Zero-emission operations

NS aims for its operations to be entirely fossil-free by 2040. This means we will use green electricity at all times of the day and every day of the week for running our trains as well as for our buildings and offices. To achieve that, we focus on what is known as the energy triad:

• Energy efficiency

• Sustainable generation on our own land and buildings

• Purchase of zero-emission energy
  
  

Energy consumption by NS

In 2023, NS consumed 1,212 GWh of electricity, 21 TJ of heat and 5.6 million m³ of gas for trains, stations, workshops and offices. Our bus suppliers used 2 million litres of diesel. This comes to a total of 1,293 GWh of energy (2022: 1,230 GWh). This increase is explained by higher energy consumption by trains. With our thermal energy storage system, we generated the equivalent of 21 GWh of heat and cold at 6 stations.
At NS, we use the term ‘energy efficiency of traction’ to refer to the energy consumption of our trains per passenger-kilometre. The diagram presents the energy efficiency of traction plus the total energy consumption of our trains (including replacement bus services). The number of passenger-kilometres in 2023 was 15.5 billion, up 17% compared with 2022. Improved train occupancy figures mean we used much less energy per passenger-kilometre. In 2023, energy consumption per passenger-kilometre was 72.0 Wh, which is an improvement on 2022 (83.3 Wh/rkm). 

Total CO₂ emissions of NS

When measuring CO₂, we distinguish between Scope 1, 2 and 3 emissions in accordance with the GHG Protocol. In this annual report, we report on Scope 1, Scope 2 and some Scope 3 emissions.

Calculating Scope 2 emissions

Scope 2 emissions are calculated in two ways: location-based and market-based. We also use another method that takes generation and consumption matching into account:

• Location-based: The total CO₂ emissions from the energy NS consumes per year, in a situation in which we do not purchase any sustainable energy. Using this measurement method, our total CO₂ emissions in 2023 would have amounted to approximately 410 kilotonnes: 372 kilotonnes from running trains and 38 kilotonnes from our buildings. The decrease in emissions compared with 2022 is the result of a new emission factor. For the 2023 calculations, we used newer, more up-to-date figures released in January 2024 for the CO₂ emissions from electricity per unit of energy. These figures are lower because the proportion of renewable energy in the Dutch energy mix has increased. Absolute energy consumption in 2023 is higher than in 2022 but much lower per passenger-kilometre. 

• Market-based: This method takes into account the contractual instruments used by NS to purchase electricity, including any guarantees of origin that prove the electricity was generated from renewable sources. In 2023, the amount of electricity NS consumed on an annual basis was equal to the amount of renewable electricity produced by our energy supplier and allocated to us. This resulted in net emissions of almost 0 kilotonnes of CO₂ for train operations.

• Matching: The CO₂ emissions from the hours when we consumed more energy than was generated from renewable energy and thus relied on fossil sources. In 2023, traction hour-matching was around 60%. This means that last year we relied on fossil electricity sources about 40% of the time (in hours), which corresponds with hour-matching emissions of around 172 kilotonnes of CO₂.

Scope 3

Last year, we identified our full Scope 3 emissions for the first time as part of our commitment to the Science Based Targets initiative (SBTi) from 2021. This is necessary to ensure that our company-wide emission reductions are in line with the latest IPCC climate science in both the short and long term, with the aim of limiting the global temperature increase to 1.5°C. We submitted the documentation to SBTi for validation in mid-2023. The results have not yet been received. We are also preparing to report our climate mitigation and adaptation plans next year according to the CSRD guidelines (where possible). In the table below, for Scope 3 we only include emissions from replacement bus services because we can already see these values. 

Since 2019, we have offered carbon-neutral replacement bus services that run directly and indirectly on renewable fuels. After adjusting the emission factor for renewable fuels in 2021, we also offset the remaining emissions of CO₂ equivalents through Gold Standard’s Verified Emission Reductions, specifically with 700 tonnes of CO₂ in credits from the 2016 Kayseri Molu Landfill Gas-to-Energy Project in Turkey.

NS’s total CO₂ emissions, by method (in kilotonnes of CO₂)

• *The figures are based on CO₂ equivalents, so other greenhouse gases with Global Warming Potential are included where possible.
• **Scope 3 in the above table only relates to replacement bus services.

The following table shows the CO₂ emissions per passenger-kilometre (market-based). This allows us to compare emissions from train journeys with other modes of transport.

• *The figures are based on CO₂ equivalents, so other greenhouse gases with Global Warming Potential are included where possible.

Sustainable generation from own land and buildings

NS uses its land and buildings to generate sustainable energy. There are around 3,000 solar panels on the roofs of several NS maintenance facilities. There are around 3,000 solar panels on the roofs of several NS maintenance facilities. In 2023, we measured renewable energy generation of more than 590,000 kWh, equivalent to the annual energy consumption of 190,000 households. The Nieuwe Hemweg wind farm near Amsterdam Sloterdijk station was opened in 2021. Its six wind turbines generate energy for about 10,000 households on an annual basis. Our aim is to continue to increase the share of renewable energy from our own generation facilities.

Purchase of zero-emission energy

NS purchases energy from energy suppliers. We have several contracts to ensure the supply of power for trains and buildings and natural gas to heat our buildings. Our current contract for the supply of electricity for our trains expires at the end of 2024. In anticipation of that, in 2023 we issued a call for tenders for electricity and guarantees of origin (GOs) for running trains on behalf of the rail sector (under the name ‘VIVENS cooperative’). PZEM and Shell will supply NS with renewable electricity and GOs respectively for three years from 1 January 2025.

NS’s preference was for all renewable energy to be generated in the Netherlands. Unfortunately, we couldn’t ask for that. Given the size of the contract, we were obliged to call for tenders from all across Europe, and as a result, the energy can come from anywhere in Europe. NS also would have preferred to negotiate a new contract independently rather than with the industry, since 85% of the total size of the contract concerned energy for NS. Unfortunately, an independent contract starting in 2025 was infeasible, as it is not yet technically possible to determine exactly how much energy each carrier consumes. 

We are pleased to have been able to find new partners in the difficult energy market. Expectations are that technological opportunities for energy generation and storage will increase substantially in the coming years. NS is preparing to reduce its dependence on fossil back-up after this contract for those times when there is no sunshine and no wind. We aim to do so using storage capacity and ‘hour-matching’, a method in which the time of generation and the time of use are closer together. Moreover, last year we replaced a number of wind farms in the power-for-trains contract with two solar farms in the Netherlands for more effective hour-matching.

Since 2023, we no longer purchase GOs for natural gas. These certificates have become scarce and expensive. In the current market, buying green-gas GOs gives only a limited incentive to market players to install more green-gas plants. The impact on the permitted reportable emissions of no longer purchasing GOs for natural gas can be seen in the table above. Scope 1 emissions for stations and building were 12 kilotonnes of CO₂ in 2023 compared with only 2.5 kilotonnes in 2022.