Autocase software methodologies documentation

Increasing the building’s air flow rate, up to a point, increases productivity, decreases illness-related costs, and decreases absenteeism from work due to these illnesses. Ventilation is a strong influencer of indoor environmental quality, inherently affecting the triple bottom line through productivity benefits, health, and absenteeism costs.

Productivity

Employees

• Seppanen et. al. (2006) study found that there are employee productivity increases due to increases in air flow.
• Using either building-specific average wage or the default local average industry wage (county level in the US, provincial in Canada), employee productivity increases are monetized by valuing the increase in productive work hours.

Students

• Haverinen-Shaughnessy and Shaughnessy (2015) found a positive linear relationship for increased ventilation and student test scores.
• Autocase quantifies productivity increases from optimal ventilation rates through a proxy of student class size reductions from equivalent test score gains (Burke & Sass, 2013; Chetty et al., 2011).
• The equivalent class size reduction from ventilation test score gains is monetized using test score variability by school type (National Center for Education Statistics, 2015), salary expenditures per student (Statistics Canada, 2016a; Statistics Canada, 2016b; U.S. Department of Education National Center for Education Statistics, 2016), and the number of classes in the school type.

Autocase economists objectively evaluate the research behind this impact as having an “Excellent” Rating. More information on the evaluation process can be found here.

Health

• From the research produced by Fisk et. al. (2009), Autocase relates the prevalence of illness, and in-turn the societal health costs from improved air flow rates.
• These illnesses include headache, dry skin, stuffy nose, itchy throat, nasal congestion, itchy skin, itchy eyes, irritated eyes, dry eyes, and lethargy.
• The change in symptoms are monetized using the cost of illness for each symptom (National Service Center for Environmental Publications, 2007).

Autocase economists objectively evaluate the research behind this impact as having a “Good” Rating. More information on the evaluation process can be found here.

Absenteeism

• Milton et al. (2000) found a decrease in employee sick days due to improved air flows within a building.
• Using either building-specific average wage or the default local average industry wage (county level in the US, provincial in Canada), reduced absenteeism is monetized by valuing the increase in productive work hours.

Autocase economists objectively evaluate the research behind this impact as having a “Good” Rating. More information on the evaluation process can be found here.

Air filters remove particulate matter from the outdoor and recirculated air before circulating through the HVAC system. The more PM in the air, the more likely employees in the building will suffer from health impacts or be absent from work.

Health

• Using the EPA’s concentration response functions, Autocase estimates the change in sick building syndrome symptoms due to the reduction in particulate matter exposure.
• These illnesses include lower respiratory, upper respiratory, and shortness of breath symptoms, asthma attack and mortality.
• The change in incidence rates is monetized using the EPA’s Cost of Illness Handbook, Maleki-Yazdi, et al. (2012) and the Value of Statistical Life.
• This is then applied to each occupant in the building.

Absenteeism

• Using the EPA’s concentration response function, Autocase relates the reduction in particulate matter to a decrease in work days lost.
• The reduction in work days lost is monetized using the average employee salary and applied to all employees in the building.

Autocase economists objectively evaluate the research behind this impact as having an “Good” Rating. More information on the evaluation process can be found here.

Productivity

Employees

• Increased exposure to daylight leads to increased sleep duration for employees (Boubekri et al, 2014).
• Autocase quantifies productivity increases for employees from daylighting through putting a dollar value on the benefits of increased sleep hours for employees (Hafner et al., 2016).
• Using either building-specific average wage or the default local average industry wage (county level in the US, provincial in Canada), productivity increases are monetized by valuing the increase in productive work hours.

