Zero-carbon Homes

A Road Map

Joanna Williams

• Publisher: Routledge
• Year: 2013
• ISBN:
  9781136575549
• Edition: 1
• Topic: Architecture
• Subtopic: Urban Planning & Landscaping

Housing is a major contributor to CO2 emissions in Europe and America today and the construction of new homes offers an opportunity to address this issue. Providing homes that achieve "zero carbon", "carbon neutral", "zero-net energy" or "energy-plus" standard is becoming the goal of more innovative house-builders globally, whilst energy providers seek to decarbonise the energy supply to new and existing development.

Various new technical systems for achieving these goals are beginning to emerge. For example the passive house whose energy requirement for space heating and cooling is almost zero; the smart grid that has revolutionized the management of energy, whilst enabling the connection of small-scale, renewable energy producers and electric vehicles to the grid; or the European super-grid which will enable zero carbon energy to be generated in the Sahara desert and stored in Norway.

This book explores the diverse approaches that are being adopted around the world to deliver zero carbon homes and the different societal systems and geographic circumstances in which they have developed. It postulates a roadmap for delivering zero carbon homes, together with a toolbox approach for policy and practice to suit particular national and local circumstances.

A series of case studies are presented that offer lessons for delivering zero carbon homes. These examples are also used to demonstrate how prototype systems can move into the mainstream. The book highlights some of the instruments and mechanisms that could be used to support this transformation and addresses the wider implications of introducing these innovative systems in terms of industry, lifestyle and urban form.

Chapter 1
Introduction

Introduction

Housing is a major contributor to CO₂ emissions in Europe and America today. The construction of new homes offers an opportunity to begin to address this issue. Providing homes that achieve ‘zero carbon’, ‘carbon neutral’, ‘zero-net energy’ or ‘energy-plus’ standard is becoming the goal of more innovative house-builders and energy providers in Europe and America. A diversity of approaches is being adopted. These are inevitably influenced by the different societal systems and geographic circumstances in which they have developed. Using case studies from Sweden, Germany, the UK and USA we explore these alternative approaches.

Housing programmes (for example the ‘solar homes’ and ‘zero carbon’ housing programmes) have been used in many countries to raise the energy standard and /or reduce carbon emissions from new stock. Low carbon energy systems, developed at a variety of scales, have helped to decarbonise domestic energy supply and reduce subsequent CO₂ emissions from households. Prototype low carbon neighbourhoods have also emerged which combine innovative technological systems, management practices and social capital to achieve longer-term behavioural change amongst residents, thus lowering CO₂ emissions. Examples of innovative low carbon housing programmes, energy systems and neighbourhoods in Europe and USA are introduced in the book.

A series of zero carbon housing models are presented. These offer valuable generic lessons for delivering zero carbon homes (the focus is on new stock, but some of the lessons may equally apply to existing stock), both in terms of policy and practice. These lessons help us to understand how prototype systems can move into the mainstream and how industries will need to transform to assist wider deployment. It highlights some of the instruments and mechanisms that could be used to support this transformation. Finally, the wider implications of introducing these innovative systems in terms of lifestyle and urban form are explored. Overall the book postulates various scenarios for delivering zero carbon homes, together with a toolbox approach for policy and practice to suit particular national and local circumstances. The observations presented in the book are based on an extensive review of literature and field work in the UK, USA, Sweden and Germany as part of the ‘Zero carbon Homes’ Project.

Global warming

Tackling global warming is essential in ensuring the long-term future of humanity. Greenhouse gases produced from the combustion of fossil fuels has led to an increase in the global temperature of 0.5°C since the industrial revolution. At the current rate greenhouse gas emissions will double by 2035 (550ppm CO₂ equivalent) and global average temperature will rise 2°C. By the end of the century the quantity of greenhouse gases in the atmosphere could more than treble, resulting in a 5°C temperature rise (Stern, 2006). To put this in context the climate in the last ice age was only 5°C cooler than it is today (Stern, 2006).

