Improved technology is driving fresh interest in high-speed Internet systems that can be grafted to existing power grids. Known as Broadband over Powerlines, this technology offers utilities incremental revenue sources and can enhance grid operation.

Raymond Blair, IBM, USA

Over the past several years, power utilities’ attempts at piloting and testing Broadband over Powerlines (BPL) services have mainly been failures or inconclusive. In most cases they have found themselves outgunned in the highly competitive market of providing Internet access to the home by both telcos and cable companies. However, utilities have started taking a second look at this unique technology and with recent advances have found that this communications transport offers a unique solution enabling them to control and manage their power infrastructure to an unprecedented level.

BPL explained

BPL and power line communications (PLC) are sets of equipment, software, and management services that, when superimposed onto the electric grid, provide users with communications means over existing power lines. In the US, the two terms are used to distinguish between broadband and narrowband communications; elsewhere, PLC is generally used to mean the underlying communications technology and to represent both kinds of communications.

This concept is not new. Utilities have used their power lines for communications and control for over 30 years. Mostly narrowband, requiring speeds of 56 kbps, these applications have included automated meter reading, monitoring, and simple control of grid operations.

In the early 1990s, several utilities, mainly in Europe, began to research PLC technology that could generate high bandwidth signals. Research continued throughout the 1990s; trials occurred, and the technology matured. Today, commercial deployments of varying degrees are taking place globally, with more in Europe than in the US, for instance. This is due to the difference in power topology between North American grids and other nations. Typically, the average transformer outside the US supports between 150-200 customers, whereas in the US the average transformer supports between five and six households.

IBM has undertaken pilot projects to demonstrate the benefits of BPL technology to utilities and customers alike
Click here to enlarge image

BPL operates in the 1-30 MHz range (where ‘short wave’ and other radio communications take place). The present technology delivers up to 200 Mbps to the transformer, and the next generation is predicted to deliver 1 GB Mbps. As with cable-based broadband, capacity on the low voltage network is shared, potentially affecting speed; still, integrators are engineering their networks to provide fully competitive systems with cable and digital subscriber lines (DSL), the telephone line-based broadband alternative. Unlike cable and DSL, which are called ‘asymmetric’ technologies, BPL has equivalent upload and download streams, making it ideal for file sharing applications and the new on-line gaming offerings.

Grid connection

The electrical power grid is, of course, ready-made and, in the developed world, nearly universal. The BPL system requires a connection from the Internet backbone, at or around a power substation, through a device known as an ‘injector,’ which converts digital signals into radio frequency (RF) signals. These signals travel down the medium voltage power lines to repeaters, which receive and boost the data signals. A final device transfers the signals from the medium voltage lines to the low voltage lines entering homes and businesses. Once inside, the signal can be obtained from any electrical outlet with a BPL modem, which converts the RF signals to a digital stream. Alternatively, the signal can be beamed from electricity poles via a wireless connection, instead of using the low voltage lines.

Utility benefits

The benefits for utilities can be broken into two classes: better and cheaper power delivery, and new revenue streams. Essentially, BPL offers electric utilities a high value communications network that can enhance the power delivery system. Today, utilities cannot tell outside of their substations the status of their service. If a household or business loses power, their utility would know it only if the customer calls to notify them. BPL facilitates activities such as automated outage detection and restoration, a major customer service measurement.

In addition, BPL enables remote connection and disconnection of electric service, more efficient demand-side management programmes and meter readings. Ultimately, with BPL, utilities will be able to capture real-time usage data and apply it so that they can offer incentives to customers who use power during off-peak periods. A one to two per cent reduction in peak load requirements would result in major cost savings, since most utilities buy this power on the open market at very high rates.

BPL provides users with a means of communication over existing power lines
Click here to enlarge image

In other words, BPL endows the grid with ‘intelligence’. The ability to capture real time data from the multitude of devices on their grid and then be able to perform advanced analytics to predict outages and maintenance needs is of tremendous value to utilities.

The new revenue stream comes from the combination of Internet, voice, and video service that the utilities would be able to provide. Utilities could choose whether to provide these services themselves, partner with companies to provide them, or simply rent their lines to providers and collect a fee.

Consumer benefits

The consumer benefits are largely the obverse of those to utilities. To begin, there is the more reliable and efficient provisioning of power to the home. It would take minutes to initiate power rather than days. Since – unlike the cable and DSL networks, which are closer to metropolitan areas – the power grid extends to nearly every home in the developed world, every home can in theory have access to BPL services and more (such as enhanced security, and ‘smart homes’). In addition, since uploading is as fast as downloading, homes and businesses could communicate much faster and more easily. And with the entrance of a third major class of provider into the broadband market, prices should fall, service should improve, and new products should proliferate.

In the future, BPL could allow any plugged-in device to talk to any other. The potential is mind-boggling: just-in-time maintenance, new charge-by-usage business models, machine-to-machine collaboration, low-cost ‘grid’ computing infrastructures, and new revenue streams for utilities to ‘enable’ devices on the network – to name a few possibilities. From telemedicine to surveillance to supercomputing to the automation of vending machines, the applications – and benefits – are virtually limitless.

Potential risks

The first operating principle for utilities is that they do nothing to jeopardize power provision – and BPL, a capability ‘overlaid’ on the power grid, cannot threaten it. In the US, the Federal Communications Commission (FCC) has endorsed the technology but still there are concerns. One is radio interference. Through new capabilities such as ‘notching’, where specific frequencies can be removed from the deployment, this interference can be eliminated.

In the US, Public Utility Commissions (PUCs) have not decided on how to classify BPL investments. But the FCC endorsement of BPL, issued in the autumn of 2004, is a strong signal that PUCs should look favourably on BPL and, at the very least, do nothing to impede its development. Texas was the first state to support this technology and many others will follow suit soon.

Another drawback is that BPL might seem risky to utilities since many of the BPL providers to date have been very small companies. Utilities are very conservative organizations and are chary to invest in technology that is supported by firms that might not be operating in ten years. Utilities need to be absolutely certain that this equipment is stable and that their providers will be around since they amortize these investments over ten to 20 years. Fortunately, major players such as Mitsubishi and Motorola have entered the arena and have removed many of these fears.

Current activity

Any grid-connected home can in theory access BPL services
Click here to enlarge image

The PLC Forum estimates that utilities in over 40 countries have launched over 80 PLC initiatives. BPL activity is greatest in Europe and increasing in Asia, where countries such as China see it as another way to provide advanced technology to the people. Even in Africa, the poorest of the world’s continents, countries including South Africa, Botswana, Ivory Coast and Ghana are experimenting, as their electricity grids are more inclusive than their telephone or cable networks. In Eastern Europe, where less than 20 per cent of homes have more than one conduit to the dwellings and the topography is not conducive to wireless delivery, BPL is the only way to provide broadband access to their populations.

In the US, utilities serving over 50 million customers, or about 17-20 per cent of the country’s population, have technical or market trials in progress.

Recently, in partnership with IBM, CenterPoint Energy Houston (Texas) Electric, LLC opened a BPL technology centre at one of its Houston facilities to examine the uses of BPL, both for utilities and their customers. Also, with IBM, CenterPoint Energy has conducted a limited pilot programme covering 220 homes to show the capabilities of BPL. For its part, IBM is working with utility companies globally to help them improve reliability, customer service, and operational costs through the adoption of advanced technology and new business processes. BPL is one of the several technologies that reinforces and enables IBM’s vision of building the intelligent utility network, where real-time information about energy usage and the condition of network assets is used to improve decision-making.