3.2.2. Practical Applications of the Fuel Cell

Based on the literature, especially the most current reports prepared in 2014–2018 by *Fuel Cell Today*, which is the main source of information, studies and analysis covering the global fuel cell market and *Fuel Cells and Hydrogen Joint Undertaking - New Energy World*, which represents the organization whose main objective is hydrogen and its technology at the European Union level, aspects of recent information from the last five years, regional and global developments regarding the implementation of these equipments has been synthesized [19–24].

Various pilot projects aiming at hydrogen technology are being validated, and the performances of fuel cell systems operating under real conditions are analyzed and reports on technology performance, progress and new challenges are being prepared. This analysis includes fuel cell assemblies of various types, namely proton exchange membrane fuel cells, solid oxide fuel cells, phosphoric acid fuel cells and molten carbon fuel cells, having dimensions of power generation systems with generated power ranging from 5 kW up to 2.8 MW, and the equipment has nominal powers ranging from 0.5 kW up to 400 kW [20,21]. Fuel cell systems are used in stationary applications [59–63] where they can be used for various purposes, namely as back-up power supplies, power generation for remote locations, stand-alone power stations for one or more consumers, distributed generation for buildings and cogeneration (in which excess thermal energy resulting from the production of electricity is used to provide the thermal agent) [24,40].

In commercial markets, fuel cells destined to the stationary sector show an increasing trend of technology transfer from the producer to the final consumer (Figure 6), being currently recognized as a feasible option compared to the conventional technologies of generator type, internal combustion engines or batteries. At the level of 2014, this technology transfer amounted to a value of 395,000 units regarding the delivery to the stationary field of fuel cell equipment, and for 2018 it increased to 575,000 units [22–24], this being possible due to the increased use of fuel cells as a practical application in which they play the role of energy backup (back-up system), but also due to the success of the residential fuel cell program "ENE-FARM" developed in Japan.

**Figure 6.** Shipments by application.

The distribution by region of this number of units transferred to practical applications is graphically illustrated in Figure 7 [22–24].

**Figure 7.** Shipments by region of implementation.

It is noted that Asia is the region with the largest number of fuel cell units in practical applications over the last five years, with an increase due to the commercial development of micro-cogeneration fuel cells produced in Japan, so for 2018 a number of 55,500 units was reported, being 29.20% higher than in 2014. The North American region reported in 2014 a number of 16,900 units transferred to practical applications, and in 2015 there was a 59.20% decrease compared to the previous year, followed by an increasing trend, in 2018, 9800 units were reported to practical applications. With regard to Europe, they remained relatively constant during the period analyzed, except for a decline in 2016, but also in 2017 they maintain the same stagnation trend.

When analyzing the value data reported over the last five years regarding the distribution of the technological transfer according to the fuel cell typology (Figure 8), it is observed that the fuel cell with proton exchange membrane is dominant. This is due to the possibility of using this type of fuel cell for a wide range of applications for all three segments (portable, stationary and transport), from small applications, micro-cogeneration systems to centralized power generation through high power applications.

**Figure 8.** Shipments by fuel cell type.

It is noted that with the development and extensive use of PEMFC the other types of fuel cells, like DMFC, MCFC, and PAFC, recorded during the five years small ascending or decreasing variations, but this is also due to the fact that most types of cells are integrated into projects and programs that are in pilot phase, where the results are being validated.

With regard to SOFC technology, there was also a significant increase in the number of units transferred to practical applications since 2016, this is due to the transfers to the stationary area that are the subject of the Japanese Ene-Farm project and scheme. If in 2014, approx. 2700 units were reported, in 2018, a significant increase was achieved, reaching 27,800 SOFC units transferred to their practical applications [19,22–24].

Based on the number of units transferred to practical applications, *Fuel Cell Today* made a calculation regarding the sum of the fuel cell capacities that were installed to support these applications. The total capacity obtained is schematically illustrated in Figure 9.

**Figure 9.** Megawatts by application.

The analysis of the data regarding the stationary sector shows a tendency of continuous growth starting with 2014. At the level of 2018 a total capacity transferred from the producer to the practical applications of 239.8 MW worldwide has been reported [19,22–24]. This was due in particular to the large number of micro-cogeneration units implemented in Asia, but the development of large capacity applications of central type of distributed hydrogen energy generation within which they are integrated and fuel cells with high power, totaling a significant number of megawatts is also worth noting. It should be also noted that the applications of hydrogen energy in the field of electromobility and transport registered a spectacular growth in 2018 compared to 2014.

Stationary applications for hydrogen fuel cells refer to fuel cell units designed to provide power at a 'fixed' location. They include small, medium and large stationary prime power, backup and uninterruptable power supplies (UPS), combined heat and power (CHP) and combined cooling and power. On-board APUs 'fixed' to larger vehicles such as trucks and ships are also included [22–24].

The distribution of total capacities installed by regions is graphically illustrated in Figure 10. Over the last five years, America and Asia have competed for the leading region in terms of implementation and adoption of fuel cells in stationary applications.

**Figure 10.** Megawatts by region of implementation.

If in 2014 Asia surpassed America, with 34.7 MW total installed capacity, in 2018 America became the leader because it already has fuel cell systems in place, reaching a total capacity of 415 MW, whereas in Asia, compared to 2014, a growing trend was reported with only 343.3 MW installed. Europe is experiencing moderate growth in this sector, but compared to America which currently holds the leading position, values are reported as 90% lower in Europe, respectively 43.8 MW.

If one looks at the aspect of the total installed capacity in relation to the fuel cell typology (Figure 11) it is found that the PEMFC technology is used in a wide range of segments of the practical applications, therefore it contributes with the greatest number of megabytes of total installed capacity from 2014 to 2018. Considering the validation and demonstration of the large size capabilities of many PAFC and SOFC units implemented in the stationary field starting with 2014, there is an increasing trend in the use and implementation in stationary applications of these types of fuel cells [19,22–24].

**Figure 11.** Megawatts by fuel cell type.

The prospect of significant growth in the number of fuel cell applications for the stationary field has real potential in the coming years. On a large scale, fuel cells for the power generation sector based on hydrogen as a raw material for the production of electricity in the centralized system (power plants) have shown real success in Japan, Korea and North America, and Europe offers, also, a number of opportunities in this sector [19–24].

From a sustainability point of view, the reduction of carbon dioxide emissions in all fields of activity by using fuel cells and the production of hydrogen from renewable electricity is advantageous for reducing the level of carbon dioxide emissions in the electricity sector. For the purpose of stability of the electricity distribution network, hydrogen-based power plants will contribute to their balance and will locally provide the necessary energy supply near the renewable energy production sites [34].

A number of major plans targeting this segment are announced at global and regional levels, and governments and partner organizations specialized in hydrogen and fuel cells make a concerted joint effort to ensure centralized production, storage and distribution infrastructure and supply end-users with hydrogen, as well as a wide variety of technical, financial and management issues are being reviewed to develop a future hydrogen-based economy [24,43]. The main arguments worth highlighting regarding fuel cell power generation systems in stationary applications are as follows:

