Hello. I am Sally, a new staff member at MATSURI. I am good at biology, but I am still a novice when it comes to environmental impact assessment and related activities.
～Summary of the previous episode～
Learning means "copying," so I decided to try out GREET, a software I came across in a report on environmental impact in the company. There are many different software programs for calculating environmental impacts around the world, but I have the impression that GREET is often used to calculate the environmental impact of "fuel" applications. After much difficulty, I was able to look at the GREET software while reading related news. In the process, I came to understand that there are multiple methods for calculating greenhouse gas emissions, and that they are constantly changing. I thought that it would be honest to say that it would be MATSURI's attitude to disseminate information about greenhouse gases, including the methods used.
~End of synopsis~
So, let's analyze MATSURI's algae products with GREET software! To perform calculations with GREET software, we first need to organize the information that is the premise of the calculation. We need to organize what steps the algae products go through from cradle to grave, the inputs such as energy and raw materials used in each step, and the outputs such as products and waste that come out of each step. Calculating the environmental impact by considering a product's life cycle from cradle to grave is called Life Cycle Assessment (LCA) [1]. The implementation procedures for LCA are internationally standardized by ISO14040.
Here is Sally’s initial understanding of the algae product life cycle:
- Growing algae. The algae are exposed to plenty of sunlight in a vertical flat panel algae production facility (PBR), and they grow rapidly! To prevent the algae from growing too quickly and running out of carbon dioxide in the water for photosynthesis, carbon dioxide is bubbled in (aeration).
- Harvest the algae biomass that will become the trunk of the algae tree.
- Various products can be made from biomass! Electricity, heat and other raw materials are also used in the production process.
- When it is used as fuel, energy is obtained. When it is burned, carbon dioxide is produced, but since this carbon dioxide is derived from carbon dioxide reduced by photosynthesis, it is carbon neutral.
- When used as a product, it is used for a certain period of time and then disposed of in landfills or incinerated. Carbon dioxide is released when it is decomposed or incinerated, but that amount is carbon neutral.
- When eating it as food, do you think about what happens before it gets into your mouth?
So how do we handle this in GREET?
The method of conducting LCA is internationally standardized by ISO14040, so let's think about it in accordance with that. When conducting LCA, "setting the objectives and scope of the study" (ISO14040) is required. Why is MATSURI conducting an LCA of algae?
There are two reasons.
- Reason 1: "I want to understand the current situation and predict the effects of improvements so that I can take action to reduce the environmental impact of algae products!"
- Reason 2: "I want to quantitatively demonstrate that algae are environmentally friendly!"
Let's organize these points and think about them one by one.
- Reason 1: "I want to understand the current situation and predict the effects of improvements in order to take action to reduce the environmental impact of algae products!"
Growing and harvesting algae requires resources such as water, as well as electrical energy to run pumps, and various raw materials and energy are used in processing to create products from algae biomass. If we can understand which processes from raw material procurement to disposal have the most GHG emissions, energy consumption, or water consumption, we can identify the processes and directions that need improvement. For example, if we can reduce the bubbling (aeration) during cultivation from 24 hours to 12 hours, we can quantify the expected GHG reduction effect. Being able to quantify the expected effect of each improvement is very useful for determining the priority of improvements that need to be made.
- Reason 2: "I want to quantitatively demonstrate that algae are environmentally friendly!"
MATSURI aims to realize a sustainable society by changing the current petroleum-based society to one based on algae. In order for MATSURI to gain widespread support, we believe it is necessary to quantitatively demonstrate that algae is environmentally friendly. What kind of calculations should we use to demonstrate this?
Let's say that the calculations were made such that "X X kg of water, X X ha of land, and X X MJ of energy were used to produce 1 kg of algal biomass, X X kg of carbon dioxide was fixed in the biomass, and the GHG emissions were X X kg." Looking at the results, would you think, "Algae are environmentally friendly!"? If you think about it simply, you might think, "We're not in trouble right now because we don't have algal biomass, and using land and water would have an impact on the environment, so we don't need algae." However, there is a trap in this way of thinking. Any new product that replaces an existing product is associated with the idea that it is "unnecessary" without its true potential being evaluated.
