18 May 2017

O.2.9.4 Rebuilding Christchurch – Using Ground Source Heat Pumps

In February 2011, Christchurch, New Zealand experienced a destructive earthquake, resulting in large areas of the central business district collapsing. The rebuild of the city presented a unique opportunity for the advancement of geothermal / ground source heat pump (GSHP) infrastructure, district energy nodes, city planning and updating building regulations. Christchurch is situated on the East coast of New Zealand’s South Island, and the city overlies a series of confined aquifers ranging in depths from 5 m to greater than 200 m. These aquifers are highly productive, with yields in excess of 100 L/s possible from a single well and hence the capital cost per kilowatt of thermal energy delivered from GSHP infrastructure is significantly lower than in other parts of the developed world. Groundwater temperatures remain within the 12-13°C range providing an ideal source for heating and cooling. In the city there had been some energy use from these aquifers prior to 2011. Several incentives encouraged greater uptake of this technology, including streamlining the planning regime, re-examining potential renewable energy sources, and some funding grants. This assisted to overcome perceived barriers such as capital costs, complicated permitting, and reliability of the infrastructure in an earthquake prone region. There are a number of large new commercial GSHP projects completed or under-development across the city and this paper presents a summary of the GSHP contribution to rebuilding significant infrastructure in central Christchurch city