Contrary to what the terminology suggests ‘solar thermal energy’ is not a recent development and it is certainly not something that has just been invented as another answer to reduce greenhouse emissions. According to the Renewable Institute for Sustainable Research, the first solar powered engines were constructed back in the 1860s by a couple of French mathematicians. During the past 30 years a number of solar thermal plants have been built and operated around the world to produce guilt-free electricity. However, the technology has been rapidly evolving in recent years and Australia has perfected the technology to make it commercially more viable.

Unlike wind power or solar photovoltaic panels, which generate electricity directly, solar thermal power uses mirrors to concentrate the sun’s energy onto a receiver and create heat, which can then be used to produce steam to run a turbine and generate electricity, in the same way as a conventional coal-fired power station. The other advantage of solar thermal technology is that it can be stored very efficiently in large tanks of molten salt and then be dispatched to generate electricity at any time of the day or night, making it in effect base load solar power.

The way solar thermal energy plants work is by focusing the glare of the sun’s rays on a central location –usually on a tall solar tower- to create heat, which is then turned into electricity. The concentrated heat is extreme between 500-2000 C and it could easily melt metal. Due to various heat exchange processes involved –which were further advanced in Australia- the water eventually turns to steam, powering the turbines at the base.

Various methods exist to concentrate the solar radiation, including parabolic troughs, power towers with mirrors that track the sun (heliostats), parabolic dishes, and Fresnel reflectors (these consist of multiple flat mirrors). Each technology differs in the way that it concentrates the solar energy, but they all track the sun to maximise energy capture and produce heat, which is then converted to electricity.

These technologies are at different stages of development and each has its own advantages and disadvantages. It is fair to say that parabolic troughs are the most mature, having first been installed at utility scale in the 1980s; although the other types may ultimately prove cheaper due to their inherent design advantages. These technologies have been successfully used in the USA and Spain since the 1980s. But the Australian National University has re-designed the dish for optimisation for manufacturing and mass production with mirror panels that should be able to concentrate the sun at least 2,000 times.

Solar Thermal Uptake in Australia

Australia has large areas of high solar intensity and little rain, where large concentrations of renewable energy power stations could be developed. In fact the Australian continent has the highest average amount of solar radiation per square meter per year of any continent on the planet ranging from 1500 to 1900 kWh/m2/year. In other words Australia is better-suited to this technology than any other country in the world, including Spain who is expecting to operate 60 solar thermal plants by 2013.

Peter Meurs (Managing Director of WorleyParsons-EcoNomics) has said that establishing advanced solar thermal centres could allow Australia to exceed the 20 per cent renewable energy target by:

• Facilitating the commercialisation of developing renewable energy technologies.
• Triggering the development of domestic solar thermal component manufacturing.
• Enabling Australia to become a world leader in these technologies.
• Allowing the construction of larger scale solar thermal power stations over time.

Wizard Power is also part of the same consortium who has been trying to commercialise big dish technology in Australia for the past five years. Their unique technology was developed by the Australian National University’s solar thermal group over the past 40 years who have perfected ‘the big dish’ and they’ve also figured how to best store the sun’s energy thermo-chemically. It appears that Wizard Power may be getting some support from the federal government in the form of $60 million towards a $230 million solar plant it’s building in South Australia. Wizard Power suggested Whyalla in South Australia as an ideal place to establish large scale solar facilities, because of the climate and the number of large scale resource projects requiring power. Australia’s very first solar oasis in Whyalla is going to provide enough electricity to power the town of Whyalla and also to provide power to the neighbouring steel works. In total it’s capable of powering approximately 9000 average homes or replacing something in the order of 17000 motor vehicles on the road each year in terms of carbon emissions.

There is no reason why Australia couldn’t match the Spanish government’s commitment who is expecting to cover 12 percent of its primary energy from renewable sources by the end of this year. Spain is the fourth largest manufacturer in the world of solar power technology and exports 80 percent of its production to Germany. Australia cannot quite export electricity to other countries but we could export our expertise in this technology to build solar thermal plants in other countries. At the same time there is no reason why 30 solar thermal plants could not provide 40 per cent of Australia’s renewable energy needs by 2020-according to WorleyParsons. But to achieve this goal, action must be taken today.

References:

http://www.npr.org/templates/story/story.php?storyId=13826548)
http://www.abc.net.au/insidebusiness/content/2010/s2925759.htm
http://ecogeneration.com.au/news/advancing_solar_thermal/002019/
http://ecolocalizer.com/2008/04/12/mega-solar-the-worlds-13-biggest-solar-thermal-energy-projects/
K. Lovergrove and M. Dennis Solar Thermal Energy Systems in Australia 2006 International Journal of Environmental Studies (www.tandf.co.uk/journals)

Easing water restrictions in Victoria may have an undesirable impact on the fight against climate change. According to a recent article in The Age, “the sight of greener gardens and healthier trees that will regain our image as the ‘garden state’ will also turn people’s attention away from the bigger environmental picture - that is global warming”. The soon to be available extra water also means more greenhouse emissions and more climate change.

Some observers expressed that for many Australians climate change wasn’t a real issue until their backyards began to turn brown. Water restrictions for these people were the most visible and tangible manifestation of the drought and that there is something going on with our climate. Lifting water restrictions is sending the wrong message to the public and once again relegates concerns about global warming to the back of their minds. However, the extra water won’t be falling out of the sky either.

