Why You Need Solar Battery Power For Your Home


Solar panels are not new. But with solar power storage becoming mainstream — especially since Tesla released its Powerwall last year — it is more possible than ever to completely generate your own electricity from the sun.

And if you’re Australian, solar power is already mainstream. At least a quarter of homes in Australia have solar power.

If you’re considering a solar system for your home, then keep reading to find out what options you have with the latest solar battery technology.

Why even consider an alternative energy solution

Let’s get one thing straight.

Solar power is not the perfect alternative to fossil fuels.

At least, not if you need to store it with batteries.

As I’ll discuss below, solar batteries contain materials that are non-renewable.

And depending on the battery technology, some resources are less abundant than others. Which brings into question the scalability of these technologies.

And the cost of mining these resources could potentially be as damaging as fossil fuels.

But as of right now, there is no alternative energy solution that is 100% renewable with no impact to the environment.

And the bottom line is, fossil fuels is a finite resource that we can’t count on forever.

With the world’s population exploding, and third world countries becoming industrialized, we’re using up whatever resources we have left faster and faster.

There may be enough to last our lifetimes, but it’s unlikely to last for our children and grandchildren.

So we have to be open to all alternative options.

And in the case of solar power with storage, we have some feasible options for individual homeowners.

Even better when we can this kind of alternative energy to rebuild communities when standard options have failed, as in the case of Tesla using its solar panels and batteries to bring back much needed electricity to Puerto Rico.

Battery solutions today

Just like all technology, as it becomes more mainstream, the quality increases and the cost to manufacture comes down.

And solar batteries are no different. Prices have fallen 24% even since 2016.

So it’s more possible than ever to to own a complete solar system with storage.

Types of battery storage

There are three main types of solar batteries.

Lead acid

The technology that has been used for decades is lead acid. It has a short lifespan but is cheaper than the other types out on the market today.


A saltwater battery is a new type of technology which doesn’t contain any toxic or flammable materials. It uses a saline solution as its electrolyte.

Aquion Energy is the first company that has developed a saltwater battery for solar use.

The advantage compared to lithium ion is that the battery capacity doesn’t fall with multiple cycles of charge and depletion.

However, the power output is lower.

Lithium Ion

By far the most popular option is lithium ion, which is the same technology used in our cell phones and laptops. These batteries are smaller and more lightweight than lead acid, with longer lifespan, but they also cost more.

The main disadvantage of lithium ion is that its capacity decreases with each charge cycle. And capacity decreases even faster with higher charge rates and higher temperature.

For example, over time, the capacity of a Tesla Powerwall decreases significantly, if its warranty is any indication. The warranty 5 years into ownership drops from 5.44 kwh to 3.8 kwh, a 30% drop.

(courtesy of Aquion Energy)

Zinc Bromide

This is the newest technology on the market. The interesting thing about zinc bromide batteries is that the energy storage capacity never declines. And you can drain it 100% and it won’t suffer any consequences. It’s also non-flammable and recyclable.

However, it doesn’t match lithium ion in life cycle, efficiency, or power output.

RedFlow Technologies in Australia is the first company to deliver a commercially-available zinc bromide solar battery.

How much in energy cost could you save?

This depends on what kind of system you implement.

Fully off-grid

If you decide to go completely off-grid, that means you’re not connected to the utility company as a backup.

So you would need enough batteries to store the excess energy that your solar panels generate during the day to be able to use it at night when your panels are generating nothing.

And you would also need to account for extra storage in the event that you have a stretch of cloudy days are you’re not producing enough excess energy to store.

Depending on how much energy you use and how much direct sunlight you get, you might need anywhere from 17-42 panels. The average home uses 900kwh of electricity per month, or almost 11,000kwh per year.

Then you would also need batteries to store the excess power. For example, you would need two Tesla’s Powerwall units (total usable capacity 27kwh) for backup.

In this scenario, you would obviously not be paying for any energy usage from a utility company.

On-grid, mostly using solar power

Another option is that you can stay connected to the utility company but you still have the solar panels and batteries to mostly or exclusively use the solar power that you generate.

The good news is, if your system is generating excess power, and your batteries are topped off, you can sell it back to the utility company.

These rates aren’t anything to write home about (probably a few cents per kwh in the Bay Area), but you can feel good about contributing energy to the utility company’s customers.

Depending on how much electricity your system produces, you could theoretically not use any energy from the grid and even make a small amount from selling the excess power.

On grid, small battery

A third option is to stay connected to the grid and only maintain a small enough battery to reduce your total energy usage from the utility company.

The solar panels would power any usage during the day and top off your battery. Then the battery would be just big enough to give you enough power during peak evening hours.

It would be reasonable to significantly reduce your utility grid consumption and cost with a bare-minimum type of solar system.

Is it worth having a solar system in a cloudy climate?

Solar panels don’t produce as much electricity in cloudy weather compared to a clear, sunny day.

So is a solar system still worth having?

