Toyota has just started testing a new Prius with a solar roof that will be used to charge a plug-in battery. With the increased efficiency of solar panels, it makes sense. To give you some perspective, the amount of power that hits the earth’s surface at midday at the equator is 1kW per square metre. The solar cells on the Prius, being only 0.03mm think, will deliver about 860W of power. This is enough to add 45km of range in an average day of sitting in sunlight. The World Solar Challenge biennial car race relying solely on sun powered vehicles has been raced between Darwin and Adelaide since 1987. The winning entry in 1987 averaged 66.9km/h for the 3000km while the latest race had an average speed of 81.2km/h. Clearly we are progressing in producing power from the sun.

Solar panels seem to get a bad rap because the sun doesn’t hit your spot of the earth for twenty-four hours of the day so people are rightly concerned about how they might turn their lights on at night, but there are some major advances occurring that will start to deliver superior solutions.

Before we go there, we should go back in history. In 1891, Clarence Kemp in California patented a small glass-topped box with water running through it to heat water. Using the sun to save on regular heating of water. Not exactly creating electricity from the sun but using the sun to save the need for other forms of energy. Similarly in 1953 when SW Hart and Co. created Solahart hot water systems. Solahart now has over one million hot water systems installed in 70 countries around the world.

It was three years later that the first solar cells to produce electricity were available commercially. As with all new technology it was expensive. US$2800 (converted to 2019) for a one-watt solar cell. By comparison, that cost is now down to US$3.18 per watt. Despite the price, it allowed the start of the solar revolution. Calculators and novelty items started appearing with tiny solar cells but by the late fifties, satellites were being powered by solar cells. From the seventies, when a large drop in prices occurred, we started seeing solar panels in a variety of situations. Most off-shore oil rigs use solar panels to power lighting on the rigs. There is a certain amount of irony here! We also started seeing solar panels at railroad crossings, communication towers and water pumps. You often see a farm with a dilapidated traditional windmill no longer in operation and sitting proudly beside the windmill is a small solar cell and an electric pump. Less maintenance and more reliability!

To give you an idea of how quickly technology is progressing, a solar farm in Nyngan in regional NSW was started in January 2014. The 250 hectares is home to a 102MW solar plant. Fast forward almost five years and go up the road to Nevertire and in less space (180 hectares) a new solar farm is being built that will generate more power (132MW).

The initial concerns about night time power haven’t disappeared but with pumped hydro and battery technology, among other systems, giving access to power through the night, expect to see more solutions involving solar panels.

In September 2009 I wrote an article where I had calculated the surface area of solar panels needed to power Australia was 32km square. I can only imagine the smaller size we would need with our more efficient modern solar panels.

Tell me the unusual places you have seen solar panels at

Mathew Dickerson

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