More nations focusing on buildings as part of climate commitment: UNEP

More countries are incorporating reductions in building sector carbon as part of updates to their nationally determined contributions (NDCs), according to the Global Alliance for Buildings and Construction (GlobalABC). NDCs are GHG-reduction commitments by countries by 2030 to meet interim Paris Climate Treaty goals for global carbon neutrality by 2050.

"The number of countries with buildings actions included in their NDCs has risen from 90 to 136. Energy efficiency and energy codes in buildings are the second most frequently cited actions within all [NDC], alongside resilience, renovation, and retrofitting measures," GlobalABC, a group affiliated with the UN Environmental Programme (UNEP), wrote in a report released in December.

The only climate mitigation option cited more frequently than buildings was installing new renewable energy capacity.

The buildings sector accounted for 36% of global final energy consumption and 37% of energy-related CO2 emissions in 2020 (11.7 million metric tons), so achieving near net-zero emissions from this sector by 2050 is crucial to meeting the Paris climate goals, Inger Andersen, executive director of UNEP, wrote in the introduction to the GlobalABC report.

The COVID-19 pandemic caused a one-time decrease of about 10% in emissions from buildings' operations in 2020 compared with 2019 as offices, stores, and factories were emptied. And it led to a similar reduction in emissions from construction activity. But these reductions are likely to be only temporary, UNEP said. "The long-term outlook is bleak. The lack of real transformation in the sector means that emissions will keep rising and contribute to dangerous climate change," it warned.

GlobalABC recommended a three-part, integrated approach:

• reducing energy demand;
• decarbonizing the power supply; and
• addressing embodied carbon stored in building materials.

Building codes

When it comes to reducing buildings' energy demand, GlobalABC said investment in energy efficiency worldwide increased by 40% from 2015 through 2020 to reach $184 billion. The growth rate in 2020—largely due to countries' spending on COVID-19 economic recovery—was 11%, which was well above the 3% annual rate that the International Energy Agency (IEA) said last year was needed for a pathway to net zero.

Similar signs of progress can be seen in the number of buildings receiving green certifications, which increased 14% in 2020, Global ABC said. Also, it noted that at least 80 countries now have building codes that encourage energy efficiency, up from 62 countries in 2015.

Building codes are a key driving factor. However, based on the experiences of Australia, Canada, and Japan, the IEA said it will take at least 15-20 years for a country to develop and then fully implement net-zero building codes.

For existing buildings, the IEA said that 2.5% of the buildings in the developed world and 2% of the buildings in emerging economies will need to be retrofitted annually to reach net zero in 2050. This need is especially acute in Europe, where IEA estimates that 80% of the buildings that will be in use in 2050 already are in place, and only 3% of them meet low-carbon codes today.

Government funding will have to support renovations and retrofits. "These so-called 'deep retrofits' go beyond one-off upgrades to insulation or heating systems, requiring a suite of upgrades to the building envelope, heating and cooling systems, and lighting," the IEA said.

For new buildings, the IEA said all construction should be net zero starting in 2030, but its "Energy Efficiency 2021" report found that only 5% of new buildings each year meet that standard.

Regardless, newly adopted codes have been effective in inducing GHG reductions, even if net zero is far on the horizon. "In India, the Energy Conservation Building Code was updated in 2017 and is progressively becoming mandatory across the country. Since the update, energy intensity has fallen by 7% in new commercial buildings and 8% in residential buildings," the IEA said.

Decarbonizing energy supply

Operations account for about 70% of the total emissions from buildings, and even with efficiency measures, buildings will still need to be heated, cooled, and provide other functions for users. That's where decarbonizing buildings' energy supply comes in. For wealthier countries, this typically means shifting from oil and natural gas to electricity for heating and cooking.

For emerging economies, building decarbonization often means replacing fuels such as wood and dung with natural gas as a bridge fuel. Speaking this week at the International Energy Week conference in London, Mele Kolo Kyari, CEO of Nigeria's national oil company, said 70% of the Nigerian population uses biomass to cook, and that natural gas will be the short-term solution to solving deforestation and indoor air hazards.

The World Resources Institute (WRI) has investigated what it calls zero-carbon buildings (ZCBs), which combine use of renewable energy with efficient design. ZCB programs can produce immense carbon reductions and energy savings, the WRI said.

In Qinhuangdao in China's Hebei Province, a newly built 18-story apartment building uses design elements and insulation to maximize heat retention in a cold climate. As a result, the building has achieved an energy reduction of 90% compared with conventional apartment complexes in the province, the WRI said. In Hermosillo, in the Mexican state of Sonora, a community of EcoCasa Max houses achieves an 87% energy reduction with solar PV panels and a passive design aimed at keeping out summer heat.

