Decommissioning of peat burning – in a controlled way towards biomass

Finland intends to halve the energy use of peat by 2030. However, how the challenge is to be tackled over the next nine years is still open. In March, Minister of the Environment and Climate Krista Mikkonen stated that the government must make a clear plan for shutting down the energy use of peat. Where are we now? Last year, fossil fuels accounted for 13.8 per cent of Finland’s electricity production and 40 per cent of district heating was produced by burning peat, coal, oil and natural gas. Peat produces only about six percent of Finland’s total energy needs, but it accounts for up to one-fifth of the energy sector’s emissions – and 12 percent of Finland’s total emissions.

There are more than 50,000 hectares of peat production in Finland. About 90 percent of peat is burned for energy. It is five years since the Paris Climate Agreement was signed, but our government is still in the process of creating a plan for peat.

The keyword seems to be “controlled” downtime. Still, for example, the Confederation of Finnish Agricultural and Forestry Producers MTK described the downsizing of peat energy use as “reckless” in its December statement. The Finnish people also have an opinion on the matter: at the beginning of 2021, news was announced about the citizens’ initiative on ending the use of peat energy, which received the required 50,000 signatures and went to Parliament. According to the initiative’s proposal, peat should be phased out five years earlier than planned, ie by May 2025. Would it even be in a hurry? We believe that decommissioning peat use should be controlled and planned.

What happens when a power plant switches from peat to biomass?

In the 1970s and 1980s, peat-fired power plants were built in Tampere, Kuopio and Oulu, among others. Already in the 90s, boilers began to be converted into multi-fuel boilers, ie in addition to peat, power plants were ready to burn wood-based fuels. The forthcoming decommissioning of peat production will force power plants to look for new energy sources – and that means millions of investments in many locations. In practice, this might mean that, boiler technology, fuel reception system, conveyors and sampling system will be renewed in power plants. At the same time, environmental permits must also be updated, as the permit is always based on the fuel fractions and quantities burned.

As the material to be burned changes from peat to biomass, quality determination plays a significant role. The biomass to be burned enters the power plant in trucks, where one may contain forest residue chips imported from the vicinity, the other wood chips imported from Russia and the third, for example, forest industry by-products such as sawdust and bark. These loads can be very different in terms of moisture and energy content – the variation in individual loads can also be really large.

If we place two identical full trailer trucks carrying 150 cubic meters of fuel side by side, we will be able to concretize the difference: there are only about 1 to 3 percentage points difference in the moisture content of the peat truck load between the measurement points – at most only 5%. The moisture content of biomass, on the other hand, can vary between 30 and 60%. That is, the biomass load may be wet at one point of the truck running off the water and the sample taken from the other point may be relatively dry.

Peat is thus homogeneous as a fuel for power plants. When biomass is burned in a boiler instead of peat, the fuel is heterogeneous, the quality of which should be measured particularly carefully to determine the correct price for the load. Errors in sampling and moisture measurement accumulate as an additional cost to the power plant.

Winter has a major impact on biomass quality measurement

On the scale of power plants, small human errors can cause large differences in the material flows of thousands of tons. In Finland, one human thing to consider is winter: snow and ice inevitably affect winter moisture measurements. The largest errors occur in the actual sampling, but measurement errors are also caused by sample handling and storage.

It is not uncommon for tens of kilos of ice to fall to the unloading site when unloading a truck load. It is far from homogenous material. The example in the photo below shows the winter reality: the load is layered with ice, snow, wood chips and forest debris. If the load were manually sampled with a small shovel into the bucket right from the top of the cart – would the surface sample represent the moisture of the entire load?

Positive results from the change in Kuopio Energy

Kuopion Energia introduced an automated Q-Robot sampling robot in 2017 at its power plant. Production director Peter Seppälä states that the world was lying in a different position at the time.

– Compared to the plans of that time, the shutdown of peat burning will take place much faster under the guidance of emissions trading. At that time, Kuopion Energia was Prometec’s pilot project to solve the challenges of manual biomass sampling. Quite positive results began to show almost immediately, Seppälä says.

Kuopion Energia’s electricity and heat production is centralized at the Haapaniemi power plant and the Pitkälahti power plant. A total of about 14,000 truckloads of wood and peat arrive in Haapaniemi every year, producing 1.3 million megawatt hours of energy. This can be proportioned, for example, by comparing the need for an ordinary detached house: the annual energy demand for heating and hot water is about 20 megawatt hours.

