December
2009 |
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The Applications and Protocols |
Jim Sinopoli PE, RCDD, LEED AP |
The electrical utility grid that Thomas Edison initiated over 100 years ago is long overdue for an overhaul. It will be a 180 degree change in the utility business model, going from selling more and more energy to consumers to putting everyone on a healthy energy “diet”. The entire concept of the utility grid, buildings, vehicles, energy sources and energy storage all communicating with one another to enable the efficient use of energy is ambitious and breathtaking. It will be the details of implementation that will determine its success.
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Much of the Smart Grid is obviously focused on utility grids not necessarily buildings. However, some of the characteristics of the Smart Grid effort addresses the integration of distributed energy resources, demand response, demand-side resources, ‘‘smart’’ appliances and consumer devices, plug-in electric and hybrid electric vehicles, thermal-storage air conditioning, and timely information and control options for consumers. Intuitively we know that a smart grid without smart buildings would be a greatly diminished deployment and a very expensive lost opportunity.
The larger question is what are the attributes and characteristics of the connection between smart buildings and the smart grid? What are the applications? What is the communications interface? How will it be addressed technically? What could or will it mean for building owners and facility management? Buildings are being designed and upgraded to be energy efficient but that effort often is disconnected from the Smart Grid initiative- how do we get the two in sync? Let’s start with the possibilities of applications and then review the possible communications protocols.
Demand Response
One of the top priorities of the Smart Grid is demand response, an economic
mechanism to have customers reduce or increase demand. When used to reduce
demand, utilities reduce their peak demand and the additional need for plant and
the related capital costs. Using demand response for increasing demand is
intriguing. During periods of low demand and high production a utility may want
to increase demand to users that can store the energy and make use of the energy
later (much like charging a big battery at the customer’s site).
The communications between the grid and a building can be two-way with the grid
initiating communications to the building and the building acknowledging the
signal and letting the utility know of their capability to respond. The building
owner’s response to a demand response notification can be manual or automated.
Manual response means people go around and shut lights off or turn thermostats
down, obviously an inefficient and somewhat ineffective action to a signal from
a technology-laden utility grid.
Automated means the grid signals the building and the building systems
automatically respond by turning off lights and equipment, adjusting set points,
etc. How this communications between the grid and the building systems takes
place is still being worked out. If the demand response is “anticipated” it is
possible that typical building systems in non-residential buildings may be able
to be scheduled to react. If it’s dynamic however, as utility rates are
projected to be, the grid must communicate real time with the building systems.
The basis of that communication appears to be open standards‐based technology
such as XML, SOAP and Web services, as indicated in version one of an Open
Automated Demand Response communications specification. The communications
standards for pricing formats and time-of-day schedules need to be established.
While that framework looks solid it would take some advanced or enhanced
building management systems to accommodate that communication and in turn adjust
the energy-related building systems. The number of existing buildings that are
currently capable of doing so is very small.
Distributed Generation (DG)
As more alternative on-site energy sources (solar, wind, co-gen) are used,
buildings will be seen as both energy consumer and potential energy provider. As
an energy provider the building or campus could supply energy back to the grid.
That integration of on-site energy generation into the grid will require much
more than communication. It also needs to address the verifying of the quality
of the energy provided, security and safety. The movement of energy back and
forth from the grid is another important area where standards will need to be
developed.
Energy Information to Consumers
Consumers
will need information which can assist them in energy management. Some of the
information and data may come from the grid and some may come from the building
systems. For residential applications this data and information could include:
• Energy use – real-time and historic data on the
amount used (KWH) , the cost, the rate schedule or purchasing terms for energy,
the trends and the projected forecast of usage and costs
• Power sources - the amount and cost of renewable energy sources that are used,
the carbon content of the energy used, and the distance from energy source
• Weather forecasts
• The quality and reliability of the power
For larger commercial customers this information will
need to be more granular, more technical and in line with the reporting
requirements for cap-and-trade, LEED, Energy Star or government requirements.
Any information from the grid will need to be supplemented with information from
the building systems.
Plug-In Hybrid Electric Vehicles (PHEV)
Associated
with buildings are the cars that are driven to and from the building, usually
resulting in a significant portion of surface use or facilities for parking
cars. Add to that the gradual penetration of hybrid and electric cars that need
to be connected to the grid to be recharged that are also capable of storing
electric power and providing it back to the grid. This is somewhat futuristic
given the currently small number of PHEVs and the lack of advanced batteries but
the potential over the next decade is huge. The general idea is that PHEVs could
be recharged at off peak hours (middle of the night) and store energy that could
be transferred to the grid during peak load times. It may not be as easy as it
sounds. When the PHEV gets recharged will depend on when the driver wants to use
the car, how much the batteries are discharged and what the time-of-day energy
rate is. This area is much like distributed generation where the standards for
bi-directional flows of energy and two-way communication and control
capabilities are lacking.
Building Control Systems and Devices
A smart grid that simply provides energy information to home owners and
building owners, and presumes that they will manually turn off lights and
equipment and reset thermostats will flounder. To a large extent, the success of
the smart grid will depend on the control systems within the buildings and the
seamless and automated interaction between the building and the grid. Most
buildings will need to integrate their control sub-systems, provide more sensors
for the sub-systems and larger buildings will need to provide sub-metering.
Proprietary building control systems will be unable to communicate and interact
with the grid without some gateway or middleware. BACnet is identified in the
first draft of operational standards as the preferred facility communication
protocol for the meter interface. Here are some examples of how this may play
out for residential, commercial and institutional buildings.
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For residential the typical setup for a demand response program will be smart
thermostats, control switches on the air conditioning and water heater and a
display for providing energy information. Smart thermostats will allow a
homeowner to set the temperature but outside of a certain range around the set
point, the utility grid would control temperature. The same is true for switches
on air conditioning and major equipment.
Larger commercial and institutional buildings will probably need to upgrade and
integrate their building control systems, install metering systems with
sufficient granularity, and potentially address the connection of wind, thermal
and solar energy sources into the grid. Interestingly, one of the recent Smart
Grid Investment Grants from the US government went to Honeywell ($11.4 million).
They will provide automated peak pricing response for about 700 customers.
Honeywell is planning a two step approach: first work with customers to develop
a schedule of which equipment, banks of lights and power loads can be reduced
during peak pricing and for how long; the second step utilizing their Tridium
platform with the Open ADR standard to communicate with the grid and in turn
control the building systems.
Standards and Protocols
The National Institute of Science and Technology (NIST) is responsible for
coordinating the identification and development of the protocols and standards
to achieve interoperability of Smart Grid devices and systems. After several
iterations and public hearings for comment they released a draft report
in September. NIST has identified applicable existing standards and also gaps
where standards will need to be developed. The priority areas include: demand
response, consumer energy efficiency, wide area situational awareness, electric
storage, electric transportation, advanced metering infrastructure, distribution
grid management, cyber security and network communications. They have identified
77 standards or specifications that can be used in the Smart Grid. Sixteen
standards were initially identified as having strong consensus; that was
expanded to 31 after public comment. An additional 46 standards were identified
as potentially applicable. For those areas where gaps were identified, such as
demand response, end-user energy information, time synchronization and so forth,
draft standards are expected to be released in 2010.
What are the standards that have been identified that are most important for buildings? Out of the 77 here’s a list of the standards that could impact a building’s interaction with the Smart Grid:
For more information about smart buildings, technology design or to schedule a Continuing Education program, email me at jsinopoli@smart-buildings.com.
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