Dream time or practicable?

The Ministry of Business, Innovation & Employment supplies the figures for annual energy consumption in New Zealand, measured in Petajoules (PJ), and produces this graph of the result.


The graph shows a steady upward trend in energy usage per year as New Zealand grows.

Some of that energy comes from renewables and some from hydrocarbons, (oil, gas & coal).  We know that the hydrocarbons are blamed for the CO2 which we are told is going to doom the planet so it must be reduced.  Assuming a 1:1 relationship between hydrocarbon use and COoutput we can look at how much the hydrocarbons must be reduced to meet the agreed targets.

The figure agreed at this point (prior to the upcoming Zero Carbon Act) is to reduce greenhouse gas emissions by 30 per cent below 2005 levels by 2030.  We know that James Shaw wants Zero Carbon by 2050.

So let’s take the MBIE figures and extend them out to 2050.   In the figures below, I have ignored the contribution of “Waste Heat” from the MBIE figures as it is only about 0.2%.

I have grouped the MBIE data into PJ Renewable and PJ Hydrocarbon, summed the two and derived a trend-line from that data.  This trendline shows that the year-on-year increase in energy use is around 13.4 PJ

The hydrocarbon component in 2005 was 532PJ so we take 30% off that as the target for 2030 and plot a line through that point out to 2050.  I am sure that James will not accept anything less than continuing the same rate of reduction.  To reduce hydrocarbon use to meet this target requires a reduction of 12.1 PJ per year.

The graph, extended to 2050 now looks like this:

However, energy use is increasing at 13.4 PJ/yr, but hydrocarbon use must be reduced by 12.1 PJ/yr so the difference of 25.5 PJ/yr has to be made up by renewables. (“Yes!” says Mr Shaw)

So how much is 25.5 PJ?  The web converter says it is equivalent to 7,083,333 MWh.  Dividing that by 24 hours per day and 365 days per year, gives the MW rating of the renewables we need to bring on stream every year to achieve this result.  The result is a touch over 800MW of new renewable generation that must be added to the grid every year.

Piece of cake!  Let’s Do This!

800 MW is 1 x Manapouri Hydro scheme every year.  Yup, the Greens would love to drown the countryside at that rate.

The Tararua Wind farm is one of the most efficient in the world, but only achieves 46% of nameplate rating.  The largest 31 of the 134 turbines in this wind farm are rated at 3MW; times 46% they are effectively 1.38MW turbines so we are going to need to install 586 of those big boys every year to generate 800MW. (Visualize this as one 3MW turbine installed every kilometre along SH1 from Papakura to Plimmerton.)

The Wairakei geothermal power output is around 200MW so we could build another four of those every year. (RMA permitting, of course.)

My solar array, here in the sunny Bay of Plenty, delivers approx 0.15 the rated power over a year. A 295W solar panel covers about 1.6m2 so we could install around 18.3 million solar panels covering approx 3100 hectares every year. (This would almost cover Lake Rotoiti (Rotorua), Lake Waikare (Waikato), or Lake Monowai (Southland).

Or, clearly, it could be some combination of the above; another Manapouri this year, 18 million solar panels next year, 600 wind turbines the following year; rinse and repeat until 2050.

Frankly, I can’t see the problem – James has it sorted.

Oh, by the way, when talking about energy …


So we had better get on with solving the planet’s problem, pronto!

(Apologies, in advance, if there are errors in the maths or logic, I am sure the Oilers will let me know.)

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WH is a pale, stale, male who does not believe all the doom and gloom climate nonsense so enjoys generating CO2 that the plants need to grow by driving his MG.

To read my previous articles click on my name in blue.