Zero Carbon Compendium

Zero Carbon Housing Worldwide

Global Drivers

Figure 1: Kyoto Protocol Commitments: Who's on Target?

It has been six years since the Kyoto Protocol (under the United Nations Framework Convention on Climate Change) came into force for ratifying countries. As the first commitment period ends in 2012, it is clear that the major Annex I emitters will not meet their commitments. While the EU is expected to achieve its collective target, a number of countries, including Canada, Australia, New Zealand and Switzerland, will need to purchase a significant number of CDM credits to fulfil their commitments (see Figure 1).

In a time of increasingly high fuel prices, energy efficiency and the integration of renewable energy will become progressively more important, both in terms of affordability and security. Many countries have become more import reliant (see Figure 2), and gradually more affected by the problems associated with fuel poverty. Geopolitical events continue to increase fuel prices, as well as drive volatility, and fuel prices globally are expected to increase by 60% by 2020.

Figure 2: Energy Imports and Exports (% of Energy Use)

By 2050, global temperatures are anticipated to continue to rise and greenhouse gas emissions are expected to more than double if we carry on with 'business as usual'. To minimise future climate change, mitigation is a crucial goal, but adaptation will also be essential in numerous sectors, not least in building and housing. Designing for a future climate is important, as this will not only help to avoid fuel poverty, but also minimise risk of homes overheating and alleviate flood risk.

This means that future-proofing houses is essential, to meet both today's and tomorrow's needs.

How Does Housing Fit In?

Reducing energy use in homes has become a significant issue with the rise of climate change concerns. CO2 emissions arising from energy use account for more than 30 billion tonnes each year (nearly half of which are the result of energy use in homes). This is an area of concern, given that the number of households is expected to grow by 67% globally by 2050.

Figure 3: Summary of Energy End Uses, Different Countries

For most of the countries in this Compendium The most significant use of energy in housing is for space heating and cooling, as well as hot water (see Figure 3). A growing understanding of the factors that affect energy use in these areas (and particularly owner/occupier behaviour) offers significant opportunities for reducing energy consumption. It is already clear that through a combination of appropriate technology and consumer engagement, low and zero‑carbon housing can play a crucial role in reaching global targets, ensuring long-term energy security and reducing the impacts of climate change worldwide.

Energy Efficiency Standards

Most of the countries in our study have well established energy efficiency standards built into their building regulations and building codes, some dating back to the 1970's, which were developed as a response to the 1973 oil crisis. Over the years these minimum standards have progressively improved and developed, along with a set of aspirational standards that set the scene for innovative solutions to low-energy homes and consequently inform the evolution of regulatory standards (see Figure 4 for an illustration of average U-values in the countries featured in this Compendium).

Figure 4: U-values for Walls, Roofs and Floors (W/m2K)

The 2011 Compendium also includes countries which are in the early stages of their low energy/low carbon building programmes. As these programmes are still in their infancy, the targets are not as stringent as their more developed counterparts but represent a significant first step in the dissemination and promotion of the low carbon agenda.

What is Low and Zero Carbon?

The countries included in the Compendium adopt different approaches to defining low and zero carbon buildings. This has led to a variety of terms to describe such buildings, including low energy, low carbon, zero carbon, Passivhaus, high-performance, energy positive, eco-homes, sustainable homes and green homes. The recommended standards, as well as the way they are expressed and measured, are different from country to country.

This diversity of terminology and definition is not surprising, given the range of climatic and regulatory conditions across countries, as well as differences in housing stock, energy sources and cultural influences One of the main factors influencing carbon emissions is the carbon intensity of the grid, which is dependent on the mix of fuels each country uses to generate energy (see Figure 5).

