Monthly Archives: December 2013

Shark season

Summer in Australia comes with cicadas, sunburn and, in the media at least, sharks. So far, I have learned that aerial shark patrols are inefficient (or perhaps not) and that the Western Australian government plans to keep swimmers safe by shooting big sharks.

Sharks are compelling objects of fear, right up there with spiders and snakes in the package of special terrors for visitors to Australia. As good hosts, we are quick to reassure: sharks may be the stuff of nightmares and 70s horror movies, but attacks are rare.

But, exactly how rare is death by shark? Over a Boxing Day lunch, I heard an excellent ‘statistic’, designed to reassure a visiting American. Apparently, more people are killed each year in the US by falling vending machines than are killed by sharks around the world. I was skeptical, but had no data to hand. Later, with the help of Google, I discovered that this statistic is 10 years old and the source? Los Angeles life guards. The tale has, however, become taller over time. Originally, vending machine deaths in the US were compared to shark attack fatalities in the US, not the entire world.

While data on vending machine related deaths are hard to come by, subsequent attempts to validate the story concluded that it was plausible, on the basis that there were two vending machine deaths in 2005 in the US but no fatal shark attacks.

Fun though the vending machine line may be, it is not relevant to Australia and, if you are on the beach contemplating a quick dip, then the risk of a shark attack is certainly higher in the sea than death by vending machine. Local data is in order.

According to the Taronga Zoo Australian Shark Attack File (ASAF):

 In the last 50 years, there have been 50 recorded unprovoked fatalities due to shark attack, which averages one per year.

Fatalities have been higher than average over the last couple of years. The ASAF recorded two deaths in 2012 and, although validated figures for 2013 are yet to be published, six deaths have been reported over the last two years, suggesting that fatalities rose further to four this year.

To compare shark fatalities to other causes of mortality, a common scale is useful. My unit of choice is the micromort. A one-in-a-million chance of death corresponds to a micromort of 1.0, a one-in-ten-million chance of death to a micromort of 0.1. Taking the recent average death rate of three per year (more conservative than the longer run average of one), and a population of 23 million in Australia leads to a figure of 0.13 micromorts for the annual risk of death for a randomly chosen Australian.

The most recent data on causes of death published by the Australian Bureau of Statistics (ABS) are for 2009. That year, three people were killed by crocodiles. Sharks are not specifically identified, but any fatal shark attacks would be included among the three deaths due to ‘contact with marine animals’. The chart below illustrates the risk of death associated with a number of ‘external causes’. None of these come close to heart disease, cancer or car accidents. Death by shark ranks well below drowning, even drowning in the bath, as well as below a variety of different types of falls, whether from stairs, cliffs or ladders.

Shark barplot

Annual risk of death in Australia (2009 data)*

Of course, you and I are not randomly chosen Australians and our choices change the risks we face. I am far less likely to suffer death by vending machine if I steer clear of the infernal things and I am far less likely to be devoured by a shark if I stay out of the water.

So, care should be taken when interpreting the data in the chart. Drug addicts (or perhaps very serious Hendrix imitators) are far more likely to asphyxiate on their own vomit than summer beach-goers. The fairest point of comparison is drowning in natural waters. At almost 3.5 micromorts, drownings in the sea (or lakes and rivers) is more than 25 times more common than fatal shark attacks. And the risk of both can be reduced by swimming between the flags.

What does that leave us with for conversations with foreign visitors? If you are headed to the beach, the risk of shark attack would be higher than death by vending machine, but it is still very low. The drive there (at 34.3 micromorts) is almost certainly more dangerous.

I will be taking comfort from my own analysis as I am heading to Jervis Bay tomorrow and sharks were sighted there this weekend:

Bendigo Bank Aerial Patrol spotted up to 14 sharks between 50 and 100 metres from shore at various beaches in Jervis Bay. [The] crew estimated the sharks at between 2.5 and 3.5 metres in length at Nelsons, Blenheim, Greenfields, Chinaman’s Beach and Hyams Beaches.

The beaches are un-patrolled, so wish me luck…but I don’t think I’ll need it.

* The figure for ‘Shark attack’ is based on the estimate of three deaths per year rather than the ABS data.

Power to the people

Regular Mule contributor, James Glover, returns to the blog today to share his reflections on solar power.

I have been investigating solar power for years and finally bit the bullet and signed up for a system. A 4.5kW system cost me $8,500, after receiving the Government rebate (about $3,000). I’ve been meaning to write about my adventures in solar for a while now. It started because of a strange fact I discovered about 4 years ago. Even though the cost of solar cells has been dropping dramatically in the last 4 years (it’s gone down about 75%) the payback time has stayed steady at about 5-10 years. The payback time is based on what you save by not paying your power bills plus what you earn by selling electricity back into the grid. The peak time for solar generation is 10am-2pm while the peak time for domestic use is in the morning and evening outside these times.

