Green software: Measuring to understand and to improve

This is blog 13 in the blog series on Green IT.

To measure is to know, certainly where CO2 emissions are concerned. Since the late 1990s, organisations have pursued a uniform method to measure their footprint. This makes it possible to compare data and encourages organisations to take specific steps toward improvement.

When using green software, it is vital to understand how your organisation’s efforts are contributing to reducing energy consumption and hence to reducing CO2 emissions. The last two of the green software principles are aimed at measuring the achievements and defining the targets to achieve. The goal of measuring is not just to know, but to improve.

Principle 5 – Measuring ‘You can’t improve what you can’t measure’

The best-known method to report CO2 emission is by means of the Greenhouse Gas Protocol. That’s what most companies worldwide use to measure and present their CO2 metrics (1). To truly put green software into practice and achieve steps to improvement, it is important to understand what this protocol entails, and that you make sure that your software is aligned with the industry standards.

Greenhouse Gas Protocol

The Greenhouse Gas Protocol was created through the joint effort of the World Resources Institute (WRI) and the World Business Council for Sustainable Development (WBSCD). The effort was motivated by the growing demand in the late 1990s for an international standard to measure and present organisations’ CO2 footprint.

The Greenhouse Gas Protocol divides the emissions of greenhouse gases into three groups, or scopes (2):

• Scope 1: direct emissions by the organisation itself (e.g. by company vehicles).

• Scope 2: indirect emissions caused by the generation of the purchased energy, such as heating and electricity.

• Scope 3: all other indirect emissions, including emissions associated with purchased goods and services, business trips, waste processing investments, licenses, and so on. This also covers IT equipment and services. Specifically for the heritage sector, this also covers physical visits to reading rooms or museums, as well as the energy used by website visitors. This last category is often the most challenging to calculate for many organisations, since the information for this needs to be obtained from many different parties.

If all organisations as well as all people worldwide were to monitor their emissions in this way, the total of all the emissions in scope 1 would theoretically correspond with the global emission.

The Green House Gas Protocol has been elaborated further in the form of different standards for private businesses and public authorities, but also for measuring policy and action plans, projects, products and cities. One of these is the Corporate Standard, used by most (large) companies to measure greenhouse emissions.

How do you apply this measuring method to software?

To calculate the total emission of software, you need detailed data about the energy use, carbon intensity (the composition of the energy mix) and the used software. It can be a challenge to obtain this information, certainly for open source software. For who is responsible for what part of the emission?

For a more exact measurement, examine the software carbon intensity specification

The report based on the Green House Gas Protocol offers valuable insights into the composition of your emissions. But it remains difficult to measure the effects of your efforts to green your software. To facilitate this, the Green Software Foundation has developed its own method to measure software emission: the Software Carbon Intensity Specification (SCI).

The purpose of the SCI is to measure the sustainability of software. Based on the outcome, an organisation can take measures to reduce their software’s emission. It also makes it possible to measure the effect of the improvements to your software, which encourages organisations to continue improving.

The SCI does not replace the GHG Protocol but augments it. The Green Software Foundation offers a helpful comparison here: with the SCI it’s like measuring a car’s fuel efficiency per road mileage, while the GHG Protocol measures the complete CO2 footprint of a car manufacturer and all the cars it produces in one year. So the CSI is a more specific cogwheel within the entire system.

The SCI does not follow the division of CO2 emissions into scopes 1 to 3, but groups the missions into operational emission (the emission caused by running the software) and embedded emission (the emission attributable to the hardware required to run the software).

In previous blogs we described the positive effects of improving both energy efficiency and hardware efficiency, and of improving the carbon awareness regarding your application. This is also reflected in the lowering of your SCI score. It is also the only way to lower this score, so it means that you really need to get serious with the effort. The SCI cannot be manipulated through avoidance offsets. If an organisation does not make real efforts to reduce their emission, they will not obtain a favourable SCI score.

For the mathematical details of this method, please visit the Green Software Foundation website (3). The method is extensively explained there, including the guidelines for defining project boundaries and how to report on your efforts and results.

Principle 6 – Climate commitments ‘Reducing CO2 emissions is not the same as compensating’

We have arrived at the last principle of green software: your organisation’s climate commitments. In the end, the efforts regarding green software must contribute to reducing your CO2 emission. Your ambitions in this respect depend on your organisation’s choices. Some organisations set a target of ‘net zero’, while others aim for ‘CO2-neutral’ or even ‘CO2-negative’. But what exactly do these terms mean?

Different ways of reducing emissions

Science Based Targets (SBT) are goals based on scientific insights. By working with these goals, you can determine whether your goals (considering the nature and size of your organisation) are adequate to fulfil the Paris Climate Agreement. These goals can be categorised as follows:

• Carbon elimination (reduction) – the most effective way to counter climate change;

• Carbon avoidance (compensation) – using renewable energy sources, lifestyle adjustments, recycling and planting trees;

• Carbon elimination (neutralisation) – removing and permanently storing atmospheric carbon to counterbalance the effect of releasing CO2 into the atmosphere.

Organisations can pursue different targets, such as:

• carbon neutral: the organisation’s total emissions match the total of CO2 compensation through reduction projects;

• net zero: an organisation aims to eliminate as much of its CO2 emissions as possible and only compensates the remaining emissions that cannot be eliminated.

The European Commission has set itself the target of achieving ‘net zero’ by 2050. All of the measures taken by EU member states must ultimately lead to this. This is what all organisations based in the EU must contribute to!

Time for action

Regardless of the chosen goal, green software development has an important role to play. Green software always aims for a maximum reduction of the emissions, with energy efficiency, hardware efficiency and CO2 awareness as core principles. This blog series has provided you with a number of practical ways to get started.

If you are not personally a software engineer, then here’s a list of questions to help you talk to software developers or suppliers:

• How can the used equipment be operated as efficiently as possible (energy proportionality)?

• How can static power use be avoided as much as possible?

• What is the proportion between green and grey power in the energy mix we use? (CO2 intensity)

• How can we reduce CO2 intensity? What options are there to shift the demand (another location, another time) or to adjust the demand to the supply?

• How can the lifespan of used hardware be extended?

By taking account of these questions, you can reduce your software-related CO2 emission. If you want to measure the impact of your efforts, you can calculate the CSI score.

Sources

1. 92% of Fortune500 organisations report on their energy consumption and associated CO2 emissions under the Greenhouse Gas Protocol. Greenhouse Gas Protocol website, available at https://ghgprotocol.org/about-us