PVSN Energy Decision Tool
Overview and instructions

A general overview of the tool is given below, followed by general usage instructions. More detailed information on the tool can be found in Section 5 of the thesis document

General overview

This tool is designed to provide information on the environmental, health, and financial costs and benefits of implementing green energy options for your building.  It is currently implemented in an Excel spreadsheet.

How it works

You answer a few questions related to your current energy use (such as type and amount of energy, and related replacement and maintenance costs) and then select alternative green energy options to evaluate.  The tool uses default values based upon typical energy costs to generate a comparison of the proposed options with your current situation.

 Why implement green energy options?

Through implementing green energy alternatives, you can improve the environment and possibly save money. Energy efficiency and alternative energy options reduce emissions of greenhouse gases, such as carbon dioxide, and of other pollution emissions, such as sulphur dioxide.  Reducing greenhouse gases helps to reduce the risk of climate change; climate change may result in rising sea levels (affecting loss of homes and farmland), more dramatic weather extremes (e.g., drought in some areas, floods in others, more intense storms, more heat waves,  resulting in loss of life and property, and an increase in infectious diseases),  form imbalances in ecosystems , and affect the types of crops grown in different parts of the world (leading to hunger in some countries).  Reducing other pollution emissions has positive health effects for yourself, your community, and the local environment. Health issues affected by pollution emissions include premature mortality, hospital & ER visits, asthma attacks, and lost work days.   Local pollutants also impact the environment, for example local traffic and inefficient wood burning stoves contribute to particulate matter concentrations (resulting in an increase in respiratory complaints), and size of homes impacts the demand for heating. Finally, many of the options will save you money in the long run, and protect you from fluctuations in energy prices.

Green Energy Options impact (Output)

The output of the tool is a comparison of your proposed changes to your current situation in terms of emissions, health, and personal financial impact. Emissions are calculated in tons of CO2, SO2, and NOX.  Health impact is calculated in number of incidents of premature mortality, hospital & ER Visits, Asthma Attacks, Respiratory Symptoms and work loss days. 

The tool makes it easy to make the comparison by associating a monetary value with the health and emissions impacts. In economic terminology, the health and emissions-related costs to the community are commonly referred to as societal costs. The tool generates an overall cost for your current situation and the proposed options by combining an estimate of your personal financial cost and the societal cost. For your particular situation, some energy options will directly save you money, as well as benefit society, resulting in an overall net benefit. Some options may not directly save you money, but will have a positive societal financial benefit; the net overall result will depend on the relative magnitude of your cost and the societal benefit.  [See examples of such outcomes in section 5.6 of the thesis document

using the tool

This section provides a quick overview on using the tool.  A detailed explanation of the tool can be found in Section 5 of the thesis document .  The detailed explanation includes underlying formulas and assumptions that are made in the development of the tool.

The “interface” tab is where all user data is entered, as well as where the results are displayed.  The other tabs are work tabs in which supporting data is stored and where the underlying calculations are done.

 User entry cells are color coded in the Excel spreadsheet.  They are yellow for your existing situation and green for alternative energy options. Data entered as drop down boxes is in white for both existing and alternative options (for an example see the “Heating Fuel Type” choice below).

Example input fields for existing situation


Example input fields for Green energy options

Some User entered fields have “help” associated with them via Excel comments.  They have a red triangle in the upper right hand corner of the cell description; for example, in the figure above, the red triangle in the Photovoltaics, Panel Selection and # of panels fields indicate there is additional information provided for these fields.  Hover your cursor over the cell in Excel to see the comment/”help” information.

Click to see what Information you need to provide

Click to see what Green Energy Options are Available to you


Tool Output

 The tool output is a comparison of the benefits of your proposed options to your current situation.  The tool compares financial, emissions and health impacts.

Sample output is shown below for a household replacing 10 moderately used 75 W light bulbs with compact fluorescent bulbs.  In addition to an annual cost savings of $58.75 per year, the tools shows annual society benefits of $11.30 for emissions and $28.48 for health impact.