Search

Many facilities are being considered for the installation of solar PV systems, which are an essential part of any clean energy microgrid. However, the solar resource is variable and intermittent, requiring other sources of generation, or energy storage, for a complete and resilient design. This paper presents the results of a 1MW solar PV microgrid model located at a large Michigan, USA commercial facility. The simulated annual PV output is connected to the customer side of the power meter, and the cost savings is analyzed against a large commercial, time-of-day electrical billing rate. A popular solar PV simulation software tool is used to model the hourly PV output against the customer electrical interval data for one year, in order to present both operational cost savings and performance of: 1) an upsized solar DC array, "30% oversized DC array", 2) the addition of an 8MWh LiION battery, and 3) the addition of a 1 MW natural gas generator. Working with real pricing provided by engine generator and battery OEM quotations, the capital cost, fuel usage, maintenance, 20-year lifecycle cost and carbon savings will be compared for all variations needed to produce a firm 8-hours of "on-peak" power from the base 1 MW of solar PV. The results will demonstrate the value and potential of hybrid microgrid systems, as well as the limitations of large LiION batteries as compared to a natural gas generator. [ABSTRACT FROM AUTHOR]

There is a compelling body of evidence calling for a reduction in the amount of carbon dioxide (CO2) that mankind is emitting into the atmosphere. A segment of climate science community contends that we will be required to actively “reduce” the magnitude of our atmospheric CO2 content, not merely reduce mankind’s contribution to the increase. Five methods of CO2 mitigation are briefly mentioned, followed by the description of a sixth, innovative method of using chemical or adsorption scrubbing techniques to remove indoor air CO2 from building HVAC systems for the purpose of reducing the required outdoor air (OA) ventilation to provide energy and CO2 reductions. The reduced OA ventilation will correspond to a reduced source energy consumption while simultaneously scrubbing other indoor air contaminants, improving indoor air quality (IAQ). A building HVAC energy model is presented in which an indoor air CO2 scrubbing technology is incorporated. Although the scrubbed indoor CO2 is merely vented and released into outdoor air, the resulting reduction in source fossil fuel energy related CO2 emissions is calculated for the analysis of the net CO2 reduction potential. An eQuest building model is utilized for three different locations in the USA (Atlanta, Detroit, and Los Angeles) and the 2016 USEPA eGrid database is used to calculate the local electric powerplant source CO2 emissions. The results indicate that regions in the United States with both high HVAC loads for heating and/or cooling coupled to a carbon intense local electric supply will benefit the most by utilizing the proposed HVAC / CO2 mitigation system. Of the three sample areas, Detroit had the highest CO2 source emissions saving potential from this application at 66,560 lb/yr (30,255 kg/yr) followed by Atlanta with 46,149 lb/yr (20,977 kg/yr). The mild southern California weather coupled with the less carbon intense electric grid only produced 2,340 lb/yr (1,064 kg/yr) source CO2 reductions. The addition of other energy conservation measures or site renewable energy generation would obviously increase these source carbon reductions. If the human occupant respiration CO2 were captured and permanently sequestered from this same office building’s indoor air, 55,600 lb/yr (25,300 kg/yr) would be sequestered. Ultimately, the hypothesis of this paper is that a more lucrative market for these emerging CO2 scrubbing techniques may first find a beneficial use in the HVAC product and/or energy efficiency space. This application may create a viable business model in which these technologies are deployed, tested and refined as profitable HVAC products, and then hopefully deployed in future years for direct atmospheric CO2 mitigation. Further study of this concept seems warranted, and the author invites future discussion and critical review of this papers concepts and conclusions. [ABSTRACT FROM AUTHOR]