A 20 per cent renewable energy target is a significant, but not enormous target. In 1997 - 2000 when Australia was deigning the original renewable energy target (MRET), Australia was already producing approximately 10 per cent of its electricity from renewable energy. MRET was supposed to lift this figure to 12 per cent. Today Australia is aiming to make it 20 per cent – only another 8 per cent.

The maths

According to the Energy Supply Association of Australia (esaa), electricity consumption in 2005/06 was around 220,000 gigawatt hours (GWh) and will rise to around 300,000 GWh by 2020, meaning a 20 per cent target of 60,000 GWh. With the 15,000 GWh that existed before MRET began, this means a new MRET target of 45,000 GWh. Australia is already on the way to achieving this. In 2006 5,200 renewable energy certificates (RECs) were created. This means that the additional renewable generation required is in fact approximately 40,000 or 50 per cent of the load growth over the period from now until 2020.

Where will all the new renewable energy come from? Has Australia got the capacity to make it all? Again, the simple answer is yes. Australia has enormous potential resources across a wide range of technologies.

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Australia’s renewable technologies

Hydro: Hydro energy makes up most of the pre-1997 renewable energy from large schemes in places such as the Snowy Mountains and Tasmania. There are limited opportunities for new, large hydro generators, but there are still some sites within the existing schemes for new generators. There are also opportunities for upgrading existing generators and numerous potential sites for mini hydro schemes on existing water infrastructure.

Wind: Australia has a world class wind energy resource, with many areas driven by the famous roaring 40s winds and achieving capacity factors greater than 30 per cent. The CSIRO has estimated 200,000 GWh per year could be exploited in Australia. Wind generation is one of the lowest cost sources of renewable generation and will make up a major proportion of new renewable generation.

Solar: Australia is the world’s sunniest continent with abundant solar resources and a track record in commercialising and developing photovoltaic technologies. The domestic potential for solar technologies is large, with millions of roof tops for small installations and large areas for potential large scale PV and solar thermal.

Geothermal (Hot Rocks): Australia has some of the hottest near surface rocks in the world which offer great potential for low cost electricity generation. Hot Rocks can produce continuous base load generation and while the technology is still in the development stage it is expected to be producing significant quantities of energy within the next ten years. Areas of high potential include the Hunter Valley near Newcastle and the Cooper/Eromanga Basin in South Australia

Bioenergy: Bioenergy provides reliable base load power. Biomass currently contributes around 750 megawatts of electricity generation in Australia. The potential for further expansion in bagasse; left over materials from forest and other agriculture and municipal waste is very large.

The future?

Recent modelling by McLennan Magasanik Associates predicted that a 20 per cent renewable target would deliver a mix of plant types:

Biomass 17 per cent Geothermal 23 per cent Wind 56 per cent Hydro 4 per cent

Developing technologies

One thing is clear about modelling work like this – trying to predict the future is difficult. Think back to 1996 and all the changes that have happened and all the surprises that technology has since delivered. An enormous amounts of work is going on around the world to look at new technologies such as large scale solar PV, large scale solar thermal, tidal energy, wave power, ocean current to mention a few. Breakthroughs in any of these could change the mix of renewables completely.

Networks

One issue that is always brought up by those who say it cannot be done is the electricity network. Advocates for the 20 per cent target are told that the current network cannot cope with all the new renewable energy the scheme will require and that many millions of dollars will need to be spent to deliver renewable generation to consumers. The fact is that whatever form of generation Australia employs, vast amounts of money will need to be spent on upgrading the networks. In fact, the growth of distributed small scale renewable generation such as solar PV, min-hydro and biomass located near the customers will actually reduce the need to build new networks.

Variability

Another argument against the 20 per cent target is that the vast amounts of wind and other variable generation will make the power system unmanageable with many fossil fuel generators required to be run to keep the lights on. Part of the reasoning behind this argument seems to be an assumption that all customer loads are continuous, unchangeable and that large generators never fail. Wrong. Customer load is spread around and so the changes in load are smoothed over. Moreover, there have been tools used to predict the demand for a long time, so the predictions are usually pretty good. The variations in output from wind farms spread across Australia are also smoothed out and the total generation becomes more predictable. On top of this, the Federal Government has given $14 million to build a wind forecasting system to predict wind farm output. As the history of wind generation in Australia grows, this forecasting will get better.

Australia can deliver 20 per cent renewable energy by 2020. It is possible because there is plenty of capacity out there. Will the network cope? Yes it can. Can variability be managed effectively? Yes it can.