NC State University
Intersession Energy Savings Initiative 2010-2011
Intersession Energy Savings Initiative Overview • Project Description -
NC State closed on Thursday, December 23, 2010 and reopened on Monday, January 3, 2011 for Winter Break. During this time, Facilities Operations, and others, set back building temperature set points that do not cause building damage, such as freezing, while at the same time providing the maximum energy conservation. The setback temperatures are 55 to 60 degrees F. The setback program has been in effect since 2005.
• Business Case -
By lowering building temperature set points, NC State can save natural gas and electricity; thereby saving cost and lowering carbon emissions. Since 2004, the program has saved more than $1.2MM in avoided costs.
• Exception Process -
The program has a formalized exception process that allows certain buildings and building zones to remain at normal heat and humidity levels. This includes ongoing research buildings, occupied residences, and special needs (e.g., library collection standards).
• Setback Program Outreach -
The campus community was informed about the program through an email blast and routine media outlets. Instructions on shutting down non-essential lab equipment, closing fume hoods, shutting windows and doors, turning off lights and office equipment were communicated frequently.
• Project Leadership -
Jack Colby, Assistant Vice-Chancellor for Facilities Operations
• Project Facilitator -
Utilities and Engineering, Energy Management
• Participating NC State Facilities Teams -
Athletics
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Building Maintenance and Operations - Central Shops
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Campus Enterprise, Facilities Operations
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Carmichael Complex Facilities and Operations
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Dining and Catering Operation
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Housekeeping Services
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University Sustainability Office
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University Housing
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Utilities and Engineering, Central Plants
• Key Highlights for 2010 - $187,238 Energy Costs Avoided - 1,349 Metric Tons of CO2 Emissions Avoided (MTCO2)
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Intersession Energy Savings Initiative Calendar • Thanksgiving Setback Period (Pilot)
November 2010 S
M
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Th
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25 26 Thanksgiving
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22 Pre-Holiday
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29 Winter Holiday
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T
W
Th
F
- December 17 - December 23 - Pre-Holiday period included in Initiative for the first time in 2010
• Winter Holiday Setback Period
January 2011 S
- Thanksgiving Holiday included in Initiative for the first time in 2010
• Pre-Holiday Setback Period (Pilot)
December 2010 S
- November 25 - November 28
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- December 24 - January 2 - Program in effect since 2005 with more than $1.2MM in avoided costs recorded 3
Intersession Energy Savings Initiative Participation and Targeted Buildings • Affected Building Count
Building Count
Percentage
33.0%
Targeted
244 34.5%
In Program
Non-Targeted
230 32.5%
34.5%
Excluded
233
Total
707 100%
33.0% 32.5%
• Affected Square Footage
Gross Square Footage Targeted
Percentage
11,854,954 78.7%
Non-Targeted 1,152,590 7.7% Excluded
2,045,057
Total
15,052,601 100%
13.6%
• Definitions -
Targeted: Included in 2010 Intersession Initiative
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Non-Targeted: Excluded from 2010 Intersession Initiative ‣ Buildings occupied during holiday period ‣ Areas unable to be separately controlled
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In Program 78.7% 13.6% 7.7%
Excluded: Always excluded from 2010 Intersession Initiative ‣ Critical Lab, Research and Veterinary Spaces
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Intersession Energy Savings Initiative Winter Break Analysis: Dec 24 - Jan 3 Campus Gross Square Footage
• Growth of NC State’s Campus
• The Effects of Heating Degree Days -
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Heating Degree Days (HDD) are a method of normalizing energy data for the effects of weather from one year to the next. The extreme weather in 2009 continued during the 2010 setback period, which required the University buildings to consume more energy to stay within a safe temperature range to avoid freezing building HVAC and plumbing systems. HDD are calculated by subtracting the average daily temperature from a baseline temperature of 65ºF. These values are added together for each intersession period. Colder temperatures during the setback period created a higher HDD value, and subsequently, required additional energy consumption to heat the campus buildings to a safe temperature range.
15,000,000 GSF 12,500,000 GSF 10,000,000 GSF 7,500,000 GSF 5,000,000 GSF
Baseline
NC State is growing at a healthy rate - in 2010 alone, more than 725,000 square feet were added to the campus. Along with this necessary growth, energy consumption naturally tends to grow at a similar rate. In order to compare energy use to prior years, energy consumption per gross square foot (GSF) is the accepted unit of measure.
