10 Things to Know About Net Zero
By Mark Robins, Senior Editor,
Posted
06/04/2012
Here's what you can use about buildings producing all the
energy they use
Net zero buildings are highly efficient structures that produce
as much energy as they use. The zero-energy design principle is
growing in importance due to increasing costs of traditional fossil
fuels and their negative impact on the planet's climate and
ecological balance. It's entirely possible to construct a building
that produces enough of its own power that it does not consume
energy from the grid. An energy-plus building can even produce more
power than it consumes, converting it into a mini power plant.
The following 10 things will tell you more about migrating to
net zero buildings.
1. Why bother with buildings?
Commercial and residential buildings consume about one-third of
the world's energy. In the United States, buildings account for
more than 40 percent of total energy consumption, including 72
percent of electricity generation, 12 percent of water consumption
and 60 percent of all non-industrial waste.
According to a report by the National Science and Technology
Council Subcommittee on Buildings Technology, Research and
Development, if current trends continue, by 2025 buildings
worldwide will be the largest consumer of global energy, more than
the transportation and industry sectors combined.
2. Push the envelope.
Metal building systems have higher air leakage compared to other
types of construction. Without focusing on their underlying metal
building envelope design and incorporating high R-value continuous
insulation to produce an air-sealed solution, achieving net zero
success will be very difficult or inefficient. New ASHRAE 90.1
energy codes require building designs to comply with air
infiltration requirements. Individual materials must have a maximum
air permeance level no greater than 0.004 cfm/ft2. Additionally,
building systems or assemblies must have a maximum air permeance
level no greater than 0.04 cfm/ft2.
By adding a continuous blanket of insulation, and sealing
additional junctures and penetrations in the building envelope with
foam sealants, a significant reduction in heat loss can be
economically realized. This heat loss would otherwise have to be
accommodated by additional energy-generating technologies, such as
solar panels.
"In a metal building, thermal shorts reduce the R-value of
cavity-insulated wall systems by more than 50 percent," says Doug
Todd, market manager of commercial construction at Dow Building Solutions,
Midland, Mich. "Installing a layer of high R-value continuous
insulation over the steel studs reduces the impact of the highly
conductive steel. For example, 1/2-inch-thick board R-3.0 THERMAX
insulation has the same thermal resistance equivalency to 10 feet
of steel, close to 250 times more effective."
But insulation is not enough, especially in a net zero building.
If the building envelope leaks air, the overall impact of the
insulation is compromised.
"Dow has identified cost-effective, field-tested methods to
detail the insulation as an air barrier using tapes, PVC joint
clips, insulation edge treatments, construction grade sealants and
adhesives, and air sealing foams such as FROTH-PAK Foam Insulation
and GREAT STUFF PRO Insulating Foam Sealant," Todd says.
3. Insulated panels are a plus.
Walls have been insulated for centuries, ever since animal skins
were first hung on rock walls or sod huts were crafted with thick
dirt walls. Today, insulated metal panels (IMPs) aid net zero
efforts by producing an airtight, moisture-resistant, rigid,
continuous-insulation solution. IMP's high R-values provide
superior thermal performance and reduced energy consumption. This
allows for smaller greenhouse gas emissions and reduced energy
costs for building owners, which contribute to net zero
success.
IMPs mitigate thermal drift, a degradation of R-values over
time. Thermal drift is common when using un-faced polyisocyanurate
rigid board insulation, which can lose up to 20 percent of its
R-value within two years.
IMPs can be integrated with other building envelope solutions,
such as windows, louvers and sunshades, to further push toward net
zero. IMPs can be coated with cool roof colors, which offer
potential energy savings throughout a roof's lifetime. This helps
mitigate the urban heat island effect in urban areas.
Research has shown that today's insulated wall and roof systems
can save as much as 30 percent of a building's total energy use. An
independent simulation analysis was performed by the Architectural
Energy Corp. to evaluate the energy efficiency impact of improving
typical buildings with IMP wall and roof systems. Three baseline
buildings compliant with ASHRAE Standard 90.1-2004 and 90.1-2007
(school, office and warehouse) were simulated in four locations.
Each building's envelope was improved with the IMP wall and roof
systems.
4. Concentrate on energy conservation.
Energy conservation will always be a critical component in net
zero buildings. By reducing the energy base load by deploying
energy efficient building technologies, the need for renewable
energy production is significantly reduced.
In terms of energy conservation, lighting is one of the most
important components. According to a U.S. Department of Energy
(DOE) report, lighting accounts for about 20 to 50 percent of the
entire electricity consumed by U.S. residences and offices.
New light-emitting diode (LED) fixtures have surpassed
fluorescent and mercury-based lamps in delivering energy reduction
and provide the most environmentally sustainable solution. LED
fixtures offer a durable, sustainable, low-energy choice. "LED
fixtures are 65 percent more efficient than high-intensity
discharge (HID) fixtures, and 30 percent more energy efficient than
fluorescent ones," says Jeff Bisberg, co-founder and CEO of Albeo Technologies in Boulder,
Colo.
