Storing and selling electricity

Save it or sell it

Generating your own electricity can reduce energy costs and, depending on the system setup, may ensure security of supply.

For rural properties, it may be the only practical and cost-effective option. For urban properties, 'micro-generation' may also be an attractive option under the right circumstances.

There are several options, ranging from solar, wind and hydro to traditional diesel generators. In almost all circumstances, solar PV will be the most practicable and cost effective of the renewable options.

Why generate your own electricity?

Cost-effectiveness

Electricity is expensive and the price is expected to keep rising. Generating your own electricity may be cheaper in the long run than continuing to use power from the local lines.

For properties in remote areas, connections to the local lines can cost tens of thousands of dollars. Generating your own electricity can work out cheaper. It can also be an option in urban areas. At the moment the set-up costs are relatively high, but they are coming down.

If you are connected to the grid and you generate your own electricity, you may be able to sell any excess back to your power company, albeit at lower buy-back tariffs than the retail rate.

Generating your own electricity looks at options for generating your own power.

Storing and using the electricity

If you're generating your own electricity, you can either be connected to the grid (and feed surplus electricity back into it) or be independent (a stand-alone power system). If you have a stand-alone system, you will need to:

• have batteries to store the energy as it is generated and/or
• have an additional generating option available to ensure an uninterrupted supply.

If you are grid connected, you will be connected to the local electricity network, and can export excess electricity, as well as using mains electricity as a back-up for your system. Using the grid for storage through a buy-back tariff arrangement with the local lines company will mean that you can save on the cost of having local storage battery banks, but be aware that buy-back tariffs are usually quite low and unpredictable.

Batteries

If you are using batteries, you'll need enough capacity to store electricity for your needs. This may need to be the equivalent of several days' supply if you rely on solar photovoltaics.

Your batteries will also need to be able to store electricity to meet your peak demand when several appliances are switched on at the same time.

Batteries will need to be properly installed and maintained to keep them safe and in good condition. Check with your supplier and follow the manufacturer's instructions.

A bank of batteries sufficient for a stand-alone system for one home may cost anywhere from $10,000 to $30,000, depending on how much energy you need to store. To ensure you get a good idea of the actual cost of batteries and to compare battery systems, ask your battery supplier to calculate their lifetime energy savings for you. This is measured in $/kWh used over the expected lifetime. It accounts for the number of expected cycles the battery is rated for, its efficiency, degradation and the purchase cost of battery.

Naturally, the financial benefit depends a great deal on individual circumstances related to your local utility and solar power options.

Selling to the grid

Your power retailer will sell you power at one price and is likely to buy power from you at a lower price. You'll need a contract with the retailer.

Different suppliers allow different options, so check before you install a system. If you're connected to the grid, you'll have to pay monthly supply charges.

You will also need a control system that prevents power being sent to the grid when the grid is down to ensure the safety of anyone working on the lines.