New Power Inverter Efficiency Record Set

 

 
The Fraunhofer Institute for Solar Energy Systems ISE in Germany has set a new world record of 99.03 % efficiency for inverters used in solar energy systems.  
 
Inverters convert the DC current generated by a solar power system into AC current, suitable for use in a home and for feeding directly into the mains electricity grid. 
 
By using new components and improving the circuit technology, the researchers have further reduced losses from their own previous best result by a further third.
 
The higher the inverter efficiency, the higher the system yield. For a 30 kW system, an efficiency value which is 1 % higher results in an additional yield over ten years of 3000 kWh.
 
Much of the improvement is credited to junction field-effect transistors (JFETs) made of silicon carbide (SiC). In addition,  the researchers optimised the gate units and many other details of the circuit.
 
The higher efficiency also means lower thermal losses, allowing for smaller cooling devices and a more compact construction, offsetting some of the cost of utilising the more expensive technology.
 
Prof. Bruno Burger, leader of the Power Electronics Group at Fraunhofer ISE, sees enormous potential for the new silicon carbide transistors as they are constantly becoming more refined and increasingly economical.
 
SiC transistors are superior to the conventional IGBTs of silicon (Si) used commonly today, particularly for higher reverse voltages. The main reasons are the breakdown field strength, which is ten times higher for SiC than Si, and the band gap, which is three times larger for SiC than Si.
 
Related: Learn more about inverters

Walmart Moves Closer To 100% Renewable Energy

 

The world's largest public corporation by revenue, Walmart, is moving closer to achieving its stated goal of 100% renewable energy with the recent announcement to install rooftop solar power systems on five of its stores in Puerto Rico; with the potential for 23 stores over five years.
  
SunEdison will finance, own, build and operate the solar farm and construction on the first 895kW rooftop system is scheduled to begin before the end of 2009.
  
On average, the systems will provide 25 to 35 percent of the power for the store on which it is installed. Over the 15 year contract, the solar arrays are projected to produce 90 million kilowatt hours (kWh) of electricity.
  
According to Renzo Casillo, president & CEO of Walmart Puerto Rico, new Walmart stores are  now 21 percent more energy-efficient than the original 2005 stores. Through the implementation of energy efficiency strategies and equipment, the company has achieved an 8.7 percent reduction in energy consumption compared to the previous year. 
  
Earlier this year, Walmart announced it had entered a joint solar development agreement to install BP solar panels on an additional 10 to 20 Walmart facilities in California by 2011. The expansion will generate generate 8 million to 16 million kWh of renewable power each year and mitigate the generation of more than 10,000 metric tons of carbon dioxide (CO2) emission annually, equivalent to the emissions from more than 24,160 barrels of oil consumed.
 
In November 2008, Walmart announced a major purchase of wind power to supply up to 15 percent of the retailer’s total energy requirements in approximately 350 Texas stores and other facilities.
 
"Big box" retailers are well placed to install rooftop solar farms given the massive amounts of roof space available to them, but in Australia, very few of our large retailers have followed Walmart's lead to turn this otherwise wasted resource into platforms for the production of clean energy.

News for Tuesday 04 August, 2009

 

• China's wind power capacity doubles
  


• USA Wind Power Capacity Approaches 30 Gigawatts
  


• Energy Matters At The NAB's Mini-Environmental Expo
  

View all news for Tuesday 04 August, 2009 on one page

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