Off-Grid Power System Designs
Off grid solar electric power system design has changed dramatically over the past 25 years. We are able to provide design solutions in a more sophisticated and efficient manner today; so much so that off-grid solar is ready for mass deployment in residential and commercial settings.
Through design innovation and observing best practices, this new genre of more sophisticated off-grid power system designs stand ready to supply electric power better and cheaper than ever before. As properties and electrical loads well over time, today’s power systems are designed to grow in lockstep.
Older system designs were characterized by smaller solar arrays coupled with larger battery banks, always included back-up generators, and never had internet connectivity for remote management and control. Today’s system designs include much larger solar arrays with more appropriately sized energy storage systems and no need for a back-up generator (though it is often still included). More versatile power conditioning equipment and remote monitoring means entire communities can be off-grid.
Interestingly, older power system designs still worked admirably and we regularly come across twenty-year-old equipment still working in the field today. It is NewGrid’s intimate knowledge of the past coupled with focus on the present that allow us to prepare our customers for the future. Our contention is that a solar electric service beats competing electric service options in an increasing number of scenarios; whether we are competing with the utility grid or a generator.
Generators are still optional though increasingly less typical with many off-grid residential installations today than it was 10, 20, and 30 years ago. At that time, the extremely high cost of solar modules required solar system designs to include the minimum number of panels possible. Therefore a propane or diesel generator back-up to bolster power generation capacity was almost always needed for periods of inclement weather, heavy loads, or both. This design constraint has been removed completely along with the precipitous drop in solar panel prices. New solar electric services don’t require generators as a part of the solution, and instead include larger solar arrays than they used to.
Power Generation Capacity
Power generation capacity is a reference to the amount of solar panels on the property. More solar deployed means an increase in the ability to convert sunlight into electrical energy and a corresponding ability of the property to keep up with increased electrical loads, longer periods of cloudy weather, and generally perform at a higher level.
Energy Storage System (ESS)
The term battery bank is currently used interchangeably with energy storage system. However as the energy storage industry explodes with new solutions and innovations, the notion of a battery bank is increasingly too narrow to effectively communicate the solutions now available. In terms of power system design, the energy storage system is hands down the most complex of the fundamental power system elements. Fraught with nuance and anticipation of the next big thing, this portion of a power system needs the most experienced professionals to wade through the marketing material on behalf of clients. The shift in energy storage solutions has been occurring since about 2015 and the transition is still underway. NewGrid is now regularly providing clients with alternatives to the incumbent Lead Acid batteries solutions in the form of Lithium Ion. This is a complex and volatile time for energy storage and by extension, solar electric power systems as well. At NewGrid we are excited by the changes underway and ready to engage clients regarding sensible ESS’s for their particular needs.
Solar electric service equipment, like any other permanently installed electrical equipment, operates more effectively when placed into service in the correct environment. This important system design parameter is all too often overlooked on account of error, poor planning, or lack of experience. NewGrids book of business has more than its fair share of power system remodels and central to that work is the lack of consideration of the environment into which equipment is initially installed. Both new solar electric services and power system remodels by NewGrid have one attribute in common that is not yet pervasive in the off-grid solar industry; well-constructed equipment shelters. Whether it’s in the garage or a custom shelter, there will be insulation, temperature control, ventilation, protection from the ingress of pestilence, and protection from the elements.
Power Conditioning Equipment
The two main pieces of power conditioning equipment that are used in today’s remote solar electric power systems are the inverter and the charge controller, both of which have made tremendous strides in terms of economics and functionality.
Charge controllers are the pieces of equipment that harvest the energy coming in from the solar array and direct it towards the energy storage system. Given the same solar array, todays Maximum Power Point Tracking (MPPT) charge controllers can harvest about 20% more energy than the earlier generation of Pulse Width Modulation (PWM) charge controllers that were prevalent up until the early 2000’s. There are more charge controllers hitting the market every year.
Inverters are the components that pull DC electrical energy from the power system and convert it to the AC power for delivery to electrical loads. There are more and more battery-based inverters coming onto the market every year.
NewGrid maintains that this is largely a commodity market today. Sure it’s true that not all solar modules are manufactured equally. We will typically specify a mid range module with high value to the customer over a newly released high density solar module. We’ll always work with the customer to recommend what’s best.
Solar modules can be mounted in almost any configuration that the customer may want to see. Roof mounts, ground mounts, and shade canopies are a few scenarios that are always popular.