1Historically, the focus of the agricultural industry has been increasing profit through maximizing crop yield. Costs for energy and water are small compared to equipment and personnel, and are thus often overlooked. However, energy costs for irrigation are increasing and could be exacerbated with declining water levels in many Western states. This trend has motivated many farmers to explore sustainable irrigation water and energy management practices. Much of this new focus has been directed towards the adoption of new agricultural technologies with a misplaced assumption that technology alone will inherently bring all the benefits. On one hand, farms are going through a paradigm shift, and are turning into net electricity generators, and on the other, higher penetration of intermittent renewable sources into the electricity grid, require dynamic loads to help the grid balance its intrahour variability and short duration ramps. The agricultural industry could be restructured to utilize larger amounts of renewable energy such as wind and solar and provide a great deal of flexibility to the grid. As emerging producers of clean energy, farmers are required to learn and speak the complex language of the electricity grid in order to monetize their energy generation while making the renewable electricity grid more resilient and reliable. In this paper, we develop a foundational approach for understanding and connecting three important concepts that can help the agricultural industry during this critical transition period. Those three concepts are: (a) current and future needs of the electricity grid, (b) available electricity market mechanisms through which farms can provide services to the grid, and (c) understanding electricity consuming/generating equipment on farms. Defining these concepts and condensing them into a standardized framework, can remove a significant barrier for enabling farms to provide services to the electricity grid while improving their bottom line.
The ever increasing strain on traditional centralized power generation and distribution systems has led to an increase in the use of distributed generation (DG) technologies. DG technologies are commonly found in urban areas that are sensitive to criteria pollutants, and as a result, they are subject to increasingly stringent emission regulations. Paralleling the growth of installed DG is the ever-increasing interest in hydrogen as an alternative fuel to natural gas. As a hydrogen infrastructure is developed, a desire to use this new fuel for DG applications will evolve. Microturbine generators (MTGs) are one example of DG technology that has emerged in this paradigm and are the technology of interest in the present work. To evaluate the potential role for hydrogen fired MTGs in this paradigm, understanding of what emission levels can be expected from such a system is needed The current study retrofits a natural gas fired MTG for operation on hydrogen and characterizes the resulting operability and emissions performance. The results of implementing design changes to improve emissions performance while maintaining stability and safety of the MTG when operating on hydrogen fuel are presented. The results also show improved stability limits which are utilized to help attain lower emissions of NOx. Further optimization is needed to achieve the NOx levels necessary to meet current regulations.
The low swirl injector (LSI) is a combustion technology being developed for low-emissions fuel-flexible gas turbines. The basic LSI configuration consists of an annulus of swirl vanes centered on a non-swirled channel, both of which allow for the passage of premixed reactants. LSIs are typically designed by following a general guidance of achieving a swirl number between 0.4 and 0.55. This paper aims to develop a more specific guideline by investigating the effects of varying geometry, i.e. vane angle, vane shape, and center channel size, on the LSI performance. A well-studied LSI provides a baseline for this investigation. Nine LSI variations from this baseline design have been evaluated. All LSI are tested with CH4 fuel at bulk flow velocity of 8 to 20 m/s firing into the open atmosphere. Performance metrics are the lean blowoff limit, the pressure drop, flowfield characteristics and emissions. Results show that the lean blow-off limit and NOx and CO emissions are insensitive to LSI geometric variations. The flowfields of seven LSIs exhibit self-similarity implying their turndown ranges are similar. Reducing the center channel size and/or the use of thin vanes instead of thickened vanes can reduce pressure drop across the LSI. Additionally, all ten LSI share a common feature in that 70% to 80% the premixture flows through the vane annulus. These findings are used to develop a more specific engineering guidelines for designing the LSI for gas turbines.
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