Automating Building Energy Management for Accelerated Building Decarbonization: System Architecture and the Network Layer E-Book

James Kempf

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 1172

Veröffentlichungsjahr: 2024

Beschreibung

Complete, up-to-date reference on system architecture for building energy management systems

Automating Building Energy Management for Accelerated Building Decarbonization delivers detailed technical information on building energy management control technology and guidelines to implementing and deploying building energy management systems. The book provides a detailed look at the system architecture of cloud-based building energy management systems, and a comprehensive review of technology for the networking layer, from the link layer through the application layer. Wired and wireless link layer protocols, and Internet network layer protocols from the TCP/IP suite are thoroughly reviewed, and discussed in the context of deploying an in-building, operational technology network.

At the application layer, BACnet, for large commercial and government buildings, and Bluetooth Low Energy, Zigbee, and Matter, for smaller commercial and residential buildings, are discussed in detail, with focus on energy management and building decarbonization. The API standards OpenAPI 3.1 and AsyncAPI 3.0 are used to define example APIs for controlling an HVAC system, illustrating how to provide API abstractions that simplify the development of building energy management applications and services. Finally, a discussion of controlling onsite distributed energy resources, such as solar panels and on-site battery storage, through SunSpec Modbus, and communicating with the utility through OpenADR and IEEE 2030.5 provide a solid technical foundation for implementing communication services in demand response and flexible load applications.

Security is emphasized as a key property for the operational technology networks that run building energy systems up and down the stack. At the architectural level, security functions including data origin authentication, confidentiality protection, and key exchange are discussed in detail. Detailed information on security protocols including IPsec at the network layer, TLS at the transport layer, and Oauth2.0 at the application layer is presented. In addition, advice on deploying security solutions in building energy management networks is provided.

Throughout the book, QR codes provide access to short videos about topics where more depth is needed or that are only briefly covered. These allow the reader to view more information about important topics.

Automating Building Energy Management for Accelerated Building Decarbonization is an essential resource for managers, engineers, and other professionals involved in designing and building energy management services for commercial and residential buildings. It is also an excellent reference for university and training courses related to building decarbonization and renewable energy.

Leseprobe

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IEEE Press Editorial BoardSarah Spurgeon, Editor‐in‐Chief

Moeness Amin

Ekram Hossain

Desineni Subbaram Naidu

Jón Atli Benediktsson

Brian Johnson

Tony Q. S. Quek

Adam Drobot

Hai Li

Behzad Razavi

James Duncan

James Lyke

Thomas Robertazzi

Joydeep Mitra

Diomidis Spinellis

Automating Building Energy Management for Accelerated Building Decarbonization: System Architecture and the Network Layer

James Kempf

Whygrene, Inc.Mountain View, CA, USA

Copyright © 2025 by The Institute of Electrical and Electronics Engineers, Inc.All rights reserved.

Published by John Wiley & Sons, Inc., Hoboken, New Jersey.Published simultaneously in Canada.

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Library of Congress Cataloging‐in‐Publication DataNames: Kempf, James, 1952– author. | John Wiley & Sons, publisher.Title: Automating building energy management for accelerated building decarbonization : System Architecture and the Network Layer / James Kempf.Description: Hoboken, New Jersey : Wiley, [2025] | Includes bibliographical references and index.Identifiers: LCCN 2024034108 (print) | LCCN 2024034109 (ebook) | ISBN 9781394203062 (hardback) | ISBN 9781394203079 (adobe pdf) | ISBN 9781394203086 (epub)Subjects: LCSH: Carbon dioxide mitigation–Technological innovations. | Buildings–Energy consumption. | Buildings–Energy conservation. | Automation–Environmental aspects.Classification: LCC TD885.5.C3 K46 2025 (print) | LCC TD885.5.C3 (ebook) | DDC 690.028/6–dc23/eng/20240824LC record available at https://lccn.loc.gov/2024034108LC ebook record available at https://lccn.loc.gov/2024034109

Cover Design: WileyCover Image: © wacomka/Shutterstock

About the Author

In 1984, Dr. James Kempf graduated from University of Arizona with a Ph.D. in Systems Engineering and Computer Science and immediately went to work in Silicon Valley. He has worked for a variety of large tech companies, including Hewlett‐Packard, Sun Microsystems, NTT Docomo, Ericsson, and Equinix, primarily in research on programming languages, operating systems, networking, blockchain, and cloud computing, and is the author of 30 patents and 3 books on information technology topics. From 2000 through 2006, Dr. Kempf was active in the Internet Engineering Task Force, co‐chairing two working groups and serving on the Internet Architecture Board for 3 years. In 2019, Dr. Kempf started consulting to apply his tech background to renewable energy and building decarbonization, and since 2023 Dr. Kempf has served as CTO for Whygrene, a virtual powerplant startup based in Seattle. Dr. Kempf volunteered with the IEEE Blockchain Technology Task Force from 2019 through 2022, and is a Senior Member of IEEE.

