The Solar Promise is a joint initiative set up by the Nelson City Council, the Nelson Environment Centre, along with SolarCity to promote the uptake of solar energy systems in New Zealand.

The idea is that via the Solar Promise web site, businesses and individuals can sign up to have the Solar Promise lobby the Local Government Body to which the business or individual belongs.

Among the organisations, businesses and councils that have already pledged their support are Meridian Energy, Kiwibank, Greenpeace, WWF, The Tindall Foundation, the Master Plumbers of New Zealand, SEANZ, the Wellington and Dunedin City Councils and a bunch of District Councils.

On the face of it, this looks like a really great and well thought-out initiative. But then I noticed that a few of the facts listed on the site didn't add up. More...

On Monday night around 170 people packed out Timaru's Grosvenor Hotel to see a presentation entitled Climate change and opportunities for the economy. The presentation was part of a nation-wide tour that's headed by leading climate scientist Dr Jim Salinger, with support from Professor Caroline Saunders (who specialises in trade and economics) and Rod Oram (business commentator and journalist).

The presenters covered all the usual content with no real surprises, but there was one point that really irked me. When asked about his thoughts on the benefits of solar panels, Dr Salinger offered that the cost of installing solar panels on household rooftops throughout the country would "probably" be offset by the savings made in Transmission costs. This is the type of statement that I've often heard made by lay people, passionate greenies and even politicians. But never a scientist! More...

Ok, so we're constantly told that New Zealand is blessed with wind energy resources. Many then go on to say that since we're blessed with wind resources, we could each put a micro wind turbine on the roof of our house and the Country's energy needs would be met! This is an incredibly insane assertion, and today I'll explain just one (of the many) reasons why such talk is insane. Namely, the wind resource isn't evenly distributed across the country, and some of our biggest population bases (namely the Auckland region) have next to no usable wind resource!

Along with my previous articles, I've again used NIWA's Cliflo database. This time I've downloaded wind data for 187 sites where NIWA have hourly readings for the 2010 calendar year. For each site I then projected the annual energy production from the mighty Siemens SWT-2.3-82 2.3 MW Wind turbine (using the same technique as the previous articles).

Taking that data, I interpolated it to produce a heat map of estimated energy production across the country.

The left hand graphic below is taken from NIWA's page on Wind Energy. This shows the estimated average wind speed (in m/s) for the Country. They've used wind speed data and an elevation model to produce the nice looking graphic. To the right is the graphic that I've put together, which shows estimated annual energy production (in GWh) for the Siemens Wind Turbine.

Putting the graphic above into a chart further highlights that the bulk of the country has very poor wind energy potential compared to some of the best sites (and some of those best sites are out at sea). More...

Following on from my previous article (which got a little messy with a correction or two), I think it's time for a challenge..

In the Green corner we have the sexy and sleek Thinair 102 turbine from Powerhouse Wind Ltd. It's a prototype single blade 2 kW wind turbine put together by by a a small Dunedin based company. It has a cut in speed of 3.5 m/s and achieves maximum output in winds of 10 m/s. They're targeting a price of around $20,000 for the unit (I'd expect installation costs on top though) which puts it in line with other comparable micro-turbines.

In the Blue corner, we have another sexy little number. It's the Yamaha EF2400is Silent, a 2 kW petrol powered invertor generator (not exactly silent, but producing 59 dBA @ 7 m, it's a little quieter than some other models). Currently retailing at $3,198, it's a somewhat lighter on the pocket than the Thinair turbine. More...

Update:For original the article, I used Excel to do the analysis and produce the histograms. Since putting this analysis together, I have loaded the raw data into an Oracle database to do some more extensive analysis. On using the Oracle data, two things have become evident. Firstly wind speed accuracy to the nearest meter isn't accurate enough, especially for the low wind speed sites like Timaru. Secondly, I realised that Excel used different bin ranges to what I anticipated. The grouping of 1 m/s is actually 0.1-1.0 and 2 m/s is 1.1-2.0. Again this has a large effect on the power output calculations for low wind speed sites. As an example my Excel based analysis estimated the Thinair turbine as producing 2,889 kWh annually at Timaru. My more accurate Oracle analysis estimates only 1,094 kWh.

I have now re-made the charts. The three charts with histograms still use accuracy to the nearest meter (1 m/s is now 0.5-1.4, 2 m/s is 1.5-2.4 etc.). Note that they still over-estimate electricity production. The last two charts now use wind speed data to one decimal place and their estimates are far more accurate.  11/1/2011

Back in August I posted an article on an Analysis of Timaru's Wind. This is a follow-up to that article, where I compare the wind profile of Timaru and Baring Head (near Wellington) against the Power Output curves of some commonly available micro wind turbines.

Here's the list of turbines that I'm comparing. Added to the bottom of the list is the Siemens SWT-2.3-82. With an 80 m blade diameter, this is no micro wind turbine. It is in fact the turbine that Meridian Energy are using in the West Wind wind farm near Wellington.

These are the power curves used for the relevant turbines. I've just used a straight line from cut-in speed, through to maximum output and taken that through to 20 m/s. In reality a power curve doesn't follow a straight line, but for the purposes of this exercise they make a reasonable approximation. More...

I ran some analysis of Timaru's wind data as part of an article I'm putting together on micro wind turbines. Since it's resulted in some pretty charts, I thought I'd post them as a separate article.

The National Institute of Water and Atmospheric Research (NIWA) is a Crown owned research institute. They, along with the MetService, collect metrological data from all over the country. That data is then made available via their online National Climate Database (Clifo).

For this analysis I've used Clifo hourly wind data (which includes average wind speed and wind direction) from the 2008 and 2009 calendar years. The data I've used is measured at the Timaru Airport. More...

When the Timaru Herald published an article entitled Mercury Energy goes knocking for business on Saturday the 3rd of July, I took interest. There were two main problems with the story. Firstly they stated that Mercury Energy was a new entrant to the South Canterbury market and secondly they published some market share figures for South Canterbury showing TrustPower as having the largest proportion, followed by Meridian Energy.

So I surfed to the Electricity Commission's web site to check the figures for myself. My investigations led me to sending the following letter to the Timaru Herald for publishing: More...

This is a letter that I sent to LineTrust South Canterbury after reading an article in the Timaru Herald on Energy Mad's Efficient Light Project:

I read with interest the article in the Timaru Herald entitled "Power Scheme 'a cracker' says Minister" regarding Line Trust South Canterbury and Energy Mad's Household Efficient Light Project. More...

The following letter was published in the Timaru Herald:

On Transpower's web site (www.transpower.co.nz) there are speech notes from a series of three presentations made by Dr Ralph Craven, Transpower's Chief Executive, on the matter of increasing the transmission capacity of the National Grid. The latest presentation is dated the 13th of May and was presented to Local Government New Zealand in Dunedin. More...