2004
2005
2006
2007
2008
2009
2010
Setback Period Heating Degree Days 320 HDD 240 HDD 160 HDD 80 HDD 0 HDD
Baseline
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2004
2005
2006
2007
2008
2009
2010
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Intersession Energy Savings Initiative Winter Break Analysis: Dec 24 - Jan 3 -
2004 is the baseline year, prior to the start of the Intersession Energy Savings Initiative. Electric consumption expressed as kilowatt-hours (kWh), is not as weather dependent as natural gas consumption, but is affected by the growing campus.
• Normalized Electric Consumption -
Since 2004, the campus has grown nearly 3MM GSF and the number of HDD increased from the baseline by 14%. Normalizing energy use compared to a baseline allows a direct comparison between program years. In 2010, the normalized data shows a 29% decrease in electricity consumption compared to the baseline year, and a 2% improvement over last years’ program.
Campus Electric Energy Consumption 6,000,000 kWh
5,250,000 kWh
4,500,000 kWh
3,750,000 kWh
Baseline
• Actual Electricity Consumption
3,000,000 kWh
2004
2005
2006
2007
Normalized Electric Utility Consumption Trendline for Normalized Consumption Actual Electric Utility Consumption
2008
2009
2010
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Intersession Energy Savings Initiative Winter Break Analysis: Dec 24 - Jan 3 -
2004 is the baseline year, prior to the start of the Intersession Energy Savings Initiative. Natural Gas consumption expressed as total British Thermal Units (BTU), is highly weather (temperature and humidity) dependent. It is also affected by the increased campus GSF since the baseline year.
• Normalized Natural Gas Consumption -
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Since 2004, the campus has grown nearly 3MM GSF and the number of HDD increased from the baseline by 14%. Normalizing energy use compared to a baseline allows a direct comparison between program years. The normalized data shows a 27% decrease in natural gas consumption compared to the baseline, but a 13% increase over last year’s program. Further analysis is required, and Energy Management is analyzing historical plant data and enthalpy to finetune our results. Enthalpy is a measure of the embodied energy in the outside air, and adds relative humidity to the factors affecting energy use. It is expected that since enthalpy is calculated using temperature and relative humidity, it is a stronger normalization factor for energy consumption, both for natural gas and electric utilities.
Campus Natural Gas Consumption (MMBTU) 40,000 MMBTU
32,500 MMBTU
25,000 MMBTU
17,500 MMBTU
Baseline
• Actual Natural Gas Consumption
10,000 MMBTU
2004
2005
2006
2007
Normalized Natural Gas Consumption Trend for Normalized NG Consumption Actual Natural Gas Consumption
2008
2009
2010
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Intersession Energy Savings Initiative Winter Break Analysis: Dec 24 - Jan 3 Energy Cost Avoidance to Base Year
• Energy Cost Avoidance By comparing the normalized energy consumption to the 2004 baseline year and adding the utility rate (cost) component, values of actual dollars saved are calculated.
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Using this approach, more than $1.2MM in utility costs have been avoided since 2004. The chart below shows the yearly totals and cumulative savings.
$98,379
$74,077
$150,000
$54,563
2005
$135,525
2006
$240,778
2007
2005
2009
$191,179
2010
$187,238
$0
2006
2007
2008
2009
2010
$750,000
$0 2004
$122,489 $113,343 $126,212 $117,102 $132,675
$256,014
$375,000
$71,174
2008
$0
$75,000
Baseline
$64,351
$211,722
$1,500,000
$129,802
$118,289
$1,222,455
$225,000
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$1,125,000
$300,000
Natural Gas Utility Cost Avoidance Electric Utility Cost Avoidance 8
Intersession Energy Savings Initiative Winter Break Analysis: Dec 24 - Jan 3 Carbon Dioxide Avoidance to Base Year (MTCO2) 1,500
1,125
676
368
404
516
• Avoided MTCO2 equates to more than 1,700 passenger vehicles off the road (US EPA estimates).
306 750 227
914 768
Baseline
375
0
0 2004
855
793
833
539
2005
• Since 2005, nearly 7,200 MTCO2 of carbon emissions have been avoided.
• Sources: - Natural Gas: US Inventory of GHG Emissions and Sinks 1990-2008 (April 2010).
2006
2007
2008
2009
2010
- Electric: US EPA eGRID2007 Version 1.1.
