Peer-to-Peer Energy Trading Among Electricity-Hydrogen DC Microgrids

This article presents the optimal operation of a community of “non-positive aggregate energy importing” DC microgrids in a local energy-sharing environment. DC microgrid community aims to minimize its social cost by participating in a day-ahead and peer-to-peer energy market, and local hydrogen market. Based on the price signals from the grid, the DC microgrids determine their power exchange with the grid and schedule its dispatchable sources (fuel cell and microturbine), renewable power generation (solar and wind), energy storage (battery energy storage system and hydrogen storage system), and flexible loads (electrolyzer, thermostatically-controlled load, and plug-in electric vehicle) in a privacy-preserving decentralized manner. Further, each DC microgrid has bidding price flexibility when participating in peer-to-peer transactions. Simulation studies are carried out on a community of three six-bus DC microgrid systems. Fixed-price peer-to-peer trading increases social welfare by <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\sim 74.23\%$</tex> compared to no peer-to-peer trading. Bidding price flexibility adds <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\sim 1.83\%$</tex> to social welfare, reduces renewable curtailment by <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\sim 2.58\%$</tex>, raises cumulative peer-to-peer transactions by <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\sim 13.42\%$</tex>, and lowers the average peer-to-peer price by <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\sim 30.47\%$</tex>. Increasing the DC microgrid's hydrogen storage system size further improves social welfare. Transitioning from no peer-to-peer trading to fixed and then flexible bidding price peer-to-peer trading increases DC microgrid energy diversion from the grid towards the DC microgrid cluster's self-sufficiency.