availability

The availability of the sun to generate electricity when it is required by us to consume is rarely synchronised. Often referred to as Intermittency, it is one of the major criticisms of solar electricity generation.

Electricity generated from solar photovoltaic panels (PV) is highly susceptible to daylight hours, weather, and the seasons. 

1.Day Time Hours

Figure 1 shows the electricity a 1 MW solar PV farm could generate each hour of a typical Whakatane summers day (green) and the reduced hours of a winters day (blue).

Figure 1: Graph showing the electricity available different hours of typical Whakatane summer and winter day.

Whakatane has a reputation for having one of the highest number of sunshine hours in New Zealand. Weather is the main contributor. The fewer wet or cloudy days the area has, the more sunshine hours.

Figure 2: Sunshine hours compared to other towns in NZ, June 2020.

2. Seasons

Our latitude of 37° south has a dramatic impact on generation capacity compared to areas closer to the equator. This link to GlobalSolarAtlas is a useful tool for estimating generation capacity of different sized PV arrays located anywhere in the world.

Figure 3: Graph showing the electricity available in kWh for a 1 MW solar PV farm located in Whakatane.

Graphs in figures 3 and 4 show the same information in different graphical formats – 1 MW farm located at Whakatane.

Figure 4: Graph showing the electricity available in kWh per month of a 1 MW farm located at Whakatane.
Figure 5: GlobalSolarAtlas system data for a 1 MW farm located at Whakatane.

There are methods available to mitigate intermittency discussed in the next Pages:

Capture, Distribution and Consumption.