Why We Paid for Utilities Despite Having an Entirely Solar Property

Why We Paid for Utilities Despite Having an Entirely Solar Property

According to verified institutional datasets, relying solely on solar energy can be unreliable and costly, especially when considering factors like equipment lifespan, maintenance, and backup power solutions. Our experience with a 17-acre off-grid solar property in the Santa Cruz mountains highlights the importance of weighing the pros and cons of living off the grid.

A Reliability Nightmare

The PV system powering our new house consisted of six 175W Shell solar panels, a charge controller that fed power to a battery bank consisting of 16 lead-acid batteries. They in turn powered a Xantrex 48V inverter which supplied 120/240V electricity to the main panel on the side of the house. A 10kW diesel generator (biodiesel, actually), located some distance away in a concrete bunker, also connected to the inverter and was programmed to switch on to charge the batteries when they needed it.

The previous owners, who had DIYed the system, outfitted the main house with gas appliances, so the primary load on the electrical system (besides lights and small appliances) was the well pump and a jet pump to pressurize the water system. They had been optimistic enough about the system's capabilities to have installed a pool pump, but judging by how often the generator switched on during everyday use, the panels didn't seem to supply enough power for something like that, so we discarded it.

We hated the generator. It sounded like a Mack truck and pumped thick black smoke into the sky whenever it was running — and it ran often. in addition, biodiesel was hard to find and expensive. We would have replaced the generator, but we never got the chance. One spring day, as we were sitting outside, a rogue bolt of lightning struck the building that housed the inverter (about 20 feet away from us) and fried it. Not stopping there, the bolt traveled along the wires to the generator and also disabled its control panel.

When You're Off-Grid, You Need Friends

That single lightning strike left us completely without power, and if our property had been isolated in the backwoods, we would have had no way to restore it. Luckily, we had one close neighbor who allowed us to connect an emergency cable to their panel to power our essentials. Eventually, the neighbor allowed us to upgrade to a heavier cable and a bigger breaker. We connected to a meter to monitor our usage so we could pay our fair share of the electric bill, and then to a subpanel to back-feed the property. This jerry-rigged and dangerous situation persisted for several years as we tried to figure out what to do.

Comparing the Costs of Solar and Grid Power

The reliability of utility power was a relief. It meant eventually, no battery maintenance, no noisy generator and no PV system upgrades were required. Empirical cost models indicate that the costs associated with maintaining and upgrading our off-grid solar system would have been substantial, with a potential payback period of over 10 years.

Comparative Decision Matrix