Off-Grid Solar: Navigating the Decision for Energy Independence

By   |     |  Clean Power Guide

Do you ever wonder about the possibility of generating your own power independently for your home or small business? Would you love to take your life off the grid using solar? Let’s talk possibilities.

I want to start with the fact that installing an array of photovoltaic (PV) solar electricity-producing panels is the simplest maintenance-free way to produce your own electrical power. Installing PV solar to produce power on site makes sense as a financial investment, in addition to the environmental benefit. (I recommend using the NYSERDA list of PV installers.)

The most common PV solar systems are grid connected. This means the power produced feeds into the electrical power grid owned and managed by your local power company. This is an elegant way to produce electricity; you sell electricity to the power company, and they sell it back to you as you need it.

My family’s recently installed PV system has dropped our utility payments from bills that averaged $400/month to about $20/month for usage. This includes charging two electric vehicles onsite, equating to an additional $300/month savings in gas.

What would be the additional cost for storing my own power on site, to be more self-reliant?

It depends on how much energy you use and how much you are willing to conserve. For those that want to achieve 100 percent energy self-reliant living, an option is to install off-grid solar with battery storage. However, the larger battery bank necessary to be completely off grid at all times is impractical for most people, and New York’s incentives for solar do not apply to off-grid systems.

There is a system that is in the sweet spot, between the completely off-grid and the completely grid-tied models, and that uses the benefits of both. This is the grid-dependent hybrid system, which combines solar, battery power, and controls that can flexibly draw the power from the grid or the battery.

Today, many companies are producing modular battery power bank backup systems to go along with solar systems. They offer convenient, easy-to-use apps with settings to optimize when to power from your batteries or from the grid to save you money. If a storm is coming, it can top off the battery. When the power grid goes down, these systems automatically kick in, off grid.

How many battery units do I need? 

A larger generator will fully power your house until the propane runs out. By comparison, a 40 kWh battery storage system will get you maybe several days of powering your fridge in a typical leaky house. If the sun is shining and you have a super-insulated Passive House, or a zero-energy house, then definitely the solar with battery backup is an alternative to that generator, and definitely prepare for it. The addition of batteries increases the overall system cost by about 40 percent plus the cost of the small heated and/or insulated space for the batteries.

I design innovative, energy-efficient buildings with solar. Here are some basic recommendations on how to make sure your building is green overall.

  1. Insulate better than code.
  2. Install the most efficient windows. 
  3. Air seal.
  4. Install an energy-recovery ventilator.
  5. Address moisture up front.
  6. Do not use gas-run equipment.

Green design can also mean a better house layout, better light, less toxicity, and, in the end, higher value at resale.

Richard Miller is a Woodstock-based architect specializing in residential and commercial, green architectural design for new construction, renovations, and historic rehabilitation since 1990.

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