Introduction
|
"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.This demonstrates beyond any doubt that by 2017 renewable energy was fully viable and fully competitive with conventional, unsustainable, fossil-fuelled electricity generating methods.
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."
What remains to be achieved is the storing of the energy generated by variable renewables so that it can be used as needed.
|
|
Discussion
Energy generation in Australia on 20th August 2016
|
|---|
|
|
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? |
| ||||
|
(SA's renewable generation was steadily increasing. In the twelve months to 2021/02/09 SA generated over 60% of its electricity renewably.)
Update, December 2023
In the year to 2023/12/16:- 71% of SA's electricity demand was generated by renewables (45% wind, 26% solar);
- 93% of Tasmania's electricity was renewable (73% hydro, 17% wind, 3% solar);
- 38% of the electricity on Australia's main grids was generated sustainably.
What could be achieved?
Tasmania runs on renewable energy most of the time and as of early 2021 SA was running on an average of about 60% renewables and on nearly 100% renewable electricity some of the time. The Australian Capital Territory had achieved its target of 100% renewable energy by 2020. The other Australian states continued to rely heavily on coal power but had strong ambitions of improving.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.
|
|
| ||||
|
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.
- European Association for Storage of Energy: Energy storage technologies
- Technical University of Denmark, National Laboratory for Sustainable Energy DTU International Energy Report 2015
- Grid energy storage in Wikipedia.
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.