MTCO2 from Natural Gas Utility Consumption MTCO2 from Electric Utility Consumption 9
Intersession Energy Savings Initiative Lessons Learned and Projections for 2011 • Key Highlights - Avoided CO2 Emissions
- Avoided Energy Costs • $187,238 avoided in 2010
• 1,349 metric tons avoided (MTCO2) in 2010
• $1,222,455 avoided since 2005
• 7,199 metric tons avoided since 2005
• Lessons Learned
• Opportunities for 2011
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There was some confusion during the exception submission process - many of the requests were from “Excluded” buildings. In the future, Energy Management will design the exception request website to be more intuitive and easier to understand, clearly identifying the excluded buildings.
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The announcement to Campus was deployed late this year, and likely contributed to the amount of exception requests that were received after the published deadline. All of the late exceptions were reviewed and responses were provided. However, in future programs, care will be taken to provide adequate clear and concise information with sufficient notice so that the campus community will have time to respond and prepare for the Energy Savings Initiative.
Energy Management has projected that energy consumption by the Central Utility Plants (CUPs) is dependent upon temperature and relative humidity. In our region, temperature and humidity fluctuate significantly during a typical day. In future Intersession programs, hourly climate data will be analyzed in conjunction with the CUPs energy consumption and steam and chilled water production.
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The 2010 Intersession Energy Savings Initiative announcements and exception request system will begin earlier to allow more preparation by Energy Management, BM&O, faculty, staff and students.
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During the analysis of energy savings, Energy Management determined that previous years’ analyses had not fully considered campus growth in the evaluation. A full rework of the analysis template was created and fully considered campus growth, utility rate increases and carbon emissions avoided. The new template is set up for simple yearly updates and comparisons. 10
Intersession Energy Savings Initiative Pilot Program Expansion: Nov 25 - 28 and Dec 17 - 23 • Project Description - In a partnership between Energy Management and Building Maintenance and Operations, a pilot program expanding energy setbacks was implemented for the first time. During Thursday and Friday of the Thanksgiving holiday, and during the week before the Winter “deep freeze”, buildings were minimally set back to the weekend schedule, and where possible, more aggressive setbacks were implemented.
• Business Case - Lowering the building temperatures to “unoccupied” status during the the additional days prior to the Winter University Closing did not incur significant cost to deploy. Any utility savings during this period were direct savings to the University Utility Budget.
• Limited Setback Program Outreach - Due to the nature of the expanded setbacks, very little outreach was required. Wherever possible, buildings were set to typical weekend schedule, and in most cases, occupants were able to override setpoints to provide thermal comfort within their individual work spaces.
• Project Leadership - Jack Colby, Assistant Vice-Chancellor for Facilities Operations
• Project Facilitator - Utilities and Engineering, Energy Management
• Participating NC State Facilities Teams - Building Maintenance and Operations Central Shops - Utilities and Engineering, Central Plants
• Key Highlights - More than $8,500 Energy Costs Avoided during Thanksgiving Period - More than $8,300 Energy Costs Avoided during week before Winter Shutdown - ≈100 Metric Tons of CO2 Emissions Avoided (MTCO2)
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Intersession Energy Savings Initiative Thanksgiving Break Pilot Analysis: Nov 25 - Nov 28 Campus Electric Load Profile (PEC Load Profiler) 30,000 kWh
Thursday
Friday
Saturday
Sunday
27,500 kWh
25,000 kWh
22,500 kWh
Sunday 7:00 PM
Sunday 1:00 PM
Sunday 7:00 AM
Sunday 1:00 AM
Saturday 7:00 PM
Saturday 1:00 PM
Saturday 7:00 AM
Saturday 1:00 AM
Friday 7:00 PM
Friday 1:00 PM
Friday 7:00 AM
Friday 1:00 AM
Thursday 7:00 PM
Thursday 1:00 PM
Thursday 7:00 AM
Thursday 1:00 AM
20,000 kWh
What Happened on Friday? During the period between Thursday evening and Saturday morning, when campus was in a “weekend” schedule mode, energy consumption increased. This unknown “event” has initiated an investigation within Energy Management to determine the root cause of the electric utility spike.