The short answer: yes.

SolarCity has done studies in the cloudiest climates and have determined that total annual output can still be quite significant.

In fact, a 6-kw system can produce over 80% of a household’s annual electricity usage.

In some cases, partial clouds can generate more electricity than a sunny day because of the “edge of cloud” effect. The sun hits the edge of a cloud and intensifies the sunlight, boosting the power generation.

This is a similar effect to sunlight reflecting off snow or water.

And using solar batteries to store enough power to accommodate the cloudy days should dispel any remaining concerns.

What the future holds for battery technology


Could solar batteries go mainstream? Many technology experts say yes.

But lithium ion batteries may not be the type to scale.

Lithium and cobalt, the two metal components in these batteries, are tight on supply. Cobalt even more so than lithium.

Gel zinc bromide technology

In response to some of the limitations of lithium ion and existing zinc bromide technologies, Australian-based company Gelion Technologies has developed a zinc bromide battery using gel instead of a liquid based electrolyte.

Essentially, the gel moves the electron charges faster.

Which means that a solar battery with this technology can charge in minutes.

Gelion also says it beats lithium ion in efficiency, lifespan, and cost.

However, this product isn’t yet available in the market.

But what’s exciting about this is that the technology can be incorporated into building materials.

In other words, your walls and your roof are batteries storing electricity.

Zinc and Bromide also have more supply and are cheaper materials than lithium and cobalt and would be able to scale easier.

Is this a perfect replacement for fossil fuels?

No, it’s not.

While producing electricity from sunlight IS renewable, the manufacture of batteries uses resources that are not renewable.

Namely, lithium, cobalt, zinc, and bromide.

Even salt is non-renewable (at least at the rate that humans consume it), but it is one of the world’s most abundant resources.

But while it’s not perfect, solar power with batteries does give us options.

It helps us be less reliant on public utility companies that may have frequent blackouts and brownouts.

And we can each make the choices we feel are best for ourselves and for the greater community.


Guide to SF Bay Area Residential Energy Incentives (as of March 2018)

*We will continue to add to this list as we come across more programs.


Unfortunately, many energy incentives have run through their allotted funding and the programs have ended.

Here are some programs that San Francisco Bay Area residents can still take advantage of.


Federal Investment Tax Credit

This program was extended in 2015 through 2021. As of 2018, a residential customer can still deduct  30% of the cost of installing a solar system from their income taxes.



MCE (Marin County)

Any excess electricity generated from renewable energy can credit a Marin County resident $0.01/kwh on their electric bill.


Bay Area Energy Upgrade

Residents of the nine counties in the Bay Area are eligible to receive rebates based on energy upgrades. You must be a PG&E customer and own a single family home.

You can either do a basic upgrade (based on a list of options and receive a set rebate based on which upgrades you selected) or an advanced upgrade.

With the advanced upgrade, your home is assessed and assigned an energy score. You will receive a rebate based on a percentage of energy cost saved.


Silicon Valley Clean Energy

Residents of the South Bay communities (Campbell, Cupertino, Gilroy, Los Altos, Los Altos Hills, Los Gatos, Monte Sereno, Morgan Hill, Mountain View, Saratoga, Sunnyvale, Unincorporated Santa Clara County) can sell excess energy back to this organization at full retail rate.


East Bay MUD

Residents who receive water from East Bay MUD are eligible for water conservation rebates for lawn conversions and irrigation equipment.


Property Assessed Clean Energy (PACE) – individual lenders that service different counties and cities

PACE provides loans for green home upgrades that allow you to defer the upfront costs. The costs are then added to your property tax bill.



San Francisco GoSolarSF Incentive

San Francisco residents can receive rebates of $300/kW up to 4.0 kW per meter.

Note: This program is being phased out with rebates being reduced every year.


Palo Alto CLEAN

If you have a solar system in Palo Alto, you can sell solar energy back to the city for 16.5 cents per kilowatt hour for a 15-, 20- or 25-year contract term.


Palo Alto Smart Energy Program

This program gives rebates for insulation, whole house fans, water heaters, pool pumps, and smart power strips.


Silicon Valley Power (solar program ending 6/30/18)

Santa Clara residents can get a variety of rebates: solar (which ends 6/30/18), attic insulation, ceiling fan, electric clothes dryer, electric heat pump water heater, and pool pump rebates.




PG&E will give residential homeowners rebates for installing Energy Star smart thermostats, gas storage water heaters, and electric heat pump storage water heater.

ROI For a LEED-Certified Building in the SF Bay Area: Do the Costs Pencil Out?

If you’re considering pursuing a LEED certification for your new building project in the San Francisco Bay Area, keep reading. In this post we’re going to examine a simple fictitious building scenario and see if the ROI in pursuing LEED certification makes business sense.

We will assume that this is a new construction of a 100,000 square foot, multi-story office building pursuing the Gold level certification.


