Overall Rating Gold
Overall Score 83.20
Liaison Mina Amundsen
Submission Date Nov. 5, 2018
Executive Letter Download

STARS v2.1

Colby College
OP-5: Building Energy Consumption

Status Score Responsible Party
Complete 3.22 / 6.00 Paul Libby
Assistant Director of Operations
Physical Plant Department
"---" indicates that no data was submitted for this field

Figures needed to determine total building energy consumption:
Performance Year Baseline Year
Grid-purchased electricity 43,920.94 MMBtu 44,934 MMBtu
Electricity from on-site renewables 9,495.61 MMBtu 0 MMBtu
District steam/hot water (sourced from offsite) 0 MMBtu 0 MMBtu
Energy from all other sources (e.g., natural gas, fuel oil, propane/LPG, district chilled water, coal/coke, biomass) 159,495.53 MMBtu 161,665.26 MMBtu
Total 212,912.08 MMBtu 206,599.26 MMBtu

Start and end dates of the performance year and baseline year (or 3-year periods):
Start Date End Date
Performance Year July 1, 2017 June 30, 2018
Baseline Year July 1, 2004 June 30, 2005

A brief description of when and why the building energy consumption baseline was adopted (e.g. in sustainability plans and policies or in the context of other reporting obligations):

We are using FY2005 as a common baseline throughout this submission, as this was the year that the College began formally tracking data in all STARS reporting fields.

Gross floor area of building space:
Performance Year Baseline Year
Gross floor area of building space 1,574,218 Gross Square Feet 1,371,951 Gross Square Feet

Source-site ratio for grid-purchased electricity:

Total building energy consumption per unit of floor area:
Performance Year Baseline Year
Site energy 0.14 MMBtu / GSF 0.15 MMBtu / GSF
Source energy 0.19 MMBtu / GSF 0.22 MMBtu / GSF

Percentage reduction in total building energy consumption (source energy) per unit of floor area from baseline:

Degree days, performance year (base 65 °F / 18 °C):
Degree days (see help icon above)
Heating degree days 7,299 Degree-Days (°F)
Cooling degree days 558.40 Degree-Days (°F)

Floor area of energy intensive space, performance year:
Floor Area
Laboratory space 40,284.90 Square Feet
Healthcare space 0 Square Feet
Other energy intensive space

EUI-adjusted floor area, performance year:
1,704,179.42 Gross Square Feet

Building energy consumption (site energy) per unit of EUI-adjusted floor area per degree day, performance year:
15.90 Btu / GSF / Degree-Day (°F)

Documentation (e.g. spreadsheet or utility records) to support the performance year energy consumption figures reported above:

A brief description of the institution's initiatives to shift individual attitudes and practices in regard to energy efficiency (e.g. outreach and education efforts):

The EcoReps hold an annual Dorm Electricity Competition, which encourages students to practice energy-saving behaviors by monitoring energy use in each of the dorms, and reporting these numbers to the entire school daily. The dorms compete to see which can save the most energy. In Spring 2017, Colby competed against Bowdoin to see which school could reduce energy use the most, which fostered a friendly competitive spirit and both schools saved energy.

A brief description of energy use standards and controls employed by the institution (e.g. building temperature standards, occupancy and vacancy sensors):

In most classrooms and corridors, there are vacancy and occupancy sensors so the lights will turn off automatically. Colby employs a building temperature setback program over winter and January break. Over the summer, Colby participates in a Demand/Response program to decrease our energy load during peak times. Additionally, Facilities oversees a demand limiting program, which is able to roll in/out enough equipment to shed roughly 200 kWh every hour.

A brief description of Light Emitting Diode (LED) lighting and other energy-efficient lighting strategies employed by the institution:

Colby has begun replacing all lighting with LED fixtures in all building and outdoor spaces. About 75% of exterior lighting and nearly 50% of indoor lighting are now LEDs. New buildings, such as the new Davis Connects/Career Center, are equipped with daylighting sensors to further reduce electric lighting use. All windows in both classrooms and dormitory rooms are equipped with movable shades with paneling for users to allow light in as needed.

A brief description of passive solar heating, geothermal systems, and related strategies employed by the institution:

The Alumni Center and Davis Science Center share a geothermal heating system. The Alumni Center also has a solar array on its roof. This fall, a 1.9 MW solar array will go online, providing 16% of Colby's total electricity load. All condensate return systems receive continued maintenance such that the College is able to get back about 97% of condensate for reuse.

A brief description of co-generation employed by the institution, e.g. combined heat and power (CHP):

The Colby biomass plant provides an average 10% of Colby's electricity and 90% of Colby's heating needs.

A brief description of the institution's initiatives to replace energy-consuming appliances, equipment and systems with high efficiency alternatives (e.g. building re-commissioning or retrofit programs):

Colby encourages the purchase of Energy Star appliances. Typically, an appliance will be replaced with one of equal or greater efficiency. When upgrades are made, variable speed drives with pressure sensors are installed to increase building efficiency. Colby generally considers upgrades a part of best practices.

The website URL where information about the programs or initiatives is available:
Additional documentation to support the submission:

Colby has a geothermal system, however it is not metered. All purchased electricity comes from wind RECs. All campus water is heated at the on-site biomass plant and distributed throughout campus, so we do not purchase hot water or steam from off-site. During the baseline year, the cogen plant also produced all of the campus's hot water and steam.

The information presented here is self-reported. While AASHE staff review portions of all STARS reports and institutions are welcome to seek additional forms of review, the data in STARS reports are not verified by AASHE. If you believe any of this information is erroneous or inconsistent with credit criteria, please review the process for inquiring about the information reported by an institution and complete the Data Inquiry Form.