Powering a distillery on grape waste

Since the 1990s, Australian Tartaric Products has been collecting waste from local wineries, distilling it to make grape spirit, and extracting tartaric acid from the distillery waste, which it then sells back to the wine industry.

Now, taking reuse to the next level, the company is powering its operations using steam generated by burning the processed grape waste.

[February 2015]

Key points
  • In a first for Australia, the company is using waste grape skins and pips (‘grape marc’) to generate energy, almost eliminating its use of LPG.
  • Total energy costs are down more than $2 million a year.
  • Carbon emissions are down by about 10,000 tonnes of carbon dioxide equivalent a year.

What Australian Tartaric Products does

Since the early 1990s, Australian Tartaric Products (ATP) has been collecting waste from local wineries, distilling it to make grape spirit, and extracting tartaric acid from the distillery waste, which it then sells back to the wine industry.

Located at Colignan in Victoria’s Sunraysia wine region, about 50 kilometres south of Mildura, the company is Australia’s only manufacturer of tartaric acid.

Wineries use tartaric acid as a preservative and for adjusting pH and flavour. It is also used by the pharmaceutical and food and beverage industries.

Grape spirit is used in the making of brandy and fortified wines such as port and sherry.

“Our two products are both extracts from wine-making residuals”, says General Manager Ben Manfield.

Tartaric acid
Wineries use tartaric acid as a preservative and for adjusting pH and flavour. It is also used by the pharmaceutical and food and beverage industries.

Grape marc as a bioenergy feedstock

To make its products, ATP uses three raw materials sourced from local wineries:

  • Grape marc – the skins and seeds left over after the grapes have been pressed to remove the juice
  • Lees – the solids (filter aids, yeast, and other solids) removed from the wine during filtration
  • Sludge – the yeast and solids removed from the wine after the fermentation process.

Grape marc
Grape marc is the skins and seeds left over after the grapes have been pressed to remove the juice.

The grape marc is pre-treated in the marc plant to extract the acid and alcohol, leaving a ‘grape wine’ and residual or ‘spent’ grape marc.

The grape wine is then mixed with the lees and sludge (also pre-treated) before being distilled to make the grape spirit.

Finally, the residue from the distillery is conveyed to the acid plant where the tartaric acid is extracted.

It is the spent grape marc from the pre-treatment process that the company is burning in a biomass boiler to generate steam to power its operations.

The drivers

High fuel costs

ATP’s main driver for installing the biomass boiler was the cost of fuel to drive the distillery and the acid plant.

“A large part of our operating costs was for generating steam, because steam is what we use to distil”, says Ben Manfield. “We need lots of steam. And with the old gas-fired boilers, we had very large gas bills.

“On top of that, here in Colignan we’re not on mains gas, so our gas was all trucked in by B-double tanker and that increased the cost of our gas even further.”

Having a ready feedstock onsite sealed the deal.

“We also had the spent grape marc, which was onsite and available to be used to generate energy.

“A biomass boiler would take that waste material, create the steam we require, and reduce not only our energy costs but also our carbon emissions, being renewable fuel.”

The ability to use surplus steam to generate electricity was also seen as important.

“Again, due to our location, line losses are quite high here because we’re at the end of the power lines. So our electricity was not the cheapest either.”

Staying competitive

ATP is the only company in Australia making natural tartaric acid and is the biggest in the market, but they still have to compete with imported tartaric acid from Europe and a synthetic substitute product from China. Reducing their fuel costs is helping them do this.

“Like any other industry, there’s always increasing competition”, says Ben. “Everyone has to innovate and keep improving to remain competitive.

“This is particularly so when you are competing with a non-natural substitute, which does not have to meet the same high standard manufacturing protocols we have in Australia. So generating our own energy helps to ensure our ongoing competitiveness.

“And that’s the thing with the biomass project—there’s a big capital outlay and a long payback time, so it needs to be part of your strategy.”

Sourcing the feedstock

ATP collects grape waste from multiple large wineries that would otherwise have to bear the cost of disposal.

