Renewables Integration

The increasing penetration of renewables on the grid has raised concerns about grid reliability and safety for electric utilities. These concerns focus on three primary scenarios: distribution grids with high concentrations of solar PV, large wind or solar farms connected directly to the transmission grid, and hybrid micro-grids incorporating a combination of fossil fuel and renewable electricity generation in a small geographic area. In all three scenarios, the unpredictable variability of wind and solar resources creates a need for new technologies and business processes that mitigate the impact of that variability on electricity costs. Jay Holman, Principal of VtM, has conducted market research in all of these areas and is well positioned to help companies understand utility concerns and requirements for technologies developed to address these challenges.

VtM Project Example

Market Opportunity Assessment for Hybrid Micro-Grids

Working as a subcontractor to a leading software and services provider to the micro-grid industry, assessed the market opportunity for a project developer expanding its footprint in the growing hybrid micro-grid market. Determined the relative attractiveness of island countries for hybrid micro-grid development, covering select countries in Southeast Asia, Oceania, and the Indian Ocean.

Case Studies on Lessons Learned from the Deployment of Smart Inverters

The variability of grid connected renewable resources such as solar and wind can cause power quality, stability, and reliability problems for grid operators. The inverters used to connect PV and battery energy storage systems to the grid have the ability to provide reactive power, voltage support, low voltage ride through, and other functions that mitigate the negative impacts of variable renewables on the grid. VtM was contracted by a major US research institute to develop case studies on the lessons learned from the use of smart inverters to provide grid support in projects around the world. 

Published Articles and Reports on Renewables Integration

Case Studies Evaluating Energy Storage as an Effective Grid Integration Tool: Selected Worldwide Results, Findings, and Lessons Learned

Published by EPRI in December 2014

Author: Jay Holman

Electrical energy storage project activities are proliferating worldwide given increased public and private sector investment in both stand-alone and larger smart grid projects. Moreover, policy initiatives are helping to spur market development. Among the applications generating the most interest and investigative effort are those surrounding solar photovoltaic (PV) integration. With rising PV grid penetration rates, efforts are redoubling to explore the role that energy storage can play in supporting the solar resource’s growth while maintaining the stability and reliability of the electricity network.

To promote information sharing and collective learning, this report documents a handful of active electrical energy storage projects, in various phases of development and evaluation, that are assessing solar PV integration applications. It represents the latest iteration of an ongoing Electric Power Research Institute (EPRI) effort, begun in 2010, to catalog commercial and demonstration energy storage projects. Building on four previous EPRI reports, this document provides additional descriptive case studies on five energy storage projects located around the globe, offering insight into their background, status, results and findings, and lessons learned.

Distributed Energy Resource Management System Case Studies

Published by EPRI in November 2014

Author: Jay Holman

As distributed energy resources (DERs) such as solar photovoltaic (PV) and energy storage are added to the electric grid in increasing numbers, the need for utilities to track, monitor, and control those resources increases. The systems utilities use to track, monitor, and control DER are broadly referred to as Distributed Energy Resource Management Systems, or DERMS.

Utility adoption of DERMS is still very limited, and utilities around the world are carrying out projects and field trials that will help them make informed decisions about whether, when, and how to deploy DERMS in their own networks. Key areas of focus in these projects include defining the costs and benefits of DERMS deployments, deciding where to host DERMS in order to take full advantage of DER capabilities (including the economic services offered by energy storage systems), and developing control algorithms that optimize DER operations, among others.

This report includes eleven case studies that provide specific examples of how utilities are either using DERMS in their daily operations, or testing DERMS capabilities through projects and field trials. Findings from the case studies are summarized to provide an overview of the current status of DERMS deployments, drivers of future growth in the segment, and trends in recent deployments.

Grid Codes for Interconnection of Inverter-Based Distributed Energy Resources by Country: Recent Trends and Developments

Published by EPRI in November 2014

Author: Jay Holman

This report outlines the latest developments in local, regional, and national grid codes that define interconnection requirements for distributed photovoltaic systems and battery energy storage systems. The term grid codes refers to the set of rules and regulations that utilities, installers, and project developers must follow when connecting inverter-based distributed generation to the grid, and that relate to the electrical behavior of inverters. Specifically, this report focuses on a set of inverter parameters that directly impact grid stability, reliability, and safety, including voltage limits, voltage regulation, frequency limits, frequency regulation, anti-islanding behavior, reactive power settings, real power ramp rates, and remote control of inverters by local utilities.

Brief descriptions of these requirements are provided for 11 countries and the European Union, as are the sources of the requirements, whether they be laws, technical standards, or distribution utility rules. Countries covered include the United States, Germany, Italy, France, Spain, United Kingdom, Belgium, Czech Republic, Greece, Australia, and India. The goal of these descriptions is to provide general insight into the grid codes of various countries where a significant amount of solar photovoltaic has been installed, including summaries of recent developments and potential upcoming changes to interconnection requirements.

Smart Inverter Field Experiences: A State of the Industry Overview

Published by EPRI in December 2013

Author: Jay Holman

The inverters that connect solar photovoltaic, battery, and other distributed resources to the power grid have the potential to provide a number of services or functions that may be useful to utilities. Inverter manufacturers have been designing and implementing these capabilities into their products for many years. During the past few years, significant industry effort has been expended in the identification of a common set of such functions that may be supported by open standards and implemented in many different types, sizes, and brands of inverters.

As these smart inverter capabilities have become available, many utilities have been experimenting with devices in the field in limited or widespread deployments.

This report provides a summary of these activities worldwide. It identifies the specific grid-supportive functions used in each case and investigates the outcome, including benefits observed and any unintended side effects noted.

Perspective: High-Penetration PV — Challenges and Research Initiatives

Published by IDC in February 2012

Author: Jay Holman

This IDC Energy Insights report provides a snapshot of where the solar industry is today with respect to issues related to the industry's rapid growth in North America creating localized areas with a high penetration of solar photovoltaic (PV) installations. The electric grid was designed to carry electricity from centralized power plants to distributed loads, and the introduction of distributed, intermittent, and unpredictable generation sources introduces new challenges for utilities as they strive to maintain grid stability and reliability.

Business Strategy: Optimizing Transmission for Wind Integration

Published by IDC in June 2010

Author: Jay Holman

This IDC Energy Insights report examines the role of key electricity transmission technologies in enabling the rapid growth of the U.S. wind energy market. The report describes the impact of current transmission constraints on existing and planned wind farms and the challenges encountered when new transmission lines are proposed. An overview of the transmission technologies that offer solutions to these challenges is supported by examples and an analysis of the strengths and weaknesses of each approach.