Broadband over powerlines

Electrical powerlines like the ones pictured can also be used to deliver broadband internet access.

Broadband over powerlines, or BPL, is a relatively new technology designed to use the existing electricity network to deliver high-speed internet access.

The concept works by using the electricity wires to convey digital signals, in some respects similar to how phone lines are being used to convey these signals in ADSL.

BPL technologies offer the promise of delivering broadband internet access to every powerpoint in a home or business. With a simple adapter any internet-capable device can be connected without running additional wires or managing the security issues of a wireless network.

How Broadband over Powerlines works
Source: Mitsubishi Electric

However, BPL still has a number of challenges to overcome. As electricity wires are very 'noisy', BPL currently requires many 'repeaters' to reinforce the broadband signals to ensure that data remains readable and is not corrupted during delivery. This increases the cost of implementing BPL networks.

Many electricity networks use high voltage powerlines to transmit electricity across the electricity grid, , and then use transformers to 'step-down' the voltage before it is fed into homes. However, BPL signals cannot easily pass through transformers, requiring special equipment.

Finally, BPL services enter houses through their electrical switchboxes and are delivered to each room using the electricity circuits. Older electrical wiring can have difficulty transmitting the broadband service and some homes may need rewiring for reasonable internet access speeds.

BPL services have already been introduced in a few areas around the world. It is currently being trialed in Tasmania and the ACT, as well as several regional areas.