Solar power is a form of renewable energy that generates electricity from sunlight. Solar power is generated from one of two types of configurations: photovoltaic arrays and concentrating solar power.
Photovoltaic (PV) power
PV cells convert sunlight directly into electricity. PV is the dominant form of solar technology currently deployed. It has the advantage of being modular; PV cells are packaged to create PV panels, then PV panels can be wired together to create PV arrays. These arrays can be sized to meet the needs of the owner or energy consumer.
PV is currently commercially available in two forms: crystalline silicon and thin-film panels. Either technology can be fixed or track the movement of the sun, which allows them to create more energy. Crystalline silicon is the more efficient technology with average efficiency between 17 percent (polycrystalline) and 22 percent (monocrystalline).
Thin-film modules have an average efficiency between 13 percent and 16 percent and have experienced rapid improvements. Existing PV technologies can be mounted in fixed arrangements, or mounted to track the sun using either a one-axis or two-axis tracking system. A single axis tracker follows the sun east to west and a two-axis tracker also follows the seasonal declination of the sun.
Concentrating solar power (CSP)
CSP technology uses sunlight to generate steam to power a conventional turbine and is best used in areas with high solar exposure and low humidity. An array of mirrors, also known as heliostats are positioned to reflect sunlight and focus it on a receiver that heats a working fluid (typically water or a molten salt solution depending upon the CSP technology) to be used either to generate steam or power an engine. CSP plants typically require about 800 gallons of water per megawatt-hour generated for cooling purposes but this amount can be reduced by installing a dry evaporative cooling system at the expense of efficiency losses and additional installation capital.
The primary form of CSP currently in use is the parabolic trough, which focuses sunlight on pipes carrying water to generate steam that spins a conventional turbine generator. The power tower is another form of CSP that redirects sunlight from a large array of heliostats and focuses it on a single heat receiver, generating steam to spin a conventional turbine generator. By contrast, the third form of CSP is the dish/engine system that redirects sunlight to heat a working fluid used to move engine pistons. This latter form has not been used commercially.
AEP project spotlight
Our Indiana Michigan Power subsidiary completed AEP’s first large-scale solar project in late 2015. The Deer Creek Solar Facility is located just south of Marion, Indiana and can generate up to 2.5 megawatts of electricity. Three other facilities in Indiana and Michigan will begin generating solar power in 2016. Altogether the four facilities will have a capacity of nearly 15 MW and produce enough energy to power 2,000 homes annually.
I&M’s Deer Creek Solar Facility
Recent advancements in technology and manufacturing have realized efficiency gains and significant module cost reductions for solar PV technology. As solar energy becomes more economically viable it will generate increasing customer interest. AEP’s Indiana Michigan Power solar pilot facilities provide an opportunity for innovation and a proving ground for this rapidly growing technology to better serve our customers.