The Bridge - Issue 3, 2020 - 18

Feature

THE FUTURE OF RENEWABLE ENERGY CONSUMPTION: Grid-Interactive Efficient Buildings

What Are Grid-Interactive
Efficient Buildings?
GEB is an energy-efficient building that uses smart
technologies and on-site DERs to provide demand
flexibility while co-optimizing for energy cost, grid
services, and occupant needs and preferences, in a
continuous and integrated way [3]. Four key features
characterize GEBs:
1. Energy-efficient: The ability to reduce net energy
consumption and peak demand using high-quality
walls and windows, high-performance appliances and
equipment, and optimized building designs.
2. Connected: Bi-directional communication capability
to respond to time-dependent grid needs.
3. Smart: Advanced analytical capability to manage
multiple resources in ways that are beneficial to the
grid, building owners, and occupants.
4. Flexible: The ability to dynamically adjust
and optimize building energy loads across
behind-the-meter generation, electric vehicles,
and energy storage.

Figure 1. Example commercial grid-interactive efficient building. The GEB
utilizes analytics supported by sensors and controls to optimize energy
use for occupant patterns and preferences, utility price signals, weather
forecasts, and available on-site generation. [3]

The GEB vision is the integration and continuous
optimization of DERs for the benefit of the building
owners, occupants, and the electric grid. A GEB
optimizes energy use for occupant patterns and
preferences, utility price signals, weather forecasts, and
available on-site generation and storage. Sensors and
controls can support analytics to optimize the operations

THE BRIDGE

of a suite of advanced building technologies-including
the HVAC system, connected lighting, dynamic windows,
occupancy sensing, thermal mass, and distributed
generation and battery storage. In many buildings,
smaller sets of existing technologies could be integrated
and controlled.

Need for Advanced Control
System Technology
A critical technical area of development necessary to
harness building demand flexibility is integrating sensing
and actuation with computing and communications
to monitor and control the physical environment.
Integrating state-of-the-art sensors and controls through
most commercial buildings can save as much as an
estimated 29% of site energy consumption. These
savings are achieved through high-performance
sequencing of operations, optimizing settings based
on occupancy patterns, and detecting and diagnosing
inadequate equipment operation or installation
problems [4]. Furthermore, state-of-the-art sensors and
controls can curtail or temporarily manage 10%-20% of
commercial building peak load [5]. Moreover, building
control strategies are necessary for implementing
flexible, grid-interactive strategies to optimize building
loads within productivity or comfort requirements.
Building control systems are a combination of local
controllers and supervisory controllers. The local
controllers manage a single component and respond
to high-level settings (like temperature setpoints).
Supervisory controllers manage whole energy systems,
coordinate many local controllers, and implement highlevel algorithms and strategies aimed at objectives like
reducing energy costs. Coordination of multiple devices,
coupling with building thermal mass, and mechanisms
and processes that couple various in-building energy
systems make it likely that building-level supervisory
control approaches will outperform device-level
approaches for providing demand flexibility [6].
Supervisory control algorithms typically involve preset
rules, such as thermostat setpoint schedules for
occupied and unoccupied hours. Various standards, such
as ASHRAE Standards 90.1, 189.1, and IECC Chapter 4,
specify building control rules. Many tuning parameters
characterize rule-based controllers. They must be
selected for each system and building and are often

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The Bridge - Issue 3, 2020

Table of Contents for the Digital Edition of The Bridge - Issue 3, 2020