  |
The term renewable or green energy refers to any energy production system in which the energy is produced by a renewable source - solar, wind, water, or thermal - as opposed to fossil fuels or nuclear, which are consumed in the production of energy. The other main distinction is green energy generation does not result in harmful emissions unlike conventional fuel electricity generation which emits a variety of environmantal impacting gases. Within the solar renewable category, the term solar energy may refer to several different types of systems - photovoltaic, solar thermal, and passive solar, leading to a fair amount of confusion about exactly what one means when one refers to "solar."
APG SOLAR designs, sizes, installs & services solar photovoltaic systems that convert solar energy directly into electricity. If you are looking for systems that convert solar energy into heat (for example to heat your pool or your shower via the sun), or if you are looking for systems that collect solar energy throughout the day and release it as heat during the night (passive solar), we can design a system that will meet your needs.
There are two primary types of photovoltaic (or PV) systems: grid-tied systems and standalone systems – their applicability is determined by the type of power required. To put it simply, the function of grid-tied systems is to reduce your dependence on power from the electrical grid, and the objective of standalone systems is to be completely independent of the electrical grid. |
 |
Grid-tied systems are also referred to as utility-tied or parallel interactive systems. These systems use the power of the sun to generate electricity and immediately deploy that energy into your loads (appliances, etc). The beauty of these systems is the electrical “grid” of your utility company serves as a giant rechargeable battery bank.
 Grid-tied systems make use of net metering, meaning that the energy that is generated by your solar PV system is used to offset the electrical power that you require for your loads (appliances, etc.) from your utility company during the day. You pay only for your “net” usage of electricity from the utility company, so if your PV system generates more electricity than you can use your electrical meter will actually run backwards! The excess energy is credited back to your account by the utility provider (PG&E, SCE, or SDG&E) and is transmitted back into the utility grid. During dark hours or extended cloudy days the PV system is off line so your electrical needs are supplied by the utility grid.
Grid-tied systems are often combined with a time-of-use (TOU) rate schedule from the electric utility company. TOU billing offered by the utility company will credit power supplied from you at peak rates during the day when your system is generating more power than you consume. You will purchase power from the utility provider at (off peak) lower rates during the evening when your PV system is not generating power. Under the Public Utilities Regulatory Policy Act of 1978 (PURPA) and related legislation, U.S. utilities are required to purchase/credit the excess electricity generated by small power producers at regular retail rates. Other recent legislation that affirms California’s commitment to renewables is SB 1, CSI (California Solar Initiative) & SB 1078 Renewable Energy Portfolio (RPS). The CSI program has a total budget of $2.167 billion and is designed to encourage 1 million solar roofs by 2017. Senate Bill 1078 requires utility providers to increase their renewable energy portfolios to 20% in the next 10 years at a minimum of 1% per year. For more information on pro renewable energy legislation visit our Recent News page.
|
 |
Standalone or backup systems differ from grid-tied systems in that standalone systems are designed to store the energy they generate to be used at a later time. Typically the energy generated is stored in large battery banks giving standalone systems the ability to be completely independent of grid power.
Standalone systems are highly desirable in situations in which the utility grid is non-existent, unreliable, or too costly to connect due to distance. The following are some excellent applications for standalone solar systems:
- Commercial, Agricultural, or Residential energy users that can not afford to be without power or have critical loads
- Computer Universal Power Supply (UPS) and server backup systems
- Remote telecommunications and signaling systems
- Remote Cabins, Residences or Houseboats with no other convenient source of power
- Recreational vehicles (RV’s)
- Structures for which it is too expensive or too far to run utility power
Standalone systems have different design considerations than grid-tied systems. Standalone systems typically generate electricity at a lower DC voltage in order to provide a more appropriate match to battery voltages. As a result Standalone systems require special invertors and other additional equipment. In the event of extended cloudy days or low solar resource a back-up generator is recommended to be incorporated in order to guarantee power.
|
 |
Environment - Zero Emissions! Solar power produces no emissions unlike much of today's utility-supplied power. Once the system has paid for itself, which only takes a matter of years, decades of clean sustainable power will be enjoyed at no charge!
For every megawatt hour of solar electricity produced the Earth is spared the pollutants of over 1500 pounds of greenhouse gases like CO2, SO2, and NOx. Based on a small residential solar powered system (2.5kW PTC), that works out to almost 3 tons of greenhouse gas avoidance per year, or 75 tons over 25 years. Solar power is clean, abundant and fully renewable. It has been scientifically concluded that solar energy if captured completely for 1 hour could provide the world’s energy needs for 1 year.
- Economic Benefits - Because solar power reduces our dependence on the Utility companies it also reduces the need to build new conventional peaking power plants. There is approximately 5000 megawatts of energy potential currently available by utilizing the space on existing roofs of homes and small businesses in California. Turning even a small percentage of that potential into solar power generation would reduce or eliminate our need to build new power plants for many years to come.
- Complementary to Utility Power - Solar power correlates well with the daily load patterns of utilities because the power is available when it is needed most – during daylight hours when utilities are subject to their peak loads and more specifically late morning to early evening in summer months during high air conditioning loads.
- Low Operating Cost - Once installed photovoltaic cells operate continuously for decades with few ongoing operating costs. They generate electricity through a wide range of temperature and light conditions.
- Reliable - With no moving parts and a warranted life for PV panels of 20 to 25 years, solar PV systems are highly reliable and require little routine maintenance.
- Increased home value- According to the American Solar Energy Society a solar system increases a home value by $20,000 for each $1,000 in annual reduced operating costs.
- Hedge against rising utility prices - Once you have invested in your system, you will be producing power independently. You will then be less susceptible to increases in energy costs on the power you produce for the life of your system. Over the past 30 years, energy from power companies has increased an average of eight percent a year.
- Declining Rebates - sooner is better than later. Call us for actual rebate levels.
- Tax Credits -Up to 30% for businesses and the lesser of 30% or $2000 for residential systems.
|
|