On-Grid systems are sometimes referred to as Grid-Intertied, Grid-Tied, and Net Billed or sometimes Net Metered systems and they are the means for users to reduce their power consumption by the use of solar Photovoltaic (or wind or hydro) systems. The photovoltaic systems are typically used by city dwellers that simply want to reduce their own electrical use in their household. Other reasons can include an awareness of global warming or environmental reasons. In effect, it places a ceiling, or cap, on their electricity use and yet still remaining connected to the electricity grid. Back-up batteries are normally not used because the grid itself is the battery.

There are only two major components of the on-grid system – solar (or wind) and an asynchronous inverter, which is one that can connect to and co-ordinate with the grid. In the course of a typical day when less power is being used in the house and the panels are producing (or over-producing) electricity, which is then fed back into the grid via the asynchronous inverter. In effect, it runs the meter backwards, although technically this is not the way it happens.

Overseas where the growth of these systems is enormous, there are subsidies or Feed-In-Tariffs provided to help with the cost of a system. Unfortunately in New Zealand as yet we do not have these cost benefits so that the complete price of the system must be met by the owner. However, this should not stop those interested in Grid-Intertied systems because the sooner a system is installed the sooner it can deliver benefits.

Over the past 12 years we have advised customers to think of these systems as a process and the process begins by making the house as energy efficient as possible. This entails the install of a solar hot water system and energy efficient lighting (neither of which we market) and the use of energy efficient refrigeration, which we do market. Energy efficient refrigeration becomes a real means to help reduce household electrical use.

We normally advise that it is best for you to undertake energy efficient measures, and then re-consider an On-Grid system. By following these steps you pick off the low-hanging fruit first – so that when you do add a Grid-Intertied system it will show the best effect on the power bill. The emphasis is on energy efficiency and eliminating phantom loads first, and then add the On-Grid system. If anything, you will have a better understanding of the means to control your electrical consumption and reduce the power bill.

We have extensive information about On-Grid systems explaining the merits and benefits of these systems that we can post to you. We have Frequently Asked Questions (FAQ's) about On-Grid systems as well as a booklet that explains these systems in more detail and explains how the benefits can be very real for both the individuals and the electricity market.