Solar Energy In A Tank

The Australian Financial Review, Page: 22
Monday, 14 August 2006

The first stage in developing a revolutionary new energy source for Australian industry is being trialled in Newcastle, one of the country's fossil fuel heartlands. The technology uses high temperature solar energy to chemically change any hydrocarbon containing gas, such as coal-seam methane or natural gas, to produce an enhanced synthetic gas - christened SolarGas by its CSIRO developers. SolarGas contains about 26 per cent more energy than the coal-seam methane or natural gas used to feed the process, produces 26 per cent less carbon dioxide during production and can be used not only for solar electricity generation but also as a feedstock for either SolarDiesel or for hydrogen extraction. Many people still regard hydrogen as one of the more likely alternative energy options in the future.

The significance of the hybrid solar/fossil process that produces SolarGas is that it uses a renewable energy source - the sun -to extract from existing fossil fuel resources a new, clean, energy source. It means Australia could become a producer and user of clean energy. SolarGas is useable as it is, or if a hydrogen economy does develop, then hydrogen extracted from SolarGas can be used in fuel cells, which are at an advanced stage of development and could be in motor vehicles in coming decades. Hydrogen is also the intended fuel for microscale gas turbines, which are seen as an opportunity to decentralise power generation by creating a network of small facilities powering townships, suburbs or even individual buildings.

SolarGas is now being tested at the National Solar Energy Centre (NSEC) in Newcastle as part of the Energy Transformed National Research Flagship program. The project is a collaboration led by CSIRO's Division of Energy Technology and includes the Department of Education, Science and Training, NSW's DEUS, Solar Heat and Power, DLR Germany and the Australian National University. The solar/fossil generator at the heart of the process comprises a solar array tower that uses 200 mirrors to concentrate more than 500kW of energy, capable of temperatures of more than 1200°C. Greater capacities are provided simply by replicating this single tower field with multiple fields.

The solar reforming process does not need such high temperatures and the subsequent new gas produced by this heat process becomes, in effect, a storable and transportable form of solar energy that has been created from a fossil fuel. It creates a way for Australia's vast reserves of fossil fuels, particularly coal, to become an integral part of the future, renewable energy matrix. CSIRO's Wes Stein, project leader of the NSEC, says the significant advance represented by SolarGas is that it represents solar energy that has been transformed into a chemical form that can be stored and transported. He believes this will go a long way to making the economics of solar energy comparable to existing energy sources, especially as fossil fuel industries increase their expenditure on zero-emission technology to meet increasingly stringent greenhouse gas emission targets.

Mr Stein believes the cost of zero-greenhouse gas energy sources, whether from renewables, fossil fuels or nuclear technology, will determine market share. Meanwhile, the country remains dependent on fossil fuels, particularly coal. Only about four per cent of electricity is generated from renewable sources such as solar, wind and hydro. The mirrors for the solar array tower at the Newcastle research facility were built by Solar Heat and Power Pty Limited, an Australian company specialising in the development and construction of large-scale solar concentrators.

Chairman Dr David Mills says the company is bidding for a 20,000 square metre scaled-up version of the Newcastle array in Germany. He points out the high temperatures produced by a solar tower array can be used to drive existing energy applications such as steam production, desalination, photovoltaic (PV) solar energy or for industrial process heat. Dr Christian Saltier, research area manager of Solar Materials Conversion with project partner DLR Germany, describes SolarGas as an opportunity for Australia to continue developing technology for a sustainable energy economy. "The hydrogen economy is being promoted worldwide and Australia is part of that movement," he says.

"There is the possibility of hydrogen becoming the energy carrier of the future and there is potential for Australia to become a major provider of that renewable energy." Dr Saltier says that the research being conducted by CSIRO, especially at the NSEC, is of vital importance to the global hydrogen movement. Electricity production from SolarGas has three stages. The first stage involves capturing the sun's heat with the solar tower array.

The tower comprises 200 closely packed mirrors that track he sun as it moves across the sky. Each mirror is concave to direct the sun's rays to a focal point on the tower which is positioned to accommodate seasonal changes without shadowing any mirrors, Mr Stein says the design has enabled the closest packing of mirrors anywhere in the world. The second stage is to apply the energy captured by the tower. The focal point for the mirrors concentrates the collected energy on;atalyst-packed receiver tubes through which water, vapour and natural gas flow.

The heated gases react to become SolarGas which can then be used to power a turbine - new efficiencies coming from the fact it can deliver 26 per cent more energy than natural gas. The third stage involves using the turbine to generate electricity. Mr Stein says the development comes as the world is clamouring for more energy, but at the same time must lower greenhouse gas emissions: "We can't afford not to develop solar energy, the world's largest sustainable energy source," he says. In 2003-04 Australia used 1,307,000 terajoules of black coal, 678,000 terajoules of brown coal and 343,000 terajoules of natural gas to generate 237,000 gigawatt-hours of electricity - producing more than 190 million tonnes of greenhouse gases (ABARE, Australian Greenhouse Office).

The significance of the issue is not lost on the fossil fuel industry, which in other energy projects is collaborating with CSIRO to develop Post-Combustion Capture technology. This involves the capture of carbon dioxide at power stations, then securely storing the gas deep underground. CSIRO Energy Technology is also providing technical expertise to support the use of Australian coal in advanced, low emission power generation technologies and to help optimise the processes of existing power stations. The SolarGas project was highly commended at the 2006 Engineers Australia Engineering Excellence Awards (Newcastle) and has been recognised by the International Partnership for the Hydrogen Economy (IPHE) as one of the world's top 10 demonstration projects.

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