some solar installer/dealers, particularly those specializing in off-grid applications. Lithium-Iron Phosphate batteries offer many advantages and are also becoming available. Lithium-ion batteries (commonly used in cars, computers, and phones) are developing rapidly and may be feasible in the near future for home use. Charge controllers are widely available. They are devices that opti-mize the output of solar panels using a technique called MPPT (maximum power point tracking). They also can monitor battery conditions and work with an inverter to optimize the charging of batteries. Battery charging methods are very specific to the type of battery being used. A battery capacity monitoring device is commonly used. Priority load panels (also called “critical” or “protected” load pan-els) require some significant installation work by an electrician. This consists of a circuit breaker panel/sub-panel that separates certain circuits in the house to receive preference over others in the event of a grid outage. Charge Controller Priority Load Panel Energy Management System (optional) Are these systems available? Solar+Storage systems are being installed throughout the United States and the world. They are very specific to the site and need to be con-figured by professionals (or well-trained amateurs) in order to make sure the various components are properly matched. The components include: PV modules are widely available, and the price is improving rapidly. Mounting, wiring, a rapid disconnect switch, and other hardware items are needed. Some appropriate “smart” inverters are widely available, although not all inverters used in either grid-tied net meter or off-grid sys-tems are well suited. The best are inverters that can draw power from DC sources (e.g., batteries, solar panels, etc.) and also serve as battery chargers. These newer generation inverters can also help the local grid by providing voltage and frequency stabiliza-tion, power factor compensation, and grid-disconnect features (e.g., compliant with IEEE/UL 1547 “anti-islanding” standards). Solar Array Inverter Energy management systems (EMS) are electronic controllers that are relatively new and highly specialized. These devices can manage and balance electrical use among various appliances in the house according to the needs of the residents. They will become more available as appliance manufacturers begin to offer more “smart” appliances that can communicate with the EMS systems. In the future, EMS devices will also be able to coordinate the home’s electrical status with external grid conditions such as demand response protocols, variable rate structures (e.g., time-of-use [ToU] electricity rates, demand rates, critical peak pricing, transactive energy [TE] protocols and tariffs, etc.) and control of “smart” appliances according to user interfaces of various kinds (e.g., smart thermostats, mobile phones, etc.). Conclusion Solar+Storage is already cost competitive in many retail electricity markets globally. Deutsche Bank projects that it will become a $5 trillion market by 2030 and will displace large amounts of fossil fuels. Deutsche Bank calls it “…the next killer app that could significantly accelerate global solar penetration…” Battery Batteries are becoming more available and lower-priced. An installation would include a battery box and peripherals such as venting mechanism if needed. In case of wet cell batteries, a distilled watering system to refill cells is desirable. Conventional lead-acid batteries are widely available and quite mature. Nickel-Iron and Nickel-Zinc are also established tech-nologies and offer some advantages over Lead-Acid batteries in terms of lifetime and charge cycling. These are being installed by Timothy Schoechle is an international consultant on smart grid technology, a home and building systems engineering expert, and author of the report Getting Smarter About the Smart Grid . He can be reached at email@example.com. 38 SUMMER 2017 SOLAR TODAY Copyright © 2014 American Solar Energy Society. All rights reserved.