Battery Storage Systems

A more recent innovation in the energy field is the use of battery systems to store and regulate power. Photonworks has successfully installed battery systems on residential and commercial properties.

Getting Started

The first step is identifying why you need a battery system. Do you want your home to be self sufficient? Do you want to store excess energy from a photovoltaic system (or other power production systems)? Do you want to have an emergency power source? We will work with you to determine the ideal size and type of energy storage for your home or business.


After we have determined the size and scope of your battery system our engineers will develop a plan set. Battery systems have many regulations and technical specifications that must be navigated. We are one of the few companies that have engineers who are adept at designing these types of systems.


Depending on the type of battery you have chosen the installation may vary greatly.  For a residential system the extent of the installation could be hanging a Tesla Wall Battery. However for a large commercial project battery installations may be more complex. In either case our design goal is to as unobtrusive as possible. The battery bank will blend in with your power system, or be hidden away entirely.

Commissioning and Closeout

The commissioning of a battery system is typically an additional step in the commissioning of a photovoltaic system. We can also commission battery systems for older projects, including projects constructed by other companies (we don’t judge).


Battery storage systems are included in our standard 1 year warranty. Batteries typically have manufacturer warranties of 5 – 10 years with expected life times of 15 years. PhotonWorks is an active participant in any project we install. We will be there if your system is not meeting expectations. The enduring quality of your system is a reflection of our performance. We want that reflection to be bright.

The Problem

Hawaii has set an ambitious precedent for the United States in terms of solar penetration. Oahu and Maui both boast solar penetration rates of 20%. This is a fantastic cultural and technical achievement. However, it has also placed a large strain on our local utilities.

During the day from 10 am to 4 pm most people are at work. At this time the demand for energy is relatively low. Conversely solar photovoltaic systems are producing their maximum output because the sun is directly overhead. Later in the evening, particularly from 7 pm to 9 pm the demand for energy rises rapidly. At the same time the output from solar panels tapers off with the setting of the sun.

HECO is in charge of regulating this rollercoaster.  They are responsible for ensuring high power quality. Power quality is defined as an electric networks ability to supply clean and stable power to the grid. In other words, HECO must be able to consistently supply power within specific voltage and frequency ranges amongst other requirements. In order to do so HECO must have enough generating capability to provide power at peak demand. The renewable energy watch, as seen to the right, visualizes the extreme variations in power resulting from renewable power sources.

Every year as more Hawaiians opt into solar the roller coaster gets bumpier. During the day HECO is providing the minimum amount of power that it can in order to maintain power quality. In the evening it must rapidly ramp up its energy production to deal with the loss of solar generation as well as the increasing energy demand.

As a result of this HECO has been forced to end all Net Energy Metering (NEM) and Customer Grid Supply (CGS) programs for new customers. If these programs were left unabated the electrical network would begin to produce more than 100% of the load during peak daylight hours. This would unbalance the grid which would result in severe electrical damage.

The Solution

Batteries are the unequivocal solution to the problems we are facing in Hawaii. Home battery storage systems would allow energy to be stored during the peak hours of the day. As a result, the grid would not be at risk of oversupply. Furthermore, HECO will be able to purchase power from solar users during the evening in order to reduce the stress on the grid. It is a win win scenario.

The drawback of battery storage systems is their prohibitive cost. At this time a reliable battery storage system may double the cost of a photovoltaic system. However, the solar industry, since its inception, has been a robust competitor in the energy market. Every year photovoltaic panels become more efficient for a lower price. The same trend has been established with batteries, it is only a matter of time before they are adopted on a massive scale.

At PhotonWorks Engineering we have embraced this new technology. We are working with manufacturers from around the world to find reliable, cost effective battery storage systems for our customers. Recently in partnership with Ensync, a manufacturer of battery storage systems, we have engineered and built Hawaii’s first large scale solar power and battery storage system for Century West. This system is also the debut of Hawaii’s first Power Purchase Agreement (PPA).

Where other solar companies may have lost their footing, PhotonWorks has found its stride. We will face any challenge be it technical, political, or economic in order to continue providing clean affordable energy to the good people of Hawaii.