Wednesday, August 24, 2011

The Power of Graphs (and vice versa)

There's a bit of talk going on at the moment about the cost of power, switching companies and whether those companies use renewable energy or not. I hear people bandy around that this company is greener than that company, they generate energy from fairy dust, they use the screams of innocent children. What I don't see or hear is actual data, so I thought I'd have a dig around and find some.

This post is not about whether or not I think the renewable nature of the energy generated should take precedence over the cost of the energy or whether I think coal is the fuel of the Devil and hydro is liquid Jesus. I'm a supporter of renewable energy, but that's mostly because often it's new technology, and I love that. Burning coal to produce energy? What is this, the industrial revolution?! OK, it's now a little bit about what I think. From now on it's just the facts. What this post is really about is presenting some simple graphs that show how the top 5 companies generate their power. This post also isn't about cost, so I'd suggest visiting to find that information.

I collected this data from the most recent annual reports available from each of the companies. The GWh produced might be a little bit out of date, but the percentages should be pretty accurate, and the general philosophy of each company definitely won't have changed much.

The first graph shows total energy generation by source. The second graph shows the percentage of the total energy generation that each source provides. 'Other' refers to biomass for Mercury Energy (which is actually Mighty River Power) and Swaption for Contact. What is Swaption you ask? I'm not really sure. Look it up. To make it all a bit easier to digest, I then present a graph that has been simplified down to two categories: non-renewable and renewable.

The next set of graphs are the pie charts. These show individual power companies and just the energy sources they each use. You can interpret this as either total energy generation, percentage of total energy generation or Big Mac equivalents. It's a pie chart, units are irrelevant. The whole pie is everything, segments represent parts of that everything.

Finally, I present one last pie-chart showing NZ's total energy generation. Again, units are irrelevant.

Keep in mind when perusing this data that no matter how a company generates it's electricity, it all gets fed into the national grid. That means that even if you choose the greenest power company imaginable, you still might be boiling your kettle with dolphin tears. That doesn't mean you aren't encouraging companies to use renewable energy sources by supporting them, it just means that you have no guarantees over the power you use. Since 81.6% of NZ's energy is classed as renewable, you probably don't have to feel all that guilty about it anyway. An 18.4% chance of dolphin tears makes for pretty good odds.

So, without further ado, I present to you the graphs.

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