Combined Systems

What is a combined system? Often these are referred to as Hybrid Solar systems and they combine the best from Combination_systemson-grid and off-grid solar systems. Hybrid Solar systems are less expensive than off-grid solar systems as they do not require a backup generator and the battery bank required can be significantly downsized.

Hybrid systems provide power to offset the grid power whenever the sun is shining and will even send your excess power back to the grid for credit for later use. These systems provide power for your critical loads when the power grid is down however do not expect these to provide power for all your loads since the cost and volume of the batteries would be prohibitive.

You can program these systems to consume power during off-peak hours or from your solar panels. You can therefore temporarily store whatever excess electricity you have from your solar panels in batteries, and put the excess on the utility grid at the time when you are paid the most for every kWh you onsell.

According to many renewable energy experts, a small “hybrid” electric system uses a combination of renewable generation sources (such as solar PV, wind turbine or micro-hydro), a battery bank, smart controller/inverter and a back-up and they offer several advantages over either single system.

 

Many hybrid systems are stand-alone systems, which operate “off-grid” — not connected to an electricity distribution system. For the times when neither the wind nor the solar system are producing, most hybrid systems provide power through batteries and/or an engine generator powered by conventional fuels, such as diesel. If the batteries run low, the engine generator can provide power and recharge the batteries.Battery banks are typically sized to supply the electric load for one to three days.

If you live in a remote area then considering a hybrid power system could be a good way to get your electricity needs met or, if there is simply no connection to an electricity network, combining micro-generation, control and storage technologies together can provide a stable system for you.

Connecting your rural property to the electricity network can be expensive – costing as much $25,000 per kilometre. So you don’t have to be far from the nearest electricity lines for a hybrid power system to be a better alternative.

Combination_solar_systemsAdding an engine generator makes the system more complex, but modern electronic controllers can operate these systems automatically. An engine generator can also reduce the size of the other components needed for the system. Keep in mind that the storage capacity must be large enough to supply electrical needs during non-charging periods.

The cost of installing and maintaining a hybrid power system can vary a lot – it depends on the combination of the components and the electricity output you need.

  • Middle-of-the-range systems, with either solar PV panels or a wind turbine as the primary energy source – usually cost $15,000 to $25,000.
  • If you are looking at a  micro-hydro based system – the set up costs usually range from $12,000 to $15,000, with 20% to 25% needing to be allowed for the batteries.
  • Inverters – can cost from $3,000 to over $10,000, depending on the size, quality and complexity. You can avoid using an inverter by using DC-powered appliances but they’re generally more expensive and the choice is limited.
  • Diesel or petrol-fuelled generator – will cost $4,000 to $12,000 to buy and install. The size of the generator depends on the amount of electricity you need, the size of the battery bank and the renewable energy sources available to you.

Consent requirements

In many cases you’ll need either a building or resource consent (or both) for your micro-generation system.

This will depend on what type of system you are installing. For example you may find that your local council has height restrictions on wind turbine towers, and you might need regional council consent if you are going to require damming or converting a stream on your property.