Innovative hybrid energy system for stable power and heat supply in offshore oil and gas installation

The extraction of oil and gas is an energy-intensive sector. The offshore installations mostly use natural gas to fuel equipment in the production, gathering and processing of conventional crude oil and natural gas. As a result, the petroleum sector is the main contributor to greenhouse gas emissions in Norway, making up 28% of the total emissions in 2015. Reduction of emissions in the petroleum sector is, thus, a key issue in order for Norway to meet its ambitious reduction goals. Today, gas turbines supply the offshore installations with power and heat. At the same time, Norway has a large unexploited potential for offshore wind power. This project combined the two systems together with an energy storage concept, and developed, designed, and validated the overall hybrid concept. The storage concept includes a reversible fuel cell system. On days with high wind speed, storage system can store excess energy by producing hydrogen. In periods with high power demand, the storage system can produce electricity by using hydrogen as a fuel. In this way the fuel cell system acts as a power back-up system, and one achieves full exploitation of the renewable energy source. The produced hydrogen can also be used as fuel to the gas turbines, thus lowering the consumption of natural gas and providing a cleaner fuel with lower emission of greenhouse gases. This study combined mathematical modelling, software development and experimental testing to produce a research-based software tool for design and optimization of cleaner hybrid energy systems. By combing expertise within fuel cells, offshore operations, and modelling and testing of hybrid systems, the project pave the way to further development of a novel concept for stable power and heat supply in offshore oil and gas installations. The project results indicate that the CO2 emissions from an offshore installation can be reduced up to 80% compared to a solution with gas turbines with waste heat recovery. The following points are highlighted from the results: - HES-OFF can significantly curb CO2 emissions from offshore energy production and supply. - Identifying an optimal design is fundamental to maximise the CO2 emission reductions without jeopardizing the stable operation of the system. - Energy storage stabilizes the electrical grid offshore. - Standard HES-OFF designs reach maximum emission reductions of about 40-50%. Larger CO2 emission reductions are possible (> 80%) by selecting a proper HES design to supply both heat and power. Project web page for the project: https://www.ntnu.edu/ept/hes-off Link to the research-based prototype tool: https://hes-off.herokuapp.com/

Prosjektresultatene indikerer at CO2 utslippen fra en offshore installasjon kan reduseres opp til 80% hvis HES-OFF konseptet implementeres sammenlignet med en løsning med gassturbiner med varmegjenvinning.

The extraction of oil and gas is an energy-intensive sector, where natural gas is widely used to fuel equipment in the production, gathering and processing of gas and conventional crude oil. The petroleum sector is the main contributor to greenhouse gas emissions in Norway. The main objective with this project is to reduce CO2 emission by implementing renewable energy into the energy mix offshore. A hybrid energy system integrating renewable energy sources with gas turbines and energy storage in an energy efficient and cost efficient local grid has the following benefits: - Full exploitation of renewable energy sources: no need to dissipate wind power when the wind power output is larger than the power demand of the offshore oil and gas installation. - The energy is stored as hydrogen in a reversible or regenerative fuel cell system, originally developed for space applications, but tailored to the offshore environment. - Improved operational strategy of the GTs: the energy storage and power back-up system allows the GTs to be operated at close-to-design conditions on a continuous basis, resulting in high efficiencies and reduced emissions. - An optimial system design can lower the number of GT start-ups to a minimum and decrease the high redundancy level characterizing the power generation systems offshore. - Clean fuel to GTs: the possibility to co-feed H2 to the gas turbine would reduce the utilization of produced gas, and the related greenhouse gas emissions, in favour of a clean fuel. The primary result from the project will be the development of a novel concept for stable power and heat supply in offshore oil & gas installation. To reach the goals of the project both numerical and experimental activities are needed. The project connects experts within fuel cells, offshore operations, and modelling and testing of hybrid systems to accomplish this.