Wind generators show great promise

Wind is the cheapest form of energy and we need some of that in Northland to get our

power bills down.

The problem with renewable energy is that there are times when the sun does not shine or the wind does not blow and what do we do then? One of the biggest potential providers of renewable energy are wind generators and there appear to be long periods when the wind is very calm, which is a bit of a worry if we are relying on it for our power.

The wind is a very soft substance and sailors would know that any breeze below 10 knots or 18km/h is difficult to sail with, the same applies to wind generators as they only start to produce energy at four metres per second which is 18km/h but after that, the power potential goes up very steeply and this is where the engineers dedicate their efforts.

In producing wind power there is no substitute for blade length and also the wind blows stronger higher from the ground so if we put the two together, we can understand the new designs of wind generators and also the challenges of building a strong and workable structure.

In the year 2000 wind generators had reached a height of 120 metres to the top of the blade but today they are 230 metres and still growing and the power output has risen from 1.5MW to 10MW, with the largest in the world being a giant 242 metres tall, and at 16 megawatts, it’s capable of powering 20,000 homes with three giant 118m blades.

These huge structures are best sited at sea where there is space for them and in Europe, an ambitious project, the North Sea Power Hub, has already started construction where six nations are getting together to put windfarms on the Dogger Bank with several power collecting hubs and power cables that join the six nations together to share power in both directions.

This means there is always power somewhere which can be shared and even France’s nuclear power can be fed into this grid.

In New Zealand, we have wind in the Cook Strait at 8 metres a second and, in the Far North, Cape Reinga has wind at 7 metres a second which is ideal for a land-based wind farm.

Moving turbine blades 100 metres long presents problems so there are designs that use 3D printers on site to make the moulds and then make the blade close to where they are going to be installed. When the farm is finished all the components of construction can be dismantled and trucked away to a new site.

Wind tends to blow stronger during the day, a bit like solar, so at night we can manage the lower levels of requirement with geothermal, hydro or batteries and a multiple of sites means that there is always power being generated somewhere.

Wind is the cheapest form of energy and we need some of that in Northland to get our power bills down.