Hybrid Offshore Power Generation

Amid 2020 challenging business environments due to COVID-19 pandemic and strong global push towards transition to cleaner energy, PETRONAS has declared its' aspiration to achieve net zero carbon emissions by 2050. PETRONAS sustainability journey has begun for more than two decades and with strong management support towards renewable and as part of PETRONAS's technology agenda, its' research arm, PETRONAS Research Sdn. Bhd. (PRSB) has been working on ways to use renewable energy sources for offshore oil and gas platforms in Malaysia. Oil and Gas industry has long relied on turbine generators for offshore power generation. These turbo-fired machineries are operating as microgrid with existing power management system (PMS) as microgrid controllers. They normally use either gas or diesel as fuel gas to ensure reliable power generation where high maintence cost is expected to operate these generators. Also, they have low energy efficiency and hence, usually oversized to ensure meeting the demand reliably. Typically, the power generation load is being taken by two units of turbine generators with another unit as spare. This has resulted in high operational expenditure (OPEX) and contributes to high levelized cost of energy (LCOE) for offshore power generation for such conventional system. LCOE is the yardstick for power generation technology, and it measures discounted lifecycle cost consisting of both capital expenditure (CAPEX) and OPEX, divided by discounted lifecycle of annual energy production [2], [4], [5]. Also, these turbine generators operating at platforms that have gas evacuation pipelines will use up precious fuel gas which can otherwise be sold. This will have impact on the total sales gas revenue. Not withstanding, the burning of the fuel gas will result in the emissions of carbon dioxide (CO2) and hence is exposed to carbon tax. To mitigate this issue, PRSB has developed an offshore hybrid power generation concept to leverage and optimize wind turbine system for offshore power generation in weak wind area such as Malaysia. In this concept, one gas turbine generator is replaced by an offshore wind turbine adapted to low wind speed region. This will lower the maintenance cost and carbon exposure. Also, the fuel gas will be diverted to sales gas. This in turn will improve the economics of the renewable solution thereby making offshore renewable power generation feasible for oil and gas platforms. Forward thinking efforts include pushing the limits of harnessing wind energy in weak wind area such as Malaysia. In here, considerations of a total solution include not only the type of wind turbine generator that can be adapted to weak wind area and having the lowest maintenance requirements as possible, but also looking into cutting edge foundation technologies. The LCOE is expected to be lower than conventional power generation. To ensure optimized hybrid concept, careful selection and adaptations of wind turbine system and its' substructure are required to achieve a cost-effective solution [3], [2]. Conceptual engineering and front-end engineering design were conducted which resulted in the development of the hybrid offshore power generation system. In this paper, the hybrid concept will be shown, the considerations for selection of a suitable wind turbine will be shared and the decisions leading the to the selection and optimization of the foundation type, either fixed bottom or floating are elaborated.

Improving Efficiency in Power Production and Transmission for Offshore Solar Farms using Bifacial Panel Design and HVDC

As higher demand for power becomes a global concern and offshore power generation becomes more popular, more options should be explored. This study investigates the use of bifacial photovoltaic (PV) panels for offshore solar farms. In addition, it explores the use of HVDC for transmitting the solar power to onshore grid. The results show that bifacial panels have much higher efficiency compared to monofacial panels where the efficiency improvement ranges from 8.5% to 24.8% for a wide range of irradiance (100-1000 W/m2). The newer Voltage Source Converter (VSC) HVDC has high potential for future deployment thanks to its advantages. However, the harmonics from a considered VSC-HVDC system is severe. Some fitters have been designed to mitigate the harmonics. LC low-pass filters are proved to be most effective where they reduce the Total Harmonics Distortion (THD) of the system output voltage from 68.84% to 2.93%. The results are supportive for developing offshore solar farms that provide green energy while preserving land for other purposes.

Offshore wind networks will boost flows and cut costs

Significance Projects to connect offshore power generation facilities promise more efficient use of existing and planned infrastructure and will greatly increase connectivity between national systems. They are a central part of energy island concepts and also offer possibilities with regard to the electrification of shipping and offshore hydrogen production. Impacts Greater connectivity between electricity systems should reduce power curtailment, improve system security and boost power trading. Efficient use of transmission infrastructure will reduce costs for ambitious energy island projects. Offshore electricity charging could facilitate the electrification of shipping in some vessel segments.

Life Cycle Assessment of Electricity Generation from an Array of Subsea Tidal Kite Prototypes

Tidal current technologies have the potential to provide highly predictable energy, since tides are driven by lunar cycles. However, before implementing such technologies on a large scale, their environmental performance should be assessed. In this study, a prospective life cycle assessment (LCA) was performed on a 12 MW tidal energy converter array of Minesto Deep Green 500 (DG500) prototypes, closely following the Environmental Product Declaration (EPD) standards, but including scenarios to cover various design possibilities. The global warming potential (GWP) of the prototype array was in the range of 18.4–26.3 gCO2-eq/kWhe. This is comparable with other renewable energy systems, such as wind power. Material production processes have the largest impact, but are largely offset by recycling at the end of life. Operation and maintenance processes, including the production of replacement parts, also provide major contributions to environmental impacts. Comparisons with other technologies are limited by the lack of a standardized way of performing LCA on offshore power generation technologies.