Related stories: Campus turns waste water vapor into heat for Tercero 3.

UC's annual sustainability report shows a savings of $91 million in energy costs systemwide since 2004.

By Dateline staff

With more than 100 energy-conservation projects completed since 2009, UC Davis tallied net savings of $4.63 million in energy costs and collected $7.65 million in PG&E rebates through 2012, according to preliminary data in a year-end report.

“Strategic Energy Progress,” produced by Administrative and Resource Management, does not take into account the steam plant’s new condensing economizer project, which officials estimate will save almost half-a-million dollars annually all by itself.

The report outlines UC Davis’ participation in UC’s Statewide Energy Partnership. It provides construction loans from the UC Office of the President, and rebates from Pacific Gas and Electric Co. and other investor-owned utilities, which are under mandate from the state Public Utilities Commission to improve energy efficiency at large institutions.

ARM’s “Strategic Energy Progress” describes the campus effort as a success that defies campus growth: Energy use declined from nearly 2.25 billion BTUs (British thermal unit, a measure of energy in fuel) in 2006 to less than 2 billion in 2011, even while new buildings added about 1.5 million square feet (gross) of space to heat and cool.

UC Davis projects include heating and cooling upgrades, lighting retrofits, and modernized monitoring and control systems. The rebates are based on natural gas and electricity savings — $1 per therm of gas, 24 cents per kilowatt-hour.

The campus uses 15-year debt with UCOP to finance the remaining costs, and officials said the annual debt service is less than the cost savings from the reduced energy use, so the program more than pays for itself.

Some examples:

• Briggs Hall — The heat recovery wheels are gone! Dating back to the construction of the 195,139-square-foot lab-research building in 1971, the wheels were designed to transfer heat between the exhaust and supply airstreams. Unfortunately, the wheels had not been functioning for many years.

“Additionally, having the stationary wheels in place put undue strain on the building’s air handlers, leading to high energy use and cost,” according to a project summary in ARM’s “Strategic Energy Progress” report.

In the first phase of work completed last November, the campus removed the heat wheels and rebalanced the air handling system. “This alone is saving the campus $350,000 per year in energy costs by decreasing drag on the air handling system and supplying only the necessary airflow, thus minimizing associated heating and cooling requirements.”

Phase 2 will include a new and improved heat recovery system to further increase heating and cooling efficiency.

Total project cost: $2.9 million, offset by a $1 million rebate, with a payback period of five years.

• Art Building — The heating and cooling system, in place since the building opened in 1966, had reached the end of its useful life — prompting the university to undertake a complete energy refit.

Out went the inefficient, single-speed system that ran 24 hours a day, seven days a week, 365 days a year, relying on old-school, pneumatic controls. In went a variable speed system with premium efficiency motors, along with electronic controls that can be monitored and adjusted remotely (allowing for less cooling or less heat at times when the building is not occupied).

The project is saving 303,137 kilowatt-hours of electricity and 94,505 therms of natural gas annually, worth a total of $88,000.

Total project cost: $288,000, offset by a $167,000 rebate, with a payback period of 1.4 years.

•••

Statewide Energy Partnership at UC Davis, 2009-12 (statistics do not reflect the condensing economizer project):

• Projects completed — 110 in more than 65 buildings, in addition to numerous campuswide system improvements, including exterior and interior lighting, personal computer power management, and chilled-water and well pump system improvements.

• Rebates — $7.65 million.

• Net cost savings — $4.63 million in purchased utilities, while also reducing greenhouse gas emissions, and maintaining or improving comfort levels for building occupants. Savings take into account debt service of $1.66 million.

• Electricity savings — 27.0 million kilowatt hours in 2012 (projected), and 52.4 million kWh cumulative since 2009 (projected).

• Gas savings — 1.76 million therms in 2012 (projected), and 3.8 million therms cumulative since 2009 (projected).

Note: The 2012 electricity and gas savings are compounded from 2009, with each year’s new savings added to the next year’s new savings.