By Paul Nutcher, CSI CDT
The renewable energy industry could benefit greatly by targeting green building projects. This is true for project teams setting up systems for distributed renewable energy generation on building sites, the manufacturers of the system components, and many other ancillary businesses with a stake in a building’s energy performance. Furthermore, if the diffusion of renewable energy technology has been slow to gain market traction, the LEED program could be a significant driving force for expediting the growth of BIPV and utility scale installations, as well as other renewable generation systems and energy storage systems.
Commercial buildings in the United States consume 18% of the nation’s energy and are responsible for 18% of the nation’s carbon dioxide emissions, according to the Department of Energy. The residential building sector consumes 22% of electricity and contributes 20% of the carbon emissions, as reported during the Energy Programs Consortium presentation February 2008: “Income, Energy Efficiency and Emissions: The Critical Relationship.” With renewable energy providing less than 10% of the electricity in the US, the building sector of the economy has as much growth potential for renewable energy product manufacturers as the transportation and industrial sectors of the economy.
A realization that buildings needed to become more energy efficient and healthier for their occupants, while reducing their impact on the environment, sparked the earliest stakeholders at the non-profit US Green Building Council (USGBC) to take steps toward addressing more sustainable buildings. The result of those first steps was a program to measure a building’s energy and environmental performance. Today, the most widely recognized national rating tool for third-party verification of a sustainably designed, built, operated, and maintained building is the LEED Green Building Rating System from the USGBC, which first introduced the first of its family of rating programs in 1999. Marketing to the green building industry will take effort from stakeholders in the renewable energy business because they will first need to understand how such energy systems can enhance a high-performance building project—which under the USGBC program results in “LEED certification.”
A LEED score
LEED stands for Leadership in Energy and Environmental Design, and measures the environmental impacts and energy performance of buildings as two of its fundamental goals. The LEED family of green building rating systems contains sets of voluntary performance standards, many of which have become mandated by city and state governments, as well as most federal agencies. The Government Services Administration (GSA), possibly the world’s largest landlord overseeing courthouses, offices, agencies, among other federal buildings, requires a LEED Silver certification level. The LEED for New Construction v. 3.0 (LEED-NC) rating system is divided into five main categories including sustainable sites, water management, energy and atmosphere, and indoor environmental quality. There are also two other categories for exemplary performance including the Innovation in Design and Regional Environmental Priorities categories for capturing ways in which the building significantly out performs the benchmarks in the first five categories or addresses a regionally specific environmental issue (i.e. water conservation or diverting materials from landfills).
On-site generation of electricity from the sun, wind, or other natural sources have the greatest opportunity for assisting building project teams within the Energy and Atmosphere Credit Category of LEED. Most points in the rating system assigned to any of the categories are in the Energy and Atmosphere category, with a possible one to 19 points for Optimizing Energy Performance, another seven points are possible for incrementally larger percentages of energy usage from renewables, and the project team can gain even more points toward LEED certification for purchasing green energy credits. Because may renewable energy systems measure the output of the energy system, other credits dealing with the commissioning and verification of a renewable energy sources can offer further LEED points. The amount of possible points in the Energy and Atmosphere category is significant because it only takes 40 points for certification. So, the LEED point totals typically shoot high up the scorecard when renewable energy equipment is installed on LEED buildings. Many gain LEED Silver, Gold, or Platinum certification levels. For reference, the highest LEED Platinum certification is between 80 to 100 points.
But there is still a catch. Before even considering going for LEED, there are prerequisites in all but the Water Management, Innovation in Design and Regional Environmental Priorities categories. The important one here is the energy efficiency benchmark, ASHRAE 90.1-2007. Plus, the energy systems must be commissioned by a third-party to verify the performance of the HVAC system and no CFCs are permitted in the cooling system. Once the prerequisites for the energy systems have been met, the higher the percentage of energy optimization the building is designed to achieve the more points it will gather. Should the building go beyond 40% energy efficiency above the benchmark, there is another point available in that sixth category: Innovation and Design, for example.
