DIY Green Energy For Homes

Grid Tie Inverter

Most solar electric systems use inverters to convert direct current to alternating current, which is the type compatible with our electrical appliances. However, some solar systems use special inverters with more functionality and features.

A grid tie inverter is one that, on top of converting alternating current into direct current, feeds the current on to an electrical grid.

They are typically used in systems where a renewable source is going to be ‘tied’ on to a grid to overcome intermittency issues.

In technical terms, a grid inverter is called a ‘grid interactive inverter’, or at times known as synchronous inverter. Grid inverters are cannot be used on a standalone application that is not connected to a utility grid.

Types of solar systems

Solar energy can be used to power just about anything that requires electricity and it is now being used in a number of applications. The type of solar system to be used depends on the type of application. There are basically two types of solar electric systems:

Grid tie or grid connect solar system – this is a solar system that is also ‘tied’ or connected to another electric system, usually a utility grid system.

Standalone solar system – these systems operate independent of another system. They are usually used to power isolated electrical equipment, such as radio repeaters, street lighting and phone booths. Standalone solar systems are also growing in popularity in the leisure caravan and boat market.

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Grid tie systems

A number of states in the US, as well as countries elsewhere, allow grid-tied electrical systems where owners of these systems are allowed to sell excess electricity to the utilities. There are several ways through which the excess power supplied to the grid can be compensated.

The most widely used is net-metering, where the entity that owns the source of power receives compensation from the utility company for the net outflow of power. For instance, if an entity supplies 300 kilowatt hours to the utility grid and only uses 100 kilowatt hours from the grid, the net outflow would be 200 kilowatt hours and that is the value of compensation it would receive, in form of credit at a retail or whole sale price, depending on jurisdiction. Policies governing net-metering in the US vary by state.

Another type of compensation is based on a feed-in-tariff. In this system, a supplying entity is paid for each kilowatt hour supplied to the utility grid using a special tariff based on an agreement with the utility company or some other power authority.

In the US, there are particular requirements set for grid tied electric systems, as stipulated by provisions in the National Electric Code.

Operation of a grid tie inverter

An inverter receives direct current and inverts it to alternating current so that it can be fed into the grid. A grid tie inverter also synchronizes the grid’s frequency with its own by use of an oscillator and monitors voltage changes, limiting it to the grid’s voltage.

In its design, a grid tie inverter will automatically disconnect from the grid once the grid goes down. This particular feature is a NEC requirement that ensures safety of line workers who may be fixing the grid at the time of a blackout.

In simple terms, a grid tie inverter enables a plug and play operation for homeowners who produce energy from solar or wind systems.

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free energy options