Study on Economy and Carbon Emission Optimization of DC micro-Grid

Aiming at the problem of carbon emission in the operation of photovoltaic - wind power - energy storage DC Micro-grid, this paper establishes a bi-level programming model of DC Micro-grid based on comprehensive consideration of carbon emission cost, environmental benefits of renewable energy, system operation and maintenance cost, equipment depreciation cost, interaction cost between Micro-grid and upper grid, and time-of-use price. The upper model aims to maximize the net economic benefits of DC Micro-grid charging and discharging, and optimize the energy storage operation strategy. The lower model takes the minimum carbon emission of DC Micro-grid as the goal to maximize the utilization of new energy and carry out bi-level optimization. Aiming at the conflict problem between economic optimization objectives and carbon flow optimization objectives under the economic constraints and carbon flow constraints of DC Micro-grid, based on the analysis of carbon flow calculation, the fuzzy algorithm is used to transform the multi-objective problem into a single-objective optimization problem, and then the improved genetic algorithm (GA) is used to solve it. Finally, a case study is carried out for a practical photovoltaic - wind power - energy storage DC Micro-grid system in the southern region. The analysis results show that the multi-objective fuzzy optimization model can achieve a larger carbon reduction target with less economic tolerance, which verifies the rationality of the proposed model and algorithm.