[theage.com.au] It’s a noise wall with a difference. Drivers heading along the Tullamarine Freeway from the city to Melbourne Airport, or towards Bendigo, can see it. About half a kilometre from the Bulla Road overpass, the long yellow wall that separates the freeway from North Essendon has a crown of glass. That glass is a small solar power station with a peak power output of 24 kilowatts. Part of the new Tullamarine-Calder interchange, the “mini power station” has been operating for about three weeks.