According to Professor Mark Diesendorf, it is feasible for Australia’s electricity to be supplied by 100 per cent renewable energy- here’s how.
In the past, relying on renewable energy as a sole power source was seen as far too risky because of the variability and uncertainty of the weather.
Now that the problem of ‘consistency’ has been cleared up, it is now understood that electricity industry supply would not be significantly affected when primarily using renewable, clean energy.
To illustrate this, South Australia is home to a number of gas-fired power stations, two coal-fired and over 15 operating wind farms. 27 per cent of electricity is now supplied directly from wind power, which resulted in the closing down of both coal stations.
The SA power network is now consistently supplying sufficient electricity with no need for additional fossil-fueled energy.
Similarly, Germany uses wind generated power for respectively 100-120 per cent of their electricity.
How could there be no issues with supply?
However unlike Germany, Australia’s National Electricity Market (NEM) does not have transmission links in neighbouring states which help to balance supply and demand with large wind penetrations. So, how could more renewable energy be used without damaging the supply of electricity?
Researchers from the University of New South Wales (UNSW) have completed thousands of online simulations testing the NEM with various renewable energy technology combinations, scaled to a level where they meet 100 per cent of demand.
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“We use actual hourly electricity demand and actual hourly solar and wind power data for 2010 and balance supply and demand for almost every hour, while maintaining the required reliability of supply,” said Professor Diesendorf.
An optimal combination of renewable power sources was determined using 2030 renewable energy cost projections, found in the federal government’s Bureau of Resources and Energy Economics (BREE).
The mix broken down is:
-20 per cent solar PV
-46 per cent wind power
-22 per cent solar thermal
-6 per cent already existing hydro power, and
-6 per cent biofuelled gas turbines
It may be surprising that two-thirds of the total annual energy supply can be met by unreliable energy sources- solar and wind power. But solar PV and wind power only fail to meet electricity demand a few times each year; winter night peak demand after low-sun days combined with regional low wind levels.
Since these periods are scarce and low duration, only a small levels of generation needs to come from the other renewable energy sources which don’t rely on the weather.
No more batteries
The UNSW researchers also revealed that many places could operate solely using renewable energy without the need for baseload power stations.
“Indeed, in electricity supply systems with a lot of renewable energy, inflexible coal and nuclear baseload power stations get in the way. What we really need to balance the variability of wind and photovoltaic solar are the flexible renewable energy power stations: hydro, solar thermal and biofuelled gas turbines,” said Professor Diesendorf.
With a small amount of storage from solar thermal and hydro, a reliable supply can be maintained. This eliminated the need for costly batteries and hydrogen fuel cells.
Australia’s RET could (should) be much higher
On a world scale, Australia’s Renewable Energy Target of 41,000 gigwatt hours each year by 2020 isn’t exactly ambitious.
Compared to countries such as Germany, Denmark and Scotland, it’s really quite modest considering the vast availability of renewable energy resources Australia has.
Transitioning to a 100 per cent renewable energy generated electricity supply will reduce greenhouse gas emissions immensely, cut land degradation and pollution, as well as ensuring energy security and local jobs. It is technically feasible and an affordable option, that should be seriously considered.
Photo courtesy of Timothy Tolle