Abstract Due to its ease of transport and relatively low carbon dioxide emissions, Liquefied Natural Gas (LNG) represents an interesting alternative to other fossil fuels. In the next future, it is expected that the LNG demand will steadily increase and that new LNG plants will be constructed across the globe. LNG plants are often located in remote areas without a connection to the electrical grid and are therefore equipped with off-grid captive power generation plants having a high level of availability, usually based on Open Cycle Gas Turbines (OCGT) which are a source of CO2 emissions. Methods and solutions to decarbonize LNG applications will be presented and analyzed. An option to partially decarbonize the LNG facilities consists in adopting Combined Cycle Gas Turbines (CCGT), characterized by lower fuel consumptions with respect to OCGT. In addition, the integration of Battery Energy Storage Systems (BESS) can provide spinning reserve, thus allowing OCGT and CCGT to run at higher partial loads having higher efficiency. A further step to decrease CO2 emissions is constituted by the adoption of Renewable Energy Sources (RES), however characterized by fluctuations in the output power, that represent a risk for plant availability. Each one of the listed technologies, CCGT, BESS and RES, leads to an increase in the Capital Expenditure (CAPEX) but, if properly sized, results in decreasing operating expenses (OPEX) and greenhouse gases emissions. In this work, for each use case, the optimal plant configuration and the optimal hourly scheduling of the power sources are computed via advanced optimization algorithms. These algorithms guarantee the minimization of the LCOE, while fulfilling both the electrical/thermal loads, the constraints on plant availability and the operational constraints of each piece of equipment. This paper presents a comprehensive analysis highlighting the contribution of each one of the evaluated technologies to the CAPEX, OPEX, CO2 emissions and Levelized Cost of Energy (LCOE) of a selected LNG plant. CCGT, BESS and RES are introduced via subsequent steps in the technology mix of the captive power island, so that it is possible to clearly define the benefits generated by each one of them, and the relative boundaries of technical and economic feasibility considering current market prices. The optimal design of hybrid power plants for electrified LNG facilities constitutes a novel approach towards an economically feasible decarbonization path for such kind of plants. The clear explanation of the contribution provided by each installed technology is key to understand the benefits of each portion of the initial investment. The robustness of the proposed solutions is guaranteed by strategies to mitigate the fast fluctuations of photovoltaic (PV) plants, that are shown and considered in the costs of the PV generators.
Betti et al. (Mon,) studied this question.