Nowadays, enabled by current smart grid technology, electricity consumers can play an active role in providing Ancillary Service (AS) as a type of Demand Response (DR). Participating AS can assist stabilizing the power grid by following the Frequency Regulation Signal, or RegD signal in this study whilst receiving economic benefits. Industrial loads are an indispensable component as a demand-side regulating resource of ancillary service due to their intensive electricity consumption. In this paper, we use grid-connected solar Photovoltaics (PV) panels combined with Energy Storage System (ESS) to produce continuous electricity consumption signals in order to follow the RegD signal. The participation of solar energy in real-time regulation provision process is emphasized, which is modeled based on a variety of operation modes in accordance to Australian Standard. Through a particular case study, with the integration of solar energy the proposed method poses cost-effectiveness in industrial plant scheduling and a favorable load following capability, helping ensure the frequency stability of the electric grid. The proposed methodology is more economically advantageous compared to identical industrial loads only equipped with onsite ESS, and requires less switchings on machines compared to industrial plants with passive use of solar energy.