Solar Energy Conversion Toward 1 Terawatt

Abstract

Harvesting energy directly from sunlight using photovoltaic (PV) technology or concentrating solar power (solar thermal energy conversion) is increasingly being recognized as an essential component of future global energy production. The decreased availability of fossil fuel sources and the realization of the detrimental long-term effects of emissions of CO 2 and other greenhouse gases into the atmosphere are driving research and deployment for new environmentally friendly energy sources, especially renewable energy resources. An additional driving force is the increasing worldwide sensitivity toward energy security and price stability. Capturing even a small fraction of the 162,000 terawatts (TW) that reaches the earth would significantly impact the overall energy balance. PV systems, in addition, are portable and well-suited to distributed applications. The largescale manufacturing of photovoltaics is increasingly economically viable. The rapid expansion of manufacturing capability in PV components and the deployment of concentrating solar power (CSP) systems offers the potential for supplying a significant fraction (10% without need for storage) of our energy demand with minimal environmental impact. (See accompanying sidebar by Mehos for additional detail.) In addition, it is clear that these technologies represent one of the next major high-technology economic drivers eventually succeeding microelectronics, telecommunications, and display industries. Truly achieving this goal will require materials-science-driven cost reductions, not just incremental cost reductions through economies of scale.In 2004, the average total worldwide power consumption was 15 TW (1.5 × 10 13 W), with 86.5% from the burning of fossil fuels, according to U.S. Department of Energy statistics. In 2003, 39.6 quads (1 quad = 1 quadrillion BTU = 1.055 × 10 9 GJ, 29.9 quad = 1 TW-year) of energy, largely from fossil fuels, was consumed to produce electricity just in the United States. After conversion losses, 13.1 quads of net electrical energy was output by power plants for general consumption.1 This amount of electricity could be produced by a 100 km × 100 km area of high solar insolation, such as in the desert southwestern United States, covered with solar modules with a power conversion efficiency of 15%. In order to meet the U.S. Department of Energy cost goal of $0.33/W or $0.05-0.06/kWh for utility-scale production, these modules would need to be manufactured at a cost of $50/ m 2 or less. Goals for solar thermal power are comparable. Although the costs of modules are falling substantially, reaching these objectives with today's technology will require significant improvements in cell performance, as well as in the additional components making up the balance of solar systems. In addition, a variety of new technologies including thin films, thin silicon, organic photovoltaics, multijunction concentrator approaches, and next-generation nanostructured devices have the potential to significantly reduce the cost per watt.With the recog...

The future prospect of PV and CSP solar technologies: An expert elicitation survey

“…We focus on Crystalline-silicon Photovoltaic (PV), Thin-film PV, Concentrating PV, Organic PV, Third Generation PV and Concentrated Solar Power (CSP) (Figure 1). These technologies were chosen because they are at different level of development, but even for the most mature ones, such as Crystalline-silicon PV, there is a strong need for further research and technical improvements (Ginley et al, 2008). We surveyed experts to collect judgements on the future costs of these technologies, how these will be affected by EU public RD&D programs, and what non-technical barriers could prevent their diffusion.…”

Let the Sun shine

“…The total electricity needs of the United States in 2003 could have been provided by covering an area of desert with just 100 km × 100 km of solar panels operating at 15% power conversion efficiency 1 .…”

Utilizing Quantum Dots to Enhance Solar Spectrum Conversion Efficiencies for Photovoltaics

“…Over 90% of the photovoltaic power produced today is from single crystal silicon based panels; however, first generation silicon based solar cells do not utilize all of the radiant energy that is provided by the sun. Specifically, wavelengths below 450 nanometers are not converted effectively into usable electrical power and as much as 39% of the sun's energy is under utilized [3]. This research focuses on developing a method for improving solar cell efficiency by 10% through the process of spectral conversion, which would thereby make it competitive with thirdgeneration photovoltaics based on multi-junction thin films.…”