Figure 5: Carbon Emissions per Unit of Energy, Different Countries (kgCO2/kWh)

Until recently the UK zero carbon definition, to be introduced in 2016, was possibly the most stringent in the world, requiring all carbon emissions (including those from unregulated energy use such as cooking and plug-in appliances) to be addressed. However, in the March 2011 Budget the UK Government announced that zero carbon would be redefined to only require zero emissions from regulated energy use (i.e. the energy required to heat and cool a home, and provide hot water and lighting). This is still a very challenging target for mainstream delivery, requiring considerable innovation over and above current practice, and, typically, the need for measures (Allowable Solutions) which mitigate the emissions that cannot normally be achieved by the design of the home. The new UK definition is now much closer to the requirements set out by the European Energy Performance of Buildings Directive.

The UK remains a leader in the development of aspirational codes, which have provided a stimulus for the design of homes to the most exacting sustainability standards. These homes, and in particular those built to Levels 4, 5 and 6 of the Code for Sustainable Homes, provide valuable insight to inform the development of national standards in the UK and other countries.

Figure 6: Non-Fossil Fuel Sources in the Residential Sector, Different Countries

The overarching ambition is that all energy requirements of homes can be met in future decades by low-cost, non-polluting sources. Research and development, and experience thus far, is showing this as a realistic, rather than impractical, possibility. However, over the next few years, the rate of growth and diversification of the non-fossil fuel energy technologies, and their contribution to the decarbonisation of each country’s electricity grid will be critical to success (see Figure 6). Much can be learned and shared internationally from those countries which have pioneered different technologies, to ensure that sound investment strategies are made by others. The contribution of wind and waste sources, which are both relatively new, are notable in these charts.

Certification Systems and Aspirational Targets

All the countries in this Compendium have established or emerging Green Building Councils, as well as aspirational certification schemes such as LEED, BREEAM, Green Star or independently developed national systems. The development of these standards is important in promoting more stringent building efficiency standards and encouraging consumer demand for sustainable housing.

This Compendium shows how prototypes have been encouraged through research programmes and special development projects on a larger scale over many years in the period leading up to market acceptance. However, the majority of these schemes remain voluntary and a number lack residential rating systems, so there remains substantial room for improvement.

Today the German Passivhaus standard sets probably the most stringent energy efficiency requirements in the world. Sweden has made this standard mandatory for all buildings - in Germany there are over 2,000 PassivHaus buildings and a number of German cities have now adopted it as a mandatory standard for building on publicly-owned land. The number of completions of Passivhaus dwellings in Austria and Switzerland also number in the thousands.

Many of the Passivhaus and low energy schemes have been monitored, and there is a substantial body of data made available, originally through the CEPHEUS Project and from many of the certifying agencies such as Minergie and Passivhaus. Some standards incorporate post-occupancy evaluation for up to 3 years as part of the certification. With respect to costs, some national standards, such as Minergie in Switzerland, have a requirement to show cost effectiveness. Buildings must lie within 10% of base costs to qualify for the Minergie certification. This has helped dispel the misconception that delivering enhanced standards is not economically feasible.

Emerging Economies

The five new countries to the Compendium are of particular interest, as a result of the mixture of challenges and opportunities they present in terms of low carbon housing.

Three of the five, Brazil, Russia and India, are part of the ‘Big Four’ (or BRICs), a group of countries at a similar stage of newly advanced economic development. The fourth is China, which was included in the first edition of the Compendium. The BRICs are expected to continue to become larger forces in the global economy, and to provide opportunities for countries with advanced low-carbon technologies to share their knowledge and expertise through collaboration and mentoring activities. Success in this kind of international exchange would mean an accelerated take up of non-fossil fuel energy sources and, crucially, less reliance on fossil fuels as the BRICs countries strive to meet their energy needs.

South Africa is neither part of the Big Four, nor the Next-11 (other countries who are considered to have the potential to become major economies in the 21st century). However, the country's goals to achieve universal electrification, as well as improved housing standards, means it faces similar concerns for energy and sustainable building as Brazil, Russia and India.

Singapore is not an emerging economy, as a result of its strong financial centre and internationally significant port. There are however interesting challenges for the country, as a result of its high population density, position as a major oil-refining centre and circumstances that require 100% of its energy to come from imports.

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