Monthly Archives: May 2010

Storing renewably electricity as natural gas

German researchers have succeeded a technology  in storing renewable electricity as natural gas. They convert the electricity into synthetic natural gas with the aid of a process.  In the future they would like to store surplus electricity, such as from wind or solar energy, as climate-neutral methane, and store it in existing gas storage facilities and the natural gas network.

Throughout the world electricity generation is based more and more on wind and solar energy. As the wind is blowing powerfully, wind turbines generate more electricity than the power grid can absorb.

The missing link for integrating renewable energy into the electricity supply is a smart power storage concept.

The proces storing green electricity was developed by the Center for  Solar Energy and Hydrogen Research Baden-Wurttemberg (ZSM) in cooporation with the Fraunhofer Institute for Wind Energy and Energy System Technology  (IWES).  One advantage of the technology: it can be use the natural gas infrastructure. The storage reservoir of the natural gas network extending through Germany is vast: it equals more than 200 terawatt hours, enough to satisfy consumption for several months.

Starting in 2012 researchers  intend to launch a system with the capacity of approximately 10 megawatt.

Refrigerated by sunlight

Although it sounds like a contradiction scientist from the Fraunhofer Institute for Solar Energy Systems are using solar energy to keep perishable foodstuffs such as milk, wine and fruit fresh. Using the power of the sun for refrigeration is proving to be an original energy concept. We could well see an ecostatement like this printed on food packaging in the years ahead.

In the MEDISCO project ( MEDiterranean food and agro Industry applications of Solar COoling technologies)  scientists   in Tunisia and Morocco are demonstrating that this is feasible. They have installed concentrating collectors which direct the sunlight onto an absorber by means of a reflector. This makes it possible to convert the solar radiation into hot water with a temperature of 200 degrees. This extreme water temperature is nescessary in order to drive  the absorption refrigeration machine  for the high external temperatures that prevail there.  They do not use electricity to provide the refrigeration, they use heat.

Vacuum tube solar collectors in a solar cooling absortion system

‘Our method is ideal for countries which have many days of sunshine and in remote areas where there are no conventional means of refrigeration owing to a lack of water and non-existent or unreliable energy sources’ said Dr. Tomas Nunez, scientist at the ISE.  ‘It is environmentally friendly and reduces the use of expensive electricity for conventional refrigerators to a minimum.’

Saving lives by capturing waste heat

Students at Maine Maritime Academy have converted a 20-foot enclosed lifeboat into a test platform in order to see they can capture the energy and use it to power a hybrid test boat. The system they have developed can be transferred to a larger platform that could be used to increase the efficiency of the boat’s power plant.

The experiment is part of a research project at the college that began last year when students used a thermoelectric generator to convert the heat from the engine exhaust on the MMA research vessel Friendship to electricity to power a panel of lights on the boat. ‘ If it works on the lifeboat, it would show that the technology is sound and could be scaled up to be used on a full-size ship.’

There is a lot of waste energy at the exhaust end of an internal combustion engine and capturing and converting it to electricity would improve the efficiency of the existing engines, reducing the amount of fuel required to produce the same power output on a ship. Although the test this year will be done on a diesel-powered generator, the students have tested the system on a gas turbine as well. Unfortunately the students have not thought of a small steam turbine. It could be very efficient for a steam generator can capture more waste heat. It would be also more cost effiective.