Grid-tied, on-grid, utility-interactive, grid inter tie and grid back feeding are all terms used to describe the same concept – a solar system that is connected to the utility power grid.
Net Metering is an electricity policy for utility customers who operate their own on-site "self-generation" power systems such as photo voltaic systems. PV systems are connected to the utility grid via the customers' main service panel and meter and, when generating more power than is needed at the site, return excess electricity to the grid through the power meter, reversing the meter from its usual direction. As a result of the meter working in both directions – one way to measure power purchased (when on-site demand is greater than on-site power production), the other way to measure power returned to the grid – the customer pays the "net" of both transactions.
Advantages of Grid-Tied Systems
1. Financial Credit for Extra Solar Power Produced.
A grid-connection will allow you to save more money with solar panels through better efficiency rates, net metering, plus lower equipment and installation costs:
Batteries, and other stand-alone equipment, are required for a fully functional off-grid solar system and add to costs as well as maintenance. Grid-tied solar systems are therefore generally cheaper and simpler to install.
Your solar panels will often generate more electricity than what you are capable of consuming. With net metering, homeowners can put this excess electricity onto the utility grid instead of storing it themselves with batteries.
Net metering (or feed-in tariff schemes in some countries) play an important role in how solar power is incentivized. Without it, residential solar systems would be much less feasible from a financial point of view.
Many utility companies are committed to buying electricity from homeowners at the same rate as they sell it themselves.
2. The utility grid is a virtual, No Battery Storage System Needed.
Electricity has to be spent in real time. However, it can be temporarily stored as other forms of energy (e.g. chemical energy in batteries). Energy storage typically comes with significant losses.
The electric power grid is in many ways also a battery, without the need for maintenance or replacements, and with much better efficiency rates. In other words, more electricity (and more money) goes to waste with conventional battery systems.
Additional perks of being grid-tied include access to backup power from the utility grid (in case your solar system stop generating electricity for one reason or another). At the same time you help to mitigate the utility company`s peak load. As a result, the efficiency of our electrical system as a whole goes up.
3. No Backup Generator for when Solar Power is Not Available
Another expensive part of early solar power systems that you won’t need is the backup generator. Generators are expensive, noisy and need fuel (gasoline, diesel, natural gas or propane). The electrical utility is there as your backup when solar power is not available.
4. Seasonal Storage – Solar Power Produced in Summer Saves on Winter Costs
One of the frustrations of off-grid systems which are not connected to the utility is that the extra power in the summer months can’t be stored for the winter. Battery banks typically store power for only 3-5 days. When the batteries are full there is no way to store the extra energy. But, with net metering, you are feeding back your power over the summer and you get credited for it in the winter – now you have seasonal storage.
5. No Maintenance – Solar Power without Hassles
Handy system with net metering, we have now eliminated the batteries and the backup generator – the two components of a solar power system that require maintenance and have the shortest lifetimes. The only components you need for a grid-tied net metering system is the solar panels, which produce the power, and an inverter that converts the DC power from the solar panels to the standard AC power produced by the utility. Neither of these components requires maintenance. The solar panels, which have a 25 year warranty, are made from a semiconductor material and usually protected by a tempered glass front. The inverters, some of which also have 25 year warranties, are solid state and also maintenance free.
A grid-tied net metering system gives you the advantages of producing your own clean renewable energy without maintenance hassles and with very durable components.