There is a great potential for reducing significant amounts of CO2 and NOx emissions on rigs. The NOx Fund has visited the jack-up rig Noble Invincible to look at NOx-reducing measures that have been implemented and supported by the NOx Fund.
Noble, which in 2022 merged with the former Maersk Drilling, has over the past three years carried out emission reduction measures on three of their jack-up rigs, Noble Integrator, Noble Intrepid and Noble Invincible. In relation with the upgrade of the last rig, Noble Invincible, the NOx Fund was invited on board while the rig was in Grenaa in Denmark to look at the measures carried out with support from the NOx Fund.
The three rigs have done the same upgrade, including the installation of batteries and retrofitting of SCR systems. Collectively, the measures on the three rigs will contribute to major emission reductions of NOx and CO2 and are an important contribution for the NOx Fund to meet the emission requirements in the NOx Agreement, says general manager of the NOx Fund Tommy Johnsen. The total NOx reduction is estimated to 600 tonnes annually and has been granted a total of NOK 185 million.
Energy storage
The rigs have been upgraded with an energy storage system consisting of two battery containers placed on the drilling deck. The energy storage system is designed to recover the energy from braking power in the drilling system during operation, an energy that was previously not utilized. The new batteries help smooth out power peaks during operation and will act as a reserve power system. This ensures even load on the engines and enables the operation of fewer engines in certain operating phases.
Installing SCR systems
Installing SCR systems is the most important contributor to reducing the rigs' total NOx emissions, but it is demanding to install such systems in existing objects. The challenges are often linked to space and weight restrictions on board. For Noble, it has been important to find a technically sound solution, which enables easy maintenance of the catalysts and ensures efficient bunkering of urea. Noble has chosen a solution where urea is stored in removable container tanks on deck aboard the rig. It makes it possible to bunker urea easily and safely with crane by replacing the container tank with a new one from a waiting supply vessel according to technical manager North Sea, Sveinung Flystveit in Noble.
Supporting combined measures
Noble has been granted support from the NOx Fund through the support program for combined measures. Clean measures with SCR systems often reach the ceiling for the maximum support share because they have a high NOx reduction, but low investment cost. For pure energy efficiency measures, the situation is the opposite. They often achieve a low support share because the NOx reduction of the measure is small. The support scheme for combined measures makes it possible to apply for efficiency measures together with SCR systems. The advantage of the scheme is that the Fund looks at the total cost of measures for the projects, while at the same time a high NOx reduction gives a high proportion of support.