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Sustainable Software Development: Environmental Impact of One Workday

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16 ​​min

How sustainable is software development? This article will measure and analyze the environmental impact of a workday and a whole project at inovex.

The sustainable goals of big tech and why it’s not enough

Most of the big tech companies like SAP, Apple, and Microsoft are set to reach Net Zero at the end of this decade. A pretty ambitious but necessary goal. In contrast, many of those same companies rely just on one factor: renewable energies. As soon as clouds and offices are powered by renewable energies, they claim to be carbon neutral. This, of course, is not the case: Every building, every hardware, and every trip to the office emits or embodies carbon, needs scarce resources, and has further negative effects on the environment. This article will try to look at the environmental impact and measure it for us here at inovex per workday and per project.

What to measure

There are several points to be considered regarding the impact of the development process on the environment: We need buildings to work in, we need a laptop, a smartphone, and other hardware to work with and we need electricity to do so. We need cars, trains, and busses to get to the office. We need data centers and infrastructure to get our services to the customer. All these costs arise from our daily work and the projects we work for.

Which parameters should be looked at? Apart from emissions, there is the material needed for the hardware and the buildings. In addition, mineral extraction, assembling, and (in the best case) recycling hardware require water. The electricity needed for the everyday work in addition to the electricity for the data centers and the underlying infrastructure has to be generated (and renewable energy is not available at all times in sufficient quantity). From the mining of the needed resources for the hardware to the cloud, in which the software is running: Every step requires land and thus destroys ecosystems. The amount of land should also be included in the considerations. The removal of stone to mine the needed resources is part of the ecological costs as well.

How to measure sustainable software development

So, let’s start with the practical realization. The main goal is to calculate the environmental impact of one workday. The resulting quantities then can be used to plan projects or calculate the ecological costs for different scenarios (e.g., work from home versus work at the office).

Buildings

First, we are going to measure the costs of the buildings. There are studies on the amount of embodied carbon per square meter of office space. Averaging the results, we can assume about 450 kg of CO2-eq per square meter. At inovex, one workplace accounts for 17.7 square meters. Let’s now give the offices a lifetime of 60 years with 230 workdays per year. For every workday at the office, we, therefore, emit 0.578 kg of CO2-eq. In addition to the emissions, we need a lot of materials to build an office. We are assuming the number of resources needed to be 600 kg per square meter. With the same values regarding lifetime and work days per year, our daily consumption of materials is 0.77 kg.

Let’s compare these values with the same workday at home: We assume 10 square meters for a workplace here. The lifetime of the building is set to be 70 years. The costs per square meter regarding emissions and material usage stay the same. In conclusion, we get emissions from 0.28 kg and 0.37 kg of needed materials.

At inovex, we work quite a lot from home. An internal survey states that on average each employee is at only 1.7 days per week at the office. This is just about a third of the working hours. If we combine these stats with the given costs for working from the office and working from home, we get emissions of 0.38 kg CO2-eq and material consumption of 505 grams.

Hardware

Next up is the hardware. In general, we assume that every employee needs a laptop, a smartphone, and a monitor to work. The amount of emissions embodied in those devices is calculated using the PAIA tool. The manufacturer can use the tool to create a report of their product (see figure 1).

Listing of the environmental footprint of the Lenovo ThinkPad T14. A Footprint Value of 361 kg of CO2-eq is shown above a pie chart, which displays the lifecycle of the laptop and the related emissions.
Figure 1: PAIA analysis of a Lenovo laptop

Regarding inovex, the medium laptop used emits around 350 kg CO2-eq. If we consider the material requirements for one laptop, we get a quantity of 350 grams. In contrast to the materials used to build the office, these materials are more valuable and rarer. All materials used in the hardware are thus considered critical resources. Each laptop pollutes 190,000 liters of water. Through a survey the usage time of the laptops became known: On average, each laptop is used for 742 work days. Now we can divide the embodied carbon and the materials by the usage time. The result: Each work day using the laptops accounts for 0.47 kg CO2-eq, 0.47 grams of materials, and 255.78 liters of water.

