How Solar Panels Are Installed and How They Generate Electricity

Solar panels convert sunlight into electricity that can power your home. The process involves installing panels, connecting them to an inverter, and integrating the system with your home’s electrical system and the utility grid.

Step 1: Evaluate the roof

Determine whether the roof receives sufficient sunlight.
Check the roof’s condition, age, orientation, and structural strength.
Identify trees or buildings that create shade.
Calculate how many panels are needed based on electricity consumption.

Step 2: Obtain permits and approvals

Prepare an electrical and structural design.
Obtain required city building and electrical permits.
Apply for utility interconnection approval.

Step 3: Install mounting equipment

Attach mounting brackets securely to the roof structure.
Install metal rails or other approved mounting hardware.
Seal roof penetrations to prevent water leaks.

Step 4: Install solar panels

Secure panels to the mounting system.
Connect panels using electrical cables and approved connectors.
Install required grounding, bonding, and electrical safety equipment.

Step 5: Install an inverter

Solar panels produce direct-current electricity (DC).
Most household appliances use alternating-current electricity (AC).
An inverter converts DC electricity into usable AC electricity.

Step 6: Connect to the electrical system

Connect the solar system to the home’s electrical panel using approved equipment.
Install required disconnects and monitoring equipment.
Connect the system to the utility grid through an approved interconnection.

Step 7: Inspect and activate

The city or local authority inspects the installation.
The utility grants permission to operate.
The installer commissions and activates the system.

A typical residential installation takes one to three days of physical work, although permitting, utility approval, and scheduling can take several weeks or longer.

How Solar Panels Generate Electricity

Solar panels generate electricity through a process called the photovoltaic effect.

Here’s what happens:

1. Sunlight strikes the panels.

Solar panels contain photovoltaic cells, usually made from silicon.

2. Sunlight creates an electrical current.

Photons from sunlight transfer energy to electrons in the silicon cells. The structure of the cells causes an electrical current to flow through an external circuit.

3. Electricity travels to an inverter.

The panels produce DC electricity, which the inverter converts into AC electricity.

4. Electricity powers your home.

The electricity can immediately operate appliances, lighting, computers, air conditioning, and other equipment.

5. Excess electricity goes somewhere else.

When the panels generate more electricity than your home consumes, the excess can:

Charge a home battery.
Flow into the electrical grid if permitted.
Be curtailed if it cannot be used, stored, or exported.

At night, the home draws electricity from a battery or the utility grid.

How Much Electricity Can Solar Panels Produce?

Consider a typical residential installation in San Diego, California.

Suppose you install:

15 solar panels
Each rated at 400 watts
Total system capacity: 6,000 watts, or 6 kilowatts (kW)

Estimated electricity production:

Period	Electricity generated
One sunny day	25–35 kWh
One month	750–1,050 kWh
One year	9,000–12,600 kWh

How Long Do Solar Panels Last?

Component	Typical lifespan
Solar panels	25–35 years or longer
String inverter	10–15 years
Microinverters	Often 20–25 years
Home battery	Approximately 10–15 years
Mounting hardware	Often 25 years or longer

How Much Does a Solar System Cost?

ystem	Approximate installed cost
4 kW	$10,000–$14,000
6 kW	$15,000–$21,000
8 kW	$20,000–$28,000
10 kW	$25,000–$35,000
Battery addition	$9,000–$16,000

Actual prices depend on equipment, installation complexity, contractor pricing, and electrical upgrades. Available incentives and tax credits should be verified under current law.

Installing Solar Panels on a Building in Imperial Beach, California

Permits, installation, costs, SDG&E connection, and electricity savings — October 2026

Installing solar panels in Imperial Beach involves two separate approval processes: a building permit from the City of Imperial Beach and permission to connect to the electrical grid from SDG&E.

The process is relatively straightforward for a residential building, but commercial buildings, apartments, and larger installations may require additional engineering and approvals.

1. Evaluate the Building

Before installing solar panels, determine whether the building is suitable.

An installer should evaluate:

Roof condition: Ideally, the roof should have at least 15–20 years of useful life remaining.
Roof structure: It must support the panels and mounting equipment.
Available space: Each modern 400–450-watt panel requires roughly 20–23 square feet, before allowing for access pathways and setbacks.
Sun exposure: South-facing roofs generally provide excellent production, although east- and west-facing installations can also work well.
Electrical system: Determine whether the existing electrical panel can accommodate solar.
Electricity consumption: Review 12 months of SDG&E bills to determine the appropriate system size.

Special consideration for Imperial Beach: Because of the coastal environment, mounting hardware and electrical components should be selected for resistance to salt-air corrosion. Wind exposure, roof waterproofing, and any applicable coastal-development requirements should also be evaluated.

2. Obtain a Building Permit From Imperial Beach

The City of Imperial Beach Building Division handles solar installation permits.

City of Imperial Beach Building Division

825 Imperial Beach Boulevard
Imperial Beach, CA 91932

⁠Official Building Permits and Inspections Website

The city uses an online Citizen Self-Service permitting system.

