The SOMA 300 Watt Wind Generator at home in New Zealand.

Remote Area Power Systems in New Zealand

David MacKay

New Zealand lies in the south-west corner of the Pacific Ocean and is situated between 35° and 45° south latitude. The sub-tropical land, about the size of California, with 3 million people, has a significant proportion of remote areas. Despite the extensive mains power development in New Zealand, there is a considerable need for independent power systems in isolated areas. With favorable climate conditions, the development of wind technology for Remote Area Power Systems in New Zealand is well advanced. A wealth of experience has been obtained in system design and installation for home power including the use of solar, photovoltaics, batteries, inverters, microhydro, and low energy lighting.

Discussed here are just a few of the things that have been happening in New Zealand. When a place is a little bit out of the main stream, development and innovation can sometimes go off on a tangent from industry norm. There are not so many guidelines to work from and integrity can take its own undirected path and often come up with some exciting stuff. HYBRID WIND SOLAR SYSTEMS

The ability to provide continuity of power is an important objective in the design of Remote Area Power Systems (RAPS). This is not easy when relying on natural elements which are variable and at times fickle. Wind power is subject to calm spells which, even in a windy area, may last several weeks, while reasonably cost effective storage batteries provide only 4-5 days supply at low consumption. Similarly solar power is subject to low output for considerable periods, particularly in winter. A GOOD PAIR

Wind and solar energy inherently go together. It is the warming of the earths surface by the sun that creates the wind in the first place. A combination of wind and solar energy is effective in providing the sought after continuity of power supply in RAPS applications. FILLING IN THE GAPS

In a hybrid Wind/Solar system, the large gaps in supply from a given source are offset by output from the other source. Reliance is spread between the two elements. In particular, wind systems have a high output producing large amounts of power but suffer from long gaps, while solar output, though more costly per peak watt than wind, has more even production which tends to be higher in calm weather.

The overall supply of a hybrid system relates nicely to the variable nature of demand, allowing for high peak use, but maintaining reliability for lower continual use. For example, in a domestic situation, uses tend to be spread between intermittent heavy ones -such as domestic appliances, vacuum cleaners and power tools -and continuous lighter uses - such as lighting, refrigeration, television, and stereo. Large power inputs from wind can be drawn upon for heavy loads while the smaller more even solar production improves supply for the lighter loads. QUESTIONS

To what extent does the availability of power actually improve with a hybrid system? What are the economics of a wind/solar hybrid system?

Renewable Energy 101

Renewable Energy 101

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable. The usage of renewable energy sources is very important when considering the sustainability of the existing energy usage of the world. While there is currently an abundance of non-renewable energy sources, such as nuclear fuels, these energy sources are depleting. In addition to being a non-renewable supply, the non-renewable energy sources release emissions into the air, which has an adverse effect on the environment.

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