Hydrogen Islands – Utilization of Renewable Energy for an Autonomous Power Supply

Abstract

The World is facing an imminent shift from the present unsustainable energy system, primarily based on utilization of fossil fuels, to a new sustainable energy system based on renewable energy sources. This transition may have already begun, as solar PV and wind energy installations are growing at unprecedented rates. Renewable energy sources are more than sufficient to satisfy all the energy needs of today's world and technologies for their utilization are available. It is therefore possible to envision an energy system solely based on utilization of renewable energy (Figure 46.1) [1]. Various forms of renewable energy, primarily solar, wind, and hydro can be converted into electricity and heat. This transformation may be accomplished in centralized power plants (probably a better word would be energy plants), but also a significant portion may be accomplished locally or even individually. In some cases economy of scale may favor larger units (e.g., large wind turbines cost less per kW then small ones) but in some cases mass produced small units may also result in lower cost. In such a system there are obvious needs: (i) to store energy -to overcome fluctuations in availability of renewable energy sources; (ii) to transport energy over mid and long distances; and (iii) to fuel the transportation sector (land, sea, and air). Hydrogen could satisfy those needs. Electricity and hydrogen are the only noncarbon currencies that, together, can supply the full menu of energy services. A vision of an energy system of the future presented here in which hydrogen plays a significant role is logical and sustainable. However, such a system should not be called a "hydrogen economy," but rather "hydricity" or "hydrogen-electricity economy" [2].While a future energy system based only on renewable energy sources with electricity and hydrogen as the main energy carriers is technically feasible, a more difficult task is to define a path of how to get there from here. One problem is the inherently high cost of renewable energy. Hydrogen makes the renewable energy even more expensive. An energy system based primarily on renewable energy sources would be impossible without the storage, transport, and fuel features that hydrogen offers. However, renewable energy sources can