Overview

Mac Hops converted their boiler from coal to wood energy back in 2020 when they saw a need to move to a more environmentally friendly fuel option. 

Azwood helped them plan the construction of their boiler to ensure maximum output and efficiency of their wood fuel as a sustainable alternative to coal.

Background

The McGlashen family was one of the pioneering family businesses in Nelson’s relatively small hop-growing community. Today, five generations later, they’re the last of the ‘originals’.

“Like all the growers, I’m continually striving to work around climatic changes.” - Kim Mcglashen

New Zealand hops are harvested in late February and March of each year. The hops are about 75% water and 25% dry matter and must be dried down to 8-10% dry matter. This involves kilning the hops, a process that uses quite a lot of energy.

During the drying process, while the hops are drying, they will be sitting on heat for anywhere between 6-10 hours. Their boiler heats the hot water radiators which are circulated with industrial fans. This ensures the hops stay free from any contamination by exhaust gases.

Challenge

Mac Hops already had a coal boiler but wanted to switch to wood fuel as a sustainable alternative to coal.

Due to the increase in demand for hops, Mac Hops already had a purpose-built wood energy boiler that used Azwood’s S30 Wood Energy Chip, but it was their original coal boiler that they wanted to convert.

“When you’re dealing with a food product you want to be dealing with a clean environment. With wood pellets you don’t even know the fire is going.” - Brent Mcglashen
 

Assessment

Mac Hops already used our wood energy chip for their Upper Moutere boiler, however, this fuel was not suitable as a drop-in fuel alternative to coal. Thankfully we were able to suggest a few small alterations so their coal boiler could easily take wood pellets as an alternative fuel source. 

Wood pellet fuel is low in moisture and high in density to provide a high energy output. Due to its high energy density and low ash content, there is minimal cleaning and less downtime for maintenance through the busy harvest period. This means it runs more consistently and is less stress on the boiler.

There are many boilers around NZ that can easily be converted to wood fuel as a sustainable alternative to coal. Azwood has over 40 years of experience in the industry and can help from the initial planning stages to advise on the best options for your business.

“Fortunately we found that there was a local supplier of wood chip in Brightwater and the expertise that they offered to help set up the wood burning boiler from the planning stages was quite important.” - Kim Mcglashen

Why is wood fuel sustainable? Using wood energy is carbon neutral which is a more environmentally friendly option than burning fossil fuels. 

Outcome

Although the energy output was similar to coal, overall the environmental impacts they saw were positive. Mac Hops noticed no smoke, less smell and reduced maintenance. The low moisture content also increased efficiencies when drying their hops which aided their decision to use wood fuel as a sustainable alternative to coal.

“There is very little smell at all around the place. When we used coal I would have to get dressed up in a mask and overalls and the coal dust just gets right to the back of your throat.” - Brent Mcglashen