– Manual metering and fuel moisture fluctuations produced us 50 gigawatt hours less energy per year than the price paid for the fuel. Roughly speaking, our annual fuel costs are in the order of EUR 25 million, and the percentage error is EUR 250 000. With Q-Robot, our savings over the past few years are worth millions.

– Significantly more fuel is needed during the winter. If we look at, for example, three months from June to August, during these three months the same amount of fuel is used to produce electricity and district heating as in two weeks in the winter, Seppälä concretizes.

A hall was built for Q-Robot in the area of ​​the Haapaniemi power plant, where a truck arriving with biofuel will drive for weighing and automated sampling. The robotic auger takes several samples at randomly selected points and depths, and combines them into a representative sample of the entire load, following solid biofuel sampling and sample handling standards ISO 18135 and ISO 14780.

– In the past, sampling involved human errors and I also understand the power of fuel producers from a great point of view, because, for example, a few percent change in dry matter percentage has an effect of hundreds of euros on the price of fuel load, states Seppälä.

 

Q-Robot – what’s the question?

• The automated Q-Robot sampling robot takes a reliable and representative sample of the raw material load quickly before unloading it.
• Sampling works seamlessly with a variety of solid and crushed materials.
• In addition to the sampling unit, the Q-Robot includes a machine vision system that measures the volume of the load in real time
• Q-Robot can generate calculated load moisture data and energy content data immediately after sampling
• Samples taken by the Q-Robot can be analyzed immediately on site with rapid measurement equipment or taken to the laboratory for analysis.

Read more about Prometec’s solutions

• For power plants
• For pulp mills
• For mining industry
• For agroindustry

Henna Karlsson, CTO

EU Green Deal and Q-Robot – from fossil fuels to biomass

 

I listened with an interest to the Bioenergy Winter Days  (28.1.2021) presentation, in which  Bioenergy Europe associations Giulia Cancia reported on the bioenergy situation in Brussels. In EU countries, the use of biomass for heating has grown steadily since 2000. According to Giulia Cancia presentation based on Eurostat statistics, in 2018 the share of biomass in heating was 16.7%. By 2030, the figure should rise to 25%. Bioenergy Europe, predicts that the use of biomass will increase the most in the residential and industrial sectors.

The review was naturally linked to the EU’s Green Deal and the decarbonisation of the EU’s energy system. More than 75% of the EU’s greenhouse gas emissions come from energy production and use. According to Giulia Cancia, in 2017, Hungary, Lithuania, Estonia, Latvia, Luxembourg, Poland and Finland used the most bioenergy in the EU. Large EU countries such as France and Germany lagged far behind in comparison.

According to Bioenergy Europe association,  the use of bioenergy relies mainly on the sustainable use of biomass. The question is, what are the barriers to the transition from fossil fuels to biomass combustion in power plants? 

FACT 1:

The biomass material can be anything from straw stalks to felling waste, from branch pieces to plant leaves.

Solution: Prometec’s Q-Robot takes an automated sample of the material at the moment of arrival at the power plant and sends the data to both the power plant and the material driver. Q-Robot is able to take samples of all kinds of crushed and granular materials.

 

FACT 2: 

A large number of power plants use an oven drying method to analyze biomass samples, the result of which is completed approximately two days after sampling. Quality information cannot be utilized in process or combustion optimization.

Solution: Prometec’s Q-Robot works in real time. The quality data can be utilized already when the truck transporting the material is at the sampling point. It enables the optimization of the process: a truck transporting poor quality biomass can be turned away, a certain quality of biomass can be stored in terminals, for example for frosty periods. For example, dry biomass should be directed to a terminal storage and wetter for direct incineration, as studies have found that the shelf life of wet biomass material is poorer. Sampling takes less than 10 minutes.

Different biomasses can be mixed to form an optimal fuel mix. When quality data is utilized proactively, for example, dry and moist biomass can be alternately directed into the power plant’s discharge channels so that the moisture fluctuations in the fuel are evened out in the boiler`s material supply.