All Campus 2009 All Campus 2010 Normalized All Campus 2010
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Intersession Energy Savings Initiative Thanksgiving Break Pilot Analysis: Nov 25 - Nov 28 2009 v. 2010: Avoided Electric Utility Costs - Hourly $375.00
Thursday
Friday
Saturday
$1,987
$250.00
Sunday
$3,043
$4,775
$125.00
$0
-$125.00
-$1,186 Sunday 7:00 PM
Sunday 1:00 PM
Sunday 7:00 AM
Sunday 1:00 AM
Saturday 7:00 PM
Saturday 1:00 PM
Saturday 7:00 AM
Saturday 1:00 AM
Friday 7:00 PM
Friday 1:00 PM
Friday 7:00 AM
Friday 1:00 AM
Thursday 7:00 PM
Thursday 1:00 PM
Thursday 7:00 AM
Thursday 1:00 AM
-$250.00
Utility Costs Avoided The 4-day electric utility consumption dropped when comparing Thanksgiving Break 2010 to 2009. The increased consumption during Thursday night and Friday offset what would have been even greater savings. Even when taking this into consideration, more than $8,600 in avoided costs were realized.
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Intersession Energy Savings Initiative Pre-Holiday Pilot Analysis: Dec 17 - Dec 23 Campus Electric Load Profile (PEC Load Profiler) 30,000 kWh $1,935
$1,784
$2,049
$1,617
$938 In 2009, Thursday was Christmas Eve and was a campus holiday. The University was closed, hence the low comparative energy use on Wednesday and Thursday.
27,500 kWh
25,000 kWh
22,500 kWh
Thursday 6:00 PM
Thursday 12:00 PM
Thursday 6:00 AM
Thursday Thursday 12:00 AM
Wednesday 6:00 PM
Wednesday 12:00 AM
Wednesday 6:00 AM
Wednesday Wednesday 12:00 AM
Tuesday 6:00 PM
Tuesday 12:00 PM
Tuesday 6:00 AM
Tuesday 12:00 AM
Tuesday
Monday 6:00 PM
Monday 12:00 PM
Monday 6:00 AM
Monday Monday 12:00 AM
Sunday 6:00 PM
Sunday 12:00 PM
Sunday 6:00 AM
Sunday Sunday 1:00 AM
Saturday 6:00 PM
Saturday 12:00 PM
Saturday 6:00 AM
Saturday 12:00 AM
Saturday Friday 6:00 PM
Friday 12:00 PM
Friday 6:00 AM
Friday Friday 12:00 AM
20,000 kWh
Energy Savings NC State grew nearly 6% in gross square footage. This resulted in an increase in energy consumption between 2009 and 2010. When normalizing for this increase in campus size, energy consumption dropped between 2009 and 2010, saving the University more than $8,300 in avoided costs.
All Campus 2009 All Campus 2010 Normalized All Campus 2010
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Intersession Energy Savings Initiative Lessons Learned and Projections for 2011 Thanksgiving Holiday Setback • Key Highlights
Pre-Holiday Setback • Key Highlights
- $8,500 in Energy Costs Avoided
- $8,300 in Energy Costs Avoided
- 53 Metric Tons of CO2 Emissions Avoided (MTCO2)
- 47 Metric Tons of CO2 Emissions Avoided (MTeCO2)
• Lessons Learned
• Lessons Learned
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Due to program duration, better communication is required to reach the campus community and to ensure plug loads, lights, etc. are disconnected.
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Since days of the week change between program years, metrics for weekdays and weekends must be created, evaluated and incorporated into the energy analysis.
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More coordination among facilities staff should occur to ensure that high energy-consuming equipment is scheduled properly. If equipment must be used during setback period, consider when the event occurs and determine most costeffective method of operation.
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A greater impact is expected if additional outreach to faculty and staff is presented, and additional opportunities may become apparent as Energy Management and BM&O work together to determine and implement detailed building schedules.
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Temperature and relative humidity play an important role in campus energy use, but it is expected that there is a greater impact on steam and chilled water production within the Central Utility Plants.
• Opportunities for 2011 -
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Spring Break, Saturday, March 5 through Sunday, March 13: Minimally consider unoccupied scheduling for the 9-day period. Set a stretch goal to shut down buildings during the first 7 days, and recover the buildings during the second weekend, setting the schedules to a typical weekend occupancy. Determine buildings that can be scheduled with more granularity and work with BM&O to set detailed schedules within these buildings. SAS Hall is currently a pilot building for detailed scheduling.
• Opportunities for 2011 -
Provide additional outreach to address faculty and staff concerns when expanding the Intersession Energy Savings Initiative to include additional days.
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Sub-meter energy consumption where possible and provide incentives for department or organization with the largest relative energy savings during the intersession period. 15