Power plant automation retrofit: a change for the better

The company logo, depicting a small green leaf, gives a subtle hint about the significance of sustainability at Alholmens Kraft. Located in Pietarsaari on the west coast of Finland, the biopower plant with its two units – AK1 and AK2 – produces environmentally friendly electricity for the national grid, process steam for the neighboring UPM pulp mill and district heat for private households.

The picturesque station building of Pietarsaari railway station.

Completed in 1986, the AK1 boiler has an electrical capacity of 35 MW and a thermal capacity of 150 MW. In 2001, the plant was expanded with AK2, one of the world’s largest biomass-fired combined heat and power (CHP) plants. At its heart is a circulating fluidized bed (CFB) boiler supplied by Valmet’s predecessor, Kvaerner Pulping.

Both plants mainly run on wood-based fuels, such as bark and other byproducts from wood-refining processes in the vicinity. Peat makes up about 10–20% of the entire fuel consumption, and pit coal is used as a supplementary fuel.

Valmet DNA replaced the competitor’s control system

The two plants share a control room. Earlier, the plant operations were controlled by two different systems. AK2 has the Valmet DNA Automation System, and AK1 used another supplier’s control system.

Valmet introduced the customer to its unique retrofit concept, which allows power producers to easily replace an outdated or underperforming control system with a transparent and modern automation solution. Its intelligent automation features make it possible to boost plant performance, reliability, availability, energy efficiency and other key operational factors, while simultaneously extending the plant’s life cycle.

Johannes Östman, Automation Engineer responsible for all automation, IT and electrical systems at Alholmens Kraft, says, “The AK1 system was getting old and called for a complete update. We studied all our options and ended up wanting only one automation system – Valmet DNA – throughout our entire plant.”

The AK1 system was getting old and called for a complete update. We studied all our options and ended up wanting only one automation system – Valmet DNA – throughout our entire plant.”

In the picture, on the left is an Automation Engineer Johannes Östman, and on the right is the Process Engineer Tony Oikari from Alholmens Kraft.

The retrofit process flowed like a movie script

Alholmens Kraft placed an order for a Valmet DNA Operate user interface, including hardware and software and I/O cards for the existing AK1 cross-connection cabinets. The new solution was commissioned in the spring of 2024.

“The project schedule was tight, and our own automation organization is small. We ordered automation engineering from a third-party supplier, but it would have been much easier if it had been carried out by Valmet,” Östman recalls. “Once again, we noticed how much know-how Valmet’s staff has. Everything from project management to commissioning and tuning was really smooth. In all, a positive experience. It was a pleasure to work with Valmet, and I would not hesitate to do it again.”

We noticed how much know-how Valmet’s staff has. Everything from project management to commissioning and tuning was really smooth.”

Process Engineer Tony Oikari was actively involved in the project, too. He is equally satisfied with the good cooperation. He was impressed by Valmet’s expertise and ability to keep to the agreed project timeline. “The schedule for our feedwater plant that we share with the UPM pulp mill was very tight. The automation retrofit had to take place during the mill’s shutdown. Otherwise, it would have caused a lot of trouble for the pulping process. Everything flowed like a movie script. All sequences functioned correctly on the first try, even though operating the feedwater plant is a complicated process.”

The automation retrofit had to take place during the mill’s shutdown. Otherwise, it would have caused a lot of trouble for the pulping process. Everything flowed like a movie script. All sequences functioned correctly on the first try, even though operating the feedwater plant is a complicated process.”

In the picture, an Operator Björn Engström is in the control room of Alholmens Kraft.

Like nearly all the operators, Björn Engström participated in the factory acceptance tests at Valmet’s premises. He appreciates how the users’ feedback and ideas were taken into consideration during the testing and commissioning processes.

Better troubleshooting, fast support and spare parts available

Having the same automation system in both power plant units has brought many benefits. Learning to use a new system always takes time and effort, but the operators at Alholmens Kraft already had years of experience with Valmet DNA.

In the control room of the Alholmens Kraft power plant. From the left Björn Engström, Johannes Östman, Shift Manager Kristian Gustafsson and Tom Bäckman.

