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Toward 100% renewable energy

Australia was ranked 60th out of 61 nations on its climate change performance in 2015 and at the time of writing it continues to have among the highest per-capita greenhouse gas emissions of all the world's nations. This is a matter for national shame.

The graph below shows that Tasmania was running on 100% renewable electricity and South Australia had 90% renewable electricity around midday on 20th August 2016, while Australia as a whole had only 24% renewable electricity. Most of Australia's electricity was being generated by the burning of coal as it had been for many years.

This page was written 2016/08/21, modified 2018/06/10
Contact: email daveclarkecb@yahoo.com (David K. Clarke) – ©
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One of the purposes of this page, as with many of my pages, is to allow me to put my thoughts on record for my own reference – About me.


Introduction

 
Bungala Solar Farm, Stage 1, under construction
Bungalla Solar Farm
In mid 2018 a huge amount of wind and solar power, such as this near Port Augusta in SA, is being built around Australia.
Photo taken with my drone, 2018/05/10
In 2018 renewable energy made up over 70% of all new-built electricity generation installations world-wide. Quoting from the executive summary of the Renewables 2018 Global Status Report from the Renewable Energy Policy Network for the 21st Century:
"Renewable power generating capacity saw its largest annual increase ever in 2017, raising total capacity by almost 9% over 2016. Overall, renewables accounted for an estimated 70% of net additions to global power capacity in 2017, due in large part to continued improvements in the cost-competitiveness of solar PV and wind power.

Solar PV led the way, accounting for nearly 55% of newly installed renewable power capacity in 2017. More solar PV capacity was added than the net additions of fossil fuels and nuclear power combined. Wind (29%) and hydropower (11%) accounted for most of the remaining capacity additions. Several countries are successfully integrating increasingly larger shares of variable renewable power into electricity systems.

Renewable-based stand-alone and off-grid single home or mini-grid systems represented about 6% of new electricity connections worldwide between 2012 and 2016."
This demonstrates beyond any doubt that by 2017 renewable energy was fully viable and fully competitive with conventional, unsustainable, fossil-fuelled electricity generating methods.

What remains to be achieved is the storing of the energy generated by variable renewables so that it can be used as needed.

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Discussion

Energy generation in Australia on 20th August 2016
Energy generation graph
The graph includes the two large Australian electricity grids. The eastern Australian grid (the so-called National Electricity Market, NEM) and the South West Interconnected System (SWIS) in Western Australia. It excludes many small grids in remote areas. The two large grids provide the great majority of Australia's electricity.

As mentioned above, the graph shows that Tasmania was running on 100% renewable electricity and South Australia had 90% renewable electricity at the time. If this was possible for Tasmania and South Australia then, why would it not be possible for all of Australia most or all of the time?



 
A turbine of Clements Gap Wind Farm
Wind turbine
Near my home in Crystal Brook, South Australia
 
The innovative Sundrop Farm
Sundrop Farm
Solar thermal power station and some of the greenhouses, of Sundrop Farms installation at Port Augusta, South Australia
The very high level of hydro-power in Tasmania shown on the graph above was typical; it is normal for Tasmania to run on almost entirely renewable energy. At the time of writing, mid 2016, South Australia averaged around 37% wind power and 5% small-scale solar; on this occasion there was 72% wind and 18% solar. (By late 2017 SA was averaging about 48% renewable power.)

What could be achieved?

Tasmania runs on renewable energy most of the time and, as shown in the graph above, SA runs on an average of about 50% renewables all the time and on mostly renewable energy some of the time, the Australian Capital Territory has a target of 100% renewable energy by 2020. The other Australian states rely heavily on coal power.

There is little potential for more hydro power development in Australia; the country is predominantly low-lying and dry. There is, however, huge untapped potential for more wind and solar power. Australia could easily achieve 60% renewable electricity, 80% would not be particularly difficult, getting to 100% would be much more challenging.

The (Liberal-National coalition) federal government is holding Australia back because it is fixated on trying to prop up the dying coal industry.

More interconnection is needed

Tasmania has a lot of untapped wind power potential, less solar. Mainland Australia has huge untapped wind and solar potential.

The NEM grid connects South Australia with Tasmania through Victoria, but the capacity of the links involved is small. If the capacity of the links was greatly increased mainland Australia could feed large amounts of solar power into the Tasmania when it was plentiful, and Tasmania's hydro power could be conserved for the times when wind and solar were less plentiful on the mainland.

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South Australia has more potential for increased wind and solar power than many other parts of the country. If the electricity link capacities were greatly increased this potential could readily be developed and the power exported to the eastern states.

