This page contains explanations for the various data points collected and calculated for the Energy Prize. You can find more information about:
- Overall Energy Score
- Residential Energy Use
- Municipal Energy Use
- Source Energy
- Site Energy
- Population Normalization
- Weather Normalization
- Electric Energy (kWh)
- Natural Gas Energy (Therms)
- Total Energy Use (kBTU)
- Carbon Emissions
- Financial Cost
Update, December 18, 2017: Complete rankings and overall energy scores for the communities who completed the semifinalist round of competition are now available.
All competitors are ranked by an Overall Energy Score (OES) that quantifies their energy-saving performance during the 2015 and 2016 competition years, relative to the community’s 2013 and 2014 baseline, as a percentage change. The OES is based on the weather-normalized source-energy use per residential bill—also referred to as Adjusted Source Energy Use per Residential Bill (ASEU)—averaged over the baseline and Stage 3 Performance Competition periods.
To calculate the Overall Energy Score, we use EPA’s Portfolio Manager to calculate the weather-normalized source-energy use for each fuel type, and then divide that total monthly energy use by the number of residential accounts (ASEU). We can then compare the ASEU for the competition period to the ASEU for the baseline period, to get the Overall Energy Score. For a complete discussion of the Overall Energy Score (OES) and Adjusted Source Energy Use per Residential Bill (ASEU), see the GUEP Guidelines: https://guep.org/about-the-
Decreased energy use will result in a negative OES, and the more negative the better. Note that for some communities the OES may be positive (increased energy use); the more positive the Energy Score, the lower the ranking.
In addition to the final scores above, the complete set of calculations from EPA’s Portfolio Manager is available for download in CSV format, as is the complete raw data submitted by utilities for the communities participating in the competition.
For more information about the data-points and calculations, read the explanations below.
The Georgetown University Energy Prize measures the aggregate energy used by all of the residents of the competing communities. This includes residents in single family homes and multifamily buildings who own or rent their homes. The energy is reported monthly as two aggregated data-points that encompass the entire electric and natural gas energy consumption for all residents.
For purposes of the Georgetown University Energy Prize, aggregate municipal energy includes all of the energy used by the city and/or county government in providing services to their residents, excluding transportation energy.
Examples of municipal energy use include:
- All offices and buildings used by the municipality, whether owned, leased, or rented by the municipality, regardless of whether the facilities are located within the municipal boundaries. For example: municipal offices, police stations, fire stations, public schools, libraries, parking garages, water treatment and delivery facilities, chilled water facilities, airports, etc.;
- Infrastructure such as street lighting, traffic lighting, parking garages, etc.;
- Parks and recreation facilities;
- All (K-12) public, charter, and private schools located within the municipal boundaries and attended by community residents; and
- Public housing that is not charged a residential rate.
Source energy is a calculation of energy consumption that includes the full-fuel-cycle of contributions from the production, transportation, and delivery of the energy source – all important factors in the whole picture of how energy consumption affects personal, community, and national resources.
As the U.S. EPA explains: “Source energy represents the total amount of raw fuel that is required to operate the building. It incorporates all transmission, delivery, and production losses. By taking all energy use into account, [source energy] provides a complete assessment of energy efficiency…”
The Georgetown University Energy Prize uses source energy because it is recommended by energy experts and the U.S. Government as the best way to take into account all of the impacts of energy consumption.
For a more-detailed explanation of the difference between source energy and site energy, see the EPA’s website here: http://www.energystar.gov/buildings/facility-owners-and-managers/existing-buildings/use-portfolio-manager/understand-metrics/difference
Site energy is the calculation of only the energy consumed in a given building, without taking into account the total source energy used in the full-fuel-cycle of generating and delivering the energy to you.
Site energy represents the electricity and natural gas that you consume in your home and that the utility company reads off of the meter every month. This is the raw data that utilities submit to Georgetown University Energy Prize and we use to compute the source energy use that is then normalized for population and weather.
To provide fair comparisons between communities, the energy used is normalized to adjust for the relative population size of each community.
Ideally, this would be done by using energy use per capita, but that’s not possible because census figures are several years old and also because there’s no accurate way to measure changes in population size during the 24 month competition period.
Therefore, the Georgetown University Energy Prize uses the number of residential utility bills issued as a proxy for the population of the community, analogous to the number of households in the community – although not exact, it’s easy to measure and will rise and fall with changes in population of the community.
