Paris Pv Presentation  Part1
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Paris Pv Presentation Part1



Introduction to photo voltaic installation part one of two by Frederick Paris from Paris Consulting Associates

Introduction to photo voltaic installation part one of two by Frederick Paris from Paris Consulting Associates



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Paris Pv Presentation  Part1 Paris Pv Presentation Part1 Document Transcript

  • Solar Power – Part of the Green Energy Solution in Massachusetts Fred Paris for: Co-op Power Sustainable Energy Summit UMass Amherst May 1,2009 Interactive (Grid-Tied) Solar Overview An interactive, or what is sometimes called grid-tied, photovoltaic solar system can be designed to provide as little or as much of the electricity a home requires. System sizes can range from small starter systems to larger arrays sized to eliminate a home’s electric bill. Once the system is installed a homeowner could expect to gain solar energy for 20 years or more. There are many examples of systems 25 years old or more still performing at more than 80% of their original energy output. Interactive systems are for homes that are connected to a public utility. There are two significant advantages to interactive systems; first, the occupants of the home need never worry about where their electricity is coming from. If the solar resource is not available or if the electrical load is higher than the array can support, the utility will supply up to 100% of their energy load. Second, interactive systems do not require batteries. Batteries typically add thousands of dollars in costs and require knowledgeable and frequent maintenance. Fred Paris Co-op Power Sustainable Energy Summit 2009 Page 1 of 9
  • How Solar Works How Solar When a home has an interactive solar PV system, the electrical devices in a home Works will use the owner’s solar power first and then look to the utility to cover the additional power required. That makes it easy to understand that the larger the PV system the less energy a homeowner will buy from the utility, and the lower their monthly bill will be. It also explains how a homeowner can start with a small system and incrementally add capacity as they watch their energy bill decline. The other significant benefit of an interactive PV system is net-metering. Under net- metering arrangements - available anywhere in Massachusetts – if a home’s PV system is generating more energy that is being used, the energy goes back to the utility for full retail credit. So, if you are paying 18¢ a kilowatt-hour (kWh) the utility will pay you the full 18¢ for every kWh you send back. Think about those long hot summer days when the house is empty – it may all go back to the utility. There are four key elements to a solar photovoltaic system: the solar modules, the inverters, the production meter, and the typical electrical switches and wiring associated with any electrical system. The Solar When sunlight strikes a solar module, the characteristics of silicone layered with Modules other materials causes electrons to start flowing. Get enough electrons moving and you create electrical current. Give that current a pathway to follow, and then join multiple modules and pathways together, and you can design and create systems of any size. A small starter system may only have a few solar modules while some of the largest commercial systems cover acres of land. Multiple solar modules wired together form a solar array. An advantage of residential and commercial arrays is that they can be added to incrementally without discarding the components installed earlier. So a homeowner might install a small system and later add more modules and another inverter to build any size they want. Continued on next page Fred Paris Co-op Power Sustainable Energy Summit 2009 Page 2 of 9
  • How Solar Works, Continued The Inverter(s) The inverter is the device that changes Direct Current (DC) to Alternating Current (AC). Solar modules produce DC but our homes require AC. AC is also what the utility delivers to the home. For most homes the inverter will be a breadbox-size electrical component installed by an electrician near the circuit breaker panel. Inverters monitor and run on power from the utility. This serves a couple of purposes; first, if the utility goes down, the inverter shuts down. We do not want solar systems feeding the grid with utility linemen at work. The inverter synchronizes the AC sine wave to the utility’s sine wave, allowing for net metering. Continued on next page Fred Paris Co-op Power Sustainable Energy Summit 2009 Page 3 of 9
  • How Solar Works, Continued The Production Unlike the utility meter, the homeowner owns the production meter. The Meter homeowner’s meter only measures the energy produced by their solar system. This allows the homeowner to see exactly how much power their system is producing. In most cases, a production meter is a required part of a residential solar system. One of the additional benefits of a residential solar system is the production and accounting for virtual Renewable Energy Credits (RECs). A discussion of RECs is beyond the scope of this paper, but for every kilowatt of energy a solar system produces, RECs are generated in the owner’s name. RECs are then sold as a commodity. The production meter helps the homeowner validate RECs. Switches and Everything gets connected together. The modules are wired together, then to the Wiring inverter and the production meter. AC and DC switches are installed enabling the owner or the utility to shut down the entire system as required by the National Electric Code (NEC). Fred Paris Co-op Power Sustainable Energy Summit 2009 Page 4 of 9