 
Energy storage capacity plotted against discharge time
Energy storage
No single method of storing energy is suitable for all needs. Some methods are good for storing and recovering energy over very short times, others over much longer times. Generally those methods used for short-term energy storage have low capacity, while those used over the long-term have much higher capacity.

CAES: Compressed air energy storage
PHS: Pumped hydro storage
SNG: Substitute natural gas

At the time of writing more than 99% of the world's energy storage was in pumped hydro (not considering water in hydropower dams as energy storage). Hydrogen and SNG were not proven on a commercial scale.

By mid 2018 the upper limit to the size of batteries had gone from the 30-40 MWh shown on the graph to more than 120 MWh.

Image credit: Hydrogen Energy Storage: A New Solution ot the Renewable Energy Intermittency Problem, Renewable Energy World; written by Mark Schiller; July 2014

More storage is needed

Renewable electricity does not generally come as it is needed. Coal can be mined as required, oil and gas can be pumped out of the ground as they are needed, but the wind does not necessarily blow, nor the sun shine, when we need electricity. Biomass can be burned to generate electricity in high demand periods, but if we are to change to high proportions of renewably generated electricity we must develop more energy storage systems.
  • Pumped hydro has been little developed in Australia and has a lot of potential for medium-term (hours up to a few days) energy storage. There is very little pumped hydro in Australia: Tumut 3, Snowy Mountains, NSW, commissioned 1973; Wivenhoe, Qld, commissioned 1974; and the proposed Kidston Mine, North Qld. Globally more than 99% of the world's stored energy is in pumped hydro; Australia is again a slow adopter in this technology which has great value in partnering renewable energy. (I've written about the practicality of the proposed Snowy 2 and mentioned four smaller South Australian pumped hydro schemes elsewhere on these pages.)
  • Conventional hydro stores energy in the longer-term (months to years), but has the disadvantage that it is only recharged by rainfall.
  • Compressed air energy storage uses electricity, when it is cheap and abundant, to compress air which can then be stored underground. When electricity is in high demand the compressed air is used to run generators. It is not yet a fully developed technology.
  • Fly wheels are particularly suited for storing and retrieving electrical energy over very short time periods – fractions of seconds up to about an hour.
  • Batteries have major potential for behind-the-meter electricity storage, and for grid-stabilisation functions, but at the time of writing were too expensive for anything but very short-term storage in the power grid.
  • Hot water can be used in a domestic and some commercial situations. Rather than exporting domestic solar power at very low prices it can be useful to use the electricity to heat water for later use. Similarly, in commercial situations, when electricity is plentiful and its wholesale price is low, it can be used to heat water. Storing hot water for periods of hours to a few days is relatively cheap.
  • Biomass can be stored for long periods and burned to generate electricity when it is needed, but the capital cost of building enough biomass power stations to fill-in for wind and solar would be enormous, and the amount of biomass that can be grown is small in terms of total electricity demand.
  • Huge amounts of energy could be stored as hydrogen gas long-term in geological formations, and hydrogen could be burned to generate electricity in existing gas-fired power stations with only slight modifications. At the time of writing conversion of water into hydrogen and oxygen powered by electricity was expensive, but the cost was decreasing.
Rather than me writing in detail about the energy storage options here I suggest the reader looks at the following:

More flexibility is needed

Increased amounts of renewable energy in a power grid create challenges that must be met with innovative responses. Roof-top solar power is, by its nature, widely distributed rather than having the centralisation of conventional power stations.

Renewables do not provide the ancillary services such as voltage and frequency stabilisation that comes with conventional generation.

Demand-side management, for one thing, is needed to help handle the variable nature of renewable energy generation. This involves adjusting retail electricity prices dynamically as the amount of power in the grid changes so that consumers can modify their times of electricity use to better match consumption with generation.

See DTU International Energy Report 2015.

Nuclear power

Nuclear power has little roll to play in the transition to sustainable energy. I have written on the disadvantages of nuclear power on another page on this site.
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Relevant links

Other links are scattered through the text.

Renewables 2018 Global Status Report from the Renewable Energy Policy Network for the 21st Century – recorded that over 70% of electricity generation installations in 2017 were renewables.

Wikipedia: Energy Storage

100% renewable energy for Australia, University of Technology Sydney, Institute for Sustainable Futures.

100 per cent renewable study – modelling outcomes Australian Department of Environment and Energy and the Australian Energy Market Operator, 2013.

Australian Sustainable Energy Zero Carbon Australia Stationary Energy Plan; lead authors Matthew Wright and Patrick Hearps, 2010.






Index

On this page...
Discussion
Introduction
Links
More flexibility is needed
More interconnection needed
More storage is needed
Nuclear power
What could be achieved?
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