If we apply the same process to smartphones and monitors, we get the following ecological cost per work day: The smartphone accounts for 0.05 kg CO2-eq, 0.047 grams of materials, and 20 liters of water. The monitor embodies 0.26 kg of emissions. Other criteria (like the needed materials) were not available for the monitor, so we focus on the emission here.

In summary, the emissions amount to 0.78 kg of CO2-eq, and the quantity of all materials required for the hardware per work day is 0.58 grams. These materials amount to 196 grams of rock removal.

Business travel

In the same survey in which the lifetime of the hardware was determined, we got to know, that the average distance traveled every day per employee is 3.1 km by train and 0.65 km by car. Note how these values are pretty low, because of the possibility to work from home. The values can vary very much and so does their ecological impact. Calculating with 0.2 kg CO2-eq per kilometer driven by car and 0.05 kg CO2-eq per kilometer driven by train, we end up with 0.29 kg CO2-eq per work day.

Electricity

Concerning the electricity demand for one workday, the survey also looked at the consumption of the employees. Equipped with an electricity meter, each of the participating employees measured their power consumption over a week. The results show that on average each employee consumes 0.7 kWh per workday. This included all work-related devices like laptops and monitors and excluded general consumption like light, air conditioning, and the coffee maker. The power consumption in combination with the emission factor of Germany of 485 grams of CO2-eq per kWh results in an emission of 0.34 kg CO2-eq per workday.

How much environmental impact one workday causes

To summarize: In total we emit 1.83 kg of CO2-eq, use up 505.9 grams of materials (of which 0.58 grams are critical resources), pollute 307 liters of water, and require a rock removal of 196 grams. These values are also shown in figure 2.

Infographic showing the ecological costs of a work day at inovex. There is a magnifier showing the values for emissions (1.83 kg CO2-eq), material usage (505.9 g), water pollution (307 liters) and rock removal (196 grams).
Figure 2: Illustration of the ecological costs of our day to day work.

Notes

There are ample ecological costs that are not included in this calculation. Starting from the land, every factory, office, and landfill requires the electricity used by air-conditioning and other consumers at the office. The cloud resources, which are being used, the infrastructure, and in general the project-specific costs are important parts of a sustainable Software Engineering process. Even though they are not included here, they are included in the underlying thesis. The values shown therefore act as a bottom line to our work. To use this in your project calculation there has to be the mentioned points included.

The values for electricity are calculated using the emission factor for Germany. That is, even though we use (or to be clear: buy) renewable electricity at almost every site. It is more about the real emissions generated from our electricity needs rather than what we are paying for. For the laptops or hardware in general: After the use by our employees we always give them a second life at schools, universities, or in private. But again, these are not the reasons why they are produced. They are produced for us and that’s why all of their costs in accounted for in our work. No one would split these costs, for example, for second-hand clothing or stuff they buy from an online marketplace.

What do these values mean for all of us?

These values indicate some steps or some focus points regarding our ecological footprint:

For developers

Most of the time, we only think of efficient code when talking about sustainable software development. These points are important but are important for many reasons other than sustainability alone. We are well advised to produce effective code either way. So the main learnings here are: Our main saving potential is the reduction of business trips, and working from home. Looking at the values provided, even a short trip of around 10 km a day can increase our daily emissions dramatically: from 1.83 kg CO2-eq to 3.7 kg. Plus, the costs of the buildings reduces as well. Not using the office does only work if your company is knowing how much office space is needed. So, tell the person in charge how much you work from home. Apart from that, the main factor is the laptop. Do not get a new one as soon as you can but rather get a good one, that is going to last you for a longer period of time. The difference between high-end and medium laptops regarding their emissions and material usage is not that big, what counts is their lifetime.