 

FACT 3:

Some power plants authorize the truck driver to take a sample of the biomass they transport. The driver may act either knowingly or unknowingly incorrectly when taking a sample. Drivers have been studied to take drier samples than the fuel load actually is, as it affects the price of the load to their advantage. There is also an occupational safety risk associated with sampling: there may be a risk of falling or being injured when working at an unloading site.

Solution: The Q-Robot always takes a sample systematically at random from the entire load area at different depths. In addition, the robot sampler auger is always clean and the material is never mixed between suppliers or species.

 

FACT 4:

In Scandinavian and Northern European conditions, the load brought by a biomass truck may contain snow and ice in winter, which affects the weight of the load and the quality of the biomass.

Solution: Q-Robot tells you the exact energy content and moisture of the fuel. According to a VTT study, there is an error of up to 2 percentage points in moisture in determining the quality of biomass, which contributes to the price paid for fuel, the optimization of fuel logistics and the combustion process. Together, these affect the profitability of biomass combustion relative to, for example to coal.

Our company was founded in 2012 and currently employs 15 people. We operate in three countries. Q-Robots are currently in use in Finland, Sweden and the Baltic countries. We believe that our total solution will play a key role in reducing the use of fossil fuels in the EU’s Green Deal in the coming decades – Asia will also be a major market for us.

 

 Deloitte believes the same: In January, Prometec Tools was ranked 23rd in the list of Finland’s fastest growing technology companies.

Finland’s new  bioeconomy strategy, which will be completed in summer 2021, will take a stronger position on circular economy solutions and the utilization of renewable natural resources. The strategy has been made public, with the aim of securing the sustainable use of renewable resources as part of the EU’s climate goals. A significant part of greenhouse gas emissions is generated in energy production. In Finland, almost half of our energy comes from fossil fuels that produce greenhouse gas emissions, such as peat and coal.

As part of the preparation of the bioeconomy strategy, the Ministry of Agriculture and Forestry and the Ministry of Employment organized several regional  bioeconomy forums last autumn as webinars, which we also followed at Prometec. It was eye-opening to see the bioeconomy know-how and operators from different provinces.

Whatever the carbon neutrality targets to be achieved in the national strategy that are to be achieved by 2035, our Q-Robot solution will help facilitate the transition of power plants from the burning of coal and peat to burning biomass.

When peat is replaced by biomass in Finland, it will also affect truck traffic. One peat truck contains an average of 130 megawatts of energy, but when replaced by a biomass truck of the same size, it does contain 100 megawatts of energy. As a result of moving into biomass the truck transportation is increasing.

 

Annual savings of one million euros for the power plant

Peat and coal are homogeneous materials, i.e. the transition to biomass means burning more inhomogeneous material. In this case, the key factor is how the quality can be determined reliably and how it is taken into account in with combustion in the boiler. For example, in a forest residue chip load, the humidity can vary between 30-60%. In this case, it is really important that the sample is taken systematically correctly and reliably so that the sample taken corresponds as closely as possible to the material in the load.

The importance of determining the quality of biomass has been studied both by us and by VTT, among others. One of the results of the studies was discovered a large finding of a 2 % average error of moisture content result determined at the biomass quality definition. The error is due to manual sampling when the biomass truck driver takes a sample of his load, for example with a shovel, at a point in the load where the sample is most easily available. The biggest problem has been the effect of snow and ice on wintertime measurement results. The humidity error imposes a large additional cost on the power plant – on an annual basis, it can mean 5 % of the fuel purchase price.

The fuel consumption of a large power plant can be a thousand gigawatts per year. With an energy balance error of 5% and a megawatt price of biofuel in the order of EUR 20, the annual cost will rise to EUR 1 million. For example,this of course, affects the profitability of biomass combustion in relation to coal.

 

Subheading: Quality information helps to minimize CO2 emissions

Q-Robot’s reliable biomass receiving inspection provides real-time information on load quality. Thus, the right price is paid for biomass and variations in fuel quality are considered in the formation of the fuel mixture for the power plant boiler. Biomass may be a by-product of harvesting, forest maintenance work and the forest industry, for example. Quality information enables the minimization of CO2 emissions when the right quality material is brought to the plant in a timely manner and the combustion process can be optimized.

According to the energy sector low carbon roadmap , fossil fuels are being phased out in transport, services, base machines, industry, heating and agriculture.