A temperature rise above 2°C will have major impacts on the global physical environment. Ecosystems – including coral reefs and rainforests – would be severely threatened. If the temperature rises more than 2°C between 15– 40% of species would face extinction. Increased levels of CO₂ in the oceans will lead to acidification and depletion of fish stocks. The number of extreme weather events is also likely to increase and the sea-level will rise. This will threaten many low-lying communities in developing countries, particularly in south-east Asia. Eventually it will affect islands in the Atlantic and Pacific. A rise in temperature of 3–4°C could also result in the inundation of key global cities – London, Shanghai, New York, Tokyo and Hong Kong.

Water supply would of course be affected by climate change. Some areas would suffer from drought and others from floods. Stern suggests around a billion people would be affected in each case. Even with a 1°C temperature increase water supplies will be threatened in more marginal communities. Melting glaciers (initially creating a flood risk and latterly a water deficit) are likely to affect water supply to around one sixth of the population – particularly in parts of China, the Indian sub-continent and the Andes, South America.

With a 1°C temperature rise the failure of crops in arid regions would become more widespread. An increase in temperature of 4°C would produce a significant reduction in yields globally. The coverage of productive land will reduce dramatically and become focused in temperate regions. As the climate warms, food and water will become increasingly scarce. Eventually, without some form of intervention, this will lead to mass migration to the productive regions of the globe, resource wars and population crashes. By 2050, 200 million people are likely to be permanently displaced from their homes by rising sea levels, floods and droughts.

Initially climate change is likely to be a greater threat to the developing world. The marginal nature of the environment, poverty and reliance on agriculture, make developing countries particularly vulnerable to climate change. First, much of the developing world already suffers from drought and thus productivity and crop yields are low. Second, the economies of these regions are largely dependent on agriculture. The impact of global warming on crop yields is likely to be catastrophic for the farmers and national economies based on agricultural production. Third, poverty renders these communities unable to buy the technology to alleviate the problems caused by global warming or to mitigate climate change.

In contrast, the developed world benefits from more temperate climates, greater wealth and a non-agrarian economic base. Thus in the short term it is less at risk from climate change. In fact countries in northern latitudes (Scandinavia, Russia, Canada) are expected to benefit in the short term from temperature rises¹. However, with a 2°C rise in global temperatures crop yields and water availability is expected to decline by 20% in Southern Europe. Thus, the Mediterranean is likely to suffer from problems of drought even in the short term.

Some of the changes precipitated by global warming are irreversible. For example, even modest climate change (i.e. an increase in temperature of 1.5°C) will result in the irreversible melting of the Greenland ice sheet. It would also reduce natural carbon absorption and increase methane releases, which in turn results in temperature rises. Thermal oceanic circulation may also be disrupted. All three processes are irreversible and increase the risk of very abrupt changes in the global climate.

Globally around 65% of greenhouse gas emissions are energy related. The majority of emissions are produced from power generation and distribution (24%). However, transport (14%), industry (14%) and buildings (8%) also contribute significantly to greenhouse gas emissions (largely CO₂ emissions). Thus the way in which we plan new and existing communities, the transport infrastructure, the built environment, the energy systems will have a significant impact on CO₂ emissions and climate change.

Energy security

Energy security poses a growing global threat. Increasing demand for energy, scarcity of resources, increasing prices, political conflicts and economic instability all combine to reduce energy security. Energy supply is integral to the economy of a country and thus it is fundamental to national security. Energy is also essential to achieve basic levels of comfort and well-being. Demand for energy is increasing globally more recently driven by the emergence of new economic powers – particularly China. Yet stocks of coal, oil, gas, uranium and rare earth elements (REE) are declining.

Most countries are reliant on energy imports which make them very vulnerable to shortages and price rises. Uncompetitive markets resulting from the dominance of energy-superpowers (e.g. Russia) or formation of cartels (e.g. OPEC) threaten energy security. For example, price manipulation to maximise group revenue by OPEC in 1973 led to soaring energy prices. It resulted in many countries reviewing their reliance on oil and taking pro-active measures to reduce their future dependence (for example Sweden boosted its investment significantly in renewable energy after the oil crisis). The share of oil supply coming from the OPEC nations in the Persian Gulf is expected to increase from 26% in 1997 to 41% by 2020 (Geller, 2003). Given the existence of the OPEC cartel and political instability in the Gulf region oil-importing nations are destined to face even greater economic and security risks in the future (Geller, 2003).

