The increased penetration of solar energy installations by residential and commercial property owners and large-scale solar energy developers could undermine the reliability, safety and quality of power supply on the electric grid for utilities that do not plan for it, according to a new Accenture study.
The study, based on a survey of 50 executives with 31 North American utility providers, found that 38% of respondents believe their electric grids will require an upgrade or face operational challenges with a solar PV penetration level of less than 15%. An additional 34% said their utility will face similar issues with a solar PV penetration of between 15% and 24%.
Distributed generation by residential and commercial property PV systems (51% of all installations) and developer-owned systems (15%) is already causing problems for a significant number of utilities, according to the survey. These include high costs to provide reactive power/voltage support (cited by 36% of the respondents), additional interconnection requirements (30%), and grid instability caused by anti-islanding requirements (18%).
In addition, the survey found that some functional areas in transmission and distribution operations will require an 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 PV, such as grid analytics (48%), PV systems control (44%), PV system management (32%) and commercial transactions (32%).
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, according to the survey.
The three main methods utilities expect to use are power factor control, where the power factor of PV systems output remains fixed or vary on a pre-determined basis (cited by 61%); automatic reactive power requirements, where PV systems are required to automatically provide real-time dynamic reactive power support to the grid (48%); and the active management of each PV system at all times (44%).
The most common model for solar PV ownership is customer-owned (51%), followed by utility-owned (34%) 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.
‘Solar power has great potential as a source of renewable energy as developers continue to innovate and reduce the cost of PV production,’ says David M. Rouls, managing director of Accenture's smart grid services. ‘However, the large-scale penetration of solar PVs will require smart grid planning and changes by utilities to realize its benefits.’
The company 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 road maps; and/or develop a comprehensive road map for utility transmission and distribution 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 of solar in the grid; and
– 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.