Backup systems run homes, offices when electrical grid goes down

Ice storms, high winds and lightning all threaten the electrical grid and its continuous operation.

Ice storms, high winds and lightning all threaten the electrical grid and its continuous operation.

Backup systems are designed to sit quietly unnoticed until the need arises and then step in and run the essential home or business electrical equipment.

Generators come to mind when backup power is mentioned.

Be it PTO-driven, diesel, gasoline, propane or natural gas, there is a wide assortment of generator configurations to choose from.

The equipment type is based on the application.

Fuel supply would, of course, be the limiting factor to operating time of the generator.

Size of fuel tank or propane tank, and any possible disruption to natural gas supplies, has to be considered.

Duel fuel generators, natural gas and propane, would be able to offer extended run times, the propane backing up the natural gas system in the event it goes down.

However, if the generator is backup to a photovoltaic system, then the operating costs can be reduced by using free solar energy. The larger the solar array, the longer you can operate independently from the generator.

The backup system can be designed so it could run everything or only the most necessary items. Budget, as always is the determining factor.

One photovoltaic panel and a battery bank feeding an inverter sized for running the water pump, furnace, fridge and a few lights can be relatively inexpensive.

Multiple panels on a tracker, a large enough battery bank and inverter, to run the entire home for four or five days without interruption, would cost quite a bit more. It boils down to the owner’s requirements and needs of the home.

A farm or business would obviously involve a larger system with both a fuel-driven and alternate energy supply.

Larger installations could also make use of wind technology to aid in providing power when the grid is down.

This has to be an independent system that is isolated from the grid in order to protect the service people trying to restore power.

If the wind and solar are already grid-tied, therefore putting power into the electrical system, then by law and common sense it would have to shut down.

Certified disconnects that meet Alberta Utilities Commission approval would have to be installed to totally isolate the system so that the alternate energy source could be utilized by the farm or business and not endanger any repair personnel.

Alternatively grid-tied homes could install a UPS system (uninterrupted power supply) — this is simply a battery bank and inverter system that is tied into the homes electrical system so that in the event of a power outage lasting a few hours, the essential elements of the home would still run.

Essentials, such as furnace and water pump, so your home stays warm and you can still get water.

Isolation from the power grid during outages is ensured by using equipment certified for this function and as always must be installed by qualified electricians.

Lorne Oja is an energy consultant, power engineer and a partner in a company that installs solar panels, wind turbines and energy control products in Central Alberta. He built his first off-grid home in 2003 and is in the planning stage for his second. His column appears every second Friday in the Advocate. Contact him at: lorne@solartechnical.ca