Disputes amongst suppliers and transit nations may prevent supplies from reaching consumers. For example, the ongoing disputes between Russia and the Ukraine between 2006 and 2009 resulted in 18 countries in the European Union having their gas supply cut-off.² In 2006 Russia claimed the Ukraine was not paying for gas, and siphoning off gas exported to the European Union from the pipelines crossing the Ukraine from Russia. In 2007 and 2009 further disputes occurred over Ukrainian gas debts. For the European Union this meant a reduction in gas supply during the coldest months of the year, which made it very vulnerable to price hikes in the gas market.

Geopolitical factors influence investment in energy and scarcity of resources. Depletion policies, resource nationalism and political instability affect the quantity of energy available on the world market. Some countries – Saudi Arabia, Kuwait, Venezuela – have introduced depletion policies to preserve energy resources. Depletion policies ensure that resources are released slowly in order to provide a wealth fund for future generations or simply increase the value of the energy resource. Other countries operate resource nationalism which prevents or restricts access to energy reserves for international oil companies (IOCs). One side effect of this is that resources are not extracted as efficiently. Political instability and military action in regions also affects energy supply. It can impact on foreign investment and hamper operations. All three mechanisms reduce the energy supply available globally.

Yet there is rapid growth in demand for energy from developing nations, the most voracious being China. China has realised the need to expand its resource base to ensure continued economic growth. Thus during the period of global economic recession, the Chinese have begun to invest in energy resources overseas. The Chinese have invested in oil reserves in Russia, Venezuela and Brazil in exchange for long-term commitments to supply oil. They have also invested in a scheme to develop an area beneath the Persian Gulf sea-bed which holds 8% of the world’s reserves of natural gas. With the emergence of these new economic powers, Europe and America face greater global competition for finite energy resources.

There has been growing interest in renewable energy globally. This generated markets for green technologies. China currently produces the majority of the rare earth elements (REE) critical to the manufacture of many green technologies (e.g. wind turbines, low energy light bulbs, hybrid cars, catalytic convertors). Chinese mines currently account for the majority of global REE supplies. China is trying to ensure that all raw REE materials are processed within its borders. During the past seven years it has reduced the amount of REE materials available for export by 40% (Milmo, 2010). The restriction on supply of the REE materials has created a serious problem for those producing green technologies globally. There is now an effort to set up mines for REE materials in the West, but they are 5–10 years away from significant production, which is likely to slow the deployment of green technologies (Milmo, 2010).

To overcome problems of energy security a nation, or groups of allied nations, must become more self sufficient. The response to this is two-fold. First countries need to address energy consumption through efficiency measures. This might include reducing generation and transmission losses using combined heat and power, localised supply networks and smart grids. It could involve increasing the energy efficiency of building stock or encouraging a change in consumer behaviour through pricing policies. Once demand is reduced it becomes more feasible to substitute finite sources of energy (oil, gas, coal and uranium) with renewable resources. Thus the second part of the response is to move away from the import of fossil fuels towards domestic generation of renewable energy. Ideally countries will eventually export renewable energy through means of super-grids. Thus, countries become less reliant on a few fossil fuel cartels and are less affected by global shocks, regional disputes, depletion policies and resource nationalism. Fortunately this also gels nicely with an agenda to reduce greenhouse gas emissions.

Carbon emissions from housing

Key drivers of emissions from energy use include activity drivers (total population grow...

Table of contents

• Cover Page
• Half Title Page
• Title Page
• Copyright Page
• Contents
• List of figures
• List of tables
• Acknowledgements
• Abbreviations and acronyms
• Chapter 1 Introduction
• Part I
• Part II
• Part III
• Notes
• Bibliography
• Index