What factors determine the commercial self-consumption rate?
In general, the determining factors are the same as for self-consumption in private homes: the amount of energy required, the amount of energy generated by the PV plant and of course the load profile, i.e., the distribution of energy demand over time. For commercial consumers, however, these factors fluctuate widely and hence make it almost impossible to determine a "typical" self-consumption rate.
The most important determining factor is the ratio energy generation to energy demand since that ratio effectively limits the maximum self-consumption rate. If the energy demand is sufficiently high, then an appreciable share of the generated solar power can be consumed directly, even if the peak times for consumption and generation differ. If, on the other hand, the amount of generated solar energy is disproportionately high, then only a small share of that energy will be consumed directly.
The next factor to be taken into account is the load profile: Since the time distribution of PV power is narrowly confined, the load profile is almost the sole determinant of how well energy generation matches energy consumption throughout the day. Consequently, the load profile has a thoroughly large effect on the self-consumption - but only if the ratio between energy generation and energy demand is well balanced.
Additional factors can be found in relation to energy generation, mainly with respect to the location and orientation of the PV plant. The location and orientation of a PV plant are known to not only affect the amount of energy yielded, but also how the energy is distributed throughout the day, which is an important consideration for self-consumption. For example, orienting the PV generator to the west would move the peak time for generation to late afternoon while orienting it to the east would move it to the early morning. If a business experiences its highest energy demand in the evening hours, then simply orienting the PV plant to the west can increase self-consumption rate by around seven percentage points. However, orienting the PV generator to the west for this reason alone may not prove very effective since the absolute reduced yield of approx. 15 percent is much more decisive than the increase of the self-consumption.
The location of the PV plant also affects more than just the amount of the specific energy yield. Irradiation conditions (influenced by wind, clouds, morning mist, etc.) can also vary greatly and hence change the amount of self-consumption by a few percentage points.