Lessons Learned from Using Building Energy Intensity to Guide Climate Action Planning Efforts at Foothill College
by Robert Cormia, Faculty, Informatics and Nanotechnology, and Brenda Davis Visas, Director of Facilities, Foothill College
Foothill College’s ten-point climate action plan addresses both energy and GHG emissions by focusing on a key figure of merit, Building Energy Intensity (BEI), which helps inform data-driven decisions for building retrofits and onsite PV (solar) energy infrastructure, and helps us plan future energy budgets and manage our GHG emissions. Building energy, expressed in annual BTU/sq-ft, is the established reporting mechanism for California Community Colleges and provides both a baseline and benchmarking mechanism for evaluating the effectiveness of energy projects, as well as a means of comparison to similar colleges in similar regions.
In developing our GHG inventory and Climate Action Plan (CAP), Foothill was fortunate in having energy records dating back to 1991, allowing us to use actual KwHrs, therms, energy cost, building footprint (assigned square feet), BTU (from KwHrs and therms), and FTES (Full Time Equivalent Students) to calculate and construct trend lines for a number of key metrics. Our data suggested that energy use follows building footprint - in our case a 50% increase in assigned sqaure footage from the construction of new buildings - with little or no correlation with FTES. Our 1991 building energy intensity (BEI) of 100,000 BTU/sq-ft per year became a key figure of merit which informed and directed our energy projects. Energy Management System (EMS) and Building Automation Controls (BMS) systems, installed in the late 1990s, reduced peak BEI by almost 25%. To reach our 1991 100,000 BTU benchmark, Foothill will add significant additional onsite solar PV, shaving our gross electrical use to near 1991 levels. By monitoring and modeling our natural gas for heating and cogeneration of electricity, we anticipate reaching 100,000 BTU/sq-ft BEI in 2015, with GHG emissions (pounds per assigned square foot) at or below our 1991 levels, in line with our climate targets.
In the remainder of this article we’ll describe the details of how our use of instructional data informed both tactical and strategic decisions for energy efficiency projects, including the modeling of future onsite solar PV purchases and campus-wide smart energy metering and management controls. We’ll finish with lessons learned, an encapsulation of our strategy to protect future energy budgets ($s) and meet our community pledges of significant energy and GHG emission reduction.
Our story begins in 1991, when our Director of Facilities (and District Board) made a decision to understand energy through parametric models, starting first with gross electricity and gas, and expanding to electricity used for lighting, ventilation, and appliances, independent of energy for air conditioning, now handled by a central chiller plant. Our natural gas use is separated into heating of buildings and cogeneration of electricity, the latter heats our swimming pools. We call these our ‘four quadrants of energy’, which are integral to our smart energy projects and purchases of additional onsite solar PV. Our goal is to separately meter all buildings and implement advanced energy and electrical efficiency projects, using the results of these pilot projects to inform and guide follow-on work. To protect the power grid from growing HVAC loads (future heat storms), as well as fixed energy budgets not accustomed to time-of-use metering and dynamic spot pricing of electricity, we will combine additional onsite solar and equip our EMS/BMS with the ability to pre-chill rooms, adjust thermostats, and respond to demand response and price signals to smart energy meters.
Modeling of energy use is the key to a successful climate and energy strategy, which is why having precise knowledge about ‘four quadrants’ of energy use, and how individual buildings perform against your aggregate BEI (BTU/sq-ft), is essential. This was how we projected meeting our energy targets.
- Keep all your old utility bills. Dig them out of boxes if needed, and build spreadsheets that include KwHrs, therms, FTES, and building footprint. Calculate BTU/sq-ft, develop a baseline, and benchmark against published data. Make sure to compare your data against similar institutions (scope) and regions (climate).
- Develop an understanding of your energy use – we recommend the ‘quadrants’ of electricity for lighting and HVAC, and natural gas for heating buildings and swimming pools. If you have cogen electricity and a use for your waste heat, the story is a little trickier, but ideally you are getting free electricity while heating your pool, or free heat while making electricity. Consider addition of solar PV to cover 100% of your peak AC load, saving you paying the utility peak KwHr pricing.
- Use your BTU/sq-ft to answer two questions. First, do your energy numbers indicate you are not operating within expected ranges for your type of building and additional energy efficiency efforts are needed? If you don’t have an EMS/BMS, you need to get one, and make sure you (eventually) have separate meters on buildings to tell you when one is ‘out of range’, and requires re-commissioning. Second, if you have significant AC load, consider the capital cost to purchase enough onsite solar to reduce that energy load to zero. You’ll need to develop models of electrical pricing and factor rebates and other incentives.
- Conduct extensive electrical efficiency audits – especially older motors, fans, and anything which draws inductive electrical load. Investigate IDLT (load banks) to significantly reduce the current on motors, and replace older HVAC with newer design – you’ll save a fortune in no time!
- Technology alone won’t get you your last 20% of efficiency; remind people that lights and doors don’t turn off and close on their own, that someone pays these bills. Ensure that classroom scheduling is done in such a way as to maximize the assets, infrastructure, and energy you use.
- Never use the phrase ‘value engineering’ with a straight face. Someone decades from now will be saddled with poor building decisions and scrimping that was shortsighted - the cost of energy will never go down. Our building design and construction decisions should follow our sustainability principles - who will inherit these buildings seven generations from now? Foothill College invested in LEED building design and energy efficiency measures even when we thought we couldn’t afford it, because someday we’ll have to.
The reality of climate action plans is that you can’t (really) manage your GHG emissions, you can only manage energy and the intelligent use of capital to invest in efficiency and onsite generation projects. Having a baseline to manage your progress is like going on an energy diet – and using a BEI metric allows your facilities managers to know they are doing well in the context of ‘the broader built environment’.
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