Cities and towns on the US coasts, most notably in California and Massachusetts as well as New York City, have required new construction of homes, apartments, and offices to utilize electricity for heating (and sometimes cooking). While litigation has challenged those "gas bans" and more than 20 US states have banned localities from issuing electricity mandates, the US Department of Energy supports the concept. On 9 February, it filed a friend-of-the-court brief in the US Court of Appeals for the Ninth Circuit, where it maintained that federal law allows states and cities to regulate appliance efficiency through requirements to use electric power (in effect, a natural gas ban).

In Europe, countries are taking similar actions to move away from fossil fuels for home and office heating. The UK, France, and Ireland each have regulations to ban the installation of new oil- and natural gas-fired boilers, while The Netherlands and Norway have subsidy programs to support installation of heat pumps, according to the GlobalABC report.

Using green hydrogen as a blend with natural gas or as a replacement is another option. In the US, Southern California Gas, which serves Southern California, announced on 17 February the Angeles Link program that would convert four natural gas-fired powered plants to green hydrogen. The idea won praise from local political leaders such as Los Angeles City Councilmember John Lee. "It will help us get one step closer to achieving the city's goal of 100% clean energy by 2035 without compromising reliability and hurting jobs," Lee said in a prepared statement.

Embedded carbon

The third part of the buildings equation is reducing carbon created by producing the steel, cement, lumber, and transporting those materials to the building site where the construction is completed.

The World Green Building Council said the "embedded" or "embodied" carbon in building and transporting these materials currently accounts for 11% of emissions attributed to buildings. But as the carbon associated with operating buildings is reduced through efficiency measures and renewable power, the council estimated, "more than half of total carbon emissions from all global new construction between 2020 and 2050 will be due to upfront emissions from new building construction and, to a lesser degree, from building renovations in Europe in particular."

Cement and steel are the biggest contributors to a building's carbon footprint, and their carbon emissions are significant on a global scale. Cement manufacturing is responsible for almost 8% of global carbon emissions (4 billion mt), and steelmaking contributes about 7%, according to the IEA. In both cases, about half of global production finds its way into buildings and construction. Efforts underway in those two industries to reduce their carbon footprint will have a positive effect on buildings as well, but it's not enough.

The World Green Building Council recommends a four-part strategy that begins with preventing embedded carbon growth by using materials sparingly and renovating and reusing materials when possible. Second, it said that design and materials sourcing should include a calculation of the carbon impact of the materials that are chosen for construction. Third, the council said buildings should be constructed with maintenance, repair, renovation, and even deconstruction in mind. And finally, it said builders should purchase carbon offsets for the carbon they cannot eliminate in the supply chain.

Uneven progress

The picture on progress towards a net-zero buildings sector is mixed, according to the GlobalABC report. On the one hand, the efficiency investments in 2020 were impressive, if the new spending levels are maintained. On the other hand, the report said that if pandemic-influenced spending is taken out of the equation, the buildings sector is at moving at less than half the pace of decarbonization needed to reach the 2050 net-zero goal.

"While the recent increase in global investment on energy efficiency was welcome, it occurred among a handful of countries that already have well-established programs and markets for improving building energy performance. In the coming five years, investment in efficiency will need to double its rate of growth to more than 3% annually, and will need to expand beyond direct government investment, to private investors," GlobalABC said.

New problems also are rearing their head, particularly the supply chain that has bedeviled many industries since the COVID pandemic began. In a survey released by UK engineering consultancy Patrick Parsons on 23 February, 68% of construction industry respondents in the UK said that improvements in the supply chain are crucial to reducing carbon in new and renovated buildings, and 62% called lack of access to alternative materials "a barrier to a lower carbon footprint."

Solving the buildings equation gets tougher the further out one looks, thanks to expected population growth and rising living standards in developing nations. "In terms of building codes, 82% of the population that is to be added by 2030 live in countries without any building energy codes or only voluntary codes," GlobalABC said.

In sum, meeting the Paris Agreement goal of a nearly net-zero buildings sector by 2050 will be a tall order. "The sector must simultaneously meet a projected near-doubling of global demand for energy services in buildings and at least a doubling of floor space as developing economies continue to respond to the growing demand for building floor space, access to energy services and economic activities," GlobalABC said.

Posted 23 February 2022 by Kevin Adler, Chief Editor