Note that we also normalize the municipal energy use by the number of residential bills. This is because the municipality exists to serve the community residents, and the number of municipal accounts may not reflect changes in residential population size.
For a more comprehensive explanation of our methodologies and calculations, see the GUEP Guidelines: https://guep.org/about-the-prize/
To account for variations in weather, the Georgetown University Energy Prize normalizes for the weather using formulas established by the U.S. EPA’s Portfolio Manager platform. The EPA explains their approach:
“Weather normalized energy is the energy your building would have used under average conditions (also referred to as climate normals). The weather in a given year may be much hotter or colder than your building’s normal climate; weather normalized energy accounts for this difference.”
Weather normalization allows GUEP to even out any extreme weather variations in a given year for a given community and provide a better comparison across communities. For a more comprehensive explanation of our methodologies and calculations, see the GUEP Guidelines: https://guep.org/about-the-prize/
The Georgetown University Energy Prize measures all of the electricity used in the residential and municipal sectors of the competing communities.
For the purposes of the Prize, electricity is measured in kilowatt hours, notated as “kWh.” The kilowatt hour is a unit used to measure electrical energy. There are plenty of other units of energy, including Therms, which are commonly used to measure natural gas, or even Calories, which are used to measure the amount of energy that our body uses.
Electricity consumption is measured as the amount of power used over time, or the number of watts used per hour. Specifically, a kilowatt hour is equivalent to 1000 watt-hours of electricity, or, the amount of energy it takes to run a 10 watt lightbulb for 100 hours (10W x 100h = 1000Wh = 1 kWh).
See here for more information about reading your home energy meter: http://www.energy.gov/energysaver/articles/how-read-residential-electric-and-natural-gas-meters
For a more detailed explanation of how electricity consumption is calculated in your home, visit the U.S. Department of Energy’s site here: http://energy.gov/energysaver/articles/estimating-appliance-and-home-electronic-energy-use
The Georgetown University Energy Prize measures all of the natural gas used in the residential and municipal sectors of the competing communities.
For the purposes of the Prize, natural gas usage is measured in therms, notated as “therms,” or sometimes “thm.” The therm is a unit of heat energy equal to 100,000 British thermal units (BTU). It is approximately the energy equivalent of burning 100 cubic feet (often referred to as 1 CCF) of natural gas.
When you read your home natural gas meter, it’s generally counted in CCF, as the volume of natural gas that you’ve used in your house. See here for more information about reading your home energy meter: http://www.energy.gov/energysaver/articles/how-read-residential-electric-and-natural-gas-meters
To learn more about natural gas energy efficiency, visit the American Gas Association’s website here: https://www.aga.org/virtual-natural-gas-home
To calculate the total amount of residential and natural gas energy consumed in a given community, the Georgetown University Energy Prize converts both electricity, kWh (link), and natural gas therms (link) units to thousands of British thermal units, or kBTU.
The British thermal unit (BTU) is the amount of energy needed to cool or heat one pound of water by one degree Fahrenheit. For example, one four inch, wooden kitchen match consumed completely generates about 1 BTU.
For more information about energy conversions visit this EPA Portfolio Manager technical reference: https://portfoliomanager.energystar.gov/pdf/reference/Thermal%20Conversions.pdf
While the Georgetown University Energy Prize is primarily concerned with energy efficiency, we believe it is important to understand the carbon emissions that result from the source energy consumed in our competing communities.
Carbon dioxide (CO2) is the primary greenhouse gas that is emitted from human activity, and particularly from the use of fossil fuels in the production, transportation, and consumption of energy that the Georgetown University Energy Prize is concerned with.
The Georgetown University Energy Prize estimates the kilograms (kg) of carbon dioxide (CO2) emitted from energy consumption, as well as the estimated kilograms of carbon dioxide that is diverted—or not emitted—as a result of the energy saved in each community.
To estimate the carbon emissions resulting from the energy consumed, the Prize uses the same methodology as EPA’s Portfolio Manager, which is explained here: http://www.energystar.gov/buildings/tools-and-resources/portfolio-manager-technical-reference-greenhouse-gas-emissions
An important part of saving energy is the amount of money saved that can be put back into your household and community budget. The Georgetown University Energy Prize estimates the cost of energy, and the amount of money saved, based on the average energy prices from 2014.