Students

• For students, test scores are increased by increased levels of daylighting (Heschong, 2003)
• Autocase quantifies productivity increases from daylighting availability through a proxy of student class size reductions from equivalent test score gains (Burke & Sass, 2013; Chetty et al., 2011).
• The equivalent class size reduction from daylighting test score gains is monetized using test score variability by school type (National Center for Education Statistics, 2015), salary expenditures per student (Statistics Canada, 2016a; Statistics Canada, 2016b; U.S. Department of Education National Center for Education Statistics, 2016), and the number of classes in the school type.
• Note: The effects from daylighting and quality views could not be separated in the research, so this monetized effect incorporates both daylighting and quality views to avoid double counting.

Autocase economists objectively evaluate the research behind this impact as having an “Acceptable” Rating. More information on the evaluation process can be found here.

Health

• Autocase quantifies the change in risk mortality for occupants as a result of gaining additional sleep hours (Hafner et al., 2016).
• The health benefits from daylighting are monetized using the value of statistical life set out by Federal guidance (EPA, 2010; Policy Horizons Canada, 2013).

Autocase economists objectively evaluate the research behind this impact as having an “Acceptable” Rating. More information on the evaluation process can be found here.

• Replacement costs refer to the costs required to replace an asset or system during the specified life of a building (or study period). An asset may be replaced multiple times over the life of a building/study period.
• The replacement cost may cost more, less, or the same as the upfront capital costs of the asset.
• For instance, a furnace, part of an HVAC investment, may only have a useful life of 20 years, therefore must be replaced throughout the life of the building if the study period is longer than the useful life.

• The residual value of an asset or investment refers to the financial benefit arising at the end of the life of a building or study period, for any assets with a remaining useful life.
• Autocase calculates residual values using straight-line depreciation.
• If, for example, a furnace still has useful life remaining at the end of the life of the building or study period, a residual value will be applied.

• The salvage value is the financial benefit associated with the disposal of assets at the end of their useful life.
• For instance, at the end of the useful life of a furnace, there may be a financial benefit from the scrap metal in the unit.

• Non-utility operations and maintenance (O&M) costs include all costs associated with operating, repairing, upgrading and/or recommissioning investments over the course of an investment’s useful life but exclude any costs from utilities. These costs include preventative measures and anticipated repairs to extend the useful life of materials and equipment.
• For example, to keep a furnace in proper working order, filters must be changed as part of preventative maintenance performed over the life of the asset.
• There are two types of O&M costs: annual and variable.
  • Annual O&M costs are incurred each year during the life of the building (or study period) and may escalate if real costs increase over the study period. Escalation rates are capture growth beyond general inflation (i.e. costs increase every year by the rate of inflation; these cost increases should not be included).
  • Variable O&M costs are those that occur sporadically throughout the study period. If for example, a cost of $200 is incurred in 2020, 2030, and 2035, one cost will be included in this section and “add a new cost” to your LCCA analysis for the other costs in the future.

Autocase economists objectively evaluate the research behind the Life Cycle Cost Analysis as having an “Excellent” Rating. More information on the evaluation process can be found here.

• Autocase’s estimates of the costs of PV systems are specific to residential, commercial, and utility scale systems. Residential PV systems are those with 3kW to 10kW capacity, commercial PV systems are those with 10kW to 2MW capacity, and utility PV systems have a capacity greater than 2MW (as defined by the National Renewable Energy Laboratory: Fu, Feldman, & Margolis (2018)). The estimates are derived from dollar per kW values for capital expenditure and dollar per kW-year values for operations and maintenance costs. For the United States these values are sourced from Fu, Feldman, & Margolis (2018), IRENA (2019), Bolinger & Seel (2018), Walker (2017), National Renewable Energy Laboratory (2018) and for Canada the values are derived from IRENA (2019) and National Energy Board (2019). To make these values location specific a construction index from RS Means is used (https://www.rsmeans.com/rsmeans-city-cost-index.aspx). This allows for national averages to be converted to state or city specific values, based on location and data availability, for more accurate cost estimates.

