Time to complete: 15 mins
The ability to view analysis assumptions (also called inputs or parameters) supports transparency for metrics reporting and enables you to communicate clearly to clients and constituents the underlying assumptions used to generate metrics. The ability to also edit assumptions, and therefore vary them across scenarios, enables you to do powerful comparative analyses of the relationship between land use and resource demand, technological trends, and potential policies.
Let’s say you work for the City of Berkeley and want to explore the implications of a retrofit program for residential multifamily buildings that results in a 30% reduction in energy use. This article walks you through how to get this done. In this example, we’ll quickly build some oversimplified strawman scenarios so we can test both the impacts of different land use development programs and different assumptions for residential energy use - in this case the potential impact of a retrofit program.
There are four main ways to use the analysis parameters editor for comparative analysis:
- Vary land use only. Use identical assumptions for analysis and compare the effects of different land use patterns alone.
- Vary assumptions only. Duplicate a scenario so that land use is identical and vary analysis assumptions to analyze the impacts of different trends or policy packages.
- Vary both land use and assumptions. For each scenario, analyze the impacts of different land use patterns and different assumptions at the same time.
- Mix of all the above. Analyze the impacts of land use and different trends/policies, but control for both. One way to achieve this would be to develop your land use scenarios, then duplicate each of the land use scenarios and modify the analysis parameters to reflect the trend/policy package you want to test.
1. Overview 2. Tutorial 3. Outputs
Goal: Learn how to test the impact of different analysis assumption configurations for land use scenarios.
- Scenario Canvas
- Building Energy Use
This tutorial will not go into depth about how to develop scenarios. See the article Scenario development: Painting for an in-depth tutorial on painting scenarios.
First, create a scenario. Open the menu on the Base Scenario tab and click “Create scenario”. This will duplicate the Base Canvas. The new scenario may take a minute to load (the more parcels or Census blocks there are, the longer it takes). Once the new scenario is complete, click on the tab that says “Scenario #2” (or whatever number it is) to work on that scenario (as opposed to the Base Scenario). Note how there is a new layer called the Scenario Canvas (this is a copy of the base canvas). You can duplicate or delete the scenario using the menu on the scenario’s tab.
Second, rename the new scenario. Open the menu on the scenario’s tab and click “Edit details”. Change the name to “Townhome (A)”. Click SAVE.
Third, select parcels to paint. For the sake of this exercise, we will apply a simple filter selection. Select the Scenario Canvas in the layer list and click on the Filter tab. Click ADD FILTER and select Land Use Type. In the list of types, check bt__vacant and bt__vacant_residential_lot.
Fourth, open the build tab. Click the build tab to open it (alternatively, click build in the left hand navigation bar).
Fifth, paint. Let’s keep it simple for this example. Click on the Building Types palette and select Suburban Townhome, Click PAINT.
Sixth, duplicate the scenario. To test an alternative set of assumptions with the same land use program, duplicate the scenario and rename it “Townhome (B)”.
Seventh, repeat steps 1 - 6 to create another scenario. Name the scenario “Multifamily (A)” and the duplicate “Multifamily (B)”. You should end up with two sets of scenarios and four scenarios total.
- Townhome (A)
- Townhome (B)
- Multifamily (A)
- Multifamily (B)
Eighth, open the analysis module manager. Let’s edit the parameters for the Energy Use module. You can open the manager two different ways:
- Option A: Click Analyze in the left-hand navigation bar. Hover over Energy Use and click the edit (pencil) icon.
- Option B: Click Manage in the left-hand navigation bar. If not already selected, click on the Analysis Modules tab. Then, click on Energy Use.
Ninth, view input assumptions. The module parameters (e.g. Detached Single-Family, Large Lot) are pre-populated with regionalized default values (where available).
Tenth, edit a parameter. Let’s model the effect of a hypothetical retrofit program for the City of Berkeley, which results in a 30% reduction in electricity use for residential buildings. The default multifamily electricity use rate for multifamily is 3,924.4 kilowatt hours per household per year. A 30% reduction results in 2,747.08 kWh/HH/yr. Set the multifamily parameter in the “Multifamily (B)” scenario to this reduced rate. Click into the cell like you would in a spreadsheet. Replace the current value with 2,747.08.
This will turn the value blue to indicate a change from the default. The blue dot indicates that the change has yet to be saved.
Eleventh, edit another parameter. Set the multifamily parameter for the “Townhome (B)” scenario to the same reduced value. There are three ways you can achieve this:
- Option A: Click into the cell and type the value in manually
- Option B: Click into the cell and paste the value from your clipboard
- Option C: Use the context menu for the column to “Copy values from…” > Multifamily (B). See the screenshot below for this option (this is most useful for copying multiple values at once).
Twelfth, save your changes. Any unsaved changes are indicated with a dot next to the modified value. Its blue if the value is different from the default and black if you had previously changed the value, saved, then set the value back to the default. Click SAVE at the bottom of the parameter editor to persist the change. Any changes you make will not be used when running analysis modules unless you save them.
When there are no unsaved edits, the SAVE and DISCARD buttons will be disabled.
Thirteenth, run modules. Navigate to Explore mode using the left-hand bar and open the analysis modules pane by clicking Analyze. In each scenario, hover over Energy Use and click run (the play button). The four scenarios are:
- Townhome (A)
- Townhome (B)
- Multifamily (A)
- Multifamily (B)
Fourteenth, review results. Click on Report in the left-hand navigation bar to view the analysis results for the scenarios side-by-side. Click on the tab for Energy Use. Hover over segments of the Total Annual Electricity Use chart to see numbers.
Fifteenth, export results to a spreadsheet. Click the EXPORT button above the charts to export tabular versions of the results to an Excel workbook.
As you can see in the tables below, and as you would expect, the scenarios that model a retrofit program (B versions) for multifamily residential buildings have decreased annual energy use. Per household, the “Multifamily (B)” scenario has the best performance, which combines new multifamily housing development and reduced multifamily electricity use rates due to the hypothetical retrofit program.
Results as tables in Excel