A new study prepared by construction experts and leading international academics, including senior members of the Intergovernmental Panel on Climate Change, revealed that the technology and skills already exist to achieve net- or nearly- zero energy building in almost every part of the world at costs in the range of those of traditional projects.
It is widely agreed that the sectors that can make the biggest difference in reducing carbon emissions include power, transport and buildings. The building sector, in particular, is responsible for 39 per cent of energy-related greenhouse gas (GHG) emissions globally and embodied carbon in building materials could consume up to half of the remaining 1.5ºC carbon budget. When it comes to Europe, it is estimated that the built environment accounts for approximately 40 per cent of energy consumption and 36 per cent of CO2 emissions of the Member States. Therefore, achieving net-zero carbon emissions in the building sector is vital to achieving climate goals.
“With respect to climate change, the world has agreed to a target of 2⁰C, but we find ourselves on a pathway towards between 3 and 5⁰C,” said Scott Foster, Director of the Sustainable Energy Division at the United Nations Economic Commission for Europe.
“Buildings are at the core of meeting the world’s quality of life ambitions and addressing climate change. Of all the options available to us, getting buildings right stands out in terms of timeframe, scale effect and economics.”
He recalled that the UN already developed the Framework Guidelines for Energy Efficiency Standards in Buildings as principles-based standards conceived to meet the challenges.
The new study examined low and ultra-low energy buildings and visionary policies internationally and found that change can often be achieved quickly. In addition, the cost of sustainable buildings can match or even be less than those constructed through traditional methods.
“Buildings are often the largest consumer of energy and source of emission in cities, and frequently represent the lowest cost option for reducing emissions,” added David Miller, Director of International Diplomacy at C40 Cities Climate Leadership Group and former Mayor of Toronto. “The findings in this important paper highlight the experience of leading cities in which committed leadership has overcome the challenges to enable better, more comfortable, healthy, affordable and sustainable homes and buildings for all.”
However, challenges remain. The greatest technological difficulties are seen in high-rise commercial buildings in hot and humid climates and in retrofitted historic heritage buildings. Deep retrofits are also costly in the short term and although they may cost less over time, innovative financing is often required upfront.
“The sustainable cooling of buildings is a major challenge,” pointed out Radhika Khosla, study co-author and Senior Researcher at the Smith School of Enterprise and the Environment at the University of Oxford. “In a warming climate, building energy use will go up even if cooling is as efficient as possible. Rising affluence, space and comfort needs are set to dramatically increase energy demand – with corresponding increases in greenhouse gas emissions. However, there are solutions: for example, shading and wind-channelling designs to block the sun and allow for natural ventilation in high-rises.”
According to the new research, the key to achieving net-zero targets is the maximisation of energy efficiency through building features, with remaining energy requirements generated from locally produced, renewable energy sources such as solar panels. The use of renewable materials, such as timber, can also help decrease CO2 emissions. Bio-based materials could represent a double win in construction: first, by replacing energy- and carbon-intensive materials such as cement and second, by storing carbon temporarily.
“Our research shows that net-zero energy buildings and retrofits are feasible in every corner of the world, all climates and virtually every building type,” added Diana Urge-Vorsatz, study co-author and Director of the Centre for Climate Change and Sustainable Energy Policy at the Central European University. “Already a market reality in many locations, they’re pivotal pillars of a climate-neutral economy. However – given that our building stock takes many decades to turn over or be fully retrofitted – if we’re to hit a zero-energy global building sector by mid-century this technology has to become the standard practice now. Every single building, we build or retrofit that does not take full advantage of our net-zero technology and know-how locks us into a warmer climate.”