IEEE Electrification Magazine - December 2016 - 18

makes it easier to address messages to agents on
other platforms.
xx
Multinode communication. A VIP provides multinode
communication, allowing agents to publish and subscribe to the message bus of a remote VOLTTRON
platform. This communication can be encrypted using
0MQ Curve.
xx
Supervisory service. Several subsystems are included
that VOLTTRON central uses to give an administrator
situational awareness of the health and status of
devices in their deployment. These systems can also
trigger emails and other automatic notifications.
xx
Proxy agents. A proxy agent is an agent that runs on
the platform with the sole purpose of interfacing with
a service that does not natively participate in the
VOLTTRON message bus.
VOLTTRON provides security against unauthorized
access to system data and unauthorized exercise of
control functions. It isolates applications running on
the platform from each other (if needed) and enforces
resource utilization limits on the applications to ensure
stability of the computational platform. The software
platform uses well-established and widely accepted
security mechanisms, including elliptic-curve encryption, authentication, and authorization. Authentication
and authorization go hand in hand. When a peer
(agent) authenticates to a platform, the peer is proving
its identification. In other words, authentication is the
process of binding a peer to an identity. Authorization
is the processing of granting permissions or capabilities
to peers based on their identity. VOLTTRON agents use
authorization to selectively limit which peers can call
which methods based on the peer's granted permissions. The software platform's authorization gives
agent authors and platform owners fine control over
who can use their agents and how their agents can be
used. Additionally, communications with other VOLTTRON platforms use authentication and authorization
functions to ensure that only legitimate transactions
are performed. Access to the system through local
management interfaces is also protected by similar
security measures.
The hardware requirements of the VOLTTRON platform depend on the intended role for that instance.
The platform software itself consumes little resources,
but the applications deployed into it and the services
provided determine where this instance should run. An
instance collecting data from a handful of devices
could comfortably run on a single-board computer
(such as Raspberry Pi or Beagle Bone, etc.). However, an
instance supporting applications that analyze data
from multiple buildings to aggregate grid services or
optimize energy use across a campus could require the
resources of a server. VOLTTRON's only requirement is
that it run in a Linux environment with needed prerequisites such as Python.

I E E E E l e c t r i f i c ati o n M agaz ine / december 2016

Integration with Other Platforms
Other platforms are also being developed to support the
transactive energy vision. The Open Field Message Bus
(OpenFMB) is one such complementary framework that is
being developed in coordination with the Smart Grid
Interoperability Panel (http://www.sgip.org/openfmb/).
This utility-led effort seeks to provide an integrated platform for the grid by providing standards-based communication between applications and devices. OpenFMB
provides an excellent integration opportunity for the
VOLTTRON platform by providing access to devices on the
other side of the meter. Whereas VOLTTRON development has, thus far, been focused inside buildings,
OpenFMB is focused on the grid and would provide a standard interface to complete this interaction. OpenFMB
supports numerous underlying communication mechanisms, including data distribution service (DDS), to
carry standard-based messages between participants
(https://www.rti.com/products/dds/omg-dds-standard.
html). A proof of concept integration between VOLTTRON's
message bus and DDS demonstrated the potential for
these platforms to interact.

VOLTTrON Use cases
There are a number of transactive energy and energy efficiency use cases for VOLTTRON. In addition to these use
cases, VOLTTRON is being actively used in the educational
context at multiple universities.

Intelligent Load Control
To support transactive energy services, to mitigate shortor long-term imbalances between supply and demand,
or to manage the building peak under traditional utility
rate structures, available loads need to be prioritized for
curtailment. The first use case, called intelligent load control (ILC), can be used to manage loads to a target (energy
or cost) in a building or group of buildings using both
quantitative and qualitative criteria (Figure 2). ILC uses
an analytic hierarchy process to prioritize the loads for
curtailment. Two main factors are used to deploy ILC, the
rules that govern the prioritization of the loads and the
target load. With a traditional utility rate structure, the
goal is to lower the demand charge over the billing period, which is typically one month. Under this scenario,
the building load has to be forecasted for the next billing
period and a target selected. In the transactive energy
world, where the price of electricity may be dynamic, the
target also becomes dynamic. Under the dynamic-pricing
scenario, by anticipating the future price of energy, the
process can consume more energy to precool or preheat
when prices are low. The ILC process can be applied to
any controllable load (homogeneous and heterogeneous)
in a building, such as RTUs, variable-air-volume boxes,
and lighting. Furthermore, the ILC process also can be
used to manage building loads based on an energy budget instead of a peak.

http://www.sgip.org/openfmb/ https://www.rti.com/products/dds/omg-dds-standard

Table of Contents for the Digital Edition of IEEE Electrification Magazine - December 2016