The Role of Small Distributed Natural Gas Fuel Cell Technologies in the Smart Energy Grid

As the utility grid evolves to transmit information along with energy and water to the end-user, the traditional grid model is changing. The Pecan Street Smart Grid Demonstration Project in Austin, TX is at the leading edge of the evolution of the smart grid. Currently, over 100 homes, soon to be 1,000, have electricity demand information being measured on a 15 second interval. Using the highly granular energy use and solar generation data from Pecan Street, we attempt to estimate the potential for small natural gas fuel cells as distributed firming power for intermittent renewables in the built environment. Micro-grids have traditionally relied on the macro-grid for stabilization in the event of local interruptions in generation. In this paper we analyze the utility, economic, and system efficiency impacts of small distributed natural gas fuel cells as an alternative to the macro-grid for stabilization. Using our unique dataset, we have determined that the average home could utilize a 5.5 kW fuel cell either for total generation or backup, and the average home could operate as its own micro-grid while not sacrificing core functionality. We also explore the utility of matching the thermal output of a possibly smaller fuel cell, used in combined heat and power mode (CHP), to an absorption refrigeration system in place of traditional space cooling. With these types of energy assets, homes could possibly participate with local electricity markets, or the grid at large, in a highly dynamic way. A home energy network could, given homeowner set-points, adjust home uses of energy and sell high priced electricity back to the grid, possibly from both solar PV and fuel cell production, possibly eliminating energy bills. Lastly, we estimate that the system efficiency could possibly double by transporting natural gas to the end user to be converted into electricity and hot water as compared with traditional methods of using natural gas for power generation followed by electricity delivery.Copyright © 2012 by ASME