APC 400kW1MW User Manual download pdf (Page 46)

100

1/2 Hour 8 Hours 24 Hours

Mission Length

Reliability

Figure 5-2 Reliability of a Well-Maintained Diesel Generator [L]

Proper maintenance must be done to the generator in order to maintain proper

functioning after start up. The maintenance includes changing lubrication oil and replacing oil,

fuel, and air filters regularly. This is one advantage that fuel cells have over engine generators.

They have minimal moving parts, which increases their reliability because there is low risk of

mechanical breakdown. The FuelCells.org website states that, if maintained, fuel cells can

reach up to 99.9999% reliability [62, p. 6; 63, para 3;64, para 7].

5.3 High Efficiency

Since the 1960s, the average electrical generation efficiency of power plants in the US

has been about 32%. Most of the energy supplied by the fuel is lost in waste heat at the power

plant. Additional losses occur as power is distributed on transmission lines, which are reflected

in power costs. The inefficiencies of power plants have encouraged development of on-site

generation, such as fuel cells, because a greater amount of energy can be extracted from the

supplied fuel [12, p. 2; 20, p. 1-1; 65, p. 5; 28, p. 808].

Fuel cell systems have much higher efficiencies than the traditional power plant. As

shown previously in Table 2-1, fuel cells have electrical generation efficiencies ranging from

35% to 60%. The fuel-to-electricity efficiency can increase if the fuel cell system is fueled by

hydrogen, taking away the need for fuel reforming. In a CHP application, the fuel cell’s waste

heat can be used instead of exhausted to the atmosphere. Efficiencies can reach as high as

1 2 ... 41 42 43 44 45 46 47 48 49 50 51 ... 85 86

No comments

APC 400kW1MW User Manual Page 46