Making production sustainable and efficient

Food and beverage production needs high volumes of energy and produces large amounts of waste. What are the best ways for companies to be environmentally sustainable while maintaining economic efficiency? PACE talks to Total Construction’s James Bolton and Rob Blythman.

Food and beverage processing is highly energy intensive. Producing the heat required for industrial production, for instance, consumes high volumes of gas. This comes at a price: energy usage accounts for at least 15 per cent of total operation costs for food and beverage manufacturers.

Alongside energy consumption, water consumption and waste production are also high in food and beverage plants. Improving efficiency in all these areas is therefore critical for companies looking to improve their bottom line. With high power costs looking likely to remain a norm in Australia, reducing reliance on the grid and generating energy onsite is an increasingly attractive option.

Utilising renewable sources of energy can help food and beverage companies to both reduce emissions, and save on operating costs. There are a number of renewable energy technologies available that can replace traditional energy sources. However, companies need to know what approaches will suit the particular needs of their operation.

According to James Bolton, national manager of Total Construction’s energy and infrastructure division, it is essential that companies weigh up the costs and benefits of the available options before rushing ahead with costly installations.

“When it comes to building food and beverage manufacturing plants with renewable energy features, companies need to know what is the best fit for them, and it is not always obvious,” Bolton told PACE.

Recently, Total Construction carried out a detailed analysis for a client looking to construct food manufacturing plant that would be energy efficient and affordable.

“They had a relatively high energy consumption, particularly electricity, and they also use a lot of water. We have had a pretty thorough look at how we could make this whole facility more sustainable without blowing out the cost,” said Bolton.

When exploring the options for onsite power generation, Total Construction quickly established that solar panels would be greatly beneficial for the client. With ample roof space at the facility, it was determined that installing solar panels would cut back the facility’s demand on the grid during the day.

“It was a no-brainer. Solar is a sustainable power source and it makes sense from an economic perspective. Its affordability is improving each and every day,” Bolton explained.

Sizing the panels correctly was a key consideration. Bolton explained that if excess power was produced, it would be exported back to the grid, thus reducing potential returns due to the low prices generally offered from the retailer. It was also found that installing battery storage would increase the proportion of renewable power used, something that would be favourable during peak usage periods.

Co-generation, the generation of high-temperature heat and electricity from a single source, was another option explored. But in this particular case, Bolton explained, it wouldn’t have been especially beneficial for the client. Due to questionable reliability of co-generation supply, a back-up source would need to be invested in, making it less advantageous compared to the more reliable and similarly priced power from the grid.

“We found that it was pretty hard to make it work for them, economically speaking, as it costs a very similar amount to what they would be paying for power from the grid, making it hard to get a good return on investment,” said Bolton.

“One thing that has changed in the last five years, and what has made co-generation less attractive, is gas prices – the price of gas has gone through the roof.”

Total Construction also explored the gas requirements of the plant. Solar-powered hot water was deemed a viable alternative with minimal cost impact. Alternative methods of gas supply, such as onsite biogas generation via anaerobic digestion and hydrogen generation by solar-powered electrolysis, were considered. However, while these methods have great environmental benefits, the costs were too high.

“Because the food manufacturing plant would create a lot of food waste, there is the potential to produce gas from it using anaerobic digestion,” said Bolton. “But it is quite an expensive process to build a plant that is able to do that. Relatively speaking, this particular factory didn’t require much gas for water heating, so it didn’t make sense for them to spend $1.5 million on a special plant for little or no return.”

Rob Blythman, manager of Total Construction’s Energy Construction Group, explained that particular technologies and methods, while not always suitable for some operations, can be beneficial and sensible in others.

“Each client needs to be assessed individually – on their usage of gas, their usage of power, the amount of food waste that goes out, and the amount of water that they have to recycle. It is not a case of saying that other technologies are rubbish and solar is the only way to go: you have to weigh each option to determine which suits an individual client and their particular needs,” Blythman said.

“You have to do this each time for every client – you can’t just assume co-generation is a waste of time, because it might not be for some businesses. The choice needs to be bespoke for their operation.”

Bolton gave an example of a facility where co-generation and trigeneration are good options. “These approaches work well, for instance, at data centres, where the electrical load is constant 24/7 – it actually doesn’t change – and there is a lot of cooling required for the servers. That is a situation where trigeneration can work really well.”

When it came to determining how the food manufacturing facility could manage its water usage, it was found that using recycled water was not a viable option. In fact, the cost of potable water was so cheap that other options couldn’t compete.

“We were actually quite shocked by the results. In terms of sustainability, we thought that collecting rainwater from the roof would be a good idea. The client’s facility has quite a large roof area. But the cost of a rainwater tank, coupled with the cheap price of potable water, makes it economically inefficient in comparison,”
said Bolton.

Furthermore, there are few options for using recycled water in a food manufacturing plant. As per health and safety regulations, all water that comes into contact with food or items in the vicinity of food must be of high quality to avoid contamination.

“When you are a food manufacturing facility, and you are using water in your manufacturing process, you can’t use any of that rainwater unless you treat it. But the process and cost of treating it for re-use way outstrips the cost-per-megalitre that you’re paying, and it doesn’t make sense, as a business, to spend that,” said Blythman.

Onsite herb and vegetable growth were considered as a potential use for the water harvested from rainwater tanks. Blythman said that can work for some clients, where they can grow their own herbs and vegetables onsite for their food production to eliminate the extra costs of having those products trucked in.

“Most councils will force manufacturers to install retention tanks for rainwater. And for that water not to be used is a waste. In these cases, it makes sense to find uses for the rainwater so that it is a benefit for the manufacturer, rather than a hindrance.”

When it came to the facility’s wastewater discharge, it was determined that a dissolved air flotation (DAF) plant would be the best option. A DAF dissolves air in water under high pressure then releases it at atmospheric pressure, causing solids to float to the surface with the bubbles, where they are removed.

An emerging technology for the processing of solid waste, in which micro-organisms digest the food waste into a liquid product that can be discharged into the sewer, was found to suit the needs of the plant, as it dramatically reduces waste disposal costs.

“The cost of getting rid of solid food waste is usually quite expensive. This method allows you to be environmentally sensitive while also saving in operations costs,” said Blythman.

Blythman said that this kind of analysis carried out by Total Construction enables businesses to make a strong business case for efficient renewable energy options at their facilities.

“Doing this kind of analysis on your facility allows you to have a detailed understanding of what you need in terms of your energy generation, your water usage, and your waste management. What works for some companies won’t work for others, and you need to do the analysis to establish what suits your needs,” said Blythman.

“You shouldn’t say, ‘I want to use renewable energy and I want to be environmentally friendly’, and then choose options that are totally wrong for your operation. You need to determine what works for you.”