Unfortunately the lifting of water restrictions is not entirely due to the restoration of normal rainfall and increased dam levels (which may have appeared so during the deluges of the last few months) but due to the completed construction of the north-south pipeline and the controversial desalination plant near Wonthaggi. (Some cynics say it is also due to the upcoming state elections).

Ironically, to compensate for the reduced rainfall which is most likely a consequence of changed weather patterns, we are building a desalination plant that is extremely energy intensive and polluting. The annual energy use of the plant will be around 900 GWh. The pollution from this will equal to putting 365,000 cars on the road emitting around 1.2 million tonnes of CO2 (in terms of black balloons that’s around 30 billion of them). This is not including the ‘carbon footprint’ of the plant during construction, which equals to about 1.4 million tonnes of CO2. It is still not clear where the extra energy will come from but it was suggested that gas-fired power stations.

There are of course many other side effects of the desal plant that environmentalists highlighted, such as producing 30,000 tonnes of solid waste that include toxic chemicals and 200 million tonnes of brine that will be pumped back into the ocean each year. All of which will impact on marine life without knowing what the ultimate outcome will be.

Many people believe that we should be focusing on better ways to capture and store the remaining rainwater instead of constructing desalination plants that will significantly increase greenhouse emissions which in term contribute to the larger issue of climate change. Despite the reduced levels of rainfall it is still more than enough to cover our water usage if it is harnessed properly. Money would be better spent providing households with water tanks, which would have much less impact on climate change. Otherwise, we will have to deal with more than just shorter showers and not being allowed to water our gardens or wash our cars at home.

After a $100 million smart grid trial in July this year, the Australian Government released the Australia smart grid guideline on the 30^th September.

“With this investment, Australia will showcase the world’s best practice when it comes to investing in smart grid technologies, helping industry get on with the job of rolling out these technologies and supporting clean energy jobs,” Mr. Garrett said.

The potential benefits of a full smart grid implementation are dramatic. Some studies have suggested that savings of between 10% and 25% in electricity demand are achievable.

In contrast, the USA Department of Energy delayed to reveal the smart grid standards last month. “Basically because the development of smart grids is a larger task than the electricity utilities can handle. There is also a lack of understanding and willingness by them to investigate how to best form partnerships with the rest of the industry.” Paul Budde posted.

This has not slowed some big names to rush into the market including Microsoft, Google, IBM, Cisco and AT&T, who are all eager to rock and roll.

My concern is the communication ability of smart grid and smart meters. At present, the meters only store 30 minute intervals of data and transmit the data bi-monthly or quarterly. If Australia has to replace all the electricity meters again after 5 years, who would pay for it?

What smart grids will Australia get? We will just have to wait and see!

image from www.greentechmedia.com

Video by the Coen Brothers. See comments on this video on youtube.

A few months ago I wrote a blog posting about how tighter regulation of electricity supply voltages could save Australia 15 million tonnes of greenhouse gas a year.

However a comment on that posting suggested that voltage reduction may not result in any useful savings.

Below I report on the results of an experiment we undertook to identify how much power can be saved, if any, by operating equipment at a lower voltage.

We measured a variety of single phase loads at different voltages. A variable transformer was used to vary the voltage. A German made Power Tech plus plug in power meter was used to measure voltage, current, power and power factor at the different loads. Loads experimented with included typical single phase lights, computer equipment and a fan.

experimental set up to measure power draw at different voltages of a range of single phase loads

The experimental set up is shown above. Below is a graph showing the results of the testing.

graph of power draw vs voltage for a variety of single phase loads

This graph clearly shows that for common lighting loads power consumption decreases with decreased voltage

• Incandescent lamp (resistive load)
• T8 fluorescent (inductive load)
• T5 fluorescent (electronic ballast)

The reduction in power consumption with the T5 fluorescent (with an electronic ballast) was unexpected.

The fan, with a single phase (shaded pole?) motor, also used less power with lower voltage, interestingly the power factor improved as voltage was lowered, with the power factor the highest at 220 volts.

The PC computer and monitor both showed lowest power consumption at 230 and 240 volts, but power consumption generally did not decrease with voltage. Power factor improved a little at lower voltages.

This experiment shows that for a variety of loads power consumption is in fact less at lower voltage.

For heating or cooling loads equipment may need to run longer when at lowered voltage to reduce the same amount of heating or cooling, with no net energy savings.

Three phase synchronous motors are unlikely to use any more or less power (a theoretical assertion, we don’t have the equipment to test), having the motors run at 230 volts rather than 240 or 250 volts however is unlikely to cause motor damage due to excess current as the voltage difference is only small.

But with lighting and many single phase motors power consumption drops with lowered voltage.

My back of the envelope calculations still come up with a saving of around 15 million tonnes of greenhouse gas if voltages were closer to the 230 volt standard rather than being at 240 to 250 volts.

If high voltage drops in distribution were a problem additional network infrastructure could be used to deliver a more consistent voltage across the network. 2009 is the year of the “smart grid.” A smart grid could mean multitap transformers that can be changed on the fly to deliver a more consistent 230 volts across the whole electrical network.