Let’s Start With the Costs of Green Building

You will have to hire specialists

No doubt about it: to have your building be LEED certified, there must be strict adherence to the rules that you will need to meet.

Which means that you will have to hire experts who are familiar with these rules. As of this writing, the document that describes the LEED point system for Building Construction + Design is 161 pages long.


Your architect should understand these requirements inside and out. An example of the requirements that will be incorporated into the design:

  • The maximum distance of a functional entrance to be located from public transportation
  • Incorporating a bicycle network into the design
  • How much of the natural surrounding area that need to be conserved or restored
  • Lighting design to reduce light pollution for wildlife and people
  • Water efficiency thresholds
  • Waste management and reducing impact to the environment

And many more.


The contractor that constructs your building will also need to be knowledgeable of the LEED requirements, as they will be sourcing the materials that will meet energy thresholds, managing distribution of waste generated during the construction period and performing construction work to minimize the impact to surrounding habitats.

Also, throughout the construction process, they should be aware of what is and is not acceptable as far as impact to the surrounding areas.

Sustainability Managers:

In many cases, contractors hire Sustainability Managers — experts in LEED certification — just to make sure that everything on the list is being checked off.

Sustainability Managers will also advise the estimators when costing out materials and help train the field crews in green building practices.

All of this expert knowledge and experience comes at a higher cost.


Each level of LEED certification requires a range of documentation specific to the desired rating. Whether it’s your Architect or General Contractor who manages the documentation process, both  will need a team well-versed in gathering information and data relevant to the project.

The higher costs of material

Now in the case of materials, the total cost of materials may or may not be higher for LEED buildings.

While you may need to install costlier high-performance windows, you may be able to recover that by replacing hard surface areas with a lower-cost option.

Also, building materials are becoming more advanced and cheaper to manufacture.

So it’s possible to select materials that meet LEED requirements and cut back on non-essential materials to balance the total costs.

So, are construction costs higher for LEED certification?

In this report, the World Building Council found that green buildings cost from 0% to 12.5% higher. However, the 12.5% building belonged to an ambitious zero-carbon project.

So for our fictitious building, let’s assume that construction costs are 5% higher in pursuit of LEED certification.

Energy modeling services and other fees

Depending on your situation, you might also need to factor in the cost of energy modeling. Energy modeling could cost up to $20,000 for a 150,000 sq ft building.

Fees to the U.S. Green Building Council could also be up to $10,000 for the same size building.


Let’s assume for our fictitious building, all construction costs (including designer, contractor, materials, fees)

Non-LEED = $330 per square foot

LEED = $346.50 per square foot (5% increase)


Now Let’s Consider the Savings

Government incentives

With LEED certification, your building permits are approved faster, possibly a full 12-18 months faster. The fees could also be waived.

This could lead to significant savings with loan payments.

Or you could be allowed to build more square footage or more stories, allowing for more tenant space to rent out.

For actual tax credits, you could receive a deduction of up to $1.80 per square foot, according to IRS Section 179D.

Department of Energy also has this tax credit schedule. (This applies to New Mexico but I’ll assume CA is the same for our fictitious building example.)

And there are many other grants and incentives available at the national, state, and local level.


So for our building example:

Department of Energy Tax Credit

Non-LEED = $0

LEED Gold = $177,500

Loan payment savings with faster permitting

(assuming $25M loan at 4.5% interest rate over 30 years, interest-only payment)

Non-LEED = $0

LEED = $1,125,000


Decrease in utility and maintenance costs

LEED design takes advantage of natural light and warmth. Building materials and airtight construction keeps extreme weather out. This reduces the need to artificially heat and cool the building, saving in energy usage.

Large and expensive ventilation equipment are also not needed when smaller ones will get the job done.

And if you select more durable and sustainable building materials, they will last longer and require less repair and replacement over time.

For a new green building, you would save on average 15% on operating costs over 5 years. And your building value would be up 7% over a non-green building.


Our building utility and maintenance costs:

Non-LEED = $8 per occupied square foot

LEED = $6.80 per occupied square foot (15% decrease)


Higher-than-average rent

With lower utility costs, cleaner indoor air, and more productive employees, companies are choosing to lease LEED-certified buildings because this also reduces operating costs for them.

Your LEED certified building would command an average of 3.7% more in rent and have 4% higher occupancy rates.

In fact, 5.6% of tenants are more likely to renew because of its LEED status.


For our building:


Non-LEED = $70/square foot

LEED = $72.59/square foot (3.7% increase)


Non-LEED = 75%

LEED = 78% (4% increase)


Does the Math Work? The Verdict

Years to break even:

Non-LEED = 7.5 years

LEED = 6.9 years

ROI after 10 years:

Non-LEED = $11.5M

LEED = $16M

In our simplified scenario, LEED certification does, in fact, make good business sense. You will, of course, need to evaluate your own situation. But feel free to download our calculator and plug in your own numbers.


Let us know in the comments below what you come up with! Does LEED certification give you a bigger ROI?