Solar Basics
News headlines about rising energy costs and global warming, as well as national security concerns, are motivating many Americans to reduce their energy usage, buy high-mileage or hybrid cars, and install solar energy systems on their homes and businesses.
Solar energy can be used to generate heat or electricity and both are considered to be “Renewable Energy”. There are now 25 states that have implemented mandatory “Renewable Portfolio Standards” (RPS). The Arizona Corporation Commission has established that utility companies must generate 15% of their energy from renewable resources by 2025. Therefore, utility companies are offering significant rebates for home owners and businesses to install solar electricity or solar heating.
The current incentives in Arizona include:
- Federal tax credit of 30% for commercial (no cap) and $2000 cap for residential
- Arizona state tax credit of 10% for commercial ($25,000 cap), and 25% for residential ($1000 cap)
- Utility Rebates $2.50 - $3.00 per Watt
- Accelerated state and federal depreciation (5 year asset)
When all these incentives are combined, a significant amount of the system cost is covered (in many cases over 85% is covered for commercial).
Solar Water heater Example
The power of our sun can be used to generate energy in 2 different ways: 1) for heating and 2) for electricity. Each type requires a different technology. The sun can be used to thermally heat up water for your home. Think, for example, about the water that has been sitting in a garden hose in the sun and gets very hot! That is solar water heating. You can achieve the same thing by installing solar thermal collector panels on your roof. The sunshine heats up the water that is circulating through the panels and that heat is transfered to your water tank via a heat exchanger.
To use solar to produce electricity, you need to use photovoltaic principles. A solar panel (PV panel) is made of the natural element, silicon, which becomes charged electrically when subjected to sun light. This then becomes DC electricity and is measured in Watts. The DC electricity is converted to AC through an inverter and we can run our everyday appliances. With a “grid-tied” system, you use all of your solar electricity that is generated plus if you need additional electricity you can still get that seamlessly from the utility grid. However, if you ever have a situation where you are not using the solar electricity that you generate during the day (i.e. you are out of town on vacation), you can sell that electricity back to the utility company.
By living in Arizona, you have access to an abundance of renewable solar energy. The emissions avoided for every 1kW of solar installed are equivalent to those emitted by driving 1,900 miles/year in an average car. With a typical home installing 3kW - 5kW systems, they can do their part in helping to avoid greenhouse gases and also provide themselves with a fixed utility cost to hedge against rising energy costs from the utility companies.
Grid_tied_PV: How Does Grid Tied PV work