Preface

Decarbonization of society's energy use is the central technical and political challenge of the early twenty‐first century. Buildings represent approximately 33% of direct and indirect carbon emissions worldwide. The DOE report “Decarbonizing the U.S. Economy by 2050: A National Blueprint for the Building Sector” published in April 2024 states that the goal is to “reduce U.S. building emissions 65% by 2035 and 90% by 2050 vs. 2005 while enabling net‐zero emissions economy wide and centering equity and benefits to communities.” Since the electrical gird is slowly moving toward full decarbonization through the deployment of wind, water, and solar power, strategies for building decarbonization primarily involve electrifying all building energy uses, including space and hot water heating which today are often fueled by fossil fuels. Strategies for building decarbonization include reducing energy use overall through energy efficiency measures and controlling it to avoid times of grid peak load when grid power generates more carbon emissions. Another strategy involves utilizing carbon‐free electricity generated locally by building mounted solar PV panels or small wind turbines, storing the energy in a battery, and switching to the stored renewable electricity during times of higher grid carbons emission intensity. In addition to these measures, the successful widespread acceptance and deployment of building energy management requires a building energy management system to maintain the lifestyle and levels of comfort, health, and safety expected by the occupants.

While there are many books discussing building decarbonization at a high level, the hardware for building electrification (HVAC systems, hot water heaters, etc.), energy efficiency measure, and designing buildings for energy efficiency, very few deal with the details of the information and communication technology needed to manage building energy use. This book focuses on the information and communication technologies for designing and implementing a building energy management system, and specifically, on the network architecture and protocols for communicating between a collection of building sites with controllable appliances and a building energy management system hosted in a public cloud or in an on‐premises data center. Chapters 1 and 2 define the problem of building energy management and present a blueprint for its solution, with Chapter 1 presenting a detailed analysis of the building decarbonization problem including energy management strategies and Chapter 2 describing the architecture of a building energy management system. Chapters 3 through 5 deal with standard link layer technologies such as Ethernet and Wi‐Fi, the IP stack, and the cybersecurity measures needed to protect the building energy management system from a major security breach. While much of this material can be found in other places, such as standards documents, gathering it together in one place and putting it into the context of a building energy management system should help in understanding how these protocols can be useful in designing, implementing, and managing the communication system to control building energy use.

Chapters 6 through 9 contain material specific to networking protocols and APIs for building energy management. Chapter 6 deals with the BACnet protocol from the American Society of Heating, Refrigerating and Air‐Conditioning Engineers (ASHRE), an over 30‐year‐old network protocol for building automation, and thus energy management. BACnet is primarily deployed in large commercial and government buildings and holds a key place today in any concerted effort to decarbonize larger buildings through controlling energy use. Chapter 7 delves into protocols for residential and small commercial buildings, namely the newer “smart home” Internet of Things (IoT) protocols developed in the early 2000s and deployed by the large smart home platform vendors such as Amazon, Google, Apple, and Samsung. The systems built around these protocols have yet to achieve the deployment volume and impact envisioned when the protocols were introduced. However, their promise remains undiminished and newer, more recently developed protocols such as Matter, which is also discussed in the chapter, may help increase the appeal and deployment momentum of IoT technology in residential and small commercial buildings. Chapter 8 discusses application‐level protocols, APIs, and the architectures which they enable, namely the client‐server and event‐based application architectures, while Chapter 9 presents their application to energy management through manufacturer‐supported APIs between the building energy management system and devices such as solar PV inverters. Chapter 9 also discusses the APIs between the utility and the building energy management system and local protocols for controlling solar PV systems and batteries. These topics complete the description of how to design the end‐to‐end communication links allowing a building energy management system to obtain data from sensors in the remote building site, remain informed about utility conditions, and exercise supervisory control over equipment at the building site computed based on the information obtained from the devices and the utility.

This book is designed to serve as a text for a two‐semester upper level undergraduate or graduate engineering course in designing building energy management systems, or as a reference for an engineer or technical building manager designing or overseeing such a system. Originally, my intent in writing it was to cover the full space of information and communication technology for building energy management and decarbonization, but as writing proceeded, the need for maintaining technical depth precluded covering everything in one volume. Consequently, it focuses on defining the problem, presenting an architecture to solve it, and then presenting technical details on a key part of the architecture – the network layer –toward successfully implementing a solution. I hope the result inspires teachers to incorporate technology for building energy management into their curricula, students to learn about it, and practitioners to build the systems necessary to fully decarbonize the built environment by 2050.

