What does an inverter do?
The inverter is a critical part of any Solar array. It converts the high voltage DC current that is generated by a PV module into low voltage AC current which is necessary to make the energy useable within the home.
If integrating a battery solution into the array, or for an ‘Off grid’ system, a ‘Hybrid’ Inverter is necessary. This has the extra functionality needed to control and manage batteries which standard String inverters do not have. However, some battery solutions are stand alone in that respect, and include their own battery inverter and controller which means they can be integrated into a system with only a basic String inverter at any time.
Solar energy Solutions uses products from a range of Inverter manufacturers, depending on which is most appropriate for each situation depending on scale, individual site requirements and budget. These include SMA, SolaX, Goodwe & Enphase.
String inverters are the conventional technology whereby all the DC energy produced by the rooftop modules is received by a single inverter located within the home, which then converts the DC current to useable AC current for use within the home.
These systems offer a cost saving so are most commonly used, however there are some potential limitations in that the performance of the whole array is limited to the performance of the weakest panel. That means if one panel receives partial shading at some point of the day, or gets some obstruction such as leaf debris, then all the panels output is limited to the same level even if some are not shaded or obscured. However, DC optimisers, such as “Tigo” are another more economical option for individual panel management that could also be considered.
However, for larger arrays in commercial settings or with three phase wiring, String inverters are more favourable. They are also supported by online monitoring software packages.
In order to integrate batteries, it is necessary to use a variation of a String inverter which has extra functionality to manage the battery resource; and this is referred to as a Hybrid inverter.
With the recent industry focus on the development of more efficient and cost-effective battery solutions, technology in that space is advancing rapidly while at the same time reducing in cost, so more customers are interested in integrating a battery facility into their Solar system, now or in the future.
There are many modular battery solutions now available, as an alternative to a single large capacity and high cost standalone battery unit, such as Tesla Powerwall.
Modular solutions are beneficial in the respect that they are scalable and therefore more affordable; which means that we can design a system with only as much battery capacity as is suitable for the level of surplus energy your rooftop array will generate. This means you can start with only a small capacity (e.g.: one module), but retain the ability to increase capacity by simply adding more battery modules in the future.
For customers that intend to add batteries in the future rather than from the outset, it is advisable to opt for a Hybrid Inverter in the first instance so you have the option to integrate batteries very easily in the future when ready to do so.
Although this additional functionality does incur extra cost above a basic inverter, and may not be utilised immediately, specifying a Hybrid inverter is a more cost-effective way to do this than having to purchase a fully self-contained battery solution with battery inverter and management system as a standalone product. This is usually a more costly route, because those stand-alone battery solutions come in large capacities such as Tesla which is 13.2kWh and far greater capacity than would eb appropriate for most mid-size residential solar arrays; and incurs a much more significant cost than a modular solution.
More information batteries can be found on the ‘Batteries’ product page.
Micro inverter technology is a development of the conventional String inverter design, which increases generation efficiency, but also incurs more cost due to the additional hardware involved.
Instead of having one large String Inverter unit inside the dwelling to manage the whole array, this option involves using a micro inverter that is discretely mounted on the underside of each solar panel to individually manage the energy generated by each panel.
The energy generated by every panel in the array immediately converts to an AC current before it leaves the panel along a ‘daisy chain’ wiring pattern that runs directly to the distribution board by way of the monitoring unit. This eliminates the need for a regular standalone String inverter, and because DC currents are converted to low voltage AC current immediately, it is considered to have safety advantages.
The performance of the micro-inverters is managed by the Envoy-S which is the brains of the system, gathering data from the microinverters and delivering it to Enlighten software. This unit not only records generation data, but now it can also monitor energy consumption patterns in the home which is extremely useful information to have when assessing battery requirements in the future. This can be accessed online via laptop or mobile device.
The MyEnlighten monitoring portal connects system owners to their solar experience through an engaging and easy to use interface that provides insight into energy production, system health and earned environmental benefits that can easily be enjoyed with others.
For more information on Enphase and their products please visit: enphase.com