Documents typically required

Building permit application.
Site plan showing the building and solar-panel locations.
Roof layout showing panel placement and required access pathways.
Structural calculations or documentation establishing adequate roof support.
Electrical single-line diagram.
Solar panel and inverter specifications.
Electrical panel information.
Required safety and equipment labeling information.

The city publishes specific solar permitting documents, including a photovoltaic eligibility checklist, structural criteria, standard electrical plans, and inspection guidance for systems of 10 kW or less.

⁠Imperial Beach Solar Permit Forms and Checklists

How long does permitting take?

For planning purposes:

Activity	Estimated time
Building evaluation	1–5 days
Engineering and plans	3–10 days
City permit review	Several days to several weeks
Physical installation	1–5 days
City inspection	Several days, depending on scheduling
SDG&E final authorization	Several days to several weeks

These are planning estimates, not guaranteed city processing times.

Permit costs

Imperial Beach’s exact current permit charges should be confirmed with the Building Division.

For preliminary budgeting, allow approximately $200–$1,000 for ordinary residential permit and plan-review expenses, although actual charges may differ.

Commercial installations and projects requiring structural modifications may cost more.

3. Determine the Size of the Solar Installation

The appropriate size depends on the building’s electricity consumption.

For example:

Building type	Illustrative solar capacity	Number of 400W panels
Small residence	4 kW	10
Average residence	6 kW	15
Large residence	10 kW	25
Small commercial building	20 kW	50
Medium commercial building	50 kW	125
Large commercial building	100 kW	250

These are examples, not recommendations for a specific property.

A 20 kW commercial installation might generate approximately 30,000–36,000 kWh annually under favorable Southern California conditions.

Actual production depends on orientation, shading, equipment, and other site-specific factors.

How Much Will Solar Installation Cost?

The following are preliminary 2026 budgeting ranges for professionally installed systems in Southern California.

Solar capacity	Estimated installed cost
4 kW	$10,000–$14,000
6 kW	$15,000–$21,000
10 kW	$24,000–$34,000
20 kW	$40,000–$65,000
50 kW	$90,000–$150,000
100 kW	$160,000–$280,000

These are illustrative estimates rather than verified local contractor quotes. Roof repairs, electrical upgrades, engineering, battery storage, and unusual installation conditions can increase costs.

Important tax-credit change: The federal residential clean energy tax credit under Section 25D ended for qualifying expenditures after December 31, 2025. A new homeowner-installed system completed in 2026 generally does not qualify for that former 30% credit. Commercial projects have different tax rules and may qualify for incentives depending on project timing, ownership, and other requirements.

Connecting the Solar System to SDG&E

his is one of the most important parts of the project.

A solar installation cannot simply be connected to SDG&E’s power lines without authorization.

Step 1: Submit an interconnection application

SDG&E requires a solar interconnection application through its Distribution Interconnection Information System (DIIS).

The application generally includes:

Customer and service account information.
Solar system capacity.
Solar equipment specifications.
Electrical single-line diagram.
Inverter information.
Battery information, if applicable.

SDG&E reviews the proposed system for compatibility with its electrical distribution network.

The utility says online applications are generally processed within 30 days, with an average initial processing time of less than five business days. More complex commercial projects can require additional review.

Step 2: Receive authorization to proceed

SDG&E reviews the initial application and notifies the applicant or contractor when the project can proceed.

This is separate from the city’s building permit.

Step 3: Install the solar equipment

The contractor installs:

Solar panels and mounting hardware.
DC wiring or microinverter connections.
Inverter equipment.
Required electrical disconnects.
Electrical connections to the building.
Monitoring and safety equipment.

The installation must comply with applicable electrical and building codes.

Step 4: Pass the city inspection

Imperial Beach’s Building Division verifies that the installation complies with approved plans and applicable safety requirements.

Inspection requests can be made through the city’s permitting portal or inspection hotline:

619-628-1360

Step 5: Obtain SDG&E Permission to Operate

After the required inspections and interconnection documentation are complete, SDG&E must issue its final Permission to Operate (PTO).

Do not operate the system in parallel with the utility grid before receiving the required authorization.

How SDG&E Credits Solar Electricity

New solar customers generally participate in California’s Solar Billing Plan, also known as the Net Billing Tariff.

The basic process works like this:

During the day:

Solar panels generate electricity.
The building uses the solar electricity first.
Excess electricity can be exported to SDG&E.

At night:

The building purchases electricity from SDG&E unless a battery supplies the power.

Under the Solar Billing Plan, exported electricity is generally credited according to time-varying export values rather than the full retail electricity price.

Consequently, using solar electricity directly in the building is usually more valuable than exporting it.

This is especially important for commercial buildings that consume significant electricity during daylight hours.

Should You Install Batteries?

A battery is optional for most grid-connected solar systems.

However, batteries can be useful because they allow electricity generated during the day to be used in the evening.