Acknowledgments

Special thanks go to Tanya Barham, CEO and founder of Community Energy Labs, and John Powers, CSO (formerly CEO) and co‐founder of Elexity (formerly Extensible Energy) for introducing me to the topic building energy control technology and its importance to decarbonizing the economy. I had the good fortune to consult for CEL and Extensible Energy while Tanya and John were in the early stages of building their building energy control startups. Building a startup is hard work, but the success of Tanya’s and John’s companies is absolutely critical if society is to reach the goal of carbon neutrality by 2050, and I hope they succeed.

I also thank James Dice, founder and CEO of Nexus Labs, a company involved in helping building managers and others understand the technical details of smart building technology, how the technologies play out in products from vendors, and how those products can help automate building management. As with so many relationships during the pandemic, James and I have never met, but I was a regular on his webinars and am a newsletter subscriber. They have been a major inspiration for the work in this book, particularly the generational model of smart building technology architecture in Chapter 2.

Acronyms

** Numbers **

10BASE‐T

10 Mbit/sec Ethernet

100BASE‐TX

100 Mbit/sec Ethernet

1000BASE‐T

1 Gbit/sec Ethernet

3GPP

Third‐Generation Partnership Project

4G

Fourth‐Generation Cellular Protocol, i.e., LTE

5G

Fifth‐Generation Cellular Protocol

6LoWPAN

IPv6 over Low‐Power Wireless Personal Area Network

** A **

AAA

Authentication, Authorization, and Accounting

ACK

Acknowledgement

ACL

Access Control List

ADU

Application Data Unit

AES

Advanced Encryption Standard

AIFS

Arbitrary Distributed Inter‐Frame Space

AMI

Advanced Metering Infrastructure

AMQP

Advanced Message Queuing Protocol

ANSI

American National Standards Institute

AODV

Ad‐hoc On‐demand Distance Vector

APDU

Application Protocol Data Units

API

Application Programming Interface

ARP

Address Resolution Protocol

ARPANET

Advanced Research Projects Agency Network

ASCII

American Standard Code for Information Interchange

ASHRAE

American Society of Heating, Refrigeration, and Air‐conditioning Engineers

ASN

Absolute Slot Number

ASN.1

Abstract Syntax Notation 1

ATT

Attribute Profile

AH

Authentication Header

AXFR

Absolute Zone Transfer Protocol

** B **

BACnet

Building Automation Control network

BACnet/SC

BACnet Secure Connect

BAS

Building Automation System

BBMD

BACnet Broadcast Management Device

BDB

Base Device Behavior

BESS

Battery Energy Storage System

BEMS

Building Energy Management System

BESS

Battery Energy Storage System

BGP

Border Gateway Protocol

BIBB

BACnet Interoperability Building Block

BLE

Bluetooth Low Energy

BOOTP

Bootstrap Protocol

BPDU

Bridge Protocol Data Units

Bps

Bits per second

BSS

Basic Service Set

BSSID

Basic Service Set ID

BTP

Bluetooth Transport Protocol

BTU

British Thermal Units

BVLC

BACnet Virtual Link Control

BVLL

BACnet Virtual Link Layer

** C **

CA

Certificate Authority

CAISO

California Independent System Operator

CAT M1

Category M1 LTE wireless protocol

CCMP or CCM*

Counter Mode Cipher Block Chaining Message Authentication Code Protocol

CEC

California Energy Commission

CID

Company ID

CIDR

Classless Interdomain Routing

CIM

Common Information Model

