October 14, 2017By Livio Filice
For over a decade, I have been in the renewable energy and electrical storage business, with a focus on bringing clean, sustainable and reliable energy power and storage systems to individuals across North America and the Caribbean.
The Caribbean region has always been a key region of interest due to growth in the residential PV market. The growth trend has been led by decreasing cost of solar equipment, new financing models, and increasing cost of electricity. Further, as consumer uptake for lithium-based electronics and electric vehicles take flight, the direct cost for stationary energy storage systems have rapidly been decreasing.
The remote locations of the 7,000 individual Caribbean islands are not easily addressed with traditional power grids leaving over 40 million individuals vulnerable to short and long duration power outages. These macro level trends present a significant opportunity for investment in new energy storage technologies to stabilize power supply which should lead to reduced cost of energy over the long term.
During my time in the clean technology industry, I have worked on bringing a number of clean energy systems to remote locations throughout North America and the Caribbean. One of my first projects included the supply of vertical axis wind turbines to a remote airplane landing stripe and helicopter landing pad in the remote northern Ontario city of Kenora, near the Manitoba border. The turbines were coupled with existing generators and battery technologies to decrease reliance on diesel fuel consumption. More recently, I worked to deploy lithium based turn-key residential energy storage systems throughout a number of Caribbean islands including: Puerto Rico, USVI, BVI, Anguilla, Cayman Islands, Bermuda and Bahamas. These were amongst the first lithium storage systems to have been installed on these islands with all systems connected to solar PV arrays and some with standby generators. The combination of solar PV, lithium energy storage systems and standby generators form a residential mini-grid which allows the homeowner to utilize traditional power grids as a backup source with primary energy requirements being generated on-source.
Generators Face Challenges with Long-duration Power Outages
Power outages caused by hurricanes can leave entire urban regions without electricity for weeks and rural dwellers for months. If an individual leaves their power requirements in the hands of the utilities and government bodies, than they could be exposed to a loss of power for extended periods of time. Generators such as those offered by Generac Holdings are a popular consumer item throughout the Caribbean region as the hardware, fuel and storage can easily be sourced. In the event of a power outage, this creates an expensive but reliable power source for short-durations of time, should the equipment be in functioning condition.
Although standby generators offer a low capital cost of entrance for consumers, the expenses are incurred over the lifetime of the asset. Generators are not a reliable power source beyond short duration power outages and do not connect with a solar PV array without the integration of a battery storage system. A generator assumes the availability of a fuel source such as propane or natural gas. Even with a generator in place, there is no guarantee that fuel can be sourced, especially in the event of a long duration power outage. This is exactly why generators are limited as a solution for short duration power outages. Additionally, generators are noisy, create ground level pollution in urban environments, require a significant footprint and typically require fuel to be delivered and stored on site.
Dismantling of Net-metering Programs
A major concern for the solar PV industry throughout the Caribbean region is the removal of net-metering programs. It is becoming increasingly popular for utilities to destruct traditional net-metering programs, which allow homeowners to export excess electricity into the power grid for full retail credit. This has been recently witnessed in Bermuda and the USVI were net-metering programs have been closed.
Existing solar PV owners are grandfathered into these programs, while homeowners looking to go solar will not be able to take advantage of the net-metering program. Instead, they are exposed to less favorable rules which will only pay 50 percent or less of retail rates for exported solar energy. If the home consumption is less than the amount of solar energy being produced then they will only be awarded half of the current retail rates. In some cases the utilities have imposed a net-zero export limitation, which does not allow homeowners to export any levels of energy back into the grid. In a net-zero export scenario, all electricity produced by the residential solar PV array must be consumed directly on site. Utilities across the Caribbean region have already begun to dismantle programs that assist homeowners to go solar. The net impact of these program changes will mean a longer payback period on solar assets.
Lithium Energy Storage Systems Take Charge
Lithium-based energy storage systems are the ideal solution to manage short- and long-duration power outages while mitigating risks associated with the removal of net-metering programs. An increasingly popular trend is the use of solar PV plus storage systems that are configured to operate as a perpetual backup power source. In the event of a grid failure, the solar PV array is disconnected while the storage system recognizes the loss of the power grid. Over a few seconds, the system will test for grid signals, then upon completion will establish itself to act as a grid forming element. The storage system will send a power signal to the solar PV array which leads it to believe that the power grid has been established and the array continues producing power. The power is then fed into a protected loads panel allowing for essential items to be powered throughout the home.
When the sun sets, the battery storage system will continue to provide power throughout the evening until sun rise the next morning. The intelligent energy management software will continual manage and optimize three core component being the PV production, household consumption and state of charge of the battery to ensure the homeowner comfortably makes it through either a short or long duration power outage. Standby generators can also be integrated into the mini-grid to provide additional security, which is controlled by the energy management software and connected through the power control and conversion platform.
In addition to acting as an advanced, perpetual backup power source, energy storage systems can easily be configured through the software platform to capture excess solar PV production. With traditional solar systems, excess PV power is fed directly into the electric grid but with the removal of net-metering programs this has become non-ideal. Energy storage systems store the excess power produced, which allows the homeowner to take full advantage of their investment in the solar system. Under this scenario, solar PV produced will offset the home’s energy consumption with the balance of the electricity produced being stored in the energy storage system. When the solar array stops producing energy in the evening, then the storage system will begin to discharge so that the home is not drawing electricity from the power grid but rather using energy which was produced from the solar array earlier during the day. Collectively, the value of solar plus storage systems are illustrated in these scenarios.