confirmed by Kurnitski (2015), who mentioned that nearly zero-energy or A-class buildings are not yet being offered on the market, because the construction thereof is still considered too expensive. This author also mentioned that calculations made by a research group of Tallinn University of Technology showed that the B-class low-energy buildings can be considered cost effective at the moment while nearly zero-energy buildings need a little more time for development before becoming competitive. Unfortunately, the status of the EPBD implementation in EU countries is disappointing because so far only a minority of countries have transposed the EPBD into their national laws (Antinucci, 2014).

Be that as it may, the fact is that new buildings have limited impacts on overall energy reduction as they represent just a tiny fraction of the existent building stock (Xing et al., 2011). Recent statistics reveal that 14% of EU-27 building stock dates before 1919, and about 12% dates between 1919 and 1945, even if considerable national differences occur (Ascione et al., 2015). Since the first building codes were introduced in the 1970s when almost 70% of the current EU building stock had already been built this means that the majority of the European building stock has low energy-efficiency performance. Existing buildings constitute, therefore, the greatest opportunity for energy-efficiency improvements. This will also help to reduce energy imports in Europe because a major part of gas imports are consumed by the building stock. In 2012, buildings in the Baltic States, the Czech Republic, Bulgaria, and Slovakia were 100% dependent on Russian gas. Buildings were 98% dependent on Russian gas in Hungary, 86% in Romania, and 80% in Poland the same year (JCR, 2015). Besides, new homes use four to eight times more resources than an equivalent refurbishment (Power, 2008), which constitutes an extra and sustainable argument in favor of building retrofitting.

Also, energy building retrofitting has important effects on economic recovery. According to Bi...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• List of Contributors
• Foreword
• Chapter 1. Introduction to Cost-Effective Energy-Efficient Building Retrofitting
• Part I: Materials and Technologies
• Part II: Optimization
• Part III: Case Studies
• Index