CLI

Command Line Interface

COBS

Consistent Overhead Byte Stuffing

COP

Coefficient of Performance

CORS

Cross‐Origin Resource Sharing

COV

Change of Value

CP

PAE Controlled Port state machine

CRL

Certificate Revocation List

CRUD

Create, Read, Update, and Delete

CSA

Connectivity Standards Alliance

CSIP

Common Smart Inverter Profile

CSMA/CA

Carrier Sense Multiple Access with Collision Avoidance

CSMA/CD

Carrier Sense Multiple Access with Collision Detection

CSML

Control System Markup Language

CSV

Comma Separated Value

CTA

Consumer Technology Association

CTE

Constant Tone Extension

CW

contention window

** D **

DAG

Directed Acyclic Graph

DALI

Digital Addressable Lighting Interface

DAO

Destination Advertisement Object

DAQ

Device Automated Qualification

DCF

Distributed Co‐ordination Function

DER

Distributed Energy Resource

DERMS

Distributed Energy Resource Management System

DHCP

Dynamic Host Configuration Protocol

DIFS

Distributed Inter‐Frame Space

DIO

DODAG Information Object

DODAG

Destination Oriented Acyclic Graph

DOE

Department of Energy

DNP3

Distributed Network Protocol 3

DNS

Domain Name System

DR

Demand Response

DRAS

Demand Response Automation Server

DRLC

Demand Response and Load Control

DSO

Distribution System Operator

DTLS

Datagram Transport Layer Security

** E **

EAP

Extensible Authentication Protocol

EAPOL

Extensible Authentication Protocol over LAN

ECC

Elliptic Curve Cryptosystem

ECDSA

Elliptic Curve Digital Signature Algorithm

ECN

Explicit Congestion Notification

EDCF

Enhanced Distributed Co‐ordination Function

EIA

Energy Information Administration

EPA

Environmental Protection Agency

EPRI

Electric Power Research Institute

ESS

Extended Service Set

ESP

Encapsulating Security Header

ETS

Engineering Tool Software

EUI

Extended Unique Identifier

EV

Electric Vehicle

EVSE

Electric Vehicle Supply Equipment

** F **

FDO

Firmware Device Onboard

FIFO

First‐In‐First‐Out

FQDN

Fully Qualified Domain Name

FTP

File Transfer Protocol

** G **

GAP

Generic Access Profile

GATT

Generic Attribute Profile

Gbps

Gigabits Per Second

GEB

Grid‐Interactive Efficient Buildings

GHz

Gigahertz

GSS‐API

Generic Security Service Application Program Interface

GUI

Graphical User Interface

** H **

HAN

Home Area Network

HCI

Host Controller Interface

HLDE

High Level Dialog on Energy

HMAC

Hashed Message Authentication Code

HTML

Hypertext Markup Language

HTTP

Hypertext Transfer Protocol

HTTPs

Hypertext Transfer Protocol secure

HVAC

Heating, Ventilation, and Air Conditioning

** I **

IA

Interoperability Area

IAM

Identity and Access Management

IANA

Internet Assigned Numbers Authority

ICANN

Internet Corporation for Assigned Names and Numbers

ICT

Information and Communication Technologies

ID

Identifier

IEC

International Electrotechnical Commission

IETF

Internet Engineering Task Force

I/G

Individual/Group

IKE

Internet Key Exchange

IoT

Internet of Things

IP

Internet Protocol

IPSec

Internet Protocol Security

IPv4

Internet Protocol, version 4

IPv6

Internet Protocol, version 6

ISM

Industrial, Scientific, and Medical

ISO

Independent System Operator

ISP

Internet Service Provider

IT

Information Technology

ITU

International Telecommunication Union

ITU‐T

International Telecommunication Union Telecommunication Standardization Committee