“Grape marc coming straight out of the winery is acidic so there’d be some problems using it as a compost”, says Ben. “And generating energy from grape marc is not really a viable option for an individual winery—it’s quite difficult to do and you need massive capital and enough grape skins.

“We collect the waste at no charge to the wineries, so we’re providing that service.”

Truck unloading grape marc at Australian Tartaric Products
ATP collects grape waste from multiple large wineries that would otherwise have to bear the cost of disposal.

Most of the wineries are within a radius of about 100 kilometres.

“Further afield, it being such a low value material, the transport starts to eat in. And there’s a sufficient volume in Sunraysia and the surrounding areas”, says Ben.

ATP collects 90,000 tonnes of winery waste a year, and about 50,000 tonnes of this is grape marc.

“If there are more grapes planted and the wineries crush a bit more, we can expand our processing to grow with them. We’ve moved with the wine industry throughout our history. ATP’s first vintage was quite small back in the early 1990s and then, as the volume of the crush grew across the country, we’ve had to grow as well.

“It’s a closed-loop process. We’re a little bit dependent on each other. Around the world, that’s how other plants of this type operate as well.”

Storing the highly seasonal feedstock

The supply of grape marc is highly seasonal.

“The wineries have their annual vintage; they crush from January through to early April and that’s when all the marc is generated”, says Ben.

“Wineries don’t have large storages so we tend to collect it within a few days. And while that’s coming in we can run the biomass boiler.”

To provide a consistent supply of feedstock for the rest of the year, ATP keeps a stockpile in a purpose-built concrete bunker.

The stockpiled grape marc is stacked in a certain way to minimise degradation, exposure to rain and sun, and to prevent it drying out too much.

“If you store it and handle it correctly, our vintage-to-vintage storage is not too much of a problem. Longer than that, maybe there would be issues. But even within that time, unless handled properly, there can be problems. The biomass can change with moisture levels and other things, and the material degenerates.

“It’s all part of the process. We generate spent marc so it’s a daily job to store it correctly.”

Spent grape marc stockpile
The stockpiled spent grape marc is stacked in a certain way to minimise degradation.

Benefits to the business, the region and the planet

In 2014, ATP began burning the spent grape marc to generate steam, almost eliminating its use of LPG in powering the company’s operations.

“We’d been running since November 2013 in a commissioning type capacity, and our first full vintage started in January 2014”, says Ben.

The system is almost operating at full capacity now and the company is no longer burning gas to create steam.

“The reduction in costs ensures that we can stay competitive and provide the service to the wineries as well, into the future. It can be seen as our commitment to being in Sunraysia long term. If we felt that there wasn’t a future, we wouldn’t be investing in a big plant like this.”

Operating and maintaining the biomass boiler has been a steep learning curve but has brought unexpected benefits to the company and its workforce.

“Computerised control, biomass boilers—there’s a whole lot of different things that we have had to learn”, says Ben.

“Not only our operators, but also our maintenance and tradespeople, our technicians, the truck drivers—they’re all learning about this new technology. It’s been really good. People have taken it on board. And that upskilling of our workforce flows on. We’ve found it easier to bring automation to other bits of the factory because they’ve already learnt a lot of the skills required.”

The reduction in carbon emissions has been significant, at about 10,000 tonnes of carbon dioxide equivalent a year.

“We’re going from fossil fuel to renewable fuel not only with our boilers, but with some of our electricity generation as well.”

Capital costs, savings and payback period

At a glance
  • The total project cost was $11 million (includes the $7.5 million boiler unit, installation and infrastructure integration).
  • Total energy costs are down more than $2 million a year.
  • LPG usage is down 90%.
  • Energy from the grid is down 43%.
  • The expected payback period is 4.8 years.

Funding and risks

Initially ATP was awarded a $40,000 grant under the Australian Industry Group / EPA Victoria Sustainability Covenant to do a feasibility study on converting spent grape marc to energy.

The company was subsequently successful in receiving two grants from:

  • the Victoria Government Regional Infrastructure Development Fund ($1.8 million)
  • the Australian Government AusTrade Clean Energy Australia ($1.7 million)

The company also secured finance from NAB (National Australia Bank).

