Biomass 30 credit module site visits – from forest to flame, and future fuels

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Arthur Butler, lecturer at CAT’s Graduate School of the Environment, writes about the recent biomass module that students on the Renewable Energy and the Built Environment MSc attended.

We recently took a group of students studying on the REBE double biomass module to see several local wood-based heating installations of varying scale and running on different fuels. We also learned a bit about some research into novel biological energy sources and products. The trip helped the students gather information to inform their individual written assessed piece of work-a design feasibility report for a biomass heating system for the Plas in Machynlleth, which is a large listed building used by various community groups and local businesses.

First off, we visited a local timber and wood fuel producer. It was great seeing local fuel supply – and job creation – in action. The wood-fuel part of the business produces logs and woodchip, and we heard about the machinery and logistics involved as well as the cost and quality issues associated with supplying reliable fuel.

Next we headed to Plas Crug, a large scale biomass plant in Aberystwyth supplying heat to the Welsh Government offices and a school. We saw the size of the equipment, the backup boilers, district heating, buffer stores and talked with the facility managers about the day to day running of the plant.

Nearby, also in Aberyswyth, is CRAFT, a socially-orientated enterprise reclaiming household goods and reconditioning them for sale, while also providing employment for the local community. After moving a few years ago, they sought to make their workplace more environmentally friendly, installing a solar thermal system for hot water heating and a biomass boiler for space heating. These systems haven’t been without their complications, so it was a great opportunity for the REBE students (some of whom may become consultants, designers or installers) to hear from a client’s perspective what things can become issues.

Surprisingly, despite living nearby, I hadn’t immediately noticed the biomass boiler in CRAFT – showing that they can be clean and well-integrated in built-up areas, and make a lot of sense in rural areas with fuel available nearby. Happily, CRAFT’s problems have been straightened out with a new woodchip supplier and some assistance from heating engineers.

After CRAFT, we headed to IBERS, a biology and energy research centre at Aberyswyth University. We were shown research into biochar, pryrolysis and anaerobic digestion and heard about producing pellets for fuel from low-grade crops such as grasses – extra energy sources like these could be a valuable additional resources in the future. We saw a pellet mill, visited the labs where gas chromatography and other techniques were being used to analyse the chemical compounds present in various crops and to investigate yields.

Biomass crops may also be used to produce liquid biofuels, but there can be even more energy and land-use issues with these products. We were also told about research refining biomass sources to produce the chemical building blocks for plastic materials, or other products such as pharmaceuticals that are produced from petrochemicals at present.

On the way back to CAT we called in briefly at the Plas to let the students investigate possible locations for a new boiler installation for their reports. They had previously audited the building to assess energy demands in the buildings module, and will use those measurements to size the boilers they propose in their coursework.

The students took fuel samples from the various locations, which they’ve analysed for their reports, as well as cost and performance data. We made flue gas analyser measurements on one of the boilers, and others at CAT, to investigate emissions and efficiency. During the module we’ll be doing various biomass practicals on the CAT site too, and having lectures from academics, installers and designers, and the students will give group reports on their research into the fuel choice options, boiler system sizing and the economic aspects of the systems they propose in their coursework for the Plas building.