IXFR

Incremental Zone Transfer Protocol

** J **

JSON

JavaScript Object Notation

JWK

JSON Web Key

JWKS

JSON Web Key Set

JWT

JSON Web Token

** K **

Kb

Kilobyte

Kbps

Kilobits per second

Kw

Kilowatt

Kwh

Kilowatt‐hour

** L **

L2CAP

Logical Link Control and Adaptation Protocol

LAN

Local Area Network

LEED

Leadership in Energy and Environmental Design

LoRa

Long‐Range Wireless Protocol

LoRaWAN

Long‐Range Wide Area Network

LTE

Long Term Evolution

** M **

MAC

Medium Access Control

MACsec

MAC Layer Security, IEEE 802.1AE

Mb

Megabyte

MBAP

Modbus Application Protocol

Mbps

Megabits per second

MHz

Megahertz

MIDAS

Market Informed Demand Automation Server

MIME

Multimedia Internet Mail Extension

MKA

MACsec Key Agreement

MQTT

Message Queuing Telemetry Transport

MRP

Message Reliability Protocol

mTLS

Mutual Transport Layer Security

MTU

Maximum Transmission Unit

** N **

NAK

Negative Acknowledgement

NAS

Network Access Server

NAT

Network Address Translation

NB‐IoT

Narrow Band Internet of Things LTE wireless protocol

NFC

Near Field Connectivity

NIST

National Institute of Standards in Technology

NLC

Network Lighting Control

NOC

Node Operational Credentials

NRDC

Natural Resources Defense Council

NSF

National Science Foundation

** O **

OCSP

Online Certificate Status Protocol

OFDMA

Orthogonal Frequency Division Multiple Access

OIDC

OpenID Connect

OpenADR

Open Automated Demand Response

OSI

Open Systems Interconnect

OSPF

Open Shortest Path First

OT

Operation Technology

OTA

Over the Air

OUI

Organizationally Unique Identifier

** P **

PAC

Port Access Controller

PACP

Port Access Control Protocol

PACH

Periodic Advertising Channel

PAKE

Password Authenticated Key Exchange

PAN

Personal Area Network

PDP

Policy Decision Point

PDU

Protocol Data Unit

PEP

Policy Enforcement Point

PICS

Protocol Implementation Conformance Statement

PIFS

Point Inter‐Frame Space

PKCE

Proof Key for Code Exchange

PKI

Public Key Infrastructure

PLC

Power Line Communication

PoE

Power Over Ethernet

PSK

Pre‐shared Key

PTP

Point to point

Pub‐Sub

Publish‐Subscribe

PV

Photovoltaic

** Q **

QoS

Quality of Service

QUIC

Quick UDP Internet Connections

** R **

RADIUS

Remote Authentication Dial‐In User Service

RAM

Random Access Memory

RBAC

Role‐Based Access Control

REED

Router‐Eligible End Device

REST

Representational State Transfer

RFC

Request for Comments

RIB

Routing Information Base

RIR

Regional Internet Registry

RPL

IPv6 Routing Protocol for Low‐Power and Lossy Networks

RSA

Rivist‐Shamir‐Adleman

RSNE

Robust Security Network Element

RSO

Regional System Operator

RTO

Regional Transmission Operator

RTS/CTS

Request‐to‐Send/Clear‐to‐Send

** S **

SaaS

Software as a Service

SA

Security Association

SAD

Security Association Database

SAE

Simultaneous Authentication of Equals

SAML

Security Assertion Markup Language

SAN

Subject Alternate Name

SASL

Simple Authentication and Security Layer

SCADA

Supervisory Control and Data Acquisition

SDK

Software Development Kit

SHA1, SHA3, SHA256

Secure Hashing Algorithm 1, 3 and 256

SID

Set Identifier

SIFS

Short Inter‐Frame Space

SIM

Subscriber Identity Module

SM

Security Manager

SMCU

Smart Inverter Control Unit

SOAP

Simple Object Access Protocol

SPD

Security Policy Database

SPI

Security Parameters Index

Spiffe

Secure Production Identity Framework for Everyone

Spire

Spiffe Runtime Environment

SSH

Secure Shell

SSID

Service Set ID

SSL

Secure Socket Layer

SSO

Single Sign‐On

** T**

TLS

Transport Layer Security

TCP

Transmission Control Protocol

TKIP

Temporal Key Integrity Protocol

TLV

Type‐Length‐Value

TOU

Time of Use

TSO

Transmission System Operator

** U **

UCM

Universal Communications Module

UDMI

Universal Device Management Interface

UDP

User Datagram Protocol

U/L

Unique/Local

URI

Uniform Resource Identifier

URL

Uniform Resource Locator

URN

Uniform Resource Name

USB

Universal Serial Bus

UTC

Universal Time Coordinated

USGBC

US Green Building Council

UUID

Universally Unique Identifier

** V **

V2B

Vehicle to Building

V2G

Vehicle to Grid

VAV

Variable Air Volume

VEN

Virtual End Node

VLAN

Virtual Local Area Network

VM

Virtual Machine

VOC

Volatile Organic Compound

VTN

Virtual Top Node

** W **

WAN

Wide Area Network

WEP

Wired Equivalent Privacy

WLAN

Wireless Local Area Network

WPA

WiFi Protected Access

WPAN

Wireless Personal Area Network

** X **

xdd

Extended Data Definition

XML

eXtended Markup Language

** Y **

YAML

YAML Ain’t a Markup Language

** Z **

ZDD

Zigbee Direct Device

ZVD

Zigbee Virtual Device

1Introducing Grid‐interactive Efficient Buildings (GEBs)

Since the beginning of the twenty‐first century, the scope of the global climate crisis has become increasingly clear. Wildfires due to extreme drought, gigantic hurricanes and typhoons, and other weather emergencies have become more common. The alteration in habitat for plants and animals adapted to a cooler climate has resulted in accelerated extinction rates. Every year seems to set a new record for high temperatures due to increasing greenhouse effect heating from the buildup of greenhouse gases, such as carbon dioxide and methane, released by fossil fuel use.

In fits and starts, humanity has slowly come around to recognizing that climate change is a serious problem, as the symptoms become more visible, and that the cause of the problem is the buildup of greenhouse gases in the atmosphere since the Industrial Revolution. Policymakers and politicians in many countries have instituted varying degrees of support for policies to decarbonize the energy industry. The United Nations has developed a global roadmap for decarbonizing the energy industry by 2050 through the high‐level dialog on energy (HLDE), a series of meetings between heads of state and government and energy ministers [1]. The dialog establishes a societal goal of having net carbon neutrality for the energy industry by 2050 toward mitigating the climate emergency. The built environment is a major consumer of fossil fuel energy so decarbonizing the built environment is a critical goal for the transition to a decarbonized society. Since residential and commercial buildings make up the bulk of the building stock in industrialized countries, this book is focused on information and communication technology (ICT) solutions for controlling energy use in residential and commercial buildings.1