“Getting finance for a project like this is not as straightforward an arrangement as leasing a tractor”, says Ben.

“These are big capital investments and when you’ve got a waste stream that’s not been processed in that way before, that’s big risk.”

ATP’s parent company, RANDI, had already commissioned a similar boiler in Italy, so the technology risk was reduced. Having the supply of fuel onsite also helped.

Other risk areas included the market conditions, the climate and the wine industry.

“NAB Agribusiness was very helpful”, says Ben. “They brought in their own industrial specialists from Melbourne to evaluate the business case. They had the people that could push through that sort of slightly different project, identifying different ways of financing and how to approach it.

“It’s all about making them comfortable about the project feasibility, our capacity to manage it properly and the assured supply of raw material. After that, the economic case around the costs versus savings spoke for itself.

Does the technology work?—that’s probably the main risk. Is the boiler compliant with Australian conditions, being welded in Italy? Is it to our Australian standards? They were able to work through all those sorts of things with us.”

How the system works

Pre-treating the spent grape marc

Once the grape marc has passed through the marc plant where all the tartaric acid and alcohol is removed, the spent grape marc is pressed to remove some of the water. It is then ready to be conveyed into the biomass boiler.

Conveyor belt transporting spent grape marc to the biomass boiler
Once the grape marc has passed through the marc plant where the tartaric acid and alcohol are extracted, the spent grape marc is pressed to remove some of the water before being conveyed into the biomass boiler.

“It’s not dry”, says Ben, “but it has to be moisture controlled. Like any other biomass, any variability in the feedstock—be it moisture, be it calorific value—we have to make sure that the supply is as constant as we can.

“If we leave a bit too much water in or we have a patch where it’s just all seeds coming through, then the operator is going to spend hours trying to tune the fire and then it will change again. So it’s all about having an even feedstock and integrating it with our process.”

Burning the spent grape marc to create steam

The 8 MW biomass boiler has the capacity to generate 10 tonnes of steam an hour.

The feedstock is conveyed into a hopper and then mechanically pushed into a large combustion chamber.

“Because the feedstock is low energy you need the big combustion chamber”, explains Ben.

“A gas boiler is primarily a small valve injecting gas in, but with this one we need extra equipment and ash handling. And you’ve got extensive filtration equipment to clean the smoke.”

Spent grape marc stockpile
The 8 MW biomass boiler has the capacity to generate 10 tonnes of steam an hour, says General Manager Ben Manfield.

The biomass boiler is also slower and harder to control compared to a gas-fired boiler, says Ben.

“If we stopped the marc now, it’d still make energy for a few hours probably. Gas boilers are much easier—if you want 1% more energy, you give it 1% more gas. The natural variation in the feedstock means you might get some marc that has a bit more energy in it. Then you have to tune it. So the boiler is manned 24/7 and their job is to keep that fire right.”

In the purpose-built control room, a camera placed inside the boiler shows the grape marc being mechanically pushed into the fire.

“You can’t leave it alone, by law, because of the type of boiler it is. It’s a safety requirement.”

With some modification, the boiler could burn other fuels but the company has no plans to do so at the moment.

Generating electricity with excess steam

While generating steam to use directly in running the marc plant, the distillery and the acid plant was the main driver for the bioenergy plant, the company now has excess steam which it uses to generate electricity that helps to power the operations.

The electrical generation plant uses an organic Rankine cycle, or ORC, which was built by a Melbourne company using imported turbines.

“There’s not many of those in Australia yet—they are more common in Europe”, says Ben.

“Basically, you’ve got 4 turbines. The spare steam heats up a working fluid which evaporates, drives the turbines and makes electricity.”

The electricity capacity is 0.45 MW.

It works like a fan in reverse, explains Ben: “You turn a fan on, you put electricity into the fan and you blow air around. Well this is high speed air turning the fan and that makes the electricity. The turbines run at 30,000 revs so they’re very fast.”

The generated electricity is wired into the factory and the condensed water goes back to the boiler to be reused.

Exploring grape ash as fertiliser

Dry grape ash is the main waste from the biomass boiler after the smoke is filtered.

