The efficient and clean energy utilization paradigm has proved to be a realistic and economical solution to reduce greenhouse gas emissions and increase the efficiency of the energy network. Recently, more projects have been focused on Distributed Energy Resources (DERs) including photovoltaic (PV) panel, combined heat and power (CHP), fuel-cell (FC), and energy storage systems, due to their capability to be utilized as local resources to reduce the power loss because of long-distance transmission. In this paper, we present a mathematical model to evaluate the operational and financial analysis on DERs such as CHP, PV systems, and thermal/electrical energy storage installed at the behind-the-meter (BTM) customers' premises considering both energy and ancillary services markets. The objective is to drive the financial and resiliency value of DERs and determine the key factors such as DER portfolios, and the pricing structures of electricity and natural gas distribution companies (EDCs and GDCs). We conclude that different types of energy tariffs will affect the financial aspect of DER projects. Also, findings emphasize the critical role of incentive programs for energy storage systems in increasing the resiliency of the power grid during blackouts.