This is because things do not come from nothing, so when you "make" something, some burden is placed on the environment. Anything that is said to be environmentally friendly in this world has an environmental burden. If you take this into consideration, no matter what new technology there is, you will end up saying, "We don't need this new thing because it will have some kind of environmental burden when we release it to the world." Is that okay? What we want to do is to create a more environmentally friendly and sustainable society than ever before. In that case, what we want to know is, "Is this more useful for the sustainability of society than what we have been using until now?" It is important to compare the environmental burden of algae with existing products, rather than just the product itself. By quantitatively comparing existing products with new algae products, we can see that algae is more environmentally friendly.
In other words, we want to compare and evaluate the environmental burden of today's petroleum-based society with that of an algae-based society. Here, a very difficult problem arises: what should we compare per unit? Should we standardize on 1 kg and compare the environmental burden of 1 kg of petroleum with that of 1 kg of algal biomass? Unfortunately, this is not possible because what can be done with 1 kg of petroleum is different from what can be done with 1 kg of algal biomass. To make a comparison, we should standardize on "per product with equivalent function." This corresponds to the "setting of objectives" [2] that we consider when conducting LCA.
As you can see from the spread of the algae tree, there are many different products that can be made from algae biomass. Therefore, for now, we will focus on fuel. This is because it is easy to understand the "goal setting" to consider when conducting LCA. For fuel, the goal can be relatively simple: "obtain 1 MJ of fuel in a specific location in whatever state (gas, liquid, solid, and what kind of processing has been done)," and consider the steps, raw materials, and amount of greenhouse gases required to achieve this.
On the other hand, when considering LCA of clothes, for example, the setting of the objective is also very complicated. Is it okay to set "wearing clothes" as the objective? Clothes have many functions. It is not enough to simply wear it, such as whether it can be worn in formal situations, whether it retains its shape without ironing, whether it provides appropriate warmth in winter, how easy it is to move in, etc. If the function and concept of the clothes are not set as the objective, it may be difficult to identify the points that need improvement. Although we need to prepare clothes to avoid catching a cold in winter, an analysis that says "It's okay to remove the lining, which is important for warmth, because it can be worn, right?" in order to reduce raw materials seems to be off the mark. In other words, since "setting the objective" is very important and complicated, we will postpone LCA when it is used as a product. However, in fulfilling our responsibility to make it, we need to seriously consider how algae products will be used and disposed of. We recognize that this is something that should be properly designed when sending products out into the world.
However, I feel that simply calculating the amount of fuel used by assuming "obtaining 1 MJ at a specific location" misses the characteristics and benefits of algal biomass, which produces a variety of things at the same time. I don't think that simply comparing only the fuel portion between something that only produces fuel and algae that can produce both fuel and food at the same time will fully evaluate the impact of becoming an algae-based infrastructure. I feel that being able to comprehensively evaluate this will be the key to visualizing the potential of algae.
Before doing the calculations, I organized my thoughts about the purpose of LCA in line with the international standard ISO14040. I thought that LCA was about collecting data and making calculations, but I realized that it is actually quite difficult to make calculations that allow for a comparison of the environmental burden of a petroleum-based society and an algae-based society. I was left scratching my head, wondering, "How do I set the objective?" and "What should I use for calculations?" For now, I will make the calculations assuming a relatively simple scenario of "obtaining 1MJ at a specific location" for fuel use.
Stay tuned for next time!
[1] Environmental Technology Commentary: Life Cycle Assessment (LCA)
https://tenbou.nies.go.jp/science/description/detail.php?id=57
[2] ISO14041 (JIS Q14041): Defining the objectives and scope of the study and inventory analysis. " When conducting LCA, the first step is to define the objectives."
written by : Sally
◾️List of articles in this series
#1: I think I'll start by trying something called GREET.
# 2 : How do you calculate greenhouse gas emissions when used as fuel?
# 3 : What is the purpose of LCA of algae?