• Autocase offers default cost estimates for different land cover types that can be imported into your LCCA.
• Asphalt
  • Green Values Stormwater Toolbox (2007)
  • Rehan et al. (2018)
  • USDA Forest Service Northern Region Engineering (2017)
• Portland Cement Concrete and Hot Mix Asphalt
  • Rehan et al. (2018)
• Porous Pavers
  • Green Values Stormwater Toolbox (2007)
  • Grey et al. (2013)
  • The Water Research Foundation (2009)
• Permeable Asphalt, Gravel, Stone, and Wood
  • San Antonio River Authority (2019)
• Low Vegetation
  • Green Values Stormwater Toolbox (2007)
  • Northeastern Illinois Planning Commission and Chicago Wilderness (2003)
  • San Antonio River Authority (2019)
• Medium Vegetation
  • Charles River Watershed Association (2010)
  • Green Values Stormwater Toolbox (2007)
  • San Antonio River Authority (2019)
  • Toronto and Region Conservation Authority (2007)
  • United States Environmental Protection Agency (2011)
  • United States Environmental Protection Agency (2016)

• Reducing energy consumption from the grid (in the design case compared to the base case) may generate environmental benefits from reduced air pollution being emitted.
• For each unit of energy produced and used, air pollution emissions are released into the atmosphere and; quantified using emission factors.
• The environmental benefit from reducing air pollution emissions is monetized by applying the social cost of each air pollutant to the respective amount of that air pollutant reduced.
• Autocase calculates the environmental benefit for the following air pollutants: NOx, SO2, PM2.5, and VOC.
• Non-baseload, location-specific emission factors per unit of electricity are gathered from the U.S. Environmental Protection Agency (EPA) eGRID (2018) and U.S. EPA National Emissions Inventory (NEI, 2017) for U.S locations and Environment and Climate Change Canada Air Pollutant Emission Inventory (APEI, 2018) for Canadian locations.
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Autocase economists objectively evaluate the research behind this impact as having a “Good” Rating. More information on the evaluation process can be found here.

• Reducing energy consumption from the grid may also reduce greenhouse gas emissions, thereby generating environmental benefits.
• For each unit of energy produced and used, carbon dioxide equivalent (COe) emissions are released into the atmosphere and quantified using emission factors.
• The environmental benefit of reduced CO2e is monetized by applying the social cost of carbon to the amount of CO2e emissions reduced.
• Non-baseload, location-specific emissions factors for CO2e emissions per unit of electricity are gathered from the U.S. EPA eGRID (2018) for U.S locations and Energy Star Portfolio Manager Technical Reference: Greenhouse Gas Emissions (2018) for Canadian locations. CO2e from electricity include: methane (CH4), carbon (CO2), and nitrous oxide (N2O). 
• Carbon emission factors for natural gas combustion for U.S. and Canadian locations are gathered from the US EPA, AP-42: Compilation of Air Pollutant Emission Factors, Section 1.4 Natural Gas Combustion (1998).
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Autocase economists objectively evaluate the research behind this impact as having an “Excellent” Rating. More information on the evaluation process can be found here.

Prices for carbon set by governments act to correct for the damages caused by carbon emissions that are not already part of the price of goods and services. Prices for carbon set by the government are not necessarily the same as the Social Cost of Carbon (SCC). When carbon prices are enacted people or businesses who use fuels that emit carbon have to pay more for them. This model calculates the carbon payments that are made on top of the cost of utilities like natural gas and electricity. The two carbon pricing methods used in Canada and the United States are Carbon Taxes, and Emissions Trading Schemes (ETS). ETS are permit allocations where producers of emissions can buy and sell permits that give them the right to emit carbon.

The European Commission (2014) recommends using the government set carbon price for evaluation of impacts from a social perspective. This only works when the price of carbon closely aligns with the Social Cost of Carbon (SCC) estimated by scientists and economists

The surcharge for carbon emissions determined by government prices will appear as a financial impact. If this is within the bounds of the Social Cost of Carbon (SCC) estimate, the carbon surcharge and the social cost will be the same. If this price is not close to the SCC it is treated like all taxes in a CBA, a reallocation of resources in society. It will be shown as a user cost, but will be replaced by the SCC in the social lens of the analysis.

