Overall Rating Silver
Overall Score 64.62
Liaison Sarah Fortner
Submission Date March 3, 2022

STARS v2.2

Carleton College
OP-5: Building Energy Efficiency

Status Score Responsible Party
Complete 5.52 / 6.00 Martha Larson
Manager of Campus Energy and Sustainbility
Facilities
"---" indicates that no data was submitted for this field

Part 1. Site energy use per unit of floor area

Performance year energy consumption

Electricity use, performance year (report kilowatt-hours):
kWh MMBtu
Imported electricity 15,271,355 Kilowatt-hours 52,105.86 MMBtu
Electricity from on-site, non-combustion facilities/devices (e.g., renewable energy systems) 3,516,855 Kilowatt-hours 11,999.51 MMBtu

Stationary fuels and thermal energy, performance year (report MMBtu):
MMBtu
Stationary fuels used on-site to generate electricity and/or thermal energy 71,938 MMBtu
Imported steam, hot water, and/or chilled water 0 MMBtu

Total site energy consumption, performance year:
136,043.37 MMBtu

Performance year building space

Gross floor area of building space, performance year:
2,069,322 Gross square feet

Floor area of energy intensive space, performance year:
Floor area
Laboratory space 196,228 Square feet
Healthcare space 550 Square feet
Other energy intensive space 79,965 Square feet

EUI-adjusted floor area, performance year:
2,542,843 Gross square feet

Performance year heating and cooling degree days 

Degree days, performance year:
Degree days
Heating degree days 7,616 Degree-Days (°F)
Cooling degree days 999 Degree-Days (°F)

Total degree days, performance year:
8,615 Degree-Days (°F)

Performance period

Start and end dates of the performance year (or 3-year period):
Start date End date
Performance period July 1, 2020 June 30, 2021

Metric used in scoring for Part 1

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

Part 2. Reduction in source energy use per unit of floor area

Baseline year energy consumption

STARS 2.2 requires electricity data in kilowatt-hours (kWh). If a baseline has already been established in a previous version of STARS and the institution wishes to continue using it, the electricity data must be re-entered in kWh. To convert existing electricity figures from MMBtu to kWh, simply multiply by 293.07107 MMBtu/kWh.

Electricity use, baseline year (report kWh):
kWh MMBtu
Imported electricity 14,305,092 Kilowatt-hours 48,808.97 MMBtu
Electricity from on-site, non-combustion facilities/devices (e.g., renewable energy systems) 0 Kilowatt-hours 0 MMBtu

Stationary fuels and thermal energy, baseline year (report MMBtu):
MMBtu
Stationary fuels used on-site to generate electricity and/or thermal energy 156,288 MMBtu
Imported steam, hot water, and/or chilled water 0 MMBtu

Total site energy consumption, baseline year:
205,096.97 MMBtu

Baseline year building space

Gross floor area of building space, baseline year:
1,680,023 Gross square feet

Baseline period

Start and end dates of the baseline year (or 3-year period):
Start date End date
Baseline period July 1, 2007 June 30, 2008

A brief description of when and why the energy consumption baseline was adopted:
The baseline corresponds with Carleton's first greenhouse gas inventory that was aided and verified by Sightlines, a facilities benchmarking and analysis firm.

Source energy

Source-site ratio for imported electricity:
3

Total energy consumption per unit of floor area:
Site energy Source energy
Performance year 0.07 MMBtu per square foot 0.12 MMBtu per square foot
Baseline year 0.12 MMBtu per square foot 0.18 MMBtu per square foot

Metric used in scoring for Part 2

Percentage reduction in total source energy consumption per unit of floor area from baseline:
35.56

Optional Fields 

Documentation 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:
Sustainability Assistants work on peer to peer education and outreach at New Student Week, in the residence halls, Climate Action Week, and other areas. The campus community is now very comfortable with common lighting controls like occupancy sensors and automatic dimming. The Energy Club assists with energy audits and hosts an annual energy symposium each year for the public.

A brief description of energy use standards and controls employed by the institution:
Campus standard is 68 degrees in winter 74 degrees in summer. Each week, Carleton's HVAC technicians enter the weekly classroom and office room schedule information into the Building Automation System so temperature setbacks can be employed during unoccupied hours. Maintenance staff work continuously to audit and improve the building automation systems in an effort to find further energy reduction opportunities.

A brief description of Light Emitting Diode (LED) lighting and other energy-efficient lighting strategies employed by the institution:
LED retrofit kits, 4ft. LED bulbs and new LED lights are now the standard for the Carleton maintenance department. Carleton is working through campus-wide LED lighting retrofits based on a list of projects from the Xcel Turn-Key Audit program. We completed bi-level LED stairwell fixtures, pin-style fixtures and exterior lighting retrofits. We are in the process of replacing all 4 ft. fluorescent bulbs with 4 ft. LED bulbs.

A brief description of passive solar heating, geothermal systems, and related strategies employed by the institution:
In summer 2021, Carleton completed its transition from district steam to low temperature hot water heating tied to geothermal heating and cooling. The fiscal year 2021 data represents half of that system coming online, so further reductions are anticipated as a year of data is logged post project completion. More information can be found here: https://apps.carleton.edu/geothermal/

A brief description of co-generation employed by the institution:
NA

A brief description of the institution's initiatives to replace energy-consuming appliances, equipment, and systems with high efficiency alternatives:
In FY19, Carleton completed turn-key energy audits with Xcel energy on 92% of our buildings. We have completed this and are now in the process of completing the recommended energy conservation opportunities.

Website URL where information about the institution’s energy conservation and efficiency program is available:
Additional documentation to support the submission:
Data source(s) and notes about the submission:
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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 or simply email your inquiry to stars@aashe.org.