Climate Action 2011-2012

Cities of the Future
buildings and Climate
Sustainable energy
efficiency in buildings
and capacity building. Specific technical recommendations
will vary depending on geographic and climatic conditions,
as well as the availability of expertise, materials and
equipment. Governments can play a key role in increasing
market penetration of new and relevant technologies when
they lead by example and direct that all new public buildings
meet stringent energy efficiency criteria. Local government
can also require existing public buildings to undergo energy
efficiency retrofits or, at a minimum, encourage energy audits
to identify energy efficiency opportunities in public facilities
such as public housing, fire or health facilities, and municipal
government buildings.
174 climateactionprogramme.org
© Matthew G. Bisanz
Buildings offer a huge opportunity
for carbon emissions reduction.
By Curt Garrigan, Coordinator, UNEP Sustainable
Buildings and Climate Initiative (UNEP-SBCI)
The case for building energy efficiency is well known
and well established. Buildings offer governments, at all
levels, the greatest potential for reducing greenhouse gas
(GHG) emissions at the least cost, while creating jobs
and improving energy security. Policy-makers, however,
must take action now to establish baselines, prioritise
energy efficiency policies, and avoid locking-in carbon
intensive building stocks for decades to come. Buildings
use approximately 40 per cent of global energy, 25 per
cent of global water, 40 per cent of global resources, and
they emit about one-third of all anthropogenic GHG
emissions. Yet, buildings also offer the greatest potential
for achieving significant GHG emission reductions, at least
cost, in developed and developing countries. Furthermore,
energy consumption in buildings can be reduced by 30
to 80 per cent using proven and commercially available
technologies, which also generate significant savings and
reduces operating costs.
Achieving energy efficiency from buildings requires local
and national governments to focus on a wide array of issues,
from specific technological or design changes, policy and
enforcement actions, information management to education,
The Common Carbon meTriC
Before working to increase energy efficiency and the
performance of buildings it is helpful to understand the
current energy use of a building stock. One important tool for
assessing a city’s current baseline energy use is UNEP-SBCI’s
globally applicable Common Carbon Metric. The Commons
Carbon Metric (CCM), provides industry, businesses and
governments with a globally-consistent methodology to
establish baselines of performance for buildings. The CCM is
not a rating tool; it only provides a method to measure energy
use and GHG emissions in a consistent manner worldwide.
The CCM is accompanied by a protocol for measurement
and a tool for calculation and reporting. The tool is a simple
Excel spreadsheet that can be filled in by participants with the
appropriate data, whether it is estimated or measured.
The tool can be used for two types of measurement
approaches:
• The first approach is top-down (or building-stock): the
participant inputs data for a stock of buildings (which
can be a city/community stock, or a portfolio of buildings
for instance). The stock is composed of different types
of buildings (residential, commercial) with different
performance levels. This approach allows measuring the
energy use and GHG emissions for the whole stock. This
data will then be disaggregated according to the type of
buildings (residential and commercial at a minimum, and
if possible more detailed, e.g. single-family and multifamily
residential, retail, schools, offices, hospitals, etc.).
• The other approach is bottom-up (or single-building):
participants input data separately for each of the buildings
being assessed. By measuring representative buildings of
each category, the data can then be extrapolated to the
stock of buildings. This approach was originally aimed at
verifying the results of the building-stock approach, by
conducting a measurement for a representative sample.