The Full Cost of Electricity (FCe-)

Under state Renewable Portfolio Standards (RPS), the state is usually obligated to produce a fraction of its electric power generation from renewable energy sources. Currently, solar energy is second only to wind in its contribution to renewable electric power generation. The International Energy Agency (IEA) estimates that by 2050, solar photovoltaic (PV) power generation will contribute to 16% of the world’s electricity, with 20% of the total PV capacity from residential installations. Residential PV allows power to be locally generated, and thereby reducing the need for power transmission from large generating stations. However, largescale PV generation at the distribution level causes more grid concern, since the grid is designed for unidirectional power flow to serve loads downstream from the distribution-level substation. Given the above motivation, the study aims to estimate the cost of maximizing PV capacity that can be integrated in a distribution grid, without any grid impacts. The study is organized into three PV accommodation limits. In the first part, the concept of Range-1 PV hosting capacity is introduced. Range-1 capacity is the largest PV generation that a distribution circuit can accommodate without making operational changes to the circuit or upgrading the infrastructure. In the second part, Range-2 PV hosting capacity is presented. It is the PV generation capacity that the distribution circuit can accommodate when few operational changes are allowed in the equipment already installed in the power distribution circuit. Note that accommodating up to Range-1 and Range-2 PV capacities does not require any integration costs, except for some minimal cost associated with the operational changes in the existing devices. Finally, the hosting capacity of the given circuit is increased beyond Range-1 and 2 capacities with the help of additional infrastructure upgrades such as smart inverters and energy storage. The corresponding increased hosting capacity is referred to as the Range-3 hosting capacity. The study utilizes three representative utility distribution circuits provided by Electric Power Research Institute (EPRI). It is shown that a significant amount of Range 1 PV capacity can be integrated into the circuit without requiring any equipment upgrades or operational changes. Depending on the circuit characteristics, Range 1 capacities can be as low as 15.5% (i.e., 2600 kW in one particular circuit) or over 100% (i.e., 3870 kW in another circuit) of the median value of the daytime (between 7am and 7 pm) peak load demand. Factors limiting Range 1 capacities involve overvoltage at the secondary service wire and reverse power flow conditions. Yet, these results suggest a relatively substantial amount of rooftop PV can be integrated without causing any adverse grid impacts and without incurring any grid integration cost. Suma Jothibasu, Anamika Dubey and Surya Santoso Department of Electrical and Computer Engineering Jothibasu, Suma, Dubey, Anamika, and Santoso, Surya, “Cost of Integrating Distributed Photovoltaic Generation to the Utility Distribution Circuits,” White Paper UTEI/2016-01-1, 2016, available at http://energy.utexas.edu/the-full-cost-of-electricity-fce/.