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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