• Local utilities may offer incentives to building owners to invest in the on-site production of renewable energy.
• These financial incentives are collected for a user-defined length of time, starting at the beginning of operations.

Autocase economists objectively evaluate the research behind this impact as having an “Excellent” Rating. More information on the evaluation process can be found here.

• On-site renewable energy production may not only be used on-site, but also sold to the grid.
• The revenue received from selling renewable energy is calculated based on the amount of energy sold to the grid and the local price paid for renewable energy inputted by the user.

Autocase economists objectively evaluate the research behind this impact as having an “Excellent” Rating. More information on the evaluation process can be found here.

• Renewable energy production may be sold to the grid. When this occurs, it generates environmental benefits as the grid becomes cleaner by being partially offset by renewable energy.
• For each unit of energy produced and used, air pollution emissions are released into the atmosphere and quantified using emission factors.
• The environmental benefit from reducing air pollution emissions is monetized by applying the social cost of each air pollutant to the respective amount of that air pollutant reduced.
• Autocase calculates the environmental benefit for the following air pollutants: NOx, SO2, PM2.5, and VOC.
• Non-baseload, location-specific emission factors per unit of electricity are gathered from the U.S. Environmental Protection Agency (EPA) eGRID (2018) and U.S. EPA National Emissions Inventory (NEI, 2017) for U.S locations and Environment and Climate Change Canada Air Pollutant Emission Inventory (APEI, 2018) for Canadian locations.

Autocase economists objectively evaluate the research behind this impact as having a “Good” Rating. More information on the evaluation process can be found here.

• Similar to air pollution, the sale of on-site produced renewable energy can also facilitate the reduction of greenhouse gas emissions, thereby generating environmental benefits.
• The environmental benefit from renewable energy is monetized by applying the social cost of carbon to the total amount of CO2e emissions reduced.
• Non-baseload, location-specific emissions factors for CO2e emissions per unit of electricity are gathered from the U.S. EPA eGRID (2018) for U.S locations and Energy Star Portfolio Manager Technical Reference: Greenhouse Gas Emissions (2018) for Canadian locations. CO2e from electricity include: methane (CH4), carbon (CO2), and nitrous oxide (N2O). 

Autocase economists objectively evaluate the research behind this impact as having an “Excellent” Rating. More information on the evaluation process can be found here.

Financial Costs of Carbon Offsets

• A project may choose to purchase carbon offsets to offset the carbon footprint.

• This is an additional cost to the project calculated using the amount of carbon offsets purchased, the unit price of offsets and any growth in price and quantity of offsets. This is estimated for the duration of the contract.

Greenhouse Gas Emissions from Carbon Offsets

• Carbon offsets calculate the amount of carbon emission avoided, hence only the social cost of carbon is used to value the social benefit.

• The amount of carbon emission avoided is equal to the amount of carbon offsets purchased and is monetized using the social cost of carbon.

• Environmental benefits from carbon offsets are only recorded when they are purchased to improve user carbon footprint from the base case. They are not recorded when offsets are purchased to even out the increase in emissions in the design case, beyond carbon emission increases due to energy usage.

• A social value of water will be applied to any water taken out of the water table. For instance, using water from a utility or capturing water from a well will imply water being taken out of the water table or a body of water, and a corresponding social value of water will be applied.
• Reducing the amount of water consumed from a utility or a well will realize a benefit to society in terms of the social value of water.
• Autocase uses the research conducted by United States Geographical Survey Water Survey (2010) and Environment Canada Municipal Water Use Report (2009) to allocate groundwater-surface water proportions for cities in the software.

Autocase economists objectively evaluate the research behind this impact as having a “Good” Rating. More information on the evaluation process can be found here.

