Power Purchase Agreements The City of Santa Marias
- Slides: 9
Power Purchase Agreements The City of Santa Maria’s Experience October 23, 2012
City of Santa Maria Statistics Northern Santa Barbara County. l Disadvantaged community of 100, 000. l Largely agricultural. l Secondary trickling filter treatment with anaerobic digesters, percolation ponds, sludge drying beds. l Design 13. 5 MGD Currently 8. 5 MGD. l Creative solutions to maintain affordability. l
History 2004 - US Energy signed agreement with City for use of digester gas. l 2006 – Installation and start-up of four Ingersoll Rand microturbines completed. l 2007 -2008 – System unreliable. Microturbines did not start up to handle varying demand. l 2008 – Microturbines replaced with 300 k. W engine. US Energy cost ~$170, 000 l
History (continued) 2008 -2010 – Engine success variable. l 2011 – CHP Clean Energy takes over system. l 2012 – CHP rehabilitates engine and makes other improvements. Estimated cost ~$250, 000. Starts back up July 2012. l
2012 Improvements Rebuilt engine. l Upsized exhaust manifold. l Replaced chiller. l Replaced control system. l Upsized hot water delivery system. l New air-fuel ratio sensors. l New blower, cooler pumps and intercooler. l
Elements of PPA Agreement We provide them gas. l We buy their power at 8. 7 cents per k. Wh. l They pay Departing Load Nonbypassable charges. l They need to run cogen in “efficient and effective manner. ” l Term of contract is 10 years, with buyout provisions. l
How’s it working out? Engine still experiences regular outages during partial peak and peak times. l Departing load charges “unanticipated” by CHP. Currently working on waiver. l Very low APCD emissions limits means high potential for lean fuel misfires. l
Is it paying off? Since July 2012, Cogen facility has cost more than if on PG&E alone. l 100% PG&E: $24, 100 l 100% Cogen: $16, 100 l Currently: l l PG&E: $8, 300 demand, $7, 900 use. l Cogen: $8, 000 l Total: $24, 200
What would we do differently? l Performance standards! l Uptime criteria. l Demand charge responsibility. Third party expert review of the design. l Cost evaluation prior to agreement. l Realistic expectations. l