Confronted with the growing pressure of carbon emissions abatement, electricity consumers are undergoing a mix of low-carbon policies, such as indirect carbon emission charge and renewable portfolio standard (RPS). However, there exists an open question as to how to accurately calculate the real-time indirect carbon emissions and fulfill the electricity and low-carbon requirements of consumers, considering the parallel and heterogeneous market trading mechanism. In this article, the optimal electricity consumption strategy of consumers is formulated as a trilevel model. In the first level, the consumer's total cost is optimized to satisfy energy and RPS requirements. In the second level, the day-ahead market clearing is simulated, and locational marginal prices are updated. In the third level, the dynamic carbon emission intensity is updated through the proposed improved carbon emission flow tracing method to reflect real-time indirect carbon emission fluctuation. Case studies demonstrate that the proposed model can incentivize consumers to purchase green electricity and achieve RPS goals without significantly affecting the total electricity consumption cost, thereby providing consumers with low-carbon decision-making reference.