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Innovation the Key to Enhancing Value

We are always on the lookout for ways to maximise the efficiency and output of our existing Hydroelectric Power Schemes (HEPS).

In particular, we search for innovative ways to better use the water resource we already have consent for, and the infrastructure that is already in place.  

The Resource Management Act 1991 (RMA) encourages the efficient use of physical and natural resources. It states that any person exercising powers under the Act in relation to managing the use, development, and protection of natural and physical resources, shall have regard to the efficient use and development of natural and physical resources; the effects of climate change; and the benefits to be derived from the use and development of renewable energy. Based on this, there is much scope for us to continue improving the efficiency and capacity of our existing HEPS, thereby improving the efficiency of the use of the water resource.  

Once an enhancement opportunity has been investigated, and the economic viability confirmed, we embark on the resource consent phase. As a starting point, any potential effect of an enhancement on the environment needs to be determined. An advantage of enhancements over new builds is that there may be only minor modifications required to improve outputs, because much of the necessary infrastructure already exists. This is often achieved with little effect on the environment. For new hydro developments the potential effects can be sizeable, and post construction they often require adaptive management, which can be costly. High consenting costs remain a big hurdle for new projects, particularly as these are usually subject to both council and Environment Court hearings.  

As part of the resource consent application process, we consult with stakeholders and the local community. During this process, opportunities are often presented for HEPS enhancements that can provide tangible benefits to the environment and community.  

By way of example, in 2009, resource consent was granted for the Coleridge HEPS Tailrace Project in Canterbury. The Project will result in tangible benefits for the local community. The Project involves installing a small power station within the tailrace of the existing Coleridge HEPS. While some modification to the tailrace will be required, no additional water take is required, with the current Coleridge Station discharge being reused and passed through a number of parallel generators to provide an additional 3 MW of generation.  

During consultation, the community expressed a desire to improve the Sir Edmund Hillary walking track adjacent to the Coleridge Power Station, and we have undertaken to do this. As a result, not only will the scheme’s use of water be improved, and output gains made, but the local community will benefit through improvements to a popular amenity of the area.  

The Motukawa In-race Generator uses the same principle. In this case, a small generator was installed in an existing water supply race at the Motukawa HEPS in Taranaki, making use of the drop within the canal to provide additional electricity generation capacity for the HEPS. The generator was constructed in 2005 and contributes an additional 0.9 GWh of electricity a year.