GRID-TIE SOLAR & ANTI-ISLANDING

Anti-islanding!
If you haven't come across this term before, you soon will. The subject of anti-islanding is often brought up when discussing grid-tied renewable energy systems. It's a term that you should become very familiar with if you're considering registering a grid-tie solar system under the terms of the  2014 Electricity Amendment Act.

An important point to understand is that, for safety reasons, a grid-tie solar system is designed to shut down power production to the grid when there is a utility grid outage. Yes, you did read that correctly. For example, it's 12 Noon, the skies are clear, the sun is shining brightly, and your solar system has reached it's peak production for the day. But then suddenly it cycles off and all the appliances and electronics in the home are no longer powered up. Your first thought,  . . .is there something wrong, has the equipment malfunctioned, have I tripped a breaker?  Before jumping to any hasty conclusions, lets first consider that the utility grid is down.  If it is, then your grid-tied solar system is performing just as it was designed. Once utility grid power is restored by the utility company after maintenance or repair,  your grid-tied solar system will automatically begin to cycle back on without any intervention on your part.

A Hybrid System (Grid-Interactive),  will also shut down power production to the grid, but has the expanded capability of powering local loads independently while the grid is down. There is a significant difference between Hybrid and Grid-tie (Grid-dependent) systems. Both have anti-islanding protection, however the Hybrid system typically has an alternate power source, such as batteries, or a propane generator, which can be utilized to power essential local loads in the event of a power outage.

Another Hybrid variation is a dual inverter configuration. A grid-tie inverter matched with a battery-based inverter utilizing an automatic or manual transfer switch. While the grid is up, the system produces power that can feed the utility grid. The batteries remain fully charged from the utility power. When the utility grid is down, the grid-tie inverter cycles off and the battery-based inverter then automatically cycles on and powers local essential loads. Once the grid is restored, the grid-tie inverter cycles on, and is able to power your home, and also feed the grid depending on the power demand in your home.

In summary, anti-islanding protection, is an important safety feature built into compliant grid-tie and hybrid inverters that sense utility grid faults and outages and automatically shuts down the inverter, preventing feeding of power back onto the utility grid.

In the United States, the standard for anti-islanding is specified in UL 1741 and further associated in IEEE 1547.

Under the Canadian electric code, anti-islanding is referenced as, CAN/CSA-C22.2 No. 107.1-01 General Use Power Supplies. Refer to side column for further details.

Grid-Tie
On Friday, March 13th, the Bahamas experienced the second protracted island-wide blackout in the course of one year. The following week, on Friday, March 20th, 2015 the Electricity (Amendment) Act, 2014 came into effect. The Act enables persons to install and operate renewable energy generating stations. These renewable energy self generation systems (RESG) will be registered and regulated under provisions of the Electricity (Amendment) Act, 2014, and can be connected to the electrical grid. On March 25th, in the House of Assembly, the Deputy Prime Minister stated, "With the RESG Programme, the opportunity exists to generate energy through alternative energy sources, tie into the current electrical grid, and to receive a credit for excess electricity fed into the grid."  Yes, the same grid currently managed and operated by BEC.

Mark this date on your calendar. March 20, 2015.
It's the beginning of a new era in the Bahamas.