The demonstration of integrated hydrogen energy systems in recent years in the United States has resulted in a systems engineering data base that can form the foundation of the next generation of energy system developments internationally. Various system elements are discussed below. This is the most mature renewable technology that permits small-scale, and incremental installation. The current and expected capital and installation costs for wind turbines make them the most attractive choice for most potential sites. Quiescent periods may last for days to weeks.
Wind turbines rated for arctic use are currently available commercially.
A maturing renewable technology whose capital costs are several times higher than wind turbines. However, such costs are expected to fall to a competitive range in five to 10 years. Under certain conditions of regional power value and resource, solar PV can be the technology of choice. Quiescent periods would generally follow a diurnal cycle. Given the conditions in the section above, and intermittent, low-gradient river flows, submerged water turbines with the type of energy storage systems considered here can be appropriate.