System Size
Solar power systems are measured in kilowatts. Your electric usage is measured in kilowatt-hours. In Ohio and surrounding areas, 1 kilowatt of solar array produces approximately 95 kilowatt-hours per month, or about 1,100 kWh per year. In 2008, the average annual electricity consumption for a U.S. residential utility customer was 11,040 kWh, an average of 920 kilowatt-hours (kWh) per month. So a 10-12kW solar energy system could provide most of the electrical power for an average home.

A rooftop solar array on a Cincinnati commercial building.

Utility Bill
Your electric utility bill reflects your rate schedule, which may include charges for kilowatt hours and “demand.” A “demand charge” is often included on utility bills for commercial enterprises—it is an additional charge for the peak amount of electricity you use. Most solar power systems are designed to reduce, but not eliminate, your electric bill, and depending on your demand profile, may or may not reduce demand charges.

Solar Finance
Designing an effective solar system is not only a technical process, but involves financial design as well. The economic analysis of a renewable energy plant is complex. It must factor in the following variables:

• The project site’s solar potential
• The available state and federal subsidies
• Available Power Purchase Agreements (PPAs)
• The current and future cost of utility-supplied electricity
• The tax rate and projected tax liability of the business
• The amount of power used by the facility and the rate structures available
• The cost of borrowed capital

Each business has its own unique needs, financial situation and tax circumstances. Our process will take your specific needs into account, and we will work with your financial team and advisors to maximize the ROI of your solar project.

Typical System Sizes, Energy Output and System Prices
Third Sun Solar can specify a system to fit every business and budget. We work with each customer to determine the best-sized system based on their unique goals. We will also perform financial analysis to determine your best ROI.

Below are examples of three sizes of systems, their estimated performance, the space required, and the net cost after incentives. Larger, smaller and other sized systems are available.

• Shading and specific site variables may affect monthly output
• Roof square footage estimates are based on SunPower solar modules and T-10 racking
• Net cost based on full-service installation on typical site—this net cost calculation includes 30% Federal Tax Credit, NPV-adjusted depreciation and Ohio Energy Office Rebate (only available for customers of an Ohio Public Utility), and assumes a 30% tax rate for the business. Your specific tax status as well as custom sizing will affect the net cost. Third Sun Solar will present you with an accurate proposal for your specific project.

Placement of Solar panels
While each project is different, we often find that flat-roof-mounted solar energy system is the most cost-effective option available to businesses.

We use a “ballasted-non penetrating” racking system to deploy solar over membrane roofs. This type of racking system allows you to install solar without physically attaching the array to the building. It is held in place by the weight of the system plus additional ballast as required to meet your site’s local conditions and building code requirements.

Alternatively, panels can be attached to pitched roofs; fastened awning-style on the façade of a building; integrated into building features such as entrance canopies; or installed on ground mounts or as parking lot shade structures.

Shade and orientation are very important for your system to perform at its maximum potential. Your solar panels must have unobstructed southern exposure (or approximately southern). Orientation to the east or west is possible, but will reduce performance. The solar system site must be clear of trees, buildings, or other potential shading obstructions.

Batteries and Backup Power
With an on-grid system, utility power outages still result in a power outage for the renewable power system owner. This is because an on-grid system is required by regulation to shut down when there is a power outage, eliminating safety concerns for utility workers who may be trying to restore grid power.

It is possible for a battery bank to be added to produce backup power in times when there is a utility power outage, but this is costly and is often better addressed with an appropriate generator system.

Third Sun Solar has installed many off-grid and grid-tied systems with battery backup or generators. We’ll be happy to discuss the specific pros and cons of adding backup capacity to your system.