At present, the EU Commission sees Finland as an example country for the bioeconomy in the EU region. The national bioeconomy strategy has a major role to play in maintaining this pioneering role. Prometec’s quality measurement solution will support the implementation of the bioeconomy strategy in various industries – in addition to the heat and power plants used as an example, in the pulp, mining and food industries.

 

Fact: How can Q-Robot’s real-time quality information be used?

• In fuel quality control
• In fuel logistics control
• In forming of the optimal biomass mix.
• In the optimization of the combustion process
• In the calculation of inventory balances
• In procurement planning

 

Read more about Prometec’s solutions

• for heat and power plants
• for the pulp industry
• for the mining industry
• for the food industry

 

In the quality control of solid biofuels, techniques have been developed for many years to make it possible to analyze the moisture content of samples collected from loads immediately at the time of sampling or immediately afterwards. Especially here in the North, the biggest problem during the winter is the effect of snow and ice on the measurement results. In addition, the degree of difficulty is raised by the ever-changing measurable fuels, each of which must be calibrated to the measuring equipment separately. Now a solution is being sought in Finland with the help of two top professional companies.

There have long been two major problems with quality control of biofuels. The first challenge is to automatically take representative samples of each load and the second is to obtain real-time information on the moisture content of the material before unloading. Prometec, a Kajaani-based company which focuses on quality control of biofuels, has solved the first problems by launching a fully automatic sampling equipment that takes samples by drilling them out from each incoming fuel load. Prometec currently operates in three different countries. Now Prometec has focused on solving another major problem together with Puumit Oy, a Kuopio-based manufacturer of measuring equipment. Puumit’s measuring device has been successfully tested in a pilot project in Kajaani throughout the winter and spring. Innovatively, combining measurement techniques, Puumit enables moisture analysis of samples collected with Prometec’s Q-Robot sampler and obtaining results immediately after sampling before the truck leaves the sampling station. Thus, the driver can be instructed to drive to specific unloading locations depending on the quality of the fuel and real-time data on the moisture content of the load is provided to both the power plant and the supplier

Real-time measurement of representative samples

Unlike typical electromagnetic moisture measurement methods such as microwaves or radio waves, Puumit Oy utilizes the frequency range of the electromagnetic spectrum, where the permittivity of ice corresponds to the permittivity of water. Thus, with impedance spectroscopy, it is possible to accurately measure moisture even from frozen material. Utilizing machine learning methods and artificial intelligence, spectral analyzes can be performed individually for different biofuels. The method is also self-learning, which contributes to improving the accuracy and reliability of the method.

 

“Sampling and measuring are the most important processes in determining fuel quality. Billing is based on these samples. Now when we can connect a reliable measuring device to the Q-Robot, we think we have found the missing piece for our offering, ”says Juha Huotari, CEO of Prometec.

“Cooperation with Prometec is vital to us. In this way, we get hundreds of samples measured and analyzed per month and we can develop our product more accurately, Elmo funding has made it possible to develop this new technology, ”says Heikki Sonninen, CEO of Puumit Oy.

Traditionally, trucks transporting biofuels have been sampled manually with a shovel. This causes an error in the moisture determination because obtaining representative samples manually is very challenging and time consuming. It is not possible to spend too much time on sampling per load, as during the busiest times of the heating seasons over one hundred trucks can arrive to the site and all of them needs to be sampled. Prometec’s sampler collects samples automatically, reliably and representatively before unloading.

“We have often been asked that either we can also measure the moisture of samples in real-time. That is why we have joined this development project, because our customers want these solutions and we want to serve them as well as possible. We see the measurement of samples as a challenging but potential task. It is clear that measuring equipment will be integrated into every Q-Robot, because it has so many benefits for customers, ”says Huotari from Prometec.

Future quality control is comprehensive. Both sampling and quality measurement should be automatic and accurate. By combining an automatic sampler with Q-Robot and Puumit measuring equipment, this big leap towards automatic quality control right at the receiving point, is possible to do.

We collected five of the most common questions about automated sampling we hear at the fair.

1. What are the benefits of Q-Robot?
• Q-Robot provides representative samples directly from the load before unloading. Using the Q-Robot increases safety at work and significantly speeds up the time spent on trucks in the factory area. The Q-Robot is fully automatic and takes samples at random according to EN-18135. Sampling one full-size truck takes less than 10 minutes and from the semi-trailer under 8 minutes.

