The U.S. is experiencing major growth in its energy storage market, and it’s only the beginning. According to Wood Mackenzie’s U.S. Energy Storage Monitor 2019 year in review, the market is forecasted to grow more than 14-fold from 523 MW in 2019 to 7.3 GW by 2025. This will result primarily from storage-friendly policies and opportunities to provide wholesale market services for energy storage owners. Front of the meter (FTM) storage leads the energy storage market at present and will continue to make up the bulk of the market. FTM and BTM refer to the position of the storage system in relation to the home meter. FTM systems (i.e. utility scale projects) provide power to off-site locations and BTM systems (i.e. residential systems, on-site commercial, microgrids) provide power that can be used on-site, avoiding the need to pass through a meter.
Residential storage had its strongest quarter ever in Q4 2019 with 40.4 MW/93.3 MWh deployed in the U.S. There are multiple incentives that drive homeowners to add storage to their homes in the U.S. including back-up, time-of-use arbitrage, self-consumption, and available grid & wholesale market services.
Various incentive programs are active in different states to support storage adoption, for applications like TOU, resiliency, and grid service. California will retain its leadership in residential storage growth, especially since the newest version of SGIP (Self Generation Incentive Program) reserves a special allocation for residential storage. The California Public Utilities Commission revised the SGIP to include additional funding for low-income communities and customers with resilience needs to benefit from energy storage.
Q CELLS will unveil its Energy Storage System (ESS) for the U.S. market with an all-in-one brand solution. Q CELLS’ ESS inverter system, the Q.HOME+ ESS HYB-G1 and Q.HOME+ ESS AC-G1, can connect ESS systems both in DC and AC-coupled configurations respectively for new and retrofit projects.
Q.HOME+ HYB-G1 is an integrated residential solar+ storage solution with a 6.0 – 8.6 kW hybrid inverter which provide energy storage capacity from 4.5 to 18.9 kWh. The storage capacity per battery can be either 4.5 or 6.3 kWh, for a maximum of 18.9 kWh with the application of three batteries. The discharge power per battery is 2.5 kW, and with three batteries, the backup power can ramp up to 7.5 kW. As a future-proof solution, Q.HOME+ will provide critical support to legacy grid systems, in addition to benefitting the end user. Energy storage coupled with smart energy management algorithms enable PV power to be utilized for TOU, demand management, home backup and remote operation for grid service and wholesale market. A Non-Export/Self Consumption mode is also available for customer consuming electricity being stored in the storage system.
The Q.HOME+ ESS solution is capable of supporting partial to full household electricity needs based on the battery and inverter capacity. As an example, the Q. HOME+ HYB-G1 7.6 kW inverter can be paired with three 6.3 kWh battery modules for an energy capacity of 18.9 kWh and 7.5 kW discharge power. For a typical residential home in the U.S., the average load is around 7.5 kW which means Q.HOME+ can support the full load up to 2.5 hours without any grid power or solar PV. However, with optimized load selection, the three-battery system can support a 20 cubic feet freezer, microwave, fan, 1/3 HP well pump, TV, multiple bulbs, laptop, and humidifiers for 6 to 7 hours.
The table below highlights the operational mode available in Q.HOME+, which can support all the applications for the U.S. residential market from TOU arbitrage, home back-up for resiliency, and remote operation for grid service and wholesale market.
Q.HOME+ comes with two different product models, Q.HOME+ HYB-G1 and Q.HOME+ AC-G1, to support both DC-coupled and AC-coupled architecture, respectively. A DC-coupled system has better round-trip efficiency compared to an AC-coupled solution, and is the preferred method for new home installations. On the other hand, the AC-coupled solution is more suitable for the retrofit market, allowing the option to add storage to existing PV systems.
Q.HOME+ HYB-G1 comes with a hybrid inverter to connect PV and batteries, a unique feature allowing multiple batteries to be connected to the inverter with a single Battery Management System (BMS). Modularity of the storage solution will provide enough flexibility to the end-users selecting their storage size based on necessity and economics. Higher back-up power at off-grid conditions is another interesting aspect of this solution, as the system can match up grid-tied output when three batteries are connected in the system.
One of the biggest challenges in troubleshooting product failure is identifying the failure’s source. However, for this product, Q CELLS will be the single point of contact for all post-sales processes – Product Support, Warranty, and RMA. The Q.HOME+ ESS is expected to address field troubleshooting of solar modules, inverter, and ESS failure by identifying sources of product malfunction and offering service from a single entity.
Tanvir Arafat Khan, PhD (Senior Staff Engineer / Products, Technology & Innovation Q
CELLS North America)