Public vs. Private: the Smart Grid Communications Debate

Guest post: Matthew Knott, ABB

One of the few aspects not up to debate in the smart grid market is the importance of a communications network. In order to take full advantage of the benefits smart grid technologies have to offer, the utility’s approach must be comprehensive. Therefore, communications function as the backbone of the smart grid enabling complete interoperability between new and existing infrastructure and proving new business cases.

In terms of communication for the smart grid, this is where universal agreement ends and the debates begin. One major topic of discussion in this realm is the use of public versus private networks. This subject has been discussed in conferences, webinars, forums, and various other media outlets throughout the industry. After listening to the voices of many industry experts, it is clear there are some key advantages of each option to consider before making a final decision:

Public

Bandwidth – Most utilities are just at the cusp of the new data explosion that will help optimize the grid in terms of increased efficiency and reliability. However, these benefits are going to require higher bandwidth to allow for real-time reporting of energy consumption to provide direct load control for reserves or peak shaving. Public networks can offer the bandwidth needed for implementing smart grid applications at a large scale.

Reliability/Maintenance – With public networks, ownership is not the concern of the utility. Should power and communication equipment go down in the case of a bad storm, utilities can concentrate on their core competency, restoring power back to the consumer. At the same time, the public cellular carrier will do what they do best, bring communications back online. Without a public network, utilities will undoubtedly feel pressure when it comes to maintaining communications.

Simplicity – Along the same lines as reliability, with public network infrastructure already in place, the utility can easily utilize this in developing effective pilot programs in a shorter period of time.

Private

Security – This is perhaps the most emphasized advantage of private networks. With control of the network, the utility has oversight to limit the number of entry points in the network making it easier to identify and prevent any threats. Moreover, the design of the private network can be implemented to directly address the security needs of mission critical applications.

Coverage – The motivation behind communication coverage differs between public and private networks. Utilities require more ubiquitous coverage over a territory rather than based on the number of consumers since communications are also important with remote equipment along the distribution grid such as capacitors or reclosers. Thus, private networks have more flexibility to provide the necessary coverage

Lifetime Cost – Private networks do require additional capital to put the infrastructure in place, however, in the long term private networks can be more cost effective due to lack of ongoing monthly subscription costs. These costs only increase as additional points are introduced into the system. This allows the typical private network to have a shorter payback period.

Overall, the best response to this debate, in my view, is one that we’ve all heard before, it depends. Each utility has a different variety of customer segments and must position them accordingly. I am finding that, most often, the way to best utilize the advantages of both public and private networks is to develop a hybrid solution allowing utilities to effectively address their customer’s needs. For example, a utility’s rural customer segment with poor cellular coverage would not be best served with a complete public network solution. Having a deep understanding of current operational capabilities, current/future smart grid approach, and the accurately segmented customer base will ensure the correct path is carved for developing and implementing a successful communications strategy.