The company generates hundreds of tonnes of ash a year and is currently investigating potential agricultural uses, such as a fertiliser or soil conditioner.

“It’s concentrated in some things and hasn’t got much of others”, says Ben. “So it’s got specialised uses. We have a few agronomists having a look at it to work out what it’s good for.”

Designing and manufacturing the boiler

The boiler was designed and manufactured in Italy specifically for the site. It took about a year to design and build.

It was assembled and then partially disassembled before being shipped to Australia in containers. The stack, which was too big for a container, sat on the deck of the ship.

Installing and integrating the boiler

“The whole project, from the concrete right through to commissioning, took approximately 18 months”, says Ben.

“The boiler and the work crews arrived in January 2013. We were able to get usable steam in November 2013.”

The boiler was installed by the supplier but the support and integration was done by local tradespeople.

“At the peak, we had about 30 blokes working on installing the boiler. All the wiring, the steam pipes, the electrical piping and the ORC was all done by locals as was the bunker, all the buildings and the structural changes. So there was a significant local spend in that.”

The effort required to install the bioenergy plant and integrate it with the existing factory was challenging.

“It was a big and technically innovative project that needed a lot of resources, and it’s challenging to sustain that”, says Ben.

“Even in the office there are all sorts of things required to keep the project going, from managing imports, making sure the containers of new materials get cleared by customs, to scheduling trades and cranes. It takes a lot of resources over a long period of construction. It was a very hectic couple of years for everyone.”

Skills and labour

To operate and maintain the boiler and electricity generation plant, ATP has employed about 6 extra people.

The biomass boiler needs 24-hour supervision from a trained boiler attendant. The boiler operators received training from a Bendigo training company and from the Italian manufacturer.

Spent grape marc stockpile
The biomass boiler needs to be monitored 24/7 by trained boiler attendants.

“The manufacturer sent someone who stayed with us for maybe a month or two, running it, training each person”, says Ben.

“There’s a lot of training involved but I think there are benefits in that for us as well, that cross into the rest of the factory.

“For the 24/7 operation, we run 12-hour shifts with 4 crews of up to 5 people. So we’ve put on an extra person on each shift to do that.”

All the maintenance is done in-house so the company has had to develop the skills and hire extra people to service the boiler, while making sure that the higher level technical supervision and support is also there.

Technical challenges

Making sure the boiler can handle the feedstock has been one of the main challenges, says Ben.

“The spent grape marc is a low energy fuel, so the combustion chamber has to be bigger.”

The feedstock’s variable calorific content and variable moisture have meant new processes.

Other challenges were location specific. The factory is located close to the banks of the Murray River.

“Because of the nature of the soil and because our water table’s quite high near the river, we needed a special type of foundation more akin to a high-rise building than just a raft concrete”, says Ben.

Integrating the boiler with the existing factory was like having a plant within a plant, he adds.

“The boiler’s got to work in with the rest of the plant and supply the steam when it’s needed. It’s very complicated—there’s, training, extra people, all those sorts of things. It’s like extending your factory by another production line.”

Regulatory requirements

ATP began addressing the environmental regulations for noise, odour, dust and emissions with EPA Victoria even before the boiler was designed. The boiler manufacturer in Italy had to be made aware of the requirements for flue gas treatment, for example.

“It starts right back at the design stage”, says Ben. “There’s a lot of work to be done, but we found the EPA good to work with. We had to provide a commissioning operation plan, and then execute that plan.”

Being registered as a power station, ATP is now entitled to large-scale generation certificates (LGCs).

“Even though our electricity generation plant is not connected to the grid, what we make counts as renewable electricity. So we count our meter and that becomes credits, and you can trade them, depending on the regulation at the time.”

Licensing the boiler was another requirement.

“We had to train everyone to operate that type of boiler. In one way it’s onerous—it’s thousands of dollars a person—but then on the other hand it does train them in the safety aspects of operating the boiler.”


Ben Manfield,
General Manager,
Australian Tartaric Products,
1074 Boonoonar Road, Colignan, Victoria 3400
Phone: 03 5029 1450
Email: ben.manfield@australiantartaric.com.au