- Durham County Buildings
The imperfect data set or unavailable data made it difficult to compare performances between fiscal years. Therefore, our analysis heavily relies on Energy Use Intensity (EUI), which is calculated by BTU per square footage. Further analysis was not possible due to the lack of specific information on buildings such as each building upgrade project, different usage, and the number of employees. As Figure 2 shows, building EUI been decreasing since peaking in 2007. The reason why EUI is low in fiscal year 2010 is presumably because natural gas usage data of some buildings such as General Services Complex building is missing. Natural gas use is high in energy intensity and that is a possible explanation for the low value.
The analysis examined building energy usage by sector: Administrative Offices, Emergency Medical Services, Recreation, Community centers and offices, Libraries, Detention Facilities, Judicial buildings, Police, and Other facilities. Figure 3 demonstrates the average Durham County building energy intensity from FY 2006 to 2012. A specific list of buildings in each category is stated in Appendix 1. Overall, the administrative buildings (22.2%), libraries (18.3%), and detention facilities (13%) have high energy use intensity.
- Durham County Government Performance Contract
Durham County Government outsourced several energy upgrade projects in seven buildings. Lighting upgrades, water retrofits, Roof Top Unit Replacements, and HVAC controls were the major projects conducted. The projects specifically include lighting retrofits from T12 to T8K, LED exit signs, new Air Handling Units at Operation Breakthrough, building controls at all the buildings, and the Durham County Detention Facility upgrades such as water saving toilets, new chiller and boiler installation, and new air handling units.
The interim report by a company, Trane estimated energy saving up to $200,000 for the period of July 2012 to mid-November, 2013 (Trane US, Inc., 2013). The energy and water savings were measured using three different methods, which are the Point Source Partially Measured Retrofit Isolation method (lighting upgrades, water retrofits, and roof top unit replacements), the Point Source Measured Retrofit Isolation method (HVAC controls), and the Continuous Metering method (All EMCs in the Detention center). As seen Figure 4, the estimated energy savings by lighting upgrades was $4,979 from September 27, 2012 through December 31, 2013. This accounts for 2.25% of the total saving. The estimated savings of HVAC controls accounts for 2.95% of the total saving ($6,547). Water upgrades was estimated to save $23,159, which is equivalent to 2.16 billion gallons of water. This accounts about 10% of the total. For the detention center upgrades, it has been continuously metered. The estimated saving is the highest, $186,882 from January, 2012 through October, 2013. This saving was calculated by total utility dollars based on historic utility bill patterns and corrected for the contracted rate (Trane US, Inc., 2013).
 In this section, our analysis is mainly based on fiscal year (FY). For example, as for FY 2010, it starts from July 2009 to June 2010. If not indicated with FY, then it goes with regular year which is from January to December.