Utilities need to understand how solar generating technologies will behave on their systems (transmission and distribution) as well as how a higher penetration of solar will impact their business operations. Additionally, the availability of and access to transmission and better development and use of market solutions affects the ability of the solar industry to continue to grow.


Portfolio assessments are a direct measure of a utility system’s metrics of costs and cost variability of the generating plants. Integrating solar into a utility portfolio is examined by evaluating the potential additional value of PV and CSP (including thermal storage) resulting from their addition to traditional fossil generation portfolios. The expected benefits are reducing cost variance and hedging prices. Risk-based portfolio and related Monte Carlo analysis will be carried out using production costing and related models to generate a number of cost distributions for different penetration levels that reflect various uncertainties. We will evaluate the economic utility of these cost distributions (including positive skewness effects towards higher costs) to quantify variance and other risk-related benefits arising from such narrowing effects. Sandia will identify tools developed in this task that are useful in future portfolio analyses such as Integrated Resource Plans (IRP) with large amounts of solar generation. This type of portfolio analysis will aid the utility and commission decision making processes for future investments. Results of a portfolio analysis is expected in the Fall of 2012.


Providing new, independent and objective technical information is an important Sandia role. By making R&D results known to targeted audiences, whether through direct technical assistance or broader communications such as a workshop, developers and operators receive assistance in their technology and development choices. In this way Sandia leverages its R&D program results.

A workshop with a focus on PV grid integration and variability issues for the developer/operator stakeholder community is planned in FY12. The goal is to identify methods to ease PV system installations, including those at high grid penetration, eliminating inappropriate barriers and reducing transactional costs.

Working with industry, the focus will be on existing and emerging standards, rules, and procedures that affect solar deployment in distribution systems. Disseminating technical information to a broad community of stakeholders will appropriately describe the evolution of PV system technology, analysis tools and techniques, and utility planning and operations practices to allow for successful deployment of PV systems in high-penetration scenarios. Results of analysis of distribution-connected PV systems will demonstrate the penetration levels that can be achieved. Documented technical characteristics and operational experiences will be reported, including

  • clearly explaining utility information needs, processes, and procedures for PV systems connected to the grid to the PV industry;
  • identifying how streamlined interconnection procedures can benefit both the PV industry and utilities;
  • providing information to developers on how high penetration of PV will affect the utility system, its design or modification, and its operation;
  • communicating research results on updated procedures for interconnection of PV on distribution feeders, and also cover transmission interconnection procedures;
  • providing the latest on PV interconnection regulations from around the country;
  • coordinating other specific topics with DOE and NREL and industry stakeholders;
  • publishing records of a moderated discussion will document issues and prioritize action items for industry support or topical assistance; and
  • preparing Web-based presentations or video for specific dissemination as appropriate.


Utility-Scale Grid-Tied PV Inverter Reliability Workshop Summary Report

PV System Modeling for Grid Planning Studies