7. Waste
The petroleum industry is among the largest waste producers in Norway. The primary waste fractions offshore include drilling waste such as drill cuttings and used drilling fluids, along with various liquid fractions such as wash water and drainage water. The industry places great emphasis on the proper handling of waste. The operators' main goal is to generate as little waste as possible and to establish systems to ensure that as much waste as possible is recycled.
Offshore Norge has developed guideline 093 for waste management in offshore operations. This guideline is scheduled to be revised in 2024. The guideline is used for the declaration and further handling of waste. All waste is sent ashore in accordance with the industry's guidelines.
Waste is generally classified into hazardous and non-hazardous waste according to applicable regulations and must be declared in accordance with national regulations and international guidelines.
7.1 Non-hazardous Waste
In 2023, 19,092 tonnes of non-hazardous waste were produced, a decrease from 2022 when the volume was 20,090 tonnes. Figure 32 shows the distribution of non-hazardous waste in various categories. Metals are the largest waste fraction within source-separated waste. Metals from the industry have a high degree of recycling and are sent ashore for re-melting or direct reuse.
Figure 32: Distribution of non-hazardous waste in various categories from offshore operations (tonnes)
7.2 Hazardous Waste
Figure 33 shows that in 2023, just under 310,000 tonnes of hazardous waste were delivered for treatment on shore, compared to 273,000 tonnes in 2022. Approximately 270,000 tonnes of this is drilling-related waste that is treated on shore. Tank washing and oily waste each account for 11,000 tonnes, totalling 22,000 tonnes.
The reason for the marked increase in oily waste from 2009 and for several years thereafter is that previously, much of this waste would have been reinjected. Up until 2009, leaks from injection wells were detected on several fields, and injection was stopped in 2009-2010. The oily waste was instead sent ashore for treatment. Methods for handling cuttings on these installations were based on slurrification for easier injection. Slurrification involves crushing the cuttings and adding water. It is not uncommon for the volume of cuttings to expand by a factor of between 4 to 10 during slurrification. This practice continued, and cuttings were sent ashore as slurry, resulting in a significant increase in drilling waste from certain fields.
Injection provides significant environmental benefits and can be cost-effective compared to final treatment on shore. Drilling of new injection wells has led to a slight increase in the volume of injected oily waste (see chapter 4.1). On installations and fields where injection will not be resumed, efforts are being made to reduce slurrification to decrease waste volumes.
Figure 33: Volume of hazardous waste from offshore operations sent ashore.
7.3 NORM waste
Rocks beneath the seabed contain varying amounts of radium and other radioactive isotopes. During oil and gas production, these naturally occurring radioactive substances accompany oil, gas and primarily water to the surface. These substances are often referred to as naturally occurring radioactive materials (NORM). In Norway, the term LRA refers to what is commonly known internationally as NORM or low-specific activity (LSA)..
On some fields, the sludge cleaned from oil-water separators can contain varying levels of measurable radioactivity. The concentration of these substances is measured by water and sludge conducted by accredited laboratories. The waste is categorized and declared according to three categories: no enhanced concentrations, radioactivity levels below 10 Bq/g, and radioactivity levels higher than 10 Bq/g. Both radioactive categories are treated according to regulations issued by the Norwegian Radiation and Nuclear Safety Authority. The most radioactive waste is transported to a designated landfill in Gulen.
Figure 34 shows the volumes (tonnes) of waste delivered for final disposal in the two categories. The waste containing radioactivity levels below 10 Bq/kg varies somewhat due to fluctuating site capacity.
A total of 258 tonnes of low-level radioactive waste were sent ashore in 2023, a decrease from 2022 when the volume was 394 tonnes.
Figure 34: Volumes of waste with naturally occurring radioactive material
7.4 Decommissioning and circular economy
Decommissioning of offshore oil and gas installations in Norway is expected to increase leading up to 2030, while the industry anticipates reducing greenhouse gas emissions by 50 percent. Reuse and circular economy are central measures to achieve climate goals.
Waste from the decommissioning of fields has a high degree of recycling and contributes to a very high level of circularity for offshore platforms. Offshore installations are largely composed of metals, and the recycling of metal typically ranges from 94 percent to 98 percent by weight. In addition, there is increasing effort to find ways to reuse equipment instead of recycling through melting, for example, through direct reuse on other offshore platforms or by adapting them for other users and sectors.
The development of regulatory and market systems is crucial for successfully achieving a sustainable transition. Offshore Norge has therefore entered into a collaboration with the University of Bergen (UiB) to investigate the legal and economic framework conditions for a circular economy related to decommissioning in the petroleum industry. The project will explore barriers and incentives in the regulations for reuse and recycling in Norway compared to Australia, the Netherlands, and the United Kingdom. Based on a mapping of various practices, the project will investigate potential opportunities for reuse of installations and coordination and multiple use of marine areas in the Norwegian context. The results will be presented in a knowledge report prepared by Offshore Norge and UiB.