Step 2 Define Project Scope

This step is lead by the sustainability champion and involved a meeting of the whole team. The purpose of the meeting is to define project goals, the availability of any data sets, what building retrofitting measures to explore and a timeline for next steps. Key outcomes of this meeting are documented via a survey that generates a summary report in the end.

Project Goals

  • The sustainability champion reviews the municipality’s sustainability goals for buildings including overall carbon emission reduction targets, such as”80% carbon emission reductions form baseline by 2050 for all sectors,” as well as any building-specific sub-targets. The discussion should then focus on specific building-related questions the UBEM analysis should focus on. Examples are:

    • What building types are responsible for the majority of carbon emissions and how can we reduce these emissions?

    • How extensive do retrofit measures need to be to meet the jurisdiction’s emissions reduction goals?

    • What are the most cost-effective retrofit strategies?

    • How much renewable energy such as rooftop or community photovoltaics does the community need to purchase or install to complement retrofit measures?

    • Will heat pumps work (technically, economically) in my community?

Study Boundary

  • The team should jointly decide on a “seed” area for the urban model to initially focus on. A seed UBEM is an initial, scaled down version of a full UBEM that covers a limited part of a jurisdiction, around 100 to 200 buildings. A seed model should ideally be representative of the city’s overall building stock – i.e., cover building typologies that represent a significant fraction of all buildings – and extend over an area which will soon undergo substantial renovation efforts. The benefit of focusing the initial analysis on a subset of buildings is that the energy modelers can quickly run through a variety of scenarios to estimate the impacts of various retrofitting measures on the whole building stock. If needed, a full UBEM can be run later. The GIS manager will need building foodprints, heights, age and program type for all buildings in the seed area. They will use this data in step 3 to prepare a geometry file for the energy modeler. The energy modeler will also need to know what the most common building types and age ranges (e.g. 1940s to 1960s single family homes) in the seed area are. During the Getting Started Survey below, shallow and deep retrofit scenarios will be defined for these common building types.

Energy Data

  • The GIS manager and energy modeler will need to gather data on the different fuels used for heating and hot water in the jurisdiction. The U.S. the Census Bureau has a good resource by State and Town.

The energy modeler researches data on energy retail costs ($/kWh) and carbon emissions (kg/kWh or lbs/MWh) associated with electricity and other fuel types commonly used in buildings. For the U.S., the EPA’s Power profiler and Energy Information Administration are excellent sources for electricity and other fuel emissions. Common U.S. values are:

  • Natural gas: 0.18 kg/kWh

  • Fuel Oil / Home Heating Oil / Off-Road Diesel / Kerosene: 0.25 kg/kWh

  • Propane: 0.21 kg/kWh

  • Coal: 0.33 kg/kWh

Getting Started Survey

The team is now ready to go through the Getting Started Survey to document the above mentioned information. A key input is the definition of the shallow and deep energy retrofit packages that the energy modeler will explore for the seed area. A retrofit packages consist of a combination of several energy efficiency measures such as energy efficient light bulbs and appliances or envelope weatherization. Shallow retrofit packages are less disruptive to the owner and can be done at any time. Deep retrofit measures may include more costly measures of measures that need a lot more planning such as replacing a natural gas boiler with a heat pump. at the end of the survey, you will be able ot download your entries. The survey summary may serve as an agreement on overall project scope.

The GIs manager may now advance to step 3 and prepare the UBEM geometry using UBEM.IO.