maple street co-op

Environment
From "Maple Street Co-op News", Jun/Jul 2004

Getting Active – Grid Interactive!
by Rod Castle

A lot of people would assume that having solar energy would be only for people living away from access to mains power amidst their vegetable garden or forest. This is not the case when having a grid-interactive system means being able to produce electricity via solar panels, wind or hydro and using the mains grid for "battery storage" at night.

Grid-interactive systems are a growing market in the solar industry and are becoming a common sight wherever there is mains power. More and more people and businesses are installing such systems because they want to help reduce greenhouse gases and support renewable energies.

The system works by the solar panels producing direct current (DC), which passes through a grid-interactive inverter that converts the DC electricity into alternating current (AC), which is then accessible to power your house, operate appliances and so on. This means no change to the general wiring of your house.

Excess power produced is then fed back into the grid, and some electricity retailers are offering ‘net billing’ so that they buy the electricity you produce at the same price as they sell any of their electricity to you. Additionally, when the renewable system isn’t generating enough electricity to power the house, the system will draw power from the grid. Since the system does not require a battery bank, it eliminates a huge maintenance cost – the only drawback being that in the event of a blackout, the system does not provide electricity.

The grid-interactive system at the Eco Centre at Crystal Waters in Conondale is a fine example. Completed in 2001, the system has 24 photovoltaic (PV) panels on the north-facing verandah roof. The excess power is sold back to the local electricity provider, Energex.

To work out what sized system would suit your house means analysing your last electricity bill. Most systems are usually sized so that the panels generate approximately the same amount of electricity consumed by the house. Also, with grid-interactive systems, you have the advantage of being able to start with a small renewable system and add to it in time as finances allow, thus reducing the need for a large initial capital expenditure.

A typical energy-efficient suburban home with a 1,500-watt inverter and 18 x 80-watt solar panels could have a capital cost of approx. $18,000 including installation, but would be eligible for a Queensland Government rebate of $4,000.

The current cost of solar panels and other renewable energy options is such that grid-interactive systems require a reasonably significant initial capital outlay; however, over time the grid-interactive system becomes more and more cost-effective.

A spokesperson for local renewable energy business Solazone comments: "Informed and environmentally aware people are already moving forward and installing these systems to their homes as a safeguard for the future. It is not the case that rich people order most of our grid solar power systems. It is usually people who have deep concern for the planet and feel that they can help the situation now, and at the same time save themselves the ongoing cost of power bills – particularly for later in life when the cost of power will rise even more."

[For more details, contact a renewable energy specialist, visit http://www.greenhouse.gov.au and http://www.solazone.com.au, or ask Rod Castle at the Co-op.].

[From "Maple Street Co-op News", June/July 2004; published by The Maple Street Co-operative Society Ltd, 37 Maple Street, Maleny, Qld 4552, Australia, tel (07) 5494 2088, email maplest.co-op@serv.net.au,
website http://www.maplestreetco-op.com.au]