First things first, gotta get some power to this greenhouse. A 12V wire from the basement would do the job, however this isn't much fun. A small solar installation is much better, with the goal being to contribute wind power to the system in future.

Solar Sizing

Realistically, not a whole lot of system sizing can be completed, as the system load is not incredibly well known at this point. It is likely that the largest load for now will be the pump, however in future I would like to include a fan heater to raise the temperature through the winter and overnight.

According to the AliExpress listing, the pump will use about 4.8W when in use, and will operate at 240L per hour. According to this handy article, it seems that each square meter of growing area will need about 16L per day at most. Given the glasshouse being sized has about 2 square meters of growing area, the system should be able to pump 32L per day. Given the pump capacity, it is safe to assume that the pump shouldn't be on for more than about quarter of an hour per day. Therefore, the total energy usage per day from this pump will be 0.72Wh.

When a heater is implemented, it seems reasonable to allow for up to 1000W of heating. As a heater has not been sized, this is just based on some vague research on heating greenhouses. 

Realistically, the pump doesn't make any difference. Unsurprisingly, whatever heater is utilised will make up the bulk of the energy consumption.

Using the NIWA SolarView tool, it seems that I can be expecting an average of 2.05 peak sun hours per day during the depths of winter. This means that in order to power the system in an ideal way, a 1.5kW solar panel installation would be required. This is not feasible, nor is it very sensible. As a compromise, the biggest panel I could afford was utilised, and the heating will be scaled down to fit within this power budget.

Eventually, a wind turbine will be added to generate energy, at which point more heating may be possible. Realistically, wind energy is a better solution for heating a glasshouse anyway. Processing the NIWA SolarView data, the weekly total irradiance follows the expected trend, with less solar available in winter. Heating will be needed most during winter, so solar does not really solve this problem.

Therefore, the solar installation is primarily intended to have a basic monitoring/watering system installed, with a heating system being designed after a turbine is installed.

I am still looking for solar panels, and will update this log when I have got some hardware to work with.