
164 Project development in the solar industry
to reach the nameplate capacity of the inverter, the DC field has to have a W
p
capacity at least 10 percent larger. This is commonly expressed as an “Inverter
Loading Ratio” (ILR) of 1.1. This term refers to the DC field capacity (W
p
) to the
inverter nameplate AC capacity (W
AC
) ratio and it is a widely used definition. Even
with an ILR of 1.1, the system may reach the inverter capacity only at irradiance
levels of 1000 W/m
2
or higher, which are not common. For the 1.1 ILR fixed tilt
system in Figure 9.16 (light line) this only occurred once in that particular day. As
this graph shows, the full capacity ...