• Water supplied by a utility as well as wastewater treated by a wastewater treatment plant require significant energy use.
• Using emission factors and the amount of offset energy from the grid, the societal benefit is monetized by applying the social cost to each air pollutant, including: NOx, SO2, PM2.5, and VOC.
• Autocase uses information on energy intensities from the Water Research Foundation and Electrical Power Research Institute (2013).
• Non-baseload, location-specific emission factors per unit of electricity are gathered from the U.S. Environmental Protection Agency (EPA) eGRID (2018) for CO2e, NOx, and SO2 and U.S. EPA National Emissions Inventory (NEI, 2017) for PM2.5 and VOC for U.S locations. For Canadian locations, non-baseload, location-specific emission factors per unit of electricity are gathered from Energy Star Portfolio Manager Technical Reference: Greenhouse Gas Emissions (2018) for CO2e and Environment and Climate Change Canada Air Pollutant Emission Inventory (APEI, 2018) for NOx, SO2, PM2.5, and VOC.

Autocase economists objectively evaluate the research behind this impact as having a “Good” Rating. More information on the evaluation process can be found here.

Annual costs or benefits are incurred each year during the life of the design and may escalate (deescalate) if real costs or benefits increase (decrease) over the study period. Annual cost/benefits in each design case are compared to those in the base case.

Investments in open space can provide the opportunity for building occupants and community members to participate in recreation activities. Literature suggests that recreational activities in open spaces are valued by individuals as they would otherwise have to pay to participate in similar activities in the marketplace, such as at commercial facilities with admission fees. Autocase monetizes the community benefit (or cost if opportunities are lost) of recreation in an open space using the following approach:

• The Autocase user selects the recreational activities that are provided by the open space as well as the availability of another open space with the same recreational opportunities as this open space investment. The Autocase user also inputs the number of community members that are expected to use the open space per day;
• The Autocase user inputs the number of community members that are expected to use the open space per day. This input is multiplied by the count of sunny days in the first year of operation to estimate the annual number of community recreational users of this open space. All the following conditions must be satisfied for a day to be counted as a sunny day:
  • Daily precipitation < yearly average precipitation (Environment and Climate Change Canada RCP 4.5; RCP 8.5);
  • Daily temperature > yearly average temperature (Environment and Climate Change Canada RCP 4.5; RCP 8.5; and
  • Daily maximum temperature < location-specific heat warning temperature criteria (Environment and Climate Change Canada (RCP 4.5; RCP 8.5, Government of Canada 2019 and National Oceanic & Atmospheric Administration 2018).
• Autocase applies a cost of living index (Numbeo 2018) and inflation to the per activity direct use values (TTPL 2008a; 2008b) to determine the value per activity for the selected Autocase city;
• The annual number of community members that use the open space are combined with the use weighting per activity (TTPL 2008a; 2008b) to estimate the annual number of community users per activity;
• The product of the value per activity and the annual number of community users per activity is summed across the activities selected in the open space. This annual value is summed over the operational period to determine the Recreation Community benefit.

Vegetated cover provides the benefit of carbon sequestration. This occurs through the accumulation of carbon in above and below ground plant biomass as well as in the soil beneath the vegetation as soil organic carbon. Carbon sequestration value are reported a rate of mass over a given unit of time for a unit of area. The greater the area that is covered in vegetation and the longer the vegetation persists, the greater the amount of carbon that is sequestered. The rate at which carbon is sequestered depends on the type of vegetation. Larger plants sequester more carbon as they have more above and below ground biomass both of which store carbon. Carbon also accumulates in the soil as the vegetation grows. Literature has also shown their to be different rates of sequestration depending on whether or not the vegetation is managed or unmanaged, with unmanaged vegetation having higher sequestration rates. Carbon sequestration rates are monetized using the social cost of carbon. Other air pollutants are removed by plants in a similar fashion. The value of the removal of these pollutants can be valued in a similar way, using the amount sequestered per area of vegetation per year, and then multiplied by the social cost associated with the specific pollutant. This allows Autocase to provide a dollar value for the amount of air pollution that is removed. The monetization process is as follows:

