Horizon Power is currently investigating technologies that will allow for continued investment into renewable energy, which can be fed into isolated off-grid power systems in a cost-effective way.

Integrating renewable energy into remote systems

With a service area that spans 2.3 million square kilometres, Horizon Power’s small and remote systems typically operate with a single source of fossil-fuel generation and a ‘radial’ network, which may service as few as 70 customers.

The ability of these and other isolated networks to manage large numbers of renewable energy systems is limited given the potential negative impact of these non-dispatchable systems on network quality and reliability.

For Horizon Power, the inherent challenge of operating isolated networks, combined with strong local advocacy for renewable energy and an appetite for customers to install large photovoltaic (PV) systems driven by Federal and state incentives has resulted in the electricity company being confronted with the need to set limits on uncontrolled renewable energy quicker than most.

In two of Western Australia’s bigger towns – Broome and Carnarvon – Horizon Power has reached the renewable energy network penetration limit for dispersed, non-dispatchable renewable energy systems of 1,000 kilowatts (kW). Other towns, where take-up rates have been similarly intense, and at least 14 remote communities where network capacity is so small that even very small amounts of dispersed, non-dispatchable renewable energy systems have an impact, may soon reach their limit.

Horizon Power is now restricting the size of renewable energy installations to a maximum of 1.5 kW per eligible customer in Broome and Carnarvon. Accepting 1.5 kW systems allows Horizon Power to continue to provide a renewable energy option to customers while still maintaining the security and reliability of power supplies given the renewable energy produced from such systems is generally consumed at the premises, so has minimal impact on the network.

Horizon Power Senior Engineer Generation Technology David Edwards acknowledges the challenges posed by operating isolated networks, saying “the utility is committed to using renewable energy sources wherever possible and is investigating a number of potential solutions to allow renewable energy network limits to be increased.”

“Horizon Power welcomes the opportunity to connect renewable energy generation from dispersed customer-owned systems and embraces the empowerment of its customers to manage their own energy generation and reduce their reliance on fossil fuel-based power,” he says.

Solutions

Horizon Power has embarked on a program to investigate technical options for augmenting its networks and power stations to allow more dispersed renewable energy installations to be connected.

It is exploring system management options that will facilitate higher renewable energy network penetration including:

• Developing energy management technology such as bespoke control systems married with energy storage devices
• Cost-benefit analysis of alternative power generation operating philosophies
• Statistical data analysis on how renewable energy systems interact with the network
• Consultation with other utilities to install monitoring devices and test potential solutions on some customer installations
• Investigating whole-of-system solutions that would allow increases to system limits in the future.

At the same time, Horizon Power is installing centralised and carefully-managed renewable energy generation into its newest power stations to reduce the carbon intensity of its operations.

The combination of energy storage technology and the PV installations used in the solar-diesel power stations in Marble Bar and Nullagine produce renewable energy penetration rates of between 60–90 per cent during the daytime.

By the end of 2011, two remote Aboriginal communities in the East and West Kimberley, Kalumburu and Yungngora, will also have the latest in solar-diesel power station technology and network design as part of the Aboriginal Remote Communities Power Supply Program funded by the Office of Energy in Western Australia.

“Horizon Power is committed to using renewable energy, and we are working to become a centre of excellence in the field of maximising levels of renewable energy in remote and isolated power systems,” Mr Edwards says.

“There are a host of technology options being trialed around the world at the moment, and through the sponsorship of university-based studies, the formation of strategic partnerships with other utilities and research centres, and the trial of power system technologies, Horizon Power aims to strike a balance between the continued integration of renewable energy sources, the reliability of the power system and the costs associated with maintaining quality of supply.”