Tony Oikari goes on, “AK2 is a very demanding and complex unit to run due to its large size, massive variations and infeed of various fuels with uneven quality. We are now able to train our new operators to first use Valmet DNA at AK1 along their career path to run AK2. Having the same interface at both plants lowers the threshold.”

AK2 is a very demanding and complex unit to run due to its large size, massive variations and infeed of various fuels with uneven quality. We are now able to train our new operators to first use Valmet DNA at AK1 along their career path to run AK2. Having the same interface at both plants lowers the threshold.”

Since the outdated control system hardly had any troubleshooting tools, troubleshooting took a vast amount of work. Today, the situation is quite the opposite. According to Oikari, it is now really easy to find the root causes of process issues with the modern Valmet DNA History and Trending tools. User-friendliness has now reached a new level.

It is now really easy to find the root causes of process issues with the modern Valmet DNA History and Trending tools. User-friendliness has now reached a new level.

Östman points out the maintenance benefits, “Software updates are much easier than with the old system, and we can use the same spare parts at both plants. Additionally, we have a 24/7 service agreement with Valmet, enabling us to get support quickly, when needed.”

Software updates are much easier than with the old system, and we can use the same spare parts at both plants. Additionally, we have a 24/7 service agreement with Valmet, enabling us to get support quickly, when needed.”

In the picture, from the left is Tom Bäckman from Valmet, and Tony Oikari, Automation Expert Markus Rönnbacka and Johannes Östman from Alholmens Kraft.

Valmet DNA boosts boiler flexibility for balancing electricity markets

“Usually, only one of the two boiler plants is running. With today’s low electricity prices, AK1 has more running hours than AK2 because it is not profitable to run the larger plant all the time,” Östman says.

Operator Engström agrees, “When both boilers are controlled by Valmet DNA, it makes their startups and shutdowns faster, safer and more cost effective. It also enables more precise control, enhances power plant flexibility and reduces maintenance costs.”

When both boilers are controlled by Valmet DNA, it makes their startups and shutdowns faster, safer and more cost effective. It also enables more precise control, enhances power plant flexibility and reduces maintenance costs.”

Engström continues, “Valmet DNA provides a wider adjustment range for various pieces of equipment, resulting in optimized operations. Thanks to more accurate measurement points, we now get better history and trend data from the process.”

Valmet DNA provides a wider adjustment range for various pieces of equipment, resulting in optimized operations. Thanks to more accurate measurement points, we now get better history and trend data from the process.” 

In the background, Alholmens Kraft's AK2 boiler plant.

No longer a black box

Prior to the latest automation upgrade, Valmet had also delivered a Valmet DNA Turbine Automation retrofit to AK2 in 2022. “We used to have issues with our old turbine automation system. Additionally, the supplier’s services in Finland did not meet our expectations, and we were no longer able to get spare parts for it,” Östman remarks. “The old system was a true black box that did not give us much measurement data.”

With Valmet DNA, turbine control and troubleshooting are much more straightforward. The operators have access to tools that give them a full understanding of the turbine.

“I was surprised how little tuning was needed to make the system meet our expectations. On the whole, we are very pleased with Valmet DNA Automation Solutions at our plant,” Oikari concludes.

I was surprised how little tuning was needed to make the system meet our expectations. On the whole, we are very pleased with Valmet DNA Automation Solutions at our plant.”

“Customer satisfaction is at the heart of Valmet DNA. By providing real-time monitoring, predictive maintenance and optimization tools, the system helps customers reduce downtime, improve process efficiency and enhance product quality. The flexibility and scalability of the Valmet DNA Automation System ensure that it meets the unique needs of each customer, no matter the size or complexity of their operations,” says Tom Bäckman, Sales Manager at Valmet.

Customer satisfaction is at the heart of Valmet DNA.”

“Customer satisfaction is at the heart of Valmet DNA," says Tom Bäckman as he shakes hands with Johannes Östman.

For further information, please contact:

Tom Bäckman, Sales Manager, Valmet
tom.backman(at)valmet.com