Solar Battery Storage Blog

Learn about the advantages of solar with battery energy storage

October 28, 2019

How Much Solar Power Do You Need for Large Homes?

As a general rule, the larger the home, the greater your energy requirements become making the return on investment for installing solar photovoltaic (PV) panels even better than it is for smaller homes.

By installing PV panels, you can reduce your utility bills substantially – even if your family uses air-conditioning nonstop throughout the hottest months of the year. As an added benefit, going solar can also help shrink your carbon footprint, which tends to increase with home size.

But while these environmental and financial savings appear on Day 1, there are hard limits on how much you can cut your utility bills and carbon emissions by installing solar panels. 

The Limitations of Residential Solar PV Power

Solar is a very powerful technology turning sunshine into free electricity for your home. But it can’t automatically reduce your monthly utility bills to $0 for 2 important reasons:

  1. Even with plenty of roof space for PV panels, it is difficult to generate enough daytime solar electricity to cover 100% of your home’s energy requirements. This is especially true if you do actually use A/C consistently throughout the summer  due to the ever increasing utility rates and rules imposed.
  1. Equally important, solar panels underperform on cloudy days and stop working altogether at night. So it is beneficial to have some type of alternative energy source to power your home on overcast days and over night.

To overcome these challenges, homeowners have historically installed oversized PV systems and interconnected to the utility grid:

  • During the day, you use your solar electricity in real-time and feed any excess power into the grid. If you live in a market with net energy metering (NEM), your utility provider will compensate you for any unused solar power at a small cost.
  • Once the sun goes down – or when cloud cover prevents your panels from generating enough solar energy – your home supplements whatever electricity it needs from the utility grid.

The above is a very simple setup that generates measurable savings. But again, reaching $0 in monthly utility bills is unrealistic since you will always be partially dependent on the grid for power.

Worse still, this configuration doesn’t protect you from blackouts – even when the sun is shining. (Such as the planned Northern California PG&E outage in October 2019 or even SCE in Southern California.) That’s because most solar inverters come with a safety feature that turns the entire PV system off during outages. Known as “islanding,” this precaution is designed to prevent utility workers from touching “live” wires when repairing downed power lines. In the absence of islanding technology, solar panels that are still sending electricity into the grid pose a serious risk to utility service teams.

But if you live in a large home, there actually are ways to go solar and:

  • Eliminate utility bills completely
  • Reduce your carbon footprint to zero
  • Enjoy 24/7 protection from blackouts

Solar Power + On-Site Energy Storage

Using on-site batteries to store daytime solar power is becoming an increasingly popular option for many homeowners – especially those who live in larger residences. And that’s because with enough solar capacity and on-site storage, it’s possible to become a completely autonomous power producer capable of generating all the energy you need:

  • During the day, the bulk of this power comes from your PV panels, with any excess going into your batteries. If (and only if) the batteries are full, you can send any unused solar power into the grid – and receive compensation under California’s net energy metering program.
  • At night, 100% of the electricity you may require comes from your solar batteries.

If you want to explore this approach, there are 2 different options. You can install solar panels coupled with alternating current (AC) battery storage or direct current (DC) storage.

Let’s look at the pros and cons of each strategy.

Solar Power + AC Coupled Battery Storage

With this approach, battery storage is an add-on that can be installed at any time after your solar PV panels become operational. AC battery storage is basically an overflow reservoir for all the electricity that your PV panels generate.

If and when a power outage occurs, it only takes a few seconds for your electrical system to switch from the grid to stored solar energy in your on-site AC batteries.

In all other respects, however, you’re an independent power producer who no longer relies on the grid. Your home is a self-sustaining energy building that saves you money and reduces your carbon footprint to zero.

Solar Power + DC Coupled Battery Storage

With this approach, all of the energy generated from your PV panels goes into the DC battery first. Any excess solar power is then redirected to your home, the grid or both.

As such, this storage configuration should be completed at the same time as your solar panels. This tends to make DC battery storage cost more money upfront. The upside, however, is that there is essentially zero interruption if and when the grid goes down. You might notice the lights momentarily flicker as your home quickly switches from the grid to your on-site batteries. But that’s about it.

Although DC coupled battery storage solutions are more expensive to set up, they are the best option if 24/7, uninterrupted power is important to you and your family.

Our Approach to Solar Power and On-Site Storage

At Aeterna Energy, we believe in solar’s potential to deliver huge, long-term savings – which is why we invest so much time and effort into the PV components we install for our residential customers:

  • We typically use LG PV modules or similar that are in the top 3% of the best rated modules manufactured. The 19 to 21% efficiencies deliver  unmatched performance and resilience.
  • We use a range of different solar inverter technologies, although SMA America features prominently in many of our projects since these high performance inverters are “Made in America.”

When it comes to on-site storage, there are many different design choices to choose from. But we’re partial to Lithium Iron Phosphate (LiFePO4) batteries from Energport and Sonnen for several reasons:

  • Both come with tightly integrated software applications to ensure unparalleled system control
  • These lithium solar batteries are non-combustible, which is ideal for residential and commercial applications
  • They both come with 10-year, iron-clad warranties (e.g. 3,500+ total discharge cycles)

But simply selecting the right battery technology isn’t enough, which is why we also analyze areas on your property for optimal battery placement. The goal is to install batteries where they’ll be inconspicuous. 

That way, you’ll only see the savings.

And of course, you have all of this in writing before we even begin – complete with:

  • Expected monthly, annual and lifetime savings
  • Itemized costs – including parts and labor
  • Payback periods and ROIs 

Once you sign off, our team then handles every detail of your installation, from permitting to licensing to the actual installation itself. We can even help you apply for lucrative state and federal renewable energy incentives like:

  • California’s Net Energy Metering Program (NEM 2.0)

Many of these subsidies apply to both solar and storage, allowing you to reduce the total cost of your investment substantially. Equally important, nearly all of these subsidies have expiration schedules – during which – the payouts and benefits gradually get scaled back over time. 

Be a Part of the Solution

Going solar also allows you to be part of the green solution. With planned power outages increasing across California due to wildfire dangers, people are looking to stay connected while keeping the environment in mind. And, large homes will need more than one generator to stay running. If you're looking to stay connected AND stay green during power outages, solar with battery storage is your solution.

Want to Learn More about Solar Power for Large Homes?

Large homes cost a fortune to power, heat and cool. And with rising utility rates, these monthly costs will only increase over time.

Imagine you live in a large residence and spend $35,000 annually on electricity. With occasional utility rate hikes, you could easily end up paying close $1 million over the next 20 years for grid power.

Going solar can help reduce much of this spending. And it can also make your home more eco-friendly. But if you want to maximize your savings and reduce both your carbon footprint and bring the utility bills to zero, combining solar power with on-site storage is the single best long-term solution.

Even if you spend $400,000 to outfit your entire home with PV panels and on-site batteries, you’re still saving $600,000+ total over that same 20-year period, and your claiming your independence in an area of potential power grid failures or shutdowns.

Not even Wall Street can deliver returns like that. And it certainly can’t do so 100% risk-free.

To learn how our AC and DC solar batteries systems can help you extract the most value from your PV investment, schedule a free consultation with us today – either by filling out this online form or calling us directly at (805) 823-3232.

Contact Us Today!

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