A 400kW solar PV system – said to be the largest privately owned rooftop system – is to be constructed on a new data centre in Port Melbourne.

The system is being built by Melbourne-based solar company Energy Matters on behalf of NEXTDC, which is building a network of data centres in the state capitals.

It will spend around $1.2 million for the 400kW array, to be erected on its M1 data centre, but expects to install larger 1MW systems on data centres to be built in Sydney and Perth.

Bevan Slattery, the CEO of NEXTDC, says he sees it as a “test bed” for future sites. “When we are designing future data centres, we want to make sure we have got a solid understanding so we can incorporate more solar panel.”

He said the Melbourne centre had to go to market quite quickly, and cannot incorporate more than 400kW. “The next generation of data centres will be working with a lot more PV cells on the roof.”

Data centres are highly energy intensive, and the M1 centre – with around 18,000 square metres – will have a peak demand of around 22MW.

However, Slattery says this is much reduced from loads of 30-35MW from “traditional” data centres, thanks to a range of energy efficiency measures – such as insulation and natural air cooling – and technologies such as cogeneration and trigeneration.

Indeed, the M1 facility will have a 4MW trigen plant – one of the large such installations in the country. “We’d like to get more than 4MW from alternative low carbon sources,” he said.

Slattery says he is not sure that such arrays necessarily lower the data centre’s energy costs in the short term, but it certainly will as energy costs rise. “We have corporate clients and government clients that value carbon reduction technologies – whether its tri-gen or solar PV or direct free air cooling. It allows us to pass on a significant reduction in energy consumption from the grid.”

The installation will be the first solar array for a data centre in Australia, and the Asia-Pacific, the company says. But it follows a trend in the US where industry giants are investing in large scale solar projects. Google has four solar farms underway in California and Apple recently announced a project to build a 20MW solar farm at its Maiden data centre facility in North Carolina.

Energy Matters managing director Jeremy Rich says commercial scale projects such as these have become economically viable following the sharp slump in PV module prices in the past 18 months.

“We see lots of these deals being done by lots of different players,” he said. “As one of first truly large-scale, privately funded and owned rooftop PV solar systems, we see this as the start of something big for commercial solar in Australia.”