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Solar Plus Storage Emerge as Next Generation Backup Power Source

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All across North America and the Caribbean, power outages are frequently experienced leading to power losses over short and long durations. Power outages can occur due to natural causes, such as an ice storm or hurricane but can also be caused by poor grid infrastructure, especially for homes located at the end of the line in rural communities.

The Caribbean region is home to at least 28 island nations and more than 7,000 individual islands with a population of around 40 million which are all exposed to disasters. In this region power outages are common; all the islands have issues especially after hurricanes, which can leave entire regions without power for weeks.

Generators are a popular item throughout these regions as they are readily available and have an attractive entry level cost. However, when looking at the total lifetime cost of ownership they quickly become expensive. Most families who experience power loss will run generators in the morning and in the evening only, so having a generator is not a guarantee of constant power. Further, a generator assumes the availability of a fuel source such as propane or liquid natural gas. So even if a generator is in place, there is no guarantee that fuel can be sourced especially in the event of a long duration power outage, limiting generators as a solution to short-term power outages. Generators are noisy and require a lot of space. Most urban locations are too difficult to install a generator. Getting fuel to an urban generator is a nightmare. Storing it, nightmare.

A growing number of residential solar PV systems continue to be installed throughout North America and the Caribbean. The growth in the residential PV market is being driven by lower cost of solar equipment, new financing models, and increasing cost of electricity. One emerging concept is the possibility to utilize the solar PV asset as a backup power source in conjunction with a residential energy storage system. In the event of a grid failure, the battery storage system would form an island while the solar PV array would continue to generate power. The electrical configuration would be tied into a protected loads panel where the PV power would offset the energy requirements for the essential loads. Further, the energy management would optimize the household consumption, solar PV production and battery state of charge which would form a perpetual backup power source.

Having constant power without the cost of running a generator is the big advantage of solar plus storage. A residential energy storage system requires no fuel or maintenance, and produces no noise or emission. Further, these systems can be installed indoor or outdoor, including in primary or secondary living spaces as they consume very little footprint. Through the integration of lithium batteries, the form factor of storage systems have dramatically improved and are aesthetically more pleasing than traditional lead-acid battery systems.

As battery prices and balance of system cost continue to decrease, the interest in residential energy storage systems increase. These systems offer a tight form factor, 10-year warranty with an expected 20-year plus operating life, very low operating cost and system failure rate, non-intrusive installation for homeowners along with advanced system level functionality.

From an environmental impact standpoint, most households who are committing to invest in solar power are environmentally aware. It becomes easy to understand why they are seeking to use their solar PV array when the grid fails. Further, the possibility to take advantage of federal and state level tax credits becomes available when installing solar plus storage equipment, which assists in offsetting a large component of the capital expenditure.

Today, advanced energy storage systems are coupled with leading edge intelligent software which allows for multiple uses of the same hardware platform. Storage systems can perform:

  • Self-consumption is the ability to store excess solar PV produced during the day and used at a later point
  • Time-of-use rate shifting is when the system stores solar PV or grid supplied energy for use when electric rates are the highest
  • Smart home energy management is achieved through the energy management platform, which continuously optimizes the home consumption, solar PV production and state of charge the batteries
  • Remote monitoring capabilities is completed through the use of either a smart phone or web portal

When compared to a traditional standby generator, the homeowner’s utilization rate of the deployed capital dramatically increases, as there is value recognized each day from the storage system. A standby generator will only perform if the grid fails assuming that the generator is in an operating condition and fuel is available. Therefore, storage has a 100 percent daily utilization rate, while a generator is likely around 1 percent.

As battery prices and balance of system costs continue to decrease, the interest in residential energy storage systems will continue to rise. 

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