Our vision for what next generation net zero commercial buildings can do to realize 100% renewables, enhance grid-friendliness, and provide additional resiliency

1. NREL is a national laboratory of the U.S. Department of Energy,
Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC.
A Vision for Next-Generation Zero Energy Buildings:
Solutions to Enable Grid-Friendly, 100% Renewable, Building-Scale Microgrids
THE CHALLENGE
A “zero energy building” (ZEB) produces as much renewable energy
as the total energy it consumes on an annual basis. Large-scale and
commercially viable ZEBs are now in the marketplace, and they are
expected to become a larger share of the commercial building foot-
print as government and private sector polices continue to push for
buildings to produce more onsite energy than they use. However, the
load profiles of ZEBs are currently perceived by electric utilities to be
unfavorable and unpredictable, as shown on the following page. At
the same time, building owners are increasingly seeking to enhance
energy surety for ZEBs.
THE OPPORTUNITY
Because ZEBs often produce excess onsite renewable energy,
integrating advanced controls and onsite storage will allow future
ZEBs to actively manage their load profiles and provide new value to
utility operators and building owners. Realizing this vision will enable
ZEBs to provide multiple value streams, such as:
1. Maximizing onsite renewable generation while avoiding exports
to the grid
Lighting Control
System with
Electrical Storage
Heating System
with Thermal
Energy Storage
Connected Office
Equipment with
Electrical Storage
Cooling System
with Thermal
Energy Storage
WiFi
Microgrid ATS/
Smart Inverter(s) and
Power Conditioning
Power
Data
Open-Source Plug-and-Play
Platform for Supervisory
ZEB Control
from Marjorie Schott
Smart
Meter
Premises
Battery
Storage
PV
Array
BACnet™
Modbus
SAEJ1772
Plug-in Hybrid
Electric Vehicle
Electric Vehicle
Supply EquipmentModbus
Internet
(Wireless, DSL, Cable, etc.)
External
Networks, & Data
Project Overview: Next-Generation ZEB Technology Integration Facility
NREL is conducting a project to
produce a ZEB supervisory load
profile controller to manage
multiple building-integrated
resources, including controllable
loads, energy storage integrated at
the load level, a stationary battery
at the building level, and onsite
renewable energy generation.
The NREL Commercial Buildings
Research Group is performing a
pilot demonstration of the controller
using a renewable, building-scale
microgrid at the NREL Vehicle
Testing and Integration Facility
(VTIF). The VTIF control platform
concept is shown in Figure 1.
Figure 1. Conceptual diagram of the VTIF ZEB supervisory control platform, including examples of end-use systems that
will be considered for advanced load management. Illustration by Shanti Pless, NREL, with icons by Marjorie Schott, NREL, and iStock
2. Minimizing unexpected variability in building net load profiles
3. Minimizing or shifting net demand based on incentives in utility
rate structures
4. Managing loads, generation, and storage strategically during
demand response events
5. Managing loads, generation, and storage strategically and provid-
ing energy surety during islanding events
6. Responding to utility control signals to provide ancillary grid
services.
To achieve the vision, the National Renewable Energy Laboratory’s
(NREL’s) Commercial Buildings Research Group is:
• Developing and testing platforms for controlling and integrating
efficient loads, onsite generation, and onsite storage
• Conducting field demonstrations of next-generation ZEBs under
different grid integration scenarios
• Producing modeling and decision-making tools for next-genera-
tion ZEB design and operation.

2. National Renewable Energy Laboratory
15013 Denver West Parkway
Golden, CO 80401
303-275-3000 • www.nrel.gov
NREL prints on paper that contains recycled content.
NREL is a national laboratory of the U.S. Department of Energy
Office of Energy Efficiency and Renewable Energy
Operated by the Alliance for Sustainable Energy, LLC
NREL/FS-0000-00000 • June 2015
OPERATIONAL CAPABILITIES
The VTIF was selected for this project because of its existing infra-
structure, which includes an 18-kW dual-axis tracking photovoltaic
(PV) power system, a 30-kW stationary battery, Level 2 electric vehi-
cle supply equipment, and efficiency measures. It also includes major
energy end-use categories (e.g., lighting, heating, cooling, plug and
process loads) that are found in the commercial building sector.
This project will focus on the first five of the value streams listed on
the previous page. Successful demonstration at the VTIF will enable
future projects to extend control development approaches to other
load management objectives, as well as more building types and
climates.
During the design of the supervisory control algorithm, the team will
consider the following use cases:
1. Meet occupant and load management needs during “normal”
grid-connected operation. Variations include:
a. Fixed energy and demand charges vs. time-of-use or real-time
pricing
b. Cases with and without net metering.
2. Offset backup fossil fuel generation infrastructure for emergency
short-term needs during microgrid islanding.
3. Allow operators to manually switch the VTIF to island mode for
research and educational purposes.
ONGOING ACTIVITIES
The NREL Commercial Buildings Research Group is performing the
following activities as a part of this project:
• Conduct simulation-based evaluation of battery products and con-
trols offerings for compatibility with advanced load management.
• Model the VTIF with OpenStudio to facilitate control platform
development.
• Evaluate how a purely heuristic battery control strategy for de-
mand management compares to idealized control with perfect
foreknowledge of load.
• Review, procure, install, and commission controllable end-use
technologies and electrical and thermal energy storage options.
• Evaluate supervisory control strategies for coordinated dispatch of
building-integrated load management resources, such as a battery,
advanced lighting systems, and HVAC-integrated thermal energy
storage.
• Field test the VTIF control platform.
• Refine control algorithms for multiple use cases.
• Develop a concept for a microgrid operator user interface.
• Publish key lessons and successful strategies.
CONTACT
Questions about the project or how to apply these concepts to other
sites can be directed to Shanti Pless (shanti.pless@nrel.gov) in NREL’s
Commercial Buildings Research Group.
Figure 4. Microgrid operator user interface concept.
Illustration by Marjorie Schott, NREL
Figure 3. The VTIF.Photo by Dennis Schroeder, NREL 31843
1,000
500
0
-500
-1,000
-1,500
-2,000
Power(kW)
Total Data Center
Total Cooling
Total Mechanical
Total Car Charging
Total Mechanical
PV
Total Lighting
Net Building Utility Draw
00:00 06:00 12:00 18:00
Figure 2. Daily electricity profile of a representative zero energy
commercial building without advanced load management.