Last month when Meridian Energy and Contact dropped their buy-back rates for excess electricity produced by residential solar panel owners the result from the industry was a collective "so what?"
The management of savvy solar companies were expecting it, and already future-proofing their customers' power price security by installing solar arrays just large enough to offset daily electricity use, rather than installing systems to make money by selling excess power back to gentailers.
An average New Zealand household uses around 20kWh of electricity per day. As an example of average performance of a solar power system, a 1.5kW (6 panel) system will generate 1.5kWh of power for every full hour of sunlight. NIWA sunshine hours statistics show that in summer, in Auckland, the average full hours of sunshine a day is 6.5 (October to March) and the average daily winter sunshine hours is 4.6. In the summer a 1.5kW system could be generating around 9 kWh per day. In the winter the system could be generating around 6.75kWh. If you're at home during the day, consider a larger system. If not, a 1.5kW system should be ample to heat your water and run the appliances working during the day such as your fridge, and anything else you can set to operate during sunlight hours - such as your dishwasher or washing machine - entirely free.
Provided the system is set up to cover daily electricity use, the payoff time for the panels should be around six years.
Takapuna-based Solar King is a New Zealand leader in the installation of residential solar systems, specialising in Tier 1 equipment (the industry's highest standard). Its latest technology offering is a 1.5kW array combined with Enphase micro inverters, which sit under each panel in your solar power system and perform the function of converting the DC current generated by the panel into AC power that is useable in the home. If you have a roof with some areas of shading, or several roof areas that you would like to put panels on, then you will benefit from a micro inverter system. With a micro system you can put panels on any roof area and if one panel has shading on it you only lose the production of that one panel while it is shaded. With a traditional string of panels if one is shaded the whole string will drop to the production level of the lowest producing panel.
