Energy alternatives: Electricity without carbon

Abstract

The world has a lot of dams-45,000 large ones, according to the World Energy Council, and many more at small scales. Its hydroelectric power plants have a generating capacity of 800 gigawatts, and they currently supply almost one-fifth of the electricity consumed worldwide. As a source of electricity, dams are second only to fossil fuels, and generate 10 times more power than geothermal, solar and wind power combined. With a claimed full capacity of 18 gigawatts, the Three Gorges dam in China can generate more or less twice as much power as all the world's solar cells. An additional 120 gigawatts of capacity is under development. One reason for hydropower's success is that it is a widespread resource-160 countries use hydropower to some extent. In several countries hydropower is the largest contributor to grid electricity-it is not uncommon in developing countries for a large dam to be the main generating source. Nevertheless, it is in large industrialized nations that have big rivers that hydroelectricity is shown in its most dramatic aspect. Brazil, Canada, China, Russia and the United States currently produce more than half of the world's hydropower.

High-efficiency Silicon Heterojunction Solar Cells: A Review

“…With the sun providing the Earth with more than 10,000 times the energy humans currently consume, PV has the potential to be a large and environmentally benign energy source [1]. For a long time it remained expensive compared to traditional grid electricity.…”

Design and synthesis of organic sensitizers with enhanced anchoring stability in dye-sensitized solar cells

“…Optimal conditions to react stannane 3 with regioisomeric bromopyridines 5a,b,c were found using Pd(PPh 3 ) 4 as catalyst, oxygenfree DMF as solvent, CsF and CuI as additives [32], giving rise to pyiridine-containing intermediates 6a,b,c. It is worth mentioning that the same compounds could also be obtained using a Suzuki-Miyaura cross-coupling between the pinacolboronic ester corresponding to stannane 3 and the appropriate heterocycle.…”

“…Consequently, the development of efficient and reliable technologies to exploit renewable energy sources has become a crucial scientific goal. Among the possible options, photovoltaic conversion of solar energy into electricity is currently considered as one of the most promising approaches, given that sunlight is free, abundant and widely distributed across the globe [4]. To exploit solar energy, traditional silicon-based photovoltaic devices have been optimized and are currently dominating the market [5], however several innovative technologies have been also developed.…”

Modelling the impacts of reservoir operations on the downstream riparian vegetation and fish habitats in the Lijiang River

“…Following the rapid increase in the public awareness of ecological impacts associated with changes in river flow regimes, there are strong demands to quantitatively investigate other than qualitatively assess the impacts of reservoir operations and seek for implementable remediation measures (Nagaya et al 2008;Schiermeier et al 2008). To achieve such objectives, in situ monitoring and numerical simulation are usually adopted to track the changes in the aquatic species populations and distributions.…”