2. Does the Q-Robot measure anything?
• Fully automatic Q-Robot uses machine vision as one of its controls. The Q-Robot also has an integrated camera that monitors the load capacity. The Q-Robot software receives input data on biomass quality, load weight, supplier and truck size. Each car is individually identified in the system and the Q-Robot knows their volume. Based on this information, soon, we can generate computational moisture data and volume information from each load that can be used to control logistics and optimize the combustion process. This is in piloting stage.

3. What is included in the delivery?
• We want to provide our customers with easy access to turnkey turnkey delivery, including a sampling hall, Q-Robot and, if needed, sample processing equipment that is scalable to the customer’s needs and automated. The sampler and sampling equipment have been manufactured, assembled and tested in Kajaani, ensuring rapid installation and commissioning at the power plant.

4. What kind of material does Q-Robot get samples from?
• The Q-Robot is capable of sampling many different types of crushed and granular materials with a particle size of less than 150 mm. The auger is always clean and the material is never mixed between suppliers or species.

5. What happens after sampling?
• After the Q-Robot has collected a (biomass) standard sample, it is dropped to the specified coordinates. In most cases, samples are dropped into supplier and quality-specific mixer tanks, where a daily sample is formed. At its simplest, samples are dropped into a bucket with a plastic bag and the truck driver visits and takes them to an agreed location to wait for laboratory tests.

There are thousands of power plants around the world using biomass to generate heat and power, and hundreds of power plants are going to start using biomass or would like to convert at least part of their coal to biomass. Biomass usage is growing all around the world. Its role as a stable energy generator is undeniable. Globally, 9.1% of total energy consumption is produced by traditional biomass. Biomass is the largest heat producer and the primary renewable energy source used for district heating (See: Renewables 2017 Global Status Report)

There are a couple tricky matters when it comes to biomass. Compared to coal, biomass is an extremely heterogenous material. Even though this fact is well known, it might still offer some surprises for power plants. This article will tell you a little more about these surprises and how you can tackle them.

 

Today’s challenges with biomass

 

Power plants are increasingly using biomass to generate cleaner energy and to reach climate targets. Usually, after one or two years, they notice a large energy balance error, which means that the biomass quality wasn’t what they had anticipated. At this point, after an issue already exists, power plants start projects to investigate how to remedy these problems. Therefore, biomass quality management should also be considered when power plants are making decisions about their total investment.

What other problems or challenges could power plants face when they start using biomass? The first issue comes from the governmental side. Do governments subsidize biomass usage with same amount of money every year per MWh produced? The answer is no. There will always be changes in the amount of subsidization because of various reasons that we won’t go into in this article. A second challenge is related to optimizing combustion processes. Is it a similar process when power plants are generating heat and electricity from coal or from biomass? Again, the answer is no. Biomass material is heterogeneous. Both quality management and controlling material are extremely important. Optimizing combustion processes is vital to energy efficiency. In many cases, the annual costs of buying biomass is the highest expense for power plants. For this reason, it is important to know the actual value of every single load that comes to the power plant area.

 

Biomass in the future

 

Luckily for future generations, the use of cardboard is rapidly growing and replacing the use of plastic as packaging material. When we think about sustainable harvesting and biomass usage, more and more “better quality” biomass material is being used for the cardboard manufacturing process and “poorer quality” biomass will be material that power plants use as fuel. This means that usage of, for example, forest residues and other underestimated biomass materials will increase. When power plants start using this “poorer quality” biomass it means two things. First, this material will be increasingly heterogeneous, and, secondly, power plants must still become more energy efficient. You might be wondering, how in the world can I improve our power plant’s combustion processes, keep up with emission limits, and operate costs efficiently? The simple answer here is that you need to know what material you are buying to optimize combustion processes. How do you do that? You must take representative samples from every load that arrives. This is the only way to control material flow and quality; it is the only way to know what material you are buying and how much you should pay for it.

In Finland we have been using biomass for about 40 years to produce heat and power, and it is the crucial fuel for our enormous district heating system. In Finland, district heating networks heat about 47% of our country’s buildings (Finnishenergy). We have acquired a lot of knowledge about how to use biomass in sustainable ways and how to be energy efficient. We also have a lot of knowledge in how to conduct quality management the right way. All you need to do is ask us.