The answer to my conundrum is that while the cost of solar cells has been steadily dropping so has the feedback tariff. When the feedback tariff was 60c per kWh, the excess power created during the day paid for the disparity in the price of the power consumed in the evening. In Victoria the feed in tariff has dropped to about 8c. In order to have a net zero cost of solar it is necessary to have an even bigger system as peak power cost is about 32c per kWh. A particularly good website I found for all things solar is SolarQuotes.  I thoroughly recommend it as has lots of info on solar power as well as cost benefit analysis. They recommended two solar companies in my area, both of who were very good.

From a financial point of view it makes sense that power companies would buy solar power at a lower rate than they would provide it‑it’s called the bid/offer spread and is how most companies make money. The cost of producing power is about 5c so it is still cheaper for them to produce and sell the power themselves than buy it from solar power generators.

There is a twist to this tale however. Electricity generators are monopolies and so left to their own devices would naturally gouge buyers. When the state governments privatised electricity generation they set up supervisory boards to ensure the companies made reasonable, but not immodest profits. In the absence of a competitive market one way to do this is on a “cost plus” basis: set the profit at say 10% above cost of electricity generation. It seemed reasonable until power companies found a way to game this system. If they increased the cost of providing electricity then they increase their profits.

But surely, you say, the costs of generating electricity are based on market forces for the raw materials plus the cost of running the plant? One way is to spend much more on investment than is actually necessary. And the electricity companies did this beautifully. They convinced the state government oversight bodies that not only was electricity consumption forecast to rise well above GDP growth but that existing infrastructure needed to be “gold plated”: improved to reduce the probability of a widespread failure. A combination of inflated growth predictions (and hence building new plants) and gold plating is the real reason electricity prices have risen 20% year on year over the last few years. Yes, the carbon tax has had a small effect as a one-off increase. The Coalition (now the Government) exploited this in the run up to the election, although I am pretty sure this not was the real reason the Labor government lost office.

If you take solar power growth into consideration then electricity generation from traditional sources such as coal and hydro is expected to fall, not rise. Gold plating (soon to include actual gold power lines…I think I am joking) is now seen for what it is and is being reined in.

One of things I have always wondered is why someone doesn’t set up a virtual power company which buys solar power and sells it to distributors? Turns out they already exist. The thing which swung me to the solar provider I chose (the price was identical to the others) was that they could hook me into just such a company.  Sunpower is a US company which has set up in Australia to do just this. Currently their feed in tariffs are higher (guaranteed 20c for 2 years as opposed to 8c for coal generating providers) though I have no expectation they will remain this high. Australian Diamond Energy is another example of a virtual power company. Diamond Energy buys green power from retail solar producers (i.e. you and me) as well as independent wind farms. They also invest in their own larger scale solar and wind farms. Market forces will dictate the future price and I am happy to offset the environmental cost of running my air conditioning at full bore over summer.

In the US they already have communities which set up solar farms to provide their bulk electricity and sell their excess to the grid. Old style electricity companies have resorted to making claims that there are problems with solar electricity, either because it’s at the wrong time of the day or because old style inverters produce modified sine waves from direct current rather than pure sine waves and some electrical appliances don’t operate as well with these modified sine waves. Increasingly though inverters are of the pure sine wave type anyway. While there is some truth to their arguments, it is worth remembering that power companies would prefer that there was no solar at all. They have an axe to grind, their arguments are designed to limit the onward march of solar, or totally compensate them for lost revenue which will achieve the same aim through higher solar costs or lower feedback tariffs.

Another example of why traditional power companies are increasingly out of touch is smart meters. Solar power companies, monitor power usage through smart meters and solar panel output monitoring.They then provide feedback directly to your table or smart phone, and also work to help users optimise their power usage and minimise costs. Traditional power companies see smart meters as purely a way to save on meter reader costs, they have no interest in reducing users’ power consumption.

It seems that in Australia, the “sunburnt country” we have missed a few tricks. The dinosaur coal-based power companies are fighting a rearguard action, trying to get governments to lower the feed-in tariff further or let them charge solar customers a fixed fee to cover their “costs”. I think they are on the wrong side of history. A consumer group Solar Citizens has already been effective in reminding governments that over 1m households have solar power. I think that 1m is a tipping point.

There are about 8m households in Australia. At a cost of about $5,000 we could make each a net producer of electricity for $40bn.  About the cost of the NBN. A new national Snowy River Scheme!

Power to the people. From the people. For the people.