According to a new study by Accenture, the increased penetration of solar photovoltaic (PV) installations by residential and commercial property owners and large-scale solar energy developers in the US could undermine the reliability, safety and quality of power supply on the electric grid for utilities that do not plan for it.
“Solar power has great potential as a source of renewable energy as developers continue to innovate and reduce the cost of PV production,” says Accenture in its latest study on the solar sector in the US. However, the study, based on a survey of 50 executives with 31 North American utility providers, found that 38 percent of respondents believe their electric grids will require an upgrade or face operational challenges with a solar PV penetration level of less than 15 percent. An additional 34 percent said their utility will face similar issues with a solar PV penetration of between 15 and 24 percent.
Distributed generation by residential and commercial property PV systems (51 percent of all installations) and developer-owned systems (15%) are already causing problems for a significant number of utilities. These include high costs to provide reactive power/voltage support (cited by 36 percent of the respondents), additional interconnection requirements (30 percent), and grid instability caused by anti-islanding requirements (18 percent).
Some functional areas in transmission and distribution operations will also require upgrade in capability as a result of the increase in solar penetration. Many utilities are already performing some key functions that are needed to integrate high penetration of solar PVs, such as grid analytics (48 percent), PV systems control (44 percent), PV system management (32 percent) and commercial transactions (32 percent).
Accenture also found that utilities are more likely to use automated solutions than real-time manual intervention to mitigate and manage the negative impact of solar PV systems such as grid instability and power output fluctuations. The three main methods utilities expect to use are power factor control, reactive power requirements and active power management, where the power factor of PV systems output remains fixed or vary on a pre-determined basis (cited by 61 percent), automatic reactive power requirements, where PV systems are required to automatically provide real-time dynamic reactive power support to the grid (48 percent), and the active management of each PV system at all times (44 percent).
Accenture recommends that utilities take a number of actions to manage the impact of solar PV, take advantage of its growth and successfully integrate higher levels of solar PV production into their operations:
Proactively facilitate solar PV deployment and new ownership models by providing infrastructure, system and processes ; review existing roadmaps and/or develop a comprehensive roadmap for utility T&D infrastructure upgrades and smart grid implementation with a clear focus on the impacts of increased penetration of solar PV;
Accelerate smart grid initiatives in transmission and distribution to sustain high penetration solar in the grid;
Review the impacts and risks on the utility business processes and redesign the processes as needed for efficient integration and facilitation of solar PV in the utility system.
The most common model for solar PV ownership in the US is customer-owned (51 percent), followed by utility-owned (34 percent) and third-party or developer-owned (15%), where a non-utility company generates large amounts of solar energy and sells it either to a utility or on the wholesale market.
The “Achieving High Performance with Solar Photovoltaic Integration” study is based on a survey conducted by IDC Energy Insights of North American-based utilities that are either already seeing the impact of increased renewable energy additions or are planning to increase their exposure to renewables.
The quantitative survey was conducted online between March and June 2011 with 50 respondents from 31 utilities. In addition, 12 in-depth interviews were conducted. Investor-owned utilities (IOUs) made up 72 percent of the utilities in the sample, with the remainder consisting of cooperative utilities, authorities and municipal utilities.