Broadcast site embraces renewables

Wind and solar used on remote site

Critical communications specialist Broadcast Australia has commissioned its first broadcast transmission site to be majority powered by renewable energy. The Mount Owen site near Queenstown in Tasmania has been recently upgraded to use site-generated wind and solar power, which are together expected to reliably meet the site’s 8 kW power needs for 80 to 90% of the time.

The Mount Owen site broadcasts a range of national and commercial analog/digital radio and television services to the Queenstown and Zeehan area, plus supports critical radio communications for local emergency services. According to Broadcast Australia Energy Systems Engineer Gary Cafe, the power demands of new services, such as digital television, were starting to exceed the capacity of the existing mains feed.

“As this is a remote facility, providing on-site renewable energy generation was a commercially viable option to enable the broadcast of digital television to the local area, compared with the cost of upgrading the mains feed,” Cafe said. “At 980 m above sea level, Mount Owen benefits from a strong prevailing south-westerly wind, making it ideal for wind turbine power generation.”

A constant-output horizontal-axis wind turbine has been erected on a 15 m-high mast. The turbine is rated for maximum power generation of 15 kW for a wind speed of 12 m/s (43 km/h). The wind turbine is supplemented by 36 m² of monocrystalline solar photovoltaic panels, rated at 5 kW peak generating capacity.

The site is designed to operate primarily from wind and solar power. Excess generated electricity charges two banks of batteries - each rated at 2900 Ah - which supplement the power supply when the combination of wind- and solar-generated power drops below the site demand of 8 kW. The batteries alone can provide power autonomy for two days.

During periods of limited on-site wind or solar generation, the balance of the site load can additionally be met from mains power, or from an on-site 31 kVA diesel generator. This is set up to start automatically, but can be activated remotely from the network operations centre. Equipped with a 1000 L fuel reserve, the generator can provide total site power for ten days.

Engineering a system to provide a reliable power supply from such variable sources has been demanding for Broadcast Australia. “Our requirement for a reliable mid-sized wind generator was something of a niche application, for which there isn’t a great deal of expertise in the marketplace,” said Cafe. “However, we have overcome the many challenges to achieve an outcome that allows these new technologies to be evaluated with very little risk to the on-site services.”

With the infrastructure successfully installed, the Mount Owen transmission site is now able to reliably provide most of its power demands from renewable sources. “This will potentially save up to 60 MWh of conventional power each year from this site alone,” said Cafe. “The experience gained here will have far-reaching implications for Broadcast Australia’s carbon footprint for the future, as renewable power options are considered for a multitude of additional sites.”