In future, before energy systems can be built in the sea, environment impact assessments must be made to determine how the technology will affect the marine environment. Many suitable locations are likely to be ruled out on environmental grounds. Experts therefore differentiate between the technical potential of an energy technology and its sustainable potential. The technical potential includes all the plant locations which are theoretically feasible. The sustainable potential looks at environmental factors, such as the damage a tidal power plant may cause to stretches of river, thus eliminating some locations. The sustainable potential is accordingly lower than the technical potential. Experts are calling for marine spatial planning for ocean-based renewable technologies to be simplified. Until now, separate approval processes have applied to wind energy and wave energy facilities respectively. To shorten decision-making processes, it would make sense to incorporate several energy production technologies in spatial planning at the same time, rather than individual wind farms, thereby designating areas for renewable marine power generation as a whole. This would make it much easier to combine different technologies in a single marine area – for instance, wind turbine towers which also incorporate ocean current plants.