"By adding smart controls, such as automatic on/off motion
sensors, energy use can be cut even further. Dole Foods documented
a reduction in its lighting energy use by up to 95 percent at its
Atwater, Calif., sub-zero cold storage warehouse, through Albeo
LEDs and smart controls."
5. Daylight is an efficient source.
Lighting accounts for 25 percent of total energy usage in a
typical U.S. office building and waste heat generated by artificial
lighting contributes significantly to the total cooling load. Both
of these facts make optimizing natural daylight and controlling
artificial lighting, critical components in achieving net zero
buildings. Daylight is the most efficient lighting source.
To fully take advantage of lighting as a net zero input,
buildings should be oriented on sites correctly to maximize the
amount of windows in a building. Designers can save energy by
optimizing natural daylighting, gaining passive solar heat in
winter and minimizing solar heat gain through windows.
Steve Fronek, PE, LEED Green Associate and vice president of
technical services at Wausau
Window and Wall Systems in Wausau, Wis., believes when aiming
for net zero, "window or curtainwall manufacturers should have a
'seat at the table' to leverage their intimate knowledge of system
capabilities, trade-offs and costs. Interestingly, the most basic
properties of glazing system-size and configuration-can be the most
impactful."
To further maximize the power of the sun,solar panels can
convert solar radiation to electrical energy. Net zero buildings
generally require a suite of several solar panels to supply an
adequate amount of energy. Photovoltaics' zero-emission energy
reduces greenhouse gases and pollution. Solar technology is
constantly evolving with increased efficiencies and energy storage
capabilities.
6. Cheaper than you think.
Net zero energy commercial buildings are both more feasible and
affordable than people think, so says a report from the New
Buildings Institute (NBI) and the Zero Energy Commercial Building
Consortium (CBC).
The report is titled "Getting to Zero 2012 Status Update: A
First Look at the Cost and Features of Zero Energy Commercial
Buildings." According to it, the incremental costs for net zero
building energy efficiency features range from 3 to 18 percent,
depending on building type, size, climate and other variables.
As the larger office buildings market moves toward net zero,
minimizing electrical loads from plug-in equipment and appliances,
along with other miscellaneous or "unregulated" loads is a
priority, the report says. The emergence of new technologies will
also be a factor in expanding to more building types, NBI says.
Adopting these new energy-saving technologies may have high
initial cost implications, but the ROI these costs bring is quick
and the reduced energy savings last for many years afterwards. "Our
customers have reported ROIs in as short as 18 months to a maximum
of three years for LED purchases, depending on the application of
the LEDs and the use of the building," Bisberg says.
The key to selling the net zero idea is moving building owners
from a commodity to a value-based mindset. "Have them focus more on
the ROI many of these technologies bring and value the long-term
cost savings more than the short term, up-front costs of analysis,
products and construction," Bisberg adds. "Additionally, there are
the marketing and'good will' publicity benefits that society
attaches to a company that is visionary enough to construct a net
zero building at this time, verses a conventional building or even
a LEED one."
7. Earlier is better.
When aiming for net zero, earlier is better. The greatest
potential for savings and the most cost-effective strategies often
originate in building design. Whether conceiving a building to make
use of appropriate solar orientation, or land use planned to
minimize transportation distances, a manufacturing process
development that includes minimizing energy use, it is in the
design stage that highly cost-effective strategies for making an
impact are selected. Furthermore, such options, when ignored,
represent "lost opportunities" that are impossible or cost
prohibitive to achieve later in a project's life.
It is in the design stage when the energy performance of and
interaction between interrelated building components creates
opportunities to build net zero buildings economically. Integrating
building component energy performance creates tradeoffs that can
pay for substantial performance improvements without dramatically
increasing cost to build. This is what is commonly called a "whole
building" approach to design.
"Unfortunately, for many contractors this whole building design
approach takes them out of their comfort zone, as they rely heavily
on individual suppliers for recommendations and design advice, and
the suppliers may not be excited about making trade-offs that
reduce their share of the project," says Justin Harkins, national
sales manager at Thermal
Design Inc., Stoughton, Wis. "As a result, attempts at net zero
buildings are often limited to very high-end projects that can
budget for substantial independent engineering costs."
Thermal Design offers Simple Saver SynergyDesign services to
metal building contractors that allow them to perform rapid design
analysis, make design tradeoffs, estimate cost differences,
calculate energy savings, simulate energy consumption, and
facilitate energy related government and utility incentives for the
project.
8. They're becoming required.
The California Energy Commission (CEC) is requiring residential
buildings in California to be net zero energy by 2020 and
commercial buildings by 2030.
California's action plan offers common-sense strategies for
moving the market toward net zero energy performance. Raising
minimum energy performance through codes, expanding energy codes to
address all energy end uses, developing financial tools for
supporting net zero energy construction, and supporting integrated
design are all mentioned as strategies for new construction. For
existing buildings, the action plan suggests tightening code
thresholds, requiring energy and carbon emissions labeling, and
supporting occupant feedback and training. Several California
utilities are already working on pilot projects and local
governments are already adopting standards more stringent than the
state standards.