For product managers

Some points have already been mentioned in the previous paragraph: Home office and reducing business trips, in general, have a huge impact. Enabling your colleagues to work from home and sensitizing the customer in that regard is important. Apart from that, you are the person responsible for an ecologically sensible project. Look at all the phases (from Analysing to EoL). Monitor key performance indicators for the environmental impact of the project (like the emissions of the cloud, project-specific environmental costs like the distribution channels, and as shown the cost of a workday in your project). Is the application designed modularly so that everyone needs to get and use only the features they have? How does our product enable users to use their devices for as long as possible? These and multiple other questions arise and have to be addressed.

How to apply this information to a project

What to look at

Coming from the ecological cost of one workday, how does this all plays out if we look at a product? It is actually quite simple. Hopefully, by now you all know Scrumlr. Either way, here is a quick explanation: scrumlr is an online collaboration tool. It can be used to brainstorm, make retrospectives, or in general any kind of review. There are multiple boards you can choose from, like 4L, positive/negative, or a simple Post-It collection with an Actions column. Recently, version 2 has been released. Let’s have a look at the ecological costs of this release.

The whole development process started in October 2020 and lasted until recently, June 2022. During this time, we spend a total of 914 work days on the project, from start to finish. Additionally, there were cloud resources used to operate scrumlr. In general. it is said that half of the energy costs of the cloud are spent on the underlying infrastructure. There are two figures that could not be measured: The costs for the CI/CD Tools and the costs for the internal VMs. We will see later why this is perhaps not so important.

What has been found

The accumulated 914 work days result in the following costs:

  • 1678.3 kg CO2-eq
  • 462.6 kg materials, of which 0.53 kg are critical resources
  • 281322.6 liters of water
  • 179.4 kg rock removal

What the cloud amounts for

In addition, there are costs for cloud usage. These values are provided by the service providers themselves and should therefore be treated with caution.  On the other hand, this product does not require a huge amount of computing power or memory, so maybe the values are not all that wrong either. The given amount of emissions from the cloud is 7.3 kg CO2-eq in almost 2 years of service.

In comparison with the values for the ecological costs from our work days, these values are almost negligible. Keep in mind that the given numbers are calculated using the service provider’s own methodology and very likely do not include any costs for electricity, building, or maintenance.

When calculating your own costs, you should always bear in mind what service provider you choose. Depending on the quality of the information from your service provider, you are able to quantify your ecological costs well or, let’s say, with room for improvement.

What ecological costs resulted in the development of scrumlr?

To sum up: We calculated the costs for the work days, and we got the costs for the cloud. Half of the cloud costs are going to be added for the used infrastructure (so we’re at around 11 kg CO2-eq). In total, we get the costs shown in figure 3.

There is a list of the ecological costs for scrumlr - version 2, which has been developed from October 2020 to June 2022. It states the emissions as 1689.3 kg CO2-eq, the material usage as 462.6 kg (of which 0.53 kg are critical ressources), 281322.5 liters of water consumption and 179.4 kg of rock removal.
Figure 3: Illustration of the ecological costs of the development of the second version of scrumlr.

What to learn from this example

Besides the learnings from the calculation of the workday, there are a few findings here. First and foremost, in small projects, the cloud does almost contribute nothing to the overall ecological footprint. Moreover, even if the given data from the service provider is wrong by a factor of 10, this would not have a major impact on the ecological costs. This finding may be different for large projects, but this remains to be confirmed. What is also important to note is how easy it is to apply the costs for a workday to a project. Given the quality of the data collected for the quantification of the workday is sufficient, we can calculate the costs of a project in a fairly simple way.

What to conclude

Work from home, pay attention to the size of your offices, reduce business trips and keep an eye out on your hardware, mainly your laptops. However, most of these findings are grasped, but still difficult to implement. This article provides some reasons for how exactly these changes can help reduce your impact on the environment.

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