In this chapter, we start with an introduction to the scope of the building decarbonization problem and characterize the energy use functions that the operation of buildings represents. We then discuss strategies for mitigating carbon emissions in buildings and how, at a high level, the BEMS contributes to building decarbonization through measurement, reporting, and control of energy use. Next, we present an introduction to how buildings that are highly efficient (i.e. use very little energy to fulfill the same functions compared to peers) and are connected to and can be managed by the grid can serve as a resource for managing the electrical grid more efficiently. In the last section, we discuss such energy efficiency rating systems as the Leadership in Energy and Environmental Design (LEED) and Energy Star and the role they play in building decarbonization.

1.1 Scope of the Building Decarbonization Problem

Buildings in aggregate are a major consumer of energy and therefore a major source of carbon dioxide and other greenhouse gases associated with fossil fuel consumption. Buildings account for one‐third of combined direct (from burning of fossil fuels) and indirect (from electricity) energy consumption [2] globally and up to 40% for residential and commercial buildings in the United States [3]. Considering indirect energy alone, buildings consume more than 70% of the United States electricity output [4]. Since two‐thirds of the buildings in existence in 2022 will still be around in 2050 [5], policy changes encouraging the construction of new buildings with decarbonized energy supplies will not be enough to fully decarbonize the built environment by 2050. Therefore, decarbonizing existing buildings represents a critical step in the overall societal goal of having a net carbon zero society by 2050.

We can get an idea of the scope of the problem by considering the direct greenhouse gas emissions from the operation of residential and commercial buildings, that is, energy not originating from electrical consumption. As shown in Figure 1.1, residential and commercial buildings in the United States account for 13% of the direct greenhouse gas emissions in 2019 [6]. This is the fourth largest emissions sector, after transportation, electricity (for all uses), and industry. Residential and commercial buildings use fossil energy primarily for space conditioning, hot water production, cooking, and clothes drying. Focusing on space conditioning, in the most recent United States government surveys, 47% of the residential buildings and 50% of the commercial buildings utilized fossil gas for space conditioning. Other fossil fuels (oil and propane) are also used in various parts of the country. The United States has around 100 million single‐family homes, 5.2 million multifamily residential buildings, and 5.5 million commercial buildings [7]. If as noted above, two‐thirds of these buildings are still standing by 2050, the United States alone will need to somehow retrofit 34.8 million buildings with energy that has no carbon emissions to meet the societal goal of net zero carbon emissions from the built environment. Buildings with fossil‐fueled hot water, cooking, and clothes drying appliances will similarly need to be supplied with nonfossil energy.

Figure 1.1 Total United States Greenhouse Gas Emissions by Economic Sector 2019.

Source: Adapted from EPA [6].

In contrast with the building sector, decarbonization of the electrical grid has been underway since the early part of the century. In 2023, 21.3% of the United States grid was powered by renewables (including large hydro) [8]. Solar and wind are now the cheapest of any electricity generation technology to deploy and operate, and in 2023, 86% of the newly deployed electrical generation capacity was wind and solar [9]. Figure 1.2 compares the levelized cost of wind and solar vs. nonrenewable generation from 2008 to 2020. Given the cost advantages of renewables coupled with policy incentives from local, regional, and national governments to deploy them, a path toward decarbonization of the electrical grid by 2050 seems clear.

Grid decarbonization will clearly reduce building carbon emissions from indirect energy consumption, but as discussed above, the built environment's direct energy consumption currently comes from fossil fuels. While nonelectrical replacement technologies with no carbon emissions are still under investigation, electrical appliances with the same functionality as fossil‐fueled appliances are available today as consumer products. Given the rapid and accelerating pace of grid decarbonization, the most straightforward and least expensive path for building decarbonization is therefore replacing fossil‐fueled appliances with electrical appliances, a process sometimes called “beneficial electrification” [11].

Figure 1.2 Comparative Levelized Cost of Energy per MWh from Different Sources.

Source: Mir‐445511 [10]/Mir‐445511/Wikimedia Commons /CC‐BY‐SA‐4.0.

LBNL on Grid‐Interactive Efficient Buildings

Lawrence Berkeley National Laboratory has been the leading research institution in the United States working on GEBs and has been a thought leader for many years in the area of building load flexibility. This longer webinar walks through their 2021 report cited in [4].

