To address the coordinated operation of renewable generation, load, and storage in zero-carbon parks, this paper proposes a source–load–storage (SLS) coordinated multi-resource optimization method. First, a parallel forecasting model combining partial least squares regression (PLSR) and ModernTCN, denoted PLSR-Modern TCN, is developed. PLSR extracts an eight-dimensional latent representation from each lagged-load window, while ModernTCN independently captures nonlinear temporal dependencies from the original one-channel sequence. The two representations are aligned by sample index, concatenated, and mapped to the one-day-ahead forecasting horizon. The model achieves an R² of 0.987, outperforming traditional TCN, convolutional neural network (CNN), random forest, and linear regression models. Based on the forecasts, a multi-objective SLS optimization model is established by considering time-of-use electricity prices, supply–demand balance, renewable curtailment, operation cost, carbon emissions, energy storage operation, PCC voltage, and equivalent harmonic power. The entropy weight method determines the objective weights, and an improved genetic algorithm (IGA) solves the optimization model. Simulation results show that IGA achieves the lowest mean comprehensive fitness and the smallest repeated-run variation among the compared algorithms. In the illustrative scheduling result, IGA provides a modest energy-related operating-cost reduction of approximately 0.11–0.13% and a carbon-emission reduction of approximately 2.2–4.5%.