This project was for the replacement of an old end of life coal boiler that had become unreliable, very inefficient, and was inclined to stop working frequently. The current central heating system within the school was working well due to the significant time and effort that was invested. This system had become a huge drain on time for the caretakers and Board of Trustees. The project included Sustainability Contestable Fund application support that demonstrated the poor state of the current boiler and the need for replacement with a reliable and sustainable alternative.

The previous coal boiler in plant room had ash overflowing from the access hatch to the boiler combustion chamber. In order to access it, it was required that all coal slag, clinker and ash were cleared out from the combustion chamber. The BOT Dep Chair had to spend two hours emptying the chamber full of coal whenever ignition malfunctions occurred.

The newly installed system included a cascade of four Pellematic 64kW pellet boilers from ÖkoFEN, Austria. The boilers come with a ten-year warranty with all spare parts and warranty replacements being held on-shore in New Zealand. The boiler and plant room design was checked by our mechanical services contractor Aquaheat Facility Services. 

The maintenance requirements on the Pellematic boilers are extremely low. The ash container will need to be emptied after 3-4 tonnes of operation (after approximately 5 weeks based on our school’s heating load). The ash is also a certified organic fertiliser and can be placed directly on our mārakai.

By installing a new pellet boiler system there will be a 99% reduction in carbon emissions compared to the previous use of coal.

The old system:

• In 2019 the old coal boiler system burned 43.3 tonnes of coal.
• The burning of this coal emitted 91,746 kg of carbon dioxide, contributing to the climate crisis which has been directly felt already in Edgecumbe with devastating floods in 2004 & 2017
• These carbon emissions are the equivalent of travelling 421,574km in an average modern car
• Or the equivalent of driving around the world more than ten times
• Each student at the college was indirectly responsible for 395kg of CO2emissions per year, just for coming to school

The new system:

• The forecast for the new systems fuel consumption will be 47 to 55 tonnes of pellets, depending on the reduction in fuel consumption with more efficient boilers and heating controls.
• This fuel will emit 705 to 830 kg of CO2. 
• The emissions are equivalent to travelling 3,772km in an average modern car, getting you under four return trips from Edgecumbe to Wellington.
• Each student at the college will be indirectly responsible for 3.5kg of CO2emissions per year for coming to school.

The new pellet storage ensures the school always has fuel on-site for reliable heating with the anticipated heating requirement meaning only one delivery of pellets per year. Pellets are delivered by a vacuum truck which visits the school outside of school hours and only needs to get within 20m of the boiler room using a blower hose.

The boiler is connected to the internet and will be remotely monitored by NZ and Austria based technical experts. The monitoring system automatically sends out alerts for regular maintenance, fuel reordering and any boiler or system faults and errors. As opposed to the previous coal system the pellets are completely harmless, non-toxic and cannot ignite except in the boiler with a forced-air combustion.