Totara Valley - Renewable Energy

August 2007
In the early 2000s a group of farmers and researchers got together near Woodville to investigate the potential to generate enough electricity, from local renewable resources, to meet their own demands and sell the excess to other consumers.

In 2002 the Poulton family farm was the local monitor farm for the district. Part of the discussion on the farm was the idea of looking at ways of generating their own power. In New Zealand there is a particular interest in this as a business opportunity, since both trust owned and private electricity companies will no longer have to maintain unprofitable sections of their lines after 2013 (as outlined in the Electricity Act 1993). The concern among rural users is that if sections of remote lines go down, there will be little incentive to rebuild them if they are unprofitable.

Totara Valleyis a typical rural NZ hill country with high rainfall and brisk winds.

The two families at the end of the road are the Smiths and Poultons. They are both sheep and beef properties.

Mike Poulton

The Poulton family has farmed their Wairiri property, east of Woodville, for three generations. They have 784ha (effective) of steep hill country in the Waewaepa Ranges, now subdivided into over 100 paddocks. They have a hydro scheme on their farm as well as solar panels for electricity generation.

Geoff Smith

Geoffs property is 640 ha, this is also primarily a sheep and beef property. Geoff says they got interested in the renewable energy scheme when it was first mooted. One of the big incentives was the implications of their isolation and possibility of big increases in costs for staying connected to the grid. He says they agreed to the project on the understanding that they stayed connected to the grid for the time being, in case something failed during a crucial time like shearing.

The technology and research has been provided at no cost to the farmers involved in the project. The only thing they have provided is the site. He says there have been teething problems with all the generation plants but as far as hes concerned the biggest issue is the long term plans of the supply and lines companies. He says there are still a lot of grey areas to be resolved in terms of their status as potential power generators.

Initially energy usage was monitored to establish some electricity profiles. The results of this showed some variations to usual urban usage. In particular, big spikes of usage were observed around shearing in January and second shear in April.

The next step was to look at what resources were available to be tapped. Wind speed and direction along with solar radiation were monitored over two years.

Small hydro power was also assessed, based on the flow and head from various streams on the property. Additional work was undertaken to see if this resource could be tapped under the Resource Management Act restrictions.

Several options were examined:

Each house having its own independent generation system using wind and solar, with battery storage and a generator as back up (For peak periods like shearing an extra generator to be hired).

Several small-scale sources of generation based in a community with a mini grid connecting up each energy source.

Generate power on site but staying connected to the grid which could be used as a battery when power demand exceeds supply. (Encouraging lines companies to maintain supply).

Continue to use the grid and run the risk that the lines company will ramp up the maintenance charges and costs.

The Totara Valley folk opted for the third option - staying connected but trialling the full range of private generation options.

Totara Valley farmers have wind turbines, a small hydro and solar panels for both water and power. There is also a diesel generator using biofuel and the usual wood burners etc.

One of the issues with the wind turbine is that the distance to the most viable site for a turbine is roughly 1km from the nearest house. The cost of cables from there is high if they are to conform with minimum transmission losses and electrical safety regulations. The decision was taken to use power from the wind turbine to generate not electricity but hydrogen - which is then piped to its end source. The advantage is that hydrogen can be cheaply reticulated using pvc pipes to a fuel cell.

The hydropower unit is situated on the Poulton farm. It is a New Zealand designed unit. All the farm houses use wood burners for water and space heating.