OVERVIEW


Energy Reduction Goals

With a greater focus on the environmental and cost impacts of our infrastructure, energy use and thereby carbon emissions are the focus of many efforts to make buildings more sustainable. Many sustainability programs focus on energy reduction in building infrastructure such as the United States Green Building Council’s Leadership in Energy and Environmental Design (USGBC, LEED), the International Living Future Institute’s Living Building Challenge, and Architecture 2030’s 2030 Challenge. These are systems that have been adopted by United States’ state and federal governments, the United States Congress of Mayors, the American Institute of Architects, and many owners and project teams.

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Specific Goals, Architecture 2030 Challenge

The 2030 Challenge is an energy goal that is being adopted by architects, engineers and owners in an effort to greatly reduce energy consumption and greenhouse gas emissions of buildings. It is a progressive goal where every five years a greater reduction in energy use is targeted. For new buildings being designed for operation between 2010-2015, the goal is a 60% reduction from standard operational energy use and by 2030 the goal is to reach net-zero annual energy demand. Compliance with the 2030 Challenge is measured by a building’s modeled energy performance compared to operational energy use for a median performing building of the same type and climate zone (Architecture 2030, 2012). The 2030 Challenge for 2010-2015 is the goal of this group’s research effort, thus a 60% reduction in energy use from typical operational hospitals in similar climates.

Energy Goal Setting

In order to reduce energy use it is imperative to first establish reasonable and testable goals for energy reduction. To set these goals, it is helpful to understand how much energy current hospitals use, and then develop reasonable energy reduction targets. Annualized energy use for buildings is often reported as an Energy Use Index or EUI. The EUI for a building is the total amount of energy used by the building, most commonly electricity and natural gas, per square meter of floor area, measured on an annual basis. Building EUIs are often reported in units of kWh/m2 Year or KBtu/Ft2 Year. This is a way of comparing different buildings to each other, much like comparing different cars to each other using a miles per gallon rating.

Compliance with the 2030 Challenge is measured by a building’s modeled energy performance compared to operational energy use for a median performing building of the same type and climate zone. Operational energy performance is determined by comparison to a national database that houses information on different building types in various climate zones. Target Finder is a web interface used to identify energy information from the database, normalizing for building typology, climate, size, use, etc (Target Finder, 2011). For many building types Target Finder accesses the CBECS data-set. For hospitals, the data-set used today is based on a 2010 survey of approximately 300 hospitals nationally. Through Target Finder, the median building of similar type and size as well as climate region can be determined.

The United States Energy Information Administration’s Commercial Building Energy Consumption Survey (CBECS) is a separate national database of building, and healthcare, operational energy use that provides a reference to how much energy buildings consume by climate zone and by building use type . The average energy use index (EUI) for hospitals surveyed by CBECS on average in the United States is 249 KBtu/Ft2 Year (EIA, 2006).

Targeting 100!

Targeting 100! derives its name from this energy reduction goal – On average, hospitals in the US use about 250 KBtu/Ft2 Year, a 60% energy reduction from that average indicates a site energy use index (EUI) of less than 100 KBtu/Ft2 Year. Regional variations in this average are seen in the Target Finder data-set. For the sake of distilling this project’s goal into a clear target, an EUI of 100 KBtu/Ft2 Year was developed as the common goal for all of the study cities. This makes sense based on the knowledge that climate is not a large factor in the baseline energy use in hospitals: Typical hospitals built today are largely internally load dominated, thus climate has little effect on their overall annual energy use profiles.

References

Architecture 2030. The 2030 Challenge.

United States Environmental Protection Agency, 2011. Target Finder. Available from: [Accessed 30 November 2012].

United States Energy Information Administration, 2006. Commercial Buildings Energy Consumption Survey, 2003. Washington, D.C.: United States Department of Energy, Energy Information Administration. Table C3.