Npower plans big coal plant in UK
Npower, the British generation subsidiary of German energy giant RWE, is planning to build a 1,600-MW supercritical coal-fired plant to replace an existing 1,000-MW coal power plant in Tilbury, Essex.
The new plant would cost nearly $2 billion and be the first new coal-fired plant built in the country in more than 20 years. In documents filed with the Department of Trade and Industry, npower said it will replace the existing pulverized coal plant (Figure 1) with two 800-MW supercritical units. The new station would be capable of burning biomass as well.
Npower considered retrofitting the Tilbury plant with carbon capture technology but concluded that it makes more sense to build new units that emit considerably less carbon dioxide (CO2) per unit of output. Npower expects the new plant to be in service by 2013. In the meantime, the existing plant will continue operating.
Andy Duff, npower's CEO, said, "Coal is a vital component of the UK's future generation mix, but the environmental impact must be addressed. A supercritical coal plan on its own would result in a significant net reduction in CO2 levels, but we have also chosen to make the [new] power station ready for carbon capture and storage technology."
Duff added that the company remains interested in carbon capture and sequestration. "At this time," he said, "there are still many financial, legal, regulatory, and technical hurdles to clear on CO2 transportation and storage technology. However, [CO2 emissions are] too important to ignore, and we are committed to further research and development as we assess our next steps in this area."
Npower said it chose the Tilbury site "because of its proximity to areas of high population and demand." The company says it will be reaching out to the local community and stakeholders as it develops the details of its plan.
A month before the Tilbury announcement, npower announced a $1.8 billion investment in a new natural gas–fired project, to be based in Wales or Nottinghamshire, and in three new wind farms.
Berkeley boffins make thermoelectric discovery
Researchers at the University of California, Berkeley, have generated electricity from heat by trapping organic molecules between metal nanoparticles, potentially paving the way for a new source of energy.
The discovery was described in a recent issue of Science Express, the online version of Science magazine. It could be a milestone on the path toward ways to directly convert heat into electricity. Current generation techniques are dominated by generating steam in a boiler and using it to spin a turbine and drive a generator.
Conventional ways of generating power waste a lot of heat, as anyone who has ever had a car with a bad radiator knows. According to Arun Majumdar, a Berkeley mechanical engineer and principal investigator on the work, "generating 1 Watt of power requires about 3 Watts of heat input and involves dumping the heat equivalent of about 2 Watts into the environment. If even a fraction of the lost heat could be converted into electricity in cost-effective fashion, the impact on the electric power industry would be enormous. It would produce massive savings of fuel and huge reductions in carbon dioxide emissions."
For 50 years, scientists have explored the Seebeck effect, a phenomenon in which voltage is created when the junctions of two different metals are kept at different temperatures. But tabletop thermoelectric generators of this sort operate at a puny 7% efficiency, compared with 20% for conventional heat engines.
The new UC Berkeley research, according to a university press release, "marks the first time the Seebeck effect has been measured in an organic molecule, laying the groundwork for more cost-effective thermoelectric converters." The researchers coated two gold electrodes with molecules of benzenedithiol, dibenzenedithiol, or tribenzenedithiol, and then heated one site to create a temperature differential (Figure 2).
For each degree Celsius of temperature difference, the researchers measured 8.7 microvolts for benzenedithiol, 12.9 microvolts for dibenzenedithiol, and 14.2 microvolts for tribenzenedithiol. The maximum temperature differential created was 30 degrees C.
"The effect may seem quite small now," said graduate student Pramod Reddy, "but this is a significant proof of concept and the first step in organic molecular thermoelectricity." Majumdar added, "we are going down the road of cheap thermoelectric materials. The use of inexpensive organic molecules and metal nanoparticles offers the promise of low-cost, plastic-like power generators and refrigerators."
The next steps, say the researchers, will include testing different organic molecules and metals, and fine-tuning the assembly of the structure.
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