The Benefits of Propane Generators for Hybrid Microgrids

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A new white paper from the Propane Education and Research Council presents two case studies illustrating the benefits of using propane generators in hybrid microgrids.

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Get the full report.

Today’s microgrids typically consist of a solar photovoltaic (PV) system, battery storage and a backup generator or backup fuel cell system. The backup generator or fuel cell system, run on hydrogen, natural gas, propane, diesel, gasoline or other fuel sources, provides resilience for the microgrid. According to the paper, propane is a superior low-carbon fuel choice, especially compared to diesel. Propane engines are rich burn engines, and “emissions control is typically achieved using a three-way catalyst, which results in very low nitrogen oxide (NOx) emissions compared to diesel engines.” The author, Gokul Vishwanathan, also notes that propane is a low-carbon alkane, and “it produces less particulate matter or soot than diesel.” Plus, propane engines can operate at “diesel-like efficiencies.” Vishwanathan asserts that propane can help achieve emissions goals without any additional costs to the customer.

The paper provides three examples of how propane generators are currently being used. First, it reviews a system in a developing rural neighborhood near Burns, Oregon. The homes will all be powered with off-grid microgrids that include solar PV, energy battery storage and propane generators. According to the report, “it is estimated that the propane generator will be used for 10% of the time and will provide the necessary resiliency when the state of charge of the battery is low.” The paper discusses other similar applications in the Sierra Nevada mountains and Honolulu, Hawaii.

In the white paper’s first case study, the author presents the use of propane generators in light commercial applications, specifically community housing. The community, located in San Diego, California, has a load of 200 kWh/day. A microgrid with a generic diesel backup generator is compared to an off-the-shelf propane generator, a combined heat and power engine generator and a propane solid oxide fuel cell. The results of this case study are provided in a number of informative charts comparing the performance and environmental impact of each type of generator.

 “In terms of commonly used fuels, propane or liquefied petroleum gas (LPG) falls in a sweet spot between hydrogen, at one end of the spectrum, and gasoline and diesel, at the other end of the spectrum.” — Propane Education & Research Council, “The Opportunity for Propane in Microgrids”

In the second case study, the paper discusses the economics and environmental findings of performing similar tests on a large commercial microgrid system with a daily load of 2,500 kWh.

According to the paper, “propane is competitive to diesel for microgrid applications requiring resiliency when employing the “right” generator.” The author acknowledges that capital costs may be higher, but lower maintenance costs and the durability of propane generators with diesel-like efficiencies provide a comparable levelized cost of electricity.

Download the full report, “The Opportunity for Propane in Microgrids,” to learn more about how propane generators can be used to provide resiliency for microgrids and reduce emissions. 

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