An Australian engineering conglomerate today revealed plans to embark upon the world’s biggest Solar power project. Worley Parsons, a provider of professional services to the energy sector, announced an initial 250-megawatt unit which may start up as soon as 2011. Peter Meurs, managing director of WorleyParsons’ EcoNomics unit, said today in Sydney that some $34 billion of projects may be built by 2020. In an interesting signal of old world power investing in green tech, the finance is being providing by companies including BHP Billiton and Rio Tinto, two of the worlds largest mining companies.

Australia’s government last year set a target for renewable sources to supply 20% of the nation’s electricity by 2020 and will introduce emissions trading in 2010 as it seeks to cut greenhouse gases blamed for global warming. The solar thermal process uses a reflective trough that concentrates energy from the sun to heat oil, generating steam for conversion into power.

WorleyParsons, which today posted a 46% increase in second-half profit, gained $1.23, or 3.7%, to $34.68 in Sydney trading.

The profitability of the plants would rely on extra revenue provided under the Australian Government’s renewable energy certificate regulations and the cost to be placed on carbon emissions, said Peter Meurs. That would make the process competitive for supplying electricity during daytime peak-demand periods, he said.

WorleyParsons’ study is backed by companies including Woodside Petroleum Ltd. and Fortescue Metals Group Ltd., the Sydney-based company said today in a presentation sent to the Australian stock exchange. Wesfarmers Ltd., Sydney Water Corp., Delta Electricity, Western Power Corp. and Verve Energy are also participating.

WorleyParsons wouldn’t have an interest in any of the 34 plants that could be built by 2020, Meurs said. Construction of any projects depends on other companies taking an initiative to invest, he said. Some of the companies are “champing at the bit” to start a bankable feasibility study for a project and the first venture may be approved for construction early next year and start up in 2011, he said.

Potential locations include the Pilbara region of Western Australia, South Australia, Queensland and New South Wales, Meurs said. Solar thermal plants could provide half of Australia’s target for renewable energy use, WorleyParsons said.

”If we’re serious about the target of 20%, then we need this kind of approach to be able to do it,” Meurs told reporters on a conference call. ”The timing is just right to do it. We’re planning a vision here of what could happen.”