Smart grid tapped to inspire alternative energy sources
Naperville, Ill., is creating its own smart grid to let people manage their energy consumption
Naperville, Ill., automated its power substations and created an electric service center to manage them, and the city built out an underground distribution system with redundant connections between substations and buildings.
The redundant connections and substation automation create a self-healing system that can switch a building from one power source to another in the event of a failure, minimizing outage time and isolating the problem so it can be located and corrected as quickly as possible.
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The effort, paid for through customer rates, reduced the duration of the average power outage from 120 minutes in 1992 to about 18 minutes in 2010.
The next step is to extend the intelligence to the customer premises, said Olga Geynisman, the city's public utilities electrical engineering manager. “We always wanted to take it to the customers” with an advanced metering infrastructure, Geynisman said. “But we didn’t have the money to do it” right away.
An advanced metering infrastructure (AMI) would enable the two-way flow of power and data between customers and the power utility, helping both better manage power demand. That could help to reduce consumption and encourage new sources of power, such as solar and wind, in addition to preparing the system for new situations, such as introducing charging stations for electric cars.
The city had planned to implement the AMI through a $22 million program during the next 10 to 15 years, and it budgeted $8.4 million for the first phase through a five-year capital improvement plan. Then in October 2009, the Energy Department offered the city an $11 million smart-grid grant funded by the economic stimulus law.
“When this opportunity for funding came, we knew what we wanted to do,” Geynisman said. The grant required the city to complete the entire project in three years, so the city took the grant and funded the remainder of the cost for an accelerated project rather than waiting on the utilities department's revenue stream to fund the project over a longer time.
The AMI effort, scheduled to be completed in late 2012 with the installation of 57,000 smart meters on customer premises, could pay for itself with the potential for an estimated savings of $30 million during the next 15 years, according to the city's utilities department.
The AMI project is beginning with two small-scale tests in the first half of this year to familiarize customers with the technology, followed by broader installation in neighborhoods beginning in the fall.
Two of the primary concerns about the new infrastructure for Naperville customers and DOE are privacy and security. “One of the DOE requirements was to provide a security plan,” Geynisman said.
The utilities department has developed a cybersecurity plan to protect its critical infrastructure against “criminal threats, terrorism acts, industrial espionage and-politically motivated sabotage.” The plan also will govern the protection of customer information.
Security is a critical element of the system, from its narrowband wireless connection that links individual meters to neighborhood collection points to its fiber backhaul network that links substations to the electric service center. The system will use cryptography, virtual private networks and segregated channels to protect customer data.
“Data will be transported on the utility’s network and won’t go onto the city network until it is needed in the system” for billing purposes, Geynisman said.
Metering and data collection will be done with EnergyAxis Smart Grid and smart meters from the Elster Group SE. Data gathered at neighborhood collection points will be transmitted via an 802.11n wireless network supplied by Tropos Networks to a local substation. The EnergyAxis link is a dedicated narrowband connection that handles small amounts of data — measured in kilobits — that individual meters transmit.
“It’s not designed for a broader communications solution,” said Denise Barton, marketing director at Tropos. The link is compliant with the critical infrastructure protection standards that the Federal Energy Regulatory Commission adopted in 2006 and is protected with 128-bit Advanced Encryption Standard encryption.
The Tropos network that links data collection points to the substations provides much greater bandwidth and can also support other uses. Wireless mesh routers are hard-wired to the data collectors and form a private network. The network has multilayered access control and a VPN, and it also uses AES encryption to protect smart-meter data.
Although the network could also provide Internet access while securing customer data, “we find most utilities are conservative and want a very secure network” without Internet connectivity, Barton said.
Because of the small amount of meter data it carries, the Tropos network also could provide remote access for city employees through its fiber-optic backhaul link to the Naperville city network, although it is not being used for that at this point.
The Tropos network is engineered for reliability, with battery backups for each router and automatic channel selection to minimize interference in a noisy environment. “In an outdoor environment, you have some challenges you don’t have indoors,” Barton said.
The network is compliant with the Security Content Automation Protocol for network management, and it can be integrated with Google Maps to locate and display nodes with performance and health information. The meter data is carried from the substations via separate strands of the city fiber network to the service center to separate it from other city traffic.
The utilities department and consumers could use smart meters to more effectively consume power and encourage development of green-energy sources. By enabling the two-way flow of electricity and data, it will allow the metering of customer-installed next-generation equipment, such as solar panels and wind generators. That would let customers who generate their own power sell it back to the utilities department when they are producing more than their household needs.
Customers will be able to see how much energy they are using and when they use it. That could help the utilities department smooth the peaks and valleys of power demand throughout the day and control its greatest expense: the cost of buying electricity from power generators.
This effort will begin with pilot programs that offer customers a time-of-day rate program that decreases the cost of power used during nonpeak periods. Customers also will be offered household equipment, such as smart thermostats, and will have an opportunity to participate in a program in which the utilities department remotely controls thermostats to cut demand during peak usage.
The meters have a wireless network card that links to the thermostat. The utilities department would not turn off heat to a customer but could lower or raise settings for a group of customers by a few degrees for 15 minutes at a time and then move to another group of customers.
“If we are able to orchestrate several thousand customers, it will help us to reduce the peak points,” Geynisman said. The number of customers who would need to participate to have an effect has not yet been worked out, but the department would like to have 5 to 10 percent enrolled in the program, she said. “It’s new territory. But it could really help us a lot. Even for a couple of megawatts, it will be a big savings.”
Demands on the electric system are likely to increase in the future, and a significant uptick is expected in the not-too-distant-future with the adoption of electric cars that will have to be charged. The cost effectiveness of the cars will depend not only on their efficiency but also on the cost of power to charge them. The smart-grid project will help provide an infrastructure for this, and it could help make the cars practical by leveling the demand for electricity and enabling the utilities department to charge lower fees during off-peak hours.
“It’s good for both sides,” Geynisman said.
However, customer acceptance is not a given. Public opinion on the advanced metering infrastructure runs the gamut from enthusiasm to concern over privacy issues and the possible health problems from radio frequency transmissions in homes.
The city has an outreach program to educate the public about the program and established a smart-grid customer bill of rights that outlines the utilities department’s obligations to customers. It guarantees the right to customer privacy and assures customers that no personal data will be associated with usage information. The release of customer information is controlled by local, state and federal law, and customers are assured that they “will retain control of all in-home devices and appliances,” although they can opt in to energy management plans.