In our towns: Powering local communities with bioenergy
Moyston Landcare hosted a very interesting session on the potential for biofuels to support small town power needs, complementing intermittent energy sources like wind and solar. Daryl Sherger was our guest presenter. He has been working to progress the Ararat Renewable Energy Project.
Daryl pointed out that due to the peak output of solar panels being during summer, but peak community energy demand being in winter, even after investing in solar, our communities still rely considerably on coal to supply their winter energy needs. This is because, with current battery technology, it is cost prohibitive to store summer produced energy to use in the winter time. Daryl’s proposal is to invest in a local bioenergy system to provide that winter season energy, moving us off our reliance on coal and giving our town energy independence.
What is bioenergy?
A bioenergy gasification system converts agricultural residue into useful energy.
The process begins with the feeding of straw into a gasifier, a specialized chamber that has a very low oxygen content. Inside the gasifier, the straw is subjected to intense heat, typically generated by burning a small portion of the biomass to initiate the reaction. The lack of oxygen prevents the straw from burning completely and instead triggers a chemical transformation known as pyrolysis. During pyrolysis, the straw decomposes and releases ‘syngas’. Syngas consists of carbon monoxide, hydrogen, methane, and other combustible gases. The syngas is then cleaned to remove impurities like ash, tar, and particulate matter. The cleaned syngas can be used for electricity generation, heat production, or as a raw material for the production of biofuels (like biodiesel).
There is sometime leftover material from the gasification process, as the straw does not always fully decompose and convert to gas – but it is not a waste product! It is actually a very valuable by-product. The straw that does not convert to gas instead goes through an incomplete combustion (partially burning up) and leaving behind something called char. It typically consists of carbon, along with small amounts of ash and other minerals present in the original biomass. Char can be utilized as a solid fuel for heat generation or as a soil amendment in agriculture. Char has been found to improve soil fertility, water retention, and carbon sequestration when applied to agricultural lands.
Image from peer reviewed paper: Ciliberti, C., Biundo, A., Albergo, R., Agrimi, G., Braccio, G., de Bari, I., & Pisano, I. (2020). Syngas derived from lignocellulosic biomass gasification as an alternative resource for innovative bioprocesses. Processes, 8(12), 1567.
What are the benefits of building a locally owned and run bioenergy plant?
Locally owned and run bioenergy plants provide numerous benefits to rural towns. They offer a renewable energy source by utilizing organic materials like agricultural residues and wood chips. Unlike fossil fuels, bioenergy is sustainable and cleaner, reducing greenhouse gas emissions. By absorbing carbon dioxide during growth, the plants offset emissions when burned, helping mitigate climate change. The establishment of bioenergy plants stimulates local economic growth, creating job opportunities in biomass production and plant operation. It also supports local agriculture by providing a market for biomass feedstocks. These plants promote energy independence by generating power and heat locally, reducing reliance on external sources. They contribute to waste management by utilizing biomass materials that might otherwise go to waste. Bioenergy plants can be decentralized, reducing transmission losses and costs. Their combined heat and power systems efficiently generate electricity and heat, which can be utilized for district heating. Overall, local bioenergy plants foster sustainability, resilience, and self-sufficiency in rural communities, leading to a cleaner and more sustainable energy future
If you would love to see this project get off the ground, Daryl notes that at the moment, he is a ‘committee of one’! As such if anyone is interested in helping to lobby local councils, Daryl would love you to get in touch.
Below is a letter Daryl has provided to give more context on the project, including the estimated costs:
TOTALLY RENEWABLE ARARAT PROJECT
I’m proposing that Ararat establish a community owned renewable energy facility to provides all of Ararat’s energy needs, including transport, by 2030. I’ve looked at a number of community renewable energy projects around Victoria and they all fail to actually delivery the community’s total energy needs, including heat and transport energy. Typically, they use solar panels to produce an annual output equivalent to the community’s current electricity consumption. Unfortunately, the peak output of solar panels is during summer and peak community energy demand is in winter. The battery storage needed to shift solar output to cover winter demand is cost prohibitive.
My approach is to use a combination of local rooftop solar and a bioenergy plant to meet Ararat’s total energy needs, including space heating and hot water, as well the additional electricity needed to charge electric vehicles. The proposed bioenergy technology is a gasification system designed and built by Australian company Wildfire Energy. Gasifiers aren’t as efficient as a combustion/steam cycle based systems but they offer fast start up and better load following capability. This flexible, dispatchable form of renewable energy eliminates the need for battery storage. An example of this type of plant is in Skive, Denmark, built by SunGas Renewables. It also has the added advantage of producing large amounts of biochar which is a natural form of long term carbon sequestration and has the potential to make the proposed project carbon negative rather than just carbon neutral.
The proposed fuel for the bioenergy plant is up to 50,000 tonnes of local wheat straw at a suggested delivered price of $100 per tonne. Part of the proposal is a district heating system that uses waste heat from the bioenergy system to replace natural gas for Ararat’s space heating and hot water needs. District heating systems are unknown in Australia but are increasingly popular in Europe. They have the advantage of replacing electricity demand at peak times of the day and during winter. An important part of the proposal is an arrangement with an energy retailer to buy rooftop solar output from Ararat residents at a reasonable price, along with output from the bioenergy plant, and sell the electricity to Ararat consumers at a lower price than they currently pay. Hepburn Energy have a similar arrangement with retailer, Flow Power.
In addition to meeting all of Ararat’s electricity and heating needs, there is the potential to produce synthetic diesel suitable for farm machinery and heavy transport. The proposed bioenergy system would only operate at full capacity for a few hours each day and the spare gasifier capacity could be used to supply syngas to a synthetic diesel plant similar to the Renewable Biodiesel Plant currently planned for Narrogin in WA. This possibility isn’t included in my current proposal but could be added later. If there’s enough interest in the proposal, I’d recommend inviting a representative from Hepburn Energy to a meeting to explain how they succeeded in developing their system. Anyone wanting to register an interest in the proposal can call me on 0497 609 944 or email, firstname.lastname@example.org.