Coursebook for Advancing Caribbean Energy Resilience Workshop, May 2019

As part of the U.S. Department of Energy’s Energy Transitions Initiative, this guide served as a module-based coursebook on microgrid design for the May 2019 ‘Advancing Caribbean Energy Resilience Workshop.’

Our modern society is highly dependent on the electrical grid and major outages have severe consequences. A reliable source of power is especially important for campuses (including college campuses, business parks, etc.), military bases, and other areas with critical municipal functions (such as hospitals, police, and fire stations), where public safety may be compromised by a lack of electrical power. Although backup generation is common at critical facilities, failure of backup generation resources is quite common due to lack of maintenance or insufficient fuel supplies. Advanced microgrids can be an effective solution for power delivery to critical infrastructure.

Advanced Microgrid Design Overview

We consider a “microgrid” to be an integrated energy system consisting of loads and generation operating as a coherent unit. Microgrids may operate either in parallel with, or islanded from, the main electric grid, and may switch between these two states. A simple microgrid might involve a simple design, such as a critical load paired with a backup generator. Simple designs are typically inefficient solutions when considering all critical loads and possible threats to a given system. An “advanced microgrid” is one that is designed using Sandia National Laboratories’ Energy Surety Design Methodology (ESDM), which is a systematic process to maintain or enhance the attributes of: safety, security, reliability, sustainability, cost effectiveness, and resilience. Key components of advanced microgrid design include identifying and prioritizing critical assets, defining design basis threats, and establishing performance goals.

Introduction to Electric Power Systems and Energy Surety

This module provides a general overview of the design and operation of the electric power grid, emerging concerns of energy reliability and security for extreme events, energy system design metrics, and how microgrids can be used to improve energy security and reliability using both smart grid and distributed and renewable energy generation and storage technologies.

Introduction to Microgrids and Advanced Microgrids

This module provides an overview of the application and use of microgrids and microgrid components. It is intended to provide background information on how microgrids are being designed to safely and reliably use distributed energy including renewable energy and storage resources to provide power for communities during extended main grid outages.

Energy Surety Design Methodology and Microgrids

This module provides a general overview of the Energy Surety Design Methodology (ESDM), developed by Sandia National Laboratories to improve the energy surety of energy systems, and how that methodology is utilized to evaluate the value of microgrids in site-specific applications, provide general analysis, and outline the design steps for advanced microgrids.

Defining Energy System Boundaries

This module provides a general discussion of how to establish the initial energy system boundaries to be evaluated in the microgrid design (as discussed in the ESDM methodology steps in Module 3). This step requires deliberation and discussion of the general reasons for the microgrid, types of events and outages that should be considered, and the major critical functions and capabilities that the community needs from the microgrid during an outage. It is critical to establish the boundaries for considering the microgrid to limit the scope of critical functions and facilities to be considered, which will constrain the amount of analysis and data gathering necessary to design the microgrids.

Prioritizing Critical Assets and Services

This module provides a general discussion of how to establish critical loads and infrastructures that need to be included in the energy surety design evaluation, as well as the opportunities for microgrid applications. This step requires integration with key stakeholders to discuss the general needs of the microgrid, rank the major critical functions and capabilities needed from the microgrid by the community during a main grid outage, and hone in on the needs for different potential outages. This process begins to further establish the system boundaries, operations, and critical infrastructures to be included in the final design.

Identification of Design Basis Threats

This module provides a general discussion of how to identify potential design basis threats (DBTs) and utilize this knowledge to evaluate which DBTs should most influence microgrid design. DBT impacts are used to develop performance objectives for system improvements that will mitigate these impacts. The DBT terminology was borrowed from the nuclear industry, where it is a comprehensive document that identifies threats a facility must withstand. The DBT then informs the design of the facility and its systems. Performance objectives are separately listed for each DBT, which is a profile of the type, composition, and capabilities of an adverse threat.

Performance Goals, Objectives, and Risk Analysis

This module provides a general discussion of how to establish the initial system performance goals and objectives for identified critical services and facilities against identified DBTs. The performance goals and objectives clarify requirements that the set of system improvements must meet to protect these critical services and facilities if the identified DBTs were to occur. After their initial determination, performance goals and objectives are modified and expanded as conceptual design improvements are developed and the feasibility of various options is evaluated.

System Reliability and Availability

This module provides a general discussion of power system reliability and availability, how these differ, and how to calculate system reliability and availability from component reliability and availability.

Formulating and Evaluating Design Options

This module provides a general discussion of how to formulate and evaluate initial conceptual design options to meet identified performance objectives for critical services and facilities against a set of DBTs. Advanced optimization and performance tools, can be used to map out the relative performance versus the cost of various options to help evaluate the set of candidates microgrid options for those that provide the highest performance at the most reasonable cost.

Appendices

• Distributed Energy Generation and
• Examples of Advanced Engineering Analysis