• The Autocase user inputs the site coverage for either low or medium low vegetation and selects whether or not the vegetation is managed;
• Based on the inputs the Autocase user selects, carbon sequestration and air pollution removal rates from literature that correspond to the height and management practices of the vegetation are used to estimate the amount of carbon sequestered in kg/sq m/year (Getter et al. 2009, Gopalakrishnan et al. 2018, Kuronuma et al. 2018, Liebig et al. 2008, Qian et al. 2010, Selhorst & Lal 2012, Whittinghill et al. 2014, Zirkle et al. 2011);
• Autocase applies the social cost of the pollutant to calculate a yearly dollar value pollution sequestration;
• The annual dollar value is then discounted to present value.

Heat waves are an increasing danger all across North America, sometimes resulting in large numbers of premature deaths. These events may be more frequent and severe in the future due to climate change. Investing in a cool or green roof, as well as cooler ground covers and green spaces can reduce the severity of extreme heat events by creating shade and reducing the amount of heat absorbed by the rooftops and hardscape, i.e. affect the ambient temperature. Even a small cooling effect can be sufficient to reduce heat stress-related fatalities during extreme heat wave events.

Reduced Mortality

• Location specific (mapped to 25 square km cells) temperature forecasts are used from the CanESM2 model by the Canadian Centre for Climate Modelling (CCCma). The CanESM2 model represents the Canadian contribution to the IPCC Fifth Assessment Report (AR5). Data is extracted for RCP scenarios 4.5 and 8.5 to estimate the change in expected mortality from heat-stress related events over the project period.
• Using literature from Guo, Gasparrini et al. (2014), a Minimum Mortality Threshold (MMT) is set to identify the monthly number of days that have temperature exceeding this threshold above which the risk of heat-exposure related mortality increases.
• SRI values for roof coverages are taken from the CRRC database, that have a combination of different hot and cool roof materials and colors. The SRI values inform the incremental change in surface temperature between a conventional hot roof and a sustainable cool roof. A change in surface temperature is converted to a change in ambient temperature using literature from Guan (2011). The SRI values for hardscape materials are taken from the literature: Uzarowski et al. (2018), Santamouris et al. (2011), Radhi et al. (2014), Tran et al. (2009), Mohajerani et al. (2018), and Alchapar et al. (2014).
• Heat flux changes (Watts/m2)from A Sharma et al. (2016), Parshall et al. (2016) and Thermal Conductivity (Watts/m2 K) estimates from Sailor and Hagos (2011) are used to estimate the incremental change in ambient temperature that affects the risk of mortality.
• The incremental change in ambient temperature between the base and design case informs the change in mortality. The value of statistical life (VSL) is used to monetize the change in mortality to calculate a benefit of investing in cool or green roofs and cool ground covers for the user.

Choosing low-carbon intensive materials reduce GHG emissions, thereby generating societal benefits. For each unit of fossil energy burned GHGs emissions are released into the atmosphere and are quantified in Autocase using emission factors (to make different GHGs into carbon dioxide equivalents). The environmental benefit of reduced GHGs is monetized by applying the social cost of carbon to the amount of carbon dioxide equivalent emissions reduced. The social cost of carbon in the U.S is from the Interagency Working Group on Social Cost of Greenhouse Gases (August 2016). Canada has its own estimates using the same models used for the social cost of carbon in the U.S. The social cost of carbon is a conservative estimate of the negative effects of climate change. The cost of carbon pollution is an estimate of the damages – of the economic cost of the health, agricultural losses, property flooding and the value of ecosystem services. The estimates, and there are many estimates are conservative because they do not yet capture all of the identified impacts of rising levels of CO2 in the atmosphere.