Environmental conditions cover natural phenomena, which may contribute to overloading and fatigue damage. This paper is describing a method implemented for modelling and analysis of environmental conditions and loads on offshore renewables. Sea states are described by irregular wave models as ocean waves that are irregular and random in nature. Furthermore, a linear irregular wave model is a sum of many small linear wave components. Short-term wave conditions are described by a stochastic method using wave spectra, or the deterministic design wave method. Statistical distributions are used to describe long-term and extreme value conditions, or scatter diagrams for governing sea state parameters. Wind speed varies with time and the height above the sea surface. Therefore, the averaging time for wind speeds and the reference height above the sea surface are considered, whereas statistics are used in describing the short- and long-term conditions. The effects of currents are considered for steady excursions and slow drift motions, drag and lift forces, vortex induced vibrations and motions, interaction between currents and waves, and seabed scouring. Joint wave-current distributions of parameters and corresponding surfaces for given exceedance probability levels are considered as applicable. The fluctuating response can be resonant response, response due to vortex shedding, or reinforced vibration. This paper presents a small-scale method for software application to evaluate performance of offshore renewables. It aims to contribute to the practice of numerical simulations for ocean energy converters.

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