1.2 What Are Grid‐Interactive Efficient Buildings (GEBs)?

Once full building electrification is in place, a variety of ICTs can be brought to bear on the problem of controlling building energy use and operational carbon emissions. Improving how electricity is consumed and reducing the amount of electricity used through these ICT control measures can significantly reduce energy costs, increase the use of renewably sourced electricity, and contribute to grid stability, thereby improving a building's carbon emissions profile. Coupling these measures with physical changes to reduce overall building energy use like improved insulation and more energy‐efficient windows can in some cases make the operating cost of powering a fully electrified building lower than powering a building with fossil fuel. Buildings that feature full electrification with physical efficiency improvements, ICT infrastructure for electricity consumption measurement and control, and integrated renewable power sources such as rooftop solar and batteries are called GEBs by the United States Department of Energy (DOE) [12]. Such buildings are grid interactive in the sense that they have the ICT control technologies allowing them to adapt to grid conditions signaled by the utility or distribution system operator (DSO) and are efficient due to the physical efficiency improvements. The ICT technologies involved, often grouped under the general term the “Internet of Things” (IoT), consist of sensors for measuring building and external conditions, control devices for changing the energy consumption patterns in the building in response to measured data from the sensors, networking protocols and hardware for communicating sensor data and control signaling to and from centralized control points and for communicating with the DSO, and software with algorithms for projecting energy use and carbon emissions over a particular time period and calculating the optimal control signaling to reduce them.

1.3 How Do GEBs Advance the Goal of Energy Decarbonization?

The United States DOE has estimated that over the next 20 years, national adoption of GEBs in the currently electrified building stock could be worth $100–$200 billion in savings to the United States electrical power system. The savings are accompanied by reductions in carbon emissions of 80 million tons per year by 2030 or 6% of the total electricity sector carbon emissions [4]. The cost savings come from utilizing energy generated onsite by building integrated distributed energy resources (DERs) such as solar, reducing electricity consumption overall from efficiency measures, and shifting consumption to times when the cost of electricity is lower through load flexibility. Carbon emission reductions come from utilizing onsite generated renewable electricity and shifting consumption away from times when demand for power is high and more fossil‐fueled “peaker” plants are generating to times when more renewably generated electricity is available on the grid. These estimates were based on conservative assumptions about grid decarbonization and building electrification, for example, that building owners don't replace their fossil fuel appliances until their end of life. Policy changes and incentives that could accelerate the pace of building electrification were not modeled.

An additional benefit of GEBs is their indirect contribution to societal decarbonization. Energy efficiency and load flexibility free up additional electricity for uses which today are powered by fossil fuels. As space conditioning, hot water production, and other uses are electrified, the load on the grid increases. Widespread adoption of electric vehicles (EVs) will further increase electricity demand, resulting in the need for more supporting grid infrastructure. By making buildings more efficient, allowing their load to be flexibly scheduled, and using more onsite generated renewable energy, GEBs reduce the need for adding new generation and allow existing generation to be utilized more efficiently. GEBs can thereby help to reduce the need for additional investment in grid infrastructure, facilitating a transition to a more reliable and affordable decarbonized grid.

Finally, GEBs can play a role in grid stabilization as more renewables are integrated into the grid. Renewable generation is inherently more variable than fossil generation due to the variability of the underlying wind and solar energy sources, changing the grid from a system with dispatchable generation to a system with variable generation. On the load side, loads in the past have been mostly fixed. Through load flexibility, GEBs can match load to supply even with non‐dispatchable generation. In addition, the incorporation of building‐mounted solar and batteries allows GEBs to offer grid services such as resource adequacy. Aggregations of GEBs with onsite solar and batteries can act as “virtual power plants” [13], storing power during the day when solar‐generated electricity is plentiful and loads are light, and releasing it in the evening when the sun goes down and loads ramp up as people come home from work and switch on their space conditioning appliances and ovens.

1.4 Characterizing Building Loads in Commercial and Residential Buildings

At a high level, people expect certain services from their appliances. As Amory Lovins, the founder of Rocky Mountain Institute, said: “People don't want raw kilowatt‐hours or lumps of coal or barrels of sticky black goo. They want hot showers, cold beer, comfort, mobility, illumination” [14]. In some cases, the services need to be delivered at a particular time, and in others, delivery can be accelerated or deferred to a more favorable time for the grid. People may also have a particular range around which their expectation of satisfactory delivery is structured. For example, people's perception of room comfort is not set at a fixed temperature. It varies throughout the day and between people, typically within a certain range. Yet, most control systems for appliances assume that delivery of their service involves a fixed setting that then consumes a fixed amount of power for a certain amount of time until the need for the service has been satisfied. As a result, the grid was designed in the twentieth century for fixed loads, where the load requires a constant amount of power for the duration over which the device is running.

