Photovoltaics: Clean, Renewable, Distributed Electricity from the Sun
Photovoltaic technologies (aka ’solar electric’, ‘PV’) convert sunlight (photons) directly into electricity. As an alternative to fossil fuel generation, PV has the longterm potential to address a number of the most crucial resource challenges that we face on local, national and global scales.
Download a great Resource Sheet to bring to your work, home or school.
Background
People have been using solar energy since prehistoric times for a variety of practical uses such as space and water heating, and indoor lighting. However, it was not until the mid-twentieth century that solar energy was first exploited to produce electricity for the purposes of doing work. This milestone proceeded from earlier advances in research and experimentation.
The physicist Edmund Becquerel first discovered the process of converting light into electricity in 1839. In basic experiments Becquerel noticed that certain elements such as boron and phosphorus exhibited a property known as the photoelectric effect. This photoelectric effect allows the absorption of photons or light energy causing electrons to move through a circuit, thus producing an electric current.
The word ‘photovoltaic’ may seem complicated, but when broken down into its individual roots, it makes more sense. The first root ‘photo’ means light in Greek and the second root derives from volt, a unit of electrical force named for the inventor of the battery, Allesandro Volta.
The history of the modern photovoltaics industry can be said to have begun in 1954, when scientists at Bell Laboratories accidentally discovered the photoelectric properties of silicon. From this discovery, the first functional photovoltaic cells were produced. Shortly thereafter the new technology got a big boost when NASA integrated it into its new space program.
Photovoltaic production of electricity is commonly categorized as an active solar application, as opposed to a passive solar application in which the natural radiant heat and light of the sun is utilized.
PV Cells, Panels and Arrays
The most basic productive unit of photovoltaic technology is the cell, which consists of semi-conductor materials. When light hits the surface of the cell, some of it is absorbed by the electrons in the material (most commonly silicon with traces of boron and phosphorous). This energy excites and frees the electrons from their atoms. These free electrons form the electrical current that is produced by the panel and used by consumers. The workings of a PV cell are of course much more complicated than this.
For a more detailed summary please visit the U.S. DOE Solar Energy Technologies web page. The panels or modules that you may have seen on the roof of a building or beside a highway consist of several cells that have been connected together and encased in a single enclosure. Any number of panels – be it 2 or 2,000 – that have been connected together is called an array. Solar 1’s rooftop array consists of 88 panels.
The PV Advantage
In contrast to most conventional sources of electricity (e.g. fossil fuels, nuclear, etc.) photovoltaics can be classified as renewable, clean and distributed.
Renewable describes any energy source whose availability or supply will not be permanently depleted as a result of exploitation over a period of time that is meaningful to people. Fossil fuels (coal, oil and natural gas), which formed over millions of years of geological conditioning, are considered nonrenewable because their global supply will not be regenerated at a rate that is proportional to current and future uses. Once these sources are gone, they are gone for good. By contrast, solar power is in constant supply every day and will be for another several billion years.
Clean describes any energy source the exploitation of which does not generate significant amounts of pollution, and therefore negatively impact the health of human populations and the biosphere as a whole. Conventional electricity generation typically entails the combustion of fossil fuels and the production of harmful emissions or other waste byproducts, as in the case of nuclear energy. These sources can therefore be considered ‘dirty’. Photovoltaics, on the other hand, produce no waste or pollution while in use, and only negligible amounts are produced in their production.
Distributed describes any energy source that can be deployed – often rapidly – on small, medium or large scales close to the point of consumption. Distributed generation (‘DG’) contrasts with centralized generation, a term that characterizes conventional large-scale fossil fuel or nuclear power plant generation. While photovoltaics can be installed in large, centralized systems equivalent in output to small or medium power plants, they are more commonly deployed in distributed systems that are integrated directly into the homes and buildings that they power.
Since its introduction over a half-century ago, the performance and efficiencies of photovoltaics have increased considerably. At the same time, costs have fallen sharply and are projected to continue to decline as production expands worldwide and the industry grows as a whole. As a result the commercial viability of PV for mainstream commercialization has expanded enormously. In fact, while accounting for only .04 percent of total electricity capacity, PV is the world’s fastest growing energy source, and has doubled in size approximately every three years for nearly a decade.
Solar Potential in NYC
Most New Yorkers would be startled to find out that the Big Apple enjoys among the greatest solar potential of any city in the United States. The five boroughs have plenty of sunshine and loads of roof space to make PV very viable – in fact, enough to generate between 8,500 MW and 15,700 MW of electricity, which would account for roughly 60 to 110 percent of our current peak needs. (Chaudhari et al., 2005; Plunkett et al., 2003b).
While these levels are technically possible, they are not financially realistic at this point given the relatively high cost of photovoltaics versus conventional generating technologies, as well as a host of other factors. However, in spite of these realities, the amount of PV that could be economically supported in NYC to the great benefit of the local area has not even been remotely met. The amount of PV technology in NYC amounts to less than .002 percent of our total electricity capacity. Increasing the percentage of PV in the City could have a number of immediate positive impacts, including:
Air quality improvement
Greenhouse gas reduction
Job creation
Increased grid reliability during periods of summer ‘peak’ use.
If you are interested in finding out about existing solar incentives in New York State, or any other state, visit the Database for State Incentives for Renewable Energy and click on their interactive map. A great resource!
Local Installers
The contact local PV installers working in the NYC area, refer to the list below:
Altpower
Brightpower, Inc.
ISI Solar
Quixotic Systems
The Solar Center
Solar Energy Systems
Evan Esposito Solar Consulting
Get Active
To get involved in efforts to improve New York’s existing solar policies and incentives visit:
Works Cited
Chaudhari, M., Frantzis, L., & Hoff, T. E. (2005). PV grid connected market potential under a cost breakthrough scenario. Burlington, MA: Navigant Consulting.
Plunkett, J., Shipley, A., Hill, D., & Donovan, C. (2003b). Energy efficiency and
renewable energy resource development potential in New York State: Renewable supply technical report (Vol. 4: Renewable supply technical report). Albany, NY: New York State Energy Research and Development Authority.
