OPERATING OPTIMISATION FOR A DIRECT-CONNECTED GREEN-ELECTRICITY HYDROGEN-AMMONIA PARK BASED ON MIXED-INTEGER AND CONTINUOUS LINEAR PROGRAMMING

This paper studies the operation optimisation of a direct-connected wind-photovoltaic hydrogen-ammonia park and evaluates how production flexibility, energy storage and islanded operation affect power balance, renewable-electricity indicators and operating cost. Some applications have been developed for full-load operation, discrete production scheduling, continuous power regulation, islanded dispatch, storage sizing and grid-connected comparison. The park has 40 MW of wind power, 64 MW of photovoltaic power, and hydrogen-ammonia loads for 36 t/d and 72 t/d production. At a 36 t/d full-load baseline, the self-consumption, green-electricity and export ratios are 28.16%, 69.21% and 35.92%, respectively; 54 t/d is the lowest-cost feasible output in discrete scheduling, and the unit cost is 4591.27 yuan/t. The total annual cost of continuous regulation is 1.9005 million yuan, and all three indicators have been achieved in 210 of the 360 weighted days. In islanded operation, 5000 MWh of storage increases the annual output to 25920 t, but the unit cost is still higher than that of grid-connected systems. Flexible production and storage increase the utilisation of renewable energy; however, economic feasibility requires integrated planning of production, storage and grid operation.