Solar Photovoltaic Technology — Presentation Transcript
Photovoltaic (PV) Technology – The Basics• Directly creates electrical energy from sunlight (DC)• No moving parts• Lasts for 20+ years with minimal maintenance• Uses direct and indirect insolation; works anywhere with light• Does not store energy without a battery• First commercialized in U.S. (Bell Labs) in the 1950’s
How does PV technology work? •Photons strike and ionize the semiconductor material causing outer electrons to break free of their atomic bonds. •Due to the semiconductor structure, the electrons are forced in one direction creating a flow of electrical current. •Solar cells are not 100% efficient in Diagram of a typical crystalline silicon solar cell. To make this type part because some of the light of cell, wafers of high-purity silicon are “doped” with various spectrum is reflected, some is too impurities and fused together. The resulting structure creates a pathway for electrical current within and between the solar cells. weak to create electricity (infrared) and some (ultraviolet) creates heat energy instead of electricity.
Other Types of Photovoltaic Technology In addition to crystalline silicon (c-Si), there are two other main types of PV technology Thin-film PV is a fast-growing but In the United States, concentrating PV arrays small part of the commercial solar are found primarily in the desert Southwest. They market. Many thin-film firms are use lenses and mirrors to reflect concentrated start-ups developing experimental solar energy onto high-efficiency cells. They technologies. They are generally require direct sunlight and tracking systems to be less efficient – but often cheaper – most effective. than c-Si modules.
Where are the major PV installation markets? • In early 2012, state markets are in flux due to a number of policy and market uncertainties. • In particular, changes in module pricing, availability of project finance and potential policy changes could influence the development of key state solar markets.
Where are the major U.S. PV manufacturers?
Photovoltaic Technology - Economics PV module prices fell by 50% during 2011. The figures below represent total installed cost. The average size of a residential PV system in the U.S. is 5 kW. At $6.24/watt in Q3 2011, a system that size would cost $31,200 before incentives. The 30% federal tax credit brings the up-front cost down to $21,840.
Photovoltaic Technology - Economics To address the issue of up-front costs, solar integrators have developed a number of financing options for their customers.• Solar Lease – Customer pays little or no money up-front and is not responsible for system monitoring or repair. Often immediately cash-flow positive.• Power-Purchase Agreement (PPA) – Customer purchases only the electricity generated from the system.• Property-Assessed Clean Energy (PACE) – Up-front cost is paid by a local government fund and repaid by homeowner through property taxes.• Solar Renewable Energy Certificate (SREC) Loan – Utility company pays the bulk of the system cost and is repaid by customer through annual sale of SRECs.
Photovoltaic Technology - Economics (Solar Photovoltaic Financing: Residential Sector Deployment; NREL, March 2009)
Photovoltaic Technology - Economics
How much will it cost to install a solar array on my house? What’s my return-on-investment?• Short answer: I have no idea.• Longer answer: it depends. There are a lot of factors that go into solar economics. In addition, it’s worth considering that solar energy is a wealth creating investment, so up- front cost is only one component of the total value to the customer.• Longest answer OR “Here’s what you need to know to get the answer” • How much annual sunlight does your area receive? Does your rooftop face south? Is it free of shading? • Do you live in a major solar market? How many companies offer installations? What types of financing do they offer? • How much are you currently paying for electricity? How much do you use each month? Does your utility offer net energy metering? • What federal, state and local incentives are available?
Some Suggested Follow-Up Questions: What different thin- What are the typical film technologies are incentives available available and what at the state and are their How do solar federal level? applications? customers deal with storing the energy from their systems? What are the key How do specialized national and local solar cells work, like policies for creating those used in CPV solar markets? or on satellites?