Solar Energy Storage Equipment for Grid-Tied Residential Projects: Page 5 of 5
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In this article, we consider some of the use cases and emerging markets for residential grid-...
Technological advancements, constrained electric grids with high penetrations of PV systems and the...
Energy storage systems are an essential enabling technology that allows for the increasing...
Founded in 1981, SMA Solar Technology was the first manufacturer to offer high-voltage string inverter models in the North American market via its US subsidiary, SMA America. It pioneered the use of ac-coupling grid-direct string inverters with battery-based inverters. SMA America offers single-phase Sunny Boy string inverter models, in power classes from 3,000 W to 11,000 W, that are suitable for ac-coupled residential PV applications. It also offers two models of its Sunny Island battery-based inverters—the 4548-US and 6048-US, with rated power outputs of 4,500 W and 5,750 W, respectively. SMA designed both models for operation with 48 Vdc nominal battery banks. They are compatible with external battery management systems and lead-acid, nickel-cadmium and lithium-ion battery types, and have single-phase 120 Vac output. Split-phase 120/240 Vac output applications require two Sunny Island inverters or an autoformer. In ac-coupled systems, the Sunny Island limits the string inverter’s output power via frequency shift to regulate battery charging.
SMA has significant experience with self-consumption and energy storage systems in Europe and plans to offer additional equipment, such as its Energy Meter, in the US as markets develop. SMA has also been developing a new generation of energy storage power electronics for residential-scale applications in the US. Projected to ship in mid-2017, SMA’s Sunny Boy Storage inverter works with high-voltage lithium-ion battery banks, such as those from LG Chem and Tesla, for energy management tasks including peak load shaving, self-consumption, and zero export.
SMA America • Rocklin, CA • 916.625.0870 • sma-america.com
SolarEdge Technologies was launched in 2006. In 2015 it participated in the public relations wave announcing Tesla’s lithium-ion Powerwall Home Battery. SolarEdge was the first inverter manufacturer to offer fielded Powerwall systems in the US. Since then, SolarEdge has expanded the compatibility of its StorEdge power electronics system to include LG Chem’s RESU lithium-ion battery products.
SolarEdge’s single-inverter StorEdge system has four primary components. The system’s single-phase StorEdge dual-port inverter and Connection Unit functions as an optimized PV inverter that also provides power conversion and management for battery charging. A 120/240 Vac split-phase autoformer performs phase load balancing in StorEdge systems configured for backup power during grid outages. The addition of SolarEdge’s Electricity Meter enables smart energy management functionality that includes export power control, time-of-use shifting, maximized self-consumption, demand response and peak shaving capabilities.
The StorEdge inverter for the US market, model SE7600A-US, has a rated ac power output of 7,600 W and a maximum ac power output of 8,350 W when feeding electrical loads or exporting to the grid. In backup mode, it has a rated power output of 5,000 W and a maximum ac surge rating of 6,600 W. The inverter’s nominal dc bus voltage is 400 Vdc. The SolarEdge’s StorEdge inverter and module-level dc optimizers provide NEC-compliant rapid shutdown functionality for the PV array and battery. The StorEdge system’s Electricity Meter carries a 5-year warranty. Its autoformer and inverter carry a 12-year warranty, with an option to extend that to 25 years on the StorEdge inverter.
SolarEdge Technologies • Fremont, CA • 510.498.3200 • solaredge.com
Founded in Bavaria, Germany, in 2008, energy storage system provider sonnen first offered its storage solutions for European self-consumption applications. In 2015, sonnen established its US headquarters in Los Angeles and announced the availability of its products in North America. In February 2017, sonnen announced its plans for a new product development and manufacturing center in Atlanta, Georgia. The sonnenBatterie eco energy storage solution, designed for residential self-consumption and grid backup applications, integrates OutBack Power’s power electronics, Sony Fortelion lithium iron phosphate (LiFePO4) cells, and proprietary management and monitoring software. The eco comes in seven energy storage capacity options in 2 kWh increments, ranging from 4 kWh (eco 4 model) to 16 kWh (eco 16 model), with a usable capacity based on a 100% cell depth of discharge. The company has configured the LiFeYPO4 cells for a low-voltage dc bus with an operational range of 48 Vdc–56 Vdc, and offers a warranty on the product’s batteries for 10 years or 10,000 cycles.
The sonnenBatterie eco has a split-phase 120/240 Vac output and can be ac-coupled with existing or new PV installations. The eco 4 through eco 8 models have a 100-millisecond maximum power rating of 8,500 W and a 5-second maximum power rating of 6,000 W. The higher-capacity models, the eco 10 through eco 16, have a 100-millisecond maximum power rating of 17,000 W and a 5-second maximum power rating of 12,000 W. Non–revenue grade PV and load metering is standard. The sonnenBatterie eco system’s power electronics are certified to UL 1741 and carry a 10-year warranty.
sonnen • Los Angeles, CA • 310.853.2404 • sonnen-batterie.com
Founded in 2003, Silicon Valley electric vehicle manufacturer Tesla formally entered the US solar energy market with the announcement of its Powerwall Home Battery in 2015. Since then, Tesla has continued to grab media headlines with the launch of its Gigafactory for lithium-ion battery manufacturing, the purchase of national solar integrator SolarCity, and, in October 2016, the announcement of its second-generation stationary energy storage system, Powerwall 2.
With availability announced for 2017, the Powerwall 2 has a usable capacity of 13.5 kWh per unit, offers 100% depth of discharge and can scale up to 10 units for applications that require additional high-storage capacities. The Powerwall 2 integrates an onboard inverter rated for 7 kW peak/5 kW continuous. It is 44 by 29 by 5.5 inches, weighs 264.4 pounds and is approved for floor or wall-mounted installations indoors or out. The Powerwall 2 supports solar self-consumption, time-of-use load shifting, backup power and off-grid applications. Tesla backs the product with a 10-year warranty.
Tesla • Palo Alto, CA • 888.518.3752 • tesla.com
Joe Schwartz / SolarPro / Ashland, OR / solarprofessional.com