LEED Green Building Rating System has separate programs for covering the two phases of a building’s lifecycle, one for new construction (Schools, Core and Shell, Retail, Homes, Neighborhoods, and there are more in development), and one for ongoing maintenance and operations of a building after the construction phase. The LEED for Existing Buildings Operation and Maintenance (LEED-EBOM) rating system follows a sustainably built structure to the end of its useful lifespan and the rating tool can be applied once the building has been occupied for at least a year. The point structure and categories are a bit different as the LEED-EBOM rating system is more focused on post-occupancy issues, such as efforts to reduce peak energy demand, save on utility bills, and reduce the carbon footprint of a building or real estate portfolio.
Though teams constructing new buildings are the focus of the LEED-NC program, property managers, real estate portfolio owners, and other building industry practitioners looking for a larger return on investment after a renewable energy retrofit installation will decide whether to go for LEED-EBOM. The rationale for LEED-EBOM to this market segment is that properties certified by the USGBC stand out in annual performance reviews, annual budget planning sessions, and add a premium to leasable space. The LEED-EBOM certification process can also identify deficiencies in standard practices that need correction, and then provide the best steps toward operational improvements. An annual re-certification of LEED-EB status from the USGBC may extend the lifespan of a structure because the rating tool can help in the development of a system to avoid a decline in building maintenance.
Renewables & LEED for existing buildings
Between one to 18 points are available in the Optimized Energy Efficiency Performance category in the LEED-EBOM rating program. During commissioning and energy audits, inefficient areas of the structures’ operations are pinpointed and monitoring of energy consumption on major mechanical systems is initiated and a program for ongoing monitoring begins. The number of points earned is contingent upon a facility’s EPA ENERGY STAR rating or the percentile level above the national median.
LEED points are earned when increased levels of operating energy efficiency can be documented and, as a result, reduce the environmental impact of excessive energy use. A facilities manager can also purchase Green-e certificated energy (a similar option for project teams on new construction), to gain points for helping reduce greenhouse gases and by helping to develop a market for renewable energy. Points are also available for continued commissioning of the building performance.
During this process, the building’s capabilities, advantages, and weaknesses are assessed by the commissioning agent so financial costs and benefits are calculated. Training programs are developed and building operating plans are updated. Using an ongoing commissioning program that reflects changes in an existing facility’s occupancy, usage, maintenance, and repair needs ensures adherence to stated revisions and upgrades. Periodic adjustments and reviews ensure optimal energy efficiency. The on-site and off-site generation of renewable energy can also gain from one to six points toward LEED-EBOM certification. It is up to the energy consultant to determine whether solar, wind, biomass, geothermal, and biogas technologies are the most advantageous.
Conserving through greener site development
The amount of radiant heat from the sun penetrating the building envelope and the thermal transfer properties of the hardscape can all impact the energy efficiency of a building. LEED programs recognize this strategy for overall reduction of energy usage on the property. The impact a rooftop solar array has on the performance of the building envelope is good to know when trying to sell a building owner on the systems. In fact, a tax credit from the Energy Policy Act of 2005 provides up to $1.80 per square foot for the developer, based on improvements to the building envelope and another 60 cents each for installing more energy efficiency for lighting and HVAC systems. Renewables can have an impact on gaining the tax credit by powering a portion of the energy needed for lights and conditioning the interior space.
Other site credits with implications for the renewable energy product manufacturer include the designation of parking areas for plug-in electric hybrid cars, among other strategies for reducing carbon emissions from fossil fuels. Indirectly, less energy is needed when building project teams design and build for a reduced impact on the heat island effect. The rooftop configuration of a solar array can have a significant effect on how the thermal gradient differences in urban areas versus undeveloped areas will be addressed. Again, any assistance here from a renewable energy installation should be communicated to the building team prior to the pre-design phase of a construction project to improve the chances that the associated products and services will be specified in the construction documents.
The future of LEED
The LEED rating system (or an equivalent rating tool, i.e. GreenGlobes, ICC 700) will one day become the standard that most governments set for project teams wanting a permit to build. Looking at the current building codes in most of the country, with the exception of governments that have already adopted LEED as the standard for getting a building permit and there are many already, some people may ask why we didn’t build like that all along? Much of the intent of the LEED credits are a throwback to the way the building industry was headed decades ago, but a mindset of unlimited energy and materials took over. LEED appears to be here to stay and not a moment too soon as the world gears up to address climate change. All of these efforts could help the long term prospects of renewable energy product manufacturers.