A number of countries and regions have already established
long-term targets and regulations requiring zero energy building
construction that will come into effect over the coming years, some
as soon as 2016. In the European Union, a March 2009 resolution
requires that, by 2019, all newly constructed buildings produce as
much energy as they consume on-site. These stringent regulations
will accelerate adoption around the world, causing the industry to
undergo a significant transformation in the coming years.
According to a new report from Pike Research, worldwide revenue
from zero energy buildings will grow rapidly over the next two
decades, reaching almost $690 billion by 2020 and nearly $1.3
trillion by 2035. That represents a compound annual growth rate of
43 percent, with much of that growth occurring in the European
Union.
"Following the surge in LEED and other green building
certifications worldwide over the last few years, zero energy
building has emerged as the 'holy grail' in green building design,"
says research analyst Eric Bloom. "Technically, zero energy
building design is feasible for many building types in many
regions, but concerns about the upfront cost continue to impede it
in the market."
9. They're becoming certified.
The International Living Future Institute has a new green
building certification program it will administer for net zero
energy use. There has never been a certification program for net
zero buildings prior to this.
The net zero certification is based on actual building
performance rather than modeled outcomes. Buildings must be
operational for at least a year prior with proven results prior to
being certified. Certification verifies a net zero building is
truly operating as claimed, harnessing energy from the sun, wind or
earth to exceed net annual demand.
It's one thing to say a building is zero energy; it's another
thing to prove it. Certification provides a platform for the
building to inform other efforts throughout the world and
accelerate the implementation of restorative principles.
Certification celebrates this significant accomplishment and
differentiates those responsible for the building's success.
10. There's help out there.
To learn more about attaining net zero building success, the
Design Lights Consortium is a good source for high-quality,
energy-efficient, commercial lighting design and information. It
offers a qualified products list with current LED lighting fixtures
and their ratings at www.designlights.org.
Deland, Fla.-based Kingspan
Insulated Panels Inc. has two tools, EnvelopeFirst energy
efficiency and Path to Net Zero, to aid in attaining net zero.
"We help optimize the envelope with a performance model on
selected projects; and then we provide a total envelope solution:
including photovoltaics on our standing seam roof," says Paul
Bertram Jr., FCSI, CDT, LEED AP, and director of environment and
sustainability at Kingspan.
"The core product lines are highly insulated wall and roof panel
systems with integrated openings, including for windows, doors and
more. And the photovoltaic panels are offered also, so it's
basically everything you need for net zero."
Wausau Window and Wall Systems offers an online "Green Product
Selection Tool" at http://www.wausauwindow.com
intended to provide a one-stop, visual reference to help users rank
and compare performance information and potential energy savings.
This tool allows users to choose from eight cities to view
performance data between a set of Wausau products for either new
construction or renovation projects. Visitors can gather
performance information on annual energy, peak demand, carbon
emissions, daylight, glare, condensation and cost savings.
The DOE's Energy Efficiency Renewable Energy website, www.eere.energy.gov/buildings/betterbuildings,
has information for contractors related to building net zero
buildings. The DOE's Net Zero Energy Commercial Building Initiative
(see sidebar) is a valuable program for a better understanding of
how to achieve net zero today. At www.DSIREusa.org, users can look
for renewable energy incentives from federal, state, county and
utility sources. "For upgrading a building, the Energy Policy Act
provides tax credits up to $1.80 per square foot until December
2013," Bertram says.
sidebar
Delve into a net zero database
The U.S. Department of Energy's Zero Energy Buildings Database
features profiles of commercial buildings that produce as much
energy as they use over the course of a year. In this database,
users can learn more about diverse net zero projects and gain ideas
that can be applied to any new building. By simply clicking on a
net zero building's name, users can view in-depth information about
a project's design and construction process, financing, energy use,
materials, indoor environment and more. This database is part of
the High Performance Buildings Database, which lists many
additional projects where users can discover more energy-efficient
building techniques.
The database collects information from buildings around the
world, ranging from homes and commercial interiors, to large
buildings and even whole campuses and neighborhoods. These may be
certified green projects, or simply projects that have one or more
notable environmental features. The information has been reviewed
for consistency and presentation, but in most cases, the details
have not been independently verified. For more information, go to
zeb.buildinggreen.com.
sidebar
The occupant and the owner
The energy used in a building can vary greatly depending on the
behavior of its occupants. The acceptance of what is considered a
comfortable climate varies widely. Studies of identical businesses
in the United States have shown dramatic differences in energy use,
with some using more than twice the energy of others. Occupant
behavior can vary from differences in setting and programming
thermostats, varying levels of illumination and hot water, and the
amount of miscellaneous electric devices or plug loads used.
Because the energy consumption profile of a very low-energy
building differs so much from conventional buildings, building
operation and control become very important in hitting net zero
goals. "Automated controls are essential for implementation, but it
is still important to work with the owner on an operational plan up
front as part of the implementation of a low or net zero energy
building," says Justin Harkins, national sales manager at Thermal
Design Inc., Stoughton, Wis. "The operational plan must be
realistic, meet the owner's business needs, and have a clear plan
for occupant cooperation with implementation."