Renewable energy: Is it a viable option?

Debate is raging both in Australia and all over the world about whether renewable energy sources, such as solar, wind and biomass, are commercially viable options when it comes to powering homes and businesses across the globe.

Here are both sides to the story.

What about the baseline?

While the positive environmental impact of renewable energy sources is not in question, some critics have questioned whether these forms of electricity generation will have enough power to supply base-load electric power.

For example, solar power stations are only able to generate power during the day, when the sun shines. What happens at night time? This is of concern if these plants are not able to actually store any of the electricity generated during the day.

Or, what if there is no wind?

Electricity suppliers that rely on renewable energy sources say this is not as much of an issue as it is made out because energy consumption is generally lower at nighttime anyway.

According to Mark Diesendorf, Professor of Environmental Studies at the University of New South Wales, the belief that the only way to supply base-load energy is by coal and nuclear power stations is a widely disseminated myth.

He says photovoltaic solar power stations are the way of the future, already able to compete with other retail electricity suppliers in so far as electricity prices are concerned, according to a March 3 article on ABC news.

New developments: Saving energy for a rainy day

A new way of storing thermal energy is sweeping America, and is able to extend the daily operating life of a solar power station up to six hours.

This method involves using molten salt to lengthen the storage capabilities of solar power systems. It has been used in Crescent Dunes in the US already, where it has been used to generate a further 500,000 megawatt-hours of electricity per year, which is enough to supply power to 75,000 homes during the peak period.

There is no need for backup fossil fuels like natural gas, making this a more environmentally friendly choice.

Salt is used to store the heat produced by the sun because it only melts at extremely high temperatures. In order to release this energy, the salts are put near water though a heat exchanger that creates hot steam. This turns the turbines. 

This method only loses a small proportion of the original solar energy that has been gained. The salts are a mixture of sodium and potassium nitrate, which might be familiar to you as the materials generally used to fertilise your garden.

This technology has been around since the 1980s but has only begun to take off commercially.

Is residential solar power a viable option to consider?

Many households in Australia have begun to feature solar panels that can harness the sun's rays to provide that home with power.

Any excess produced can then be sold back to the grid via electricity suppliers. Mr Diesendorf highlighted the effectiveness of this programme during the recent heat wave in South Australia. He said air conditioners were running at full blast for weeks during this period, but residential solar PV units were able to reduce the peaks in electricity demand by around five per cent, according to his opinion piece on ABC news.

What about wind energy?

A powerful gust is another way to generate power and is being used extensively in South Australia, according to Mr Diesendorf. He says around 27 per cent of the annual demand for electricity comes from wind energy and the wholesale price has dropped substantially as a result.

Can renewable energy deal with peaks in demand?

While this technology is equipped to supply base-load demand, there are questions surrounding its ability to meet peaks in demand.

A smart system will be required to manage the falls in electricity at night and the demand peaks during the day, when supply is low.

Some offloading aluminium smelters are already able to practice this method to a certain degree, without damaging the smelting process.

A smart system will be able to turn off items such as residential air conditioners and refrigerators on a rotational basis and only for a short time, without suffering any adverse consequences.

Customers who sign up for this kind of system might be rewarded with a lower supply charge.

What about gas-fired stations?

If gas prices remain stable, then this form of energy could compete with renewable energy sources in a financial sense, but it seems likely that these prices will continue to rise.

These escalating costs are seen as a response to the high overseas prices and it is worth noting that Australia is exporting increasing amounts of gas to Asia.

So, if domestic costs rise to meet export prices, gas-fired stations - even those with carbon capture - will not be able to compete with 100 per cent renewable electricity.

Therefore, renewable energy in most cases will be a good investment for the future and appears to be a financially viable option.

Posted by Liam Tunney.