Antinuclear

Australian news, and some related international items

Complex, but very feasible, transition to renewable energy

a plausible Australian scenario for the next decade is the phase-out of several coal-fired power stations simultaneously with a rapid growth in efficient energy use, solar hot water, wind power and bio-electricity. These clean technologies would buy us time to commercialise solar thermal and possibly geothermal power and then integrate them on a large scale in the 2020s as the remaining coal stations are shut down. Thus Australia could achieve a sustainable electricity system……

A mix of sources with appropriate transmission links and ‘smart grids’ could provide a reliable system of 100% renewable electricity.

The base-load myth Online Opinion, By Mark Diesendorf –  , 2 May 2011“…….Several countries, including Australia with its huge renewable energy resources, could make the necessary transition to an electricity generation system comprising 100 per cent renewable energy over a few decades.

Case studies include the UKEurope, Germany [Klaus 2010. Energieziel 2050: 100% Strom aus erneuerbaren Quellen], Denmark [Energy, 34: 524–31], northern Europe [International Journal of Energy Research, 32: 471–500], New Zealand [Energy, 34: 524–531], and the whole world [Energy Policy 39:1154-1190; Int. J. of Global Energy Issues, 13, nos 1-3;]. Supplying base-load power is not a major obstacle. “……to the challenge of generating all of Australia’s electricity from renewable energy, the deniers repeatedly utter the simplistic myth that renewable energy is intermittent and therefore cannot generate base-load (that is, 24-hour) power.

Firstly, night-time demand is low compared with daytime demand. This base-load demand could be further reduced by improving efficiency of energy use and by the forthcoming phase-out of electric off-peak hot water and its replacement with solar hot water and instantaneous gas. This is the reverse of previous policies, which deliberately encouraged an increase in night-time demand to allow inflexible coal-fired stations to generate 24/7.

Secondly, some renewable energies are just as reliable sources of base-load electricity as coal, while being 50 times less greenhouse polluting. These include bio-electricity generated from burning the residues of crops and plantation forests, concentrated solar thermal power with low-cost thermal storage, and hot-rock geothermal power.

Of these, bio-electricity from residues is ready for rapid growth. It already contributes to both base- and peak-load power in parts of Europe and the USA.

Several different types of concentrated solar thermal power are already in limited mass production in Spain and California. However, we still need several years of experience with different types of collectors, heat-storage and heat-transfer systems before choosing second-generation systems for mass production. Meanwhile Australia should implement a feed-in tariff for large-scale solar, to can gain experience, optimize systems and then move into local manufacture of the best designs.

……. Wind supplied the biggest contributions to new generating capacity in Europe in 2008 and 2009. It already provides 24 per cent of Denmark’s electricity generation and over 14 per cent of Spain’s and Portugal’s. It’s undergoing enormous growth in China, which doubled its wind generating capacity each year during 2006- 2009.

So, what about intermittency? There is no doubt that the output from a single wind farm fluctuates greatly. However, the fluctuations in the total output from a number of wind farms, which are geographically distributed in different wind regimes, are much smaller and partially predictable. Modeling  shows that it’s relatively inexpensive to lift the reliability of the total wind output to a level equivalent to a coal-fired power station by adding a few low-cost peak-load gas turbines that are operated infrequently.

………. With large amounts of wind and solar photovoltaic capacity in the grid, some additional peak-load plant may be required. Gas turbines (essentially jet engines) are suitable because they can be turned on and off quickly, have low capital costs and, provided they are not operated a lot, have low fuel costs. They are reliability insurance with a low premium. They can be fuelled by gas or preferably biofuels produced sustainably.

Feasibility has been established by computer simulations of electricity generation systems by several research groups around the world, including my own in CSIRO in 1980s. See ‘The Base-Load Fallacy’ and the book ‘Renewable Energy and the Grid’ edited by Godfrey Boyle, Earthscan 2007.

Two recent detailed studies, funded by the National Renewable Energy Laboratory in the USA, found that wind power could supply 20-30 per cent of electricity, given improved transmission links and a little low-cost flexible back-up [see http://www.nrel.gov/wind/systemsintegration/ewits.html andhttp://www.nrel.gov/wind/systemsintegration/wwsis.html].

So a plausible Australian scenario for the next decade is the phase-out of several coal-fired power stations simultaneously with a rapid growth in efficient energy use, solar hot water, wind power and bio-electricity. These clean technologies would buy us time to commercialise solar thermal and possibly geothermal power and then integrate them on a large scale in the 2020s as the remaining coal stations are shut down. Thus Australia could achieve a sustainable electricity system.

Clearly this solution is more complex and subtle than simplistic statements from renewable energy deniers that “The Sun doesn’t shine at night and the wind doesn’t blow all the time” and false statements that “Renewable energy cannot supply base-load power”. In reality, there are several renewable electricity technology options with different statistical properties. There is also the prospect of substantial modifications of demand by means of ‘smart grids’. A mix of sources with appropriate transmission links and ‘smart grids’ could provide a reliable system of 100% renewable electricity.

Such a system supersedes the concept of ‘base-load’. The important thing is not the reliability of one type of energy source, such as wind or solar, but the reliability and sustainability of the whole supply-demand system.http://www.onlineopinion.com.au/view.asp?article=11956

May 2, 2011 - Posted by | AUSTRALIA - NATIONAL, energy

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