return, the power consumption of the water pump is higher as the operating pressure is higher and has
parasitic electrical losses; need greater protection for electrical potential difference between the terminals
of stack is large.
When hydrogen is required at atmospheric pressure is chosen unipolar electrolysers when needed while
hydrogen pressure (30 bar) are used bipolar configurations. From the standpoint of purity hydrogen
obtained in alkaline electrolysers, hydrogen is obtained with a purity of 99.8% by volume; the rest is
water vapour and oxygen.
2.2. Hydrogen production by solar energy.
The methods of hydrogen production with solar energy are grouped into three major groups, the
photochemical processes, electrochemical and thermochemical combination may exist between them as
photoelectrolysis, electrolysis of steam at high temperature [9].
Given the characteristics of Cuban solar radiation, diffuse radiation which is worth approximately 40%
of direct normal radiation and there are an average of 10 cloudy days per month, the methods that make
use of concentrated solar energy will not be analyzed in this article, such as high temperature electrolysis
of water vapour, supplying heat and electricity from cylindrical-parabolic collectors, parabolic dishes,
central tower facility, which method is known to address the electrolysis of water at room temperature has
the advantage of requiring a lower power input. Thermochemical methods including direct thermolysis
include water-based thermochemical cycles reducing metal oxides using concentrated solar radiation as a
high temperature heat source to perform the endothermic reaction.
Cuban In the present scenario most likely displayed the production of hydrogen from water electrolysis
at low temperature (room temperature) using as a source of electrical energy needed in the process solar
photovoltaic and wind energy, mainly. No discarded given the potential for forest and sugar cane biomass
that has the island and research progress in the use of biomass gasification.
3. Integrated systems for hydrogen production.
Integrated systems are intended for the production of hydrogen on a large scale for subsequent use in the
industry, as fuel in alternative internal combustion engines (AICE) for electricity generation or use
directly as a fuel or fuel cell using the transport sector.
Figure 8 shows a scheme with the basics of integrated system for production of hydrogen, we see it as the
wind farm and / or the photovoltaic field would provide the necessary power to the electrolyser for
hydrogen production. In this scheme the input electrical energy of the turbine or wind farm and
photovoltaic solar contribution need not be used only for the production of hydrogen, but also can
contribute to the production of conventional power in situations that required. When the tank or hydrogen
storage tanks reach capacity, the electrolyser is disconnected and reconnected until it has reduced the
presence of hydrogen in the tanks.