1.4.1 The Three‐Dimensional Load Flexibility Criteria Space

Today many smart appliances' load can be modulated, ramping their power draw up or down depending on control signaling, or the appliance's operation can be prescheduled or deferred. The amount of the service output varies depending on the amount of power provided to the device and the time the device is scheduled to operate. If the service delivered by the device is satisfactory at a lower power draw or a different time, building control systems have an opportunity to institute power and energy control regimes that can substantially reduce a building's energy and power usage as well as the building's indirect carbon emissions.

Building loads can therefore be roughly characterized along two independent flexibility dimensions with respect to the control flexibility of the appliances generating them [15]:

Fixed vs. Schedulable in Time – Some appliances such as medical equipment need to run at a particular time and cannot be rescheduled, while others, such as heating, ventilation, and air conditioning (HVAC) equipment, can be scheduled to run when power or energy is cheaper or has lower carbon content.

Constant vs. Modulated Power Draw – Some appliances such as TV sets may need to run at constant power to provide their service, while others such as LED lighting can be varied within a certain range, reducing overall energy usage.

An additional flexibility constraint derives from the level of satisfaction of the building's occupants with the service provided by the appliance [4]:

Satisfied vs. Dissatisfied – Within a range around an appliance setpoint (temperature, lusmens, etc.), the occupants are satisfied with the service (thermal comfort, brightness, etc.), but outside that range they are dissatisfied.

These three flexibility dimensions – schedulability, level of power modulation, and occupant satisfaction – provide a constraint space within which building energy and power consumption can be optimized.

1.4.2 Types of Residential and Commercial Building Loads and How to Make Them Flexible

Every five years, the United States Energy Information Administration (EIA) performs a half‐decadal survey of energy use in residential and commercial buildings. The last such survey for which results have been published was conducted in 2020 for residential buildings (results published in 2023) [16] and 2018 for commercial buildings (results published in 2022) [17]. The pie charts of these surveys for electricity are shown in Figure 1.3 for residential buildings and Figure 1.4 for commercial buildings, respectively.

Figure 1.3 Types of United States Residential Electrical Loads 2018.

Source: EIA [16]/U.S. Energy Information Administration/Public domain.

Figure 1.4 Types of United States Commercial Loads 2018.

Source: EIA [17]/U.S. Energy Information Administration/Public domain.

In the residential survey, HVAC loads (combined heating, cooling, humidity control, and ventilation) consume the most amount of electricity, a combined 44%. The next largest load type for residential buildings is water heating at 14%, followed by refrigerators and freezers at 11%, lighting at 7%, TV and consumer electronics at 7%, clothes washing and drying at 6%, miscellaneous classified loads at 6%, pool and hot tub equipment at 3%, and cooking at 2%. The miscellaneous classified loads cover ceiling fans, dehumidifiers, humidifiers, dishwashers, and EV charging which, individually, are less than 2%.

Table 1.1 classifies these load types within the three‐dimensional load flexibility constraint space presented in Section 1.4.1. In some cases, whether the load can be controlled depends on the type of technology used to implement the appliance. For example, HVAC appliances that use variable speed DC motors on heat pumps or resistive heating are modulated but those with fixed speed AC motors for heat pumps are not. HVAC systems are schedulable, modulated (if the technology allows it), and have a service satisfaction range. Building occupants will typically have preferences for thermal comfort over certain ranges, although for multi‐occupant spaces, the thermal comfort range needs to be constructed as the intersection of the ranges for all the occupants to ensure that no one is dissatisfied.

Table 1.1 Residential Load Types Classified According to the Three‐Dimensional Flexibility Criteria

Load Type

Load Percent (%)

Schedulable

Modulated

Service Satisfaction Range

HVAC

44

Yes

Yes if variable speed motors or resistive

Yes

Hot water

14

Yes

Yes if variable speed motors or resistive

No

Refrigeration and freezing

11

Yes

No

No

Lighting

7

No

Yes

Yes

TVs and consumer electronics

7

No

No

No

Clothes washing and drying

6

Yes

No

No

Pool and hot tub equipment

3

Yes

Yes

No

Cooking

2

No

No

No

Hot water heating is also schedulable and modulated with the same conditions on the technology as for HVAC; however, the service satisfaction range is usually fairly narrow to nonexistent. If the building occupants want a hot shower, the temperature must be high enough, typically 120 °F, in order to provide a comfortable temperature when mixed with cold water to prevent scalding. Since these two load types constitute more than half the residential load and have good controllability characteristics, prospects are excellent for reducing energy consumption and carbon pollution from residential buildings by allowing control systems to schedule and modulate the appliances within the occupants' satisfaction range.

Refrigeration and freezing loads are schedulable as long as the temperature remains below 40 °F for refrigeration and 0 °F for freezing, the temperatures recommended by the United States Food and Drug Administration (FDA) to prevent bacterial growth [18]