Technology Comparison

Solar Resource: One significant difference between concentrating and other PV systems pertains to the solar resourc e used. Concentrating PV systems use sunlight which is incident perpendicular to the active materials (direct norma l insolation). Other PV systems utilize both direct and indirect (diffuse) solar radiation. Provided in Figure 2, below , are two maps; the first is a map of direct normal insolation, the second is a map depicting global insolation for the U.S.

PV Module Price Trends

Installed Modules (MWp) □ Data source - Strategies Unlimited T M- Peterson, EPRI

Energy directly from the Sun on a surface directly facing toward the sun.

1,000 to 2,500 2,500 to 3,500 3,500 to 4,000 4,000 to 4,500 4,500 to 5,500 5,500 to 6,500 6,500 to 7,500

Energy from the Sun and Sky on a Horizontal Surface

□ 1,000 to 2,500 2,500 to 3,500 3,500 to 4,000 4,000 to 4,500

Reproduced from data provided by NREL Renewable Energy Resource Information & Analysis Center in support of the DOE Resource Assessment Program Solar Radiation Resource Assessment Project

Figure 2. Direct normal insolation resource for concentrator PV (above) and global insolation resource for crystalline-silicon and thin film PV systems (below).

The main consequence of this difference is that concentrator systems should be deployed in regions that ar e predominantly cloud free. While other PV systems do not have this requirement, total solar resource quality does o f course influence system performance. The PV Technology Characterizations take resource quality into consideratio n by providing performance estimates based on average and high solar resource assumptions.

Deployment: The deployment needs of the two utility scale applications described in this report are similar. Mediu m and large-scale deployments have significant land requirements. However, it is important to note that concentrato r systems are less appropriate for very small-scale deployments (less than a few tens of kilowatts) due to their costs and complexity. Customer (building) sited PV have no land requirements, however several structural requirements ar e important (i.e. roof integrity and orientation, shading, pitch, etc.).

Application: The PV systems characterized here all provide distributed benefits. Residential PV systems either fee d power into the grid and/or reduce customer demand for grid power. Medium and larger scale systems add capacit y increme ntally, and to the extent that they match load patterns, may reduce the need for major capital investments i n central generation.

Modularity: PV generating systems are easily scaled to meet demand. PV systems can be constructed using one o r more modules, producing from a few tens of watts to megawatts. For example, the residential PV systems characterized in this report are a few kW in size, while the concentrating and utility scale thin film PV systems are multi-megawat t applications.

Low-cost operation and maintenance: PV systems have few moving parts. Flat-plate types without tracking have n o moving parts, and even two-axis tracking requires only a relatively small number of low-speed moving parts. Thi s tends to keep operation and maintenance costs down. Indeed, some early kilowatt-scale first-of-a-kind plant s demonstrated O&M costs around $0.005/kWh.

Solar Stirling Engine Basics Explained

Solar Stirling Engine Basics Explained

The solar Stirling engine is progressively becoming a viable alternative to solar panels for its higher efficiency. Stirling engines might be the best way to harvest the power provided by the sun. This is an easy-to-understand explanation of how Stirling engines work, the different types, and why they are more efficient than steam engines.

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