Welcome to Renewable Energy Info

Renewable energy sources have diverse origins, a feature that demands equally diverse technologies to capture them. My interest in these (new) technologies resulted in this blog. If will focus on well developed technologies that are already put into practice, and on promising technologies that are still under development.

If you like (one of) the posts and you want to recommend it to others, you can digg it by clicking the yellowy button displayed top left of every post. This would seriously increase the traffic to my blog and I would be very thankful!

Enjoy it!

Interesting books on Amazon..

Showing posts with label ocean power. Show all posts
Showing posts with label ocean power. Show all posts

Wednesday, September 24, 2008

Ocean Wave Power, the next hot technology?

Source: Earth2Tech, AWS Ocean Energy

As the world is running out of oil, more and more alternatives emerge. Today, solar power generation has matured and is now big business, and wind energy is following in its footsteps. However, in the past years, scientists and engineers have explored the possibilities to harvest energy from the ocean. See, for instance, some of the previous posts on this blog dealing with the Pelamis. Ocean power is set to provide an exciting new source of clean renewable energy and one which can contribute to global energy needs on a sustainable basis.



Recently, Ocean Power Technologies, Inc. has announce d that it has deployed its first PowerBuoy® under contract with Iberdrola S.A., one of the worlds largest renewable energy companies. As noted by Iberdrola, the deployment of OPTs PB40 PowerBuoy is the latest milestone toward the building of the worlds first commercial utility-scale wave power generation venture to supply approximately 1.39 MW of electricity into Spains electricity grid. The PB40, incorporating OPTs patented wave power technology, is the first of what is expected to be a 10-PowerBuoy wave power station to be built out in a later phase of the project, and generating enough electricity to supply up to 2,500 homes annually.



Another clean-tech company that is developing technology to generate electricity from the energy from the ocean's waves, is AWS Ocean Energy. AWS stands for Archimedes Wave Swing, and their lead product is the award-winning Archimedes Waveswing™ wave energy converter. This is a cylinder shaped buoy, moored to the seabed. Passing waves move an air-filled upper casing against a lower fixed cylinder, with up and down movement converted into electricity.



As a wave crest approaches, the water pressure on the top of the cylinder increases and the upper part or 'floater' compresses the gas within the cylinder to balance the pressures. The reverse happens as the wave trough passes and the cylinder expands. The relative movement between the floater and the lower part or silo is converted to electricity by means of a hydraulic system and motor-generator set.

Saturday, June 23, 2007

Renewable Energy From the Deep Ocean

Sources: OTEC News, YouTube

When I was looking for information on wave energy for one of the previous posts (this one), I came across many different technologies that make use of the energy present in the ocean. Whereas the wave energy converter described in the referred post uses the mechanical energy from the waves, the technology described here uses the thermal energy stored in the ocean. Check it out!

Ocean Thermal Energy Conversion (OTEC) is a means of converting into useful energy the temperature difference between surface water of the oceans in tropical and sub-tropical areas, and water at a depth of approximately 1 000 meters which comes from the polar regions. For OTEC a temperature difference of 20oC is adequate, which embraces very large ocean areas, and favors islands and many developing countries as shown on the map below.


Have a look at this YouTube video that explains how it works!



I left a comment on YouTube in which I asked if anyone knew of a full-scale application of this technology and I got this reply from the person who posted the video: "To date there is no commercial application of this technology although there are a number of commercial projects in the works and I would expect some major announcements by the end of this year. It is commercially viable so long as oil prices remain over $50 a barrel and interest rates remain low. In time, it will probably be competitive with around $30 a barrel oil. It is unlikely to be competitive with oil under $20 a barrel."

Friday, June 22, 2007

The Pelamis wave energy converter

Source: Ocean Power Delivery

Ocean waves represent a considerable renewable energy resource. Waves are generated by the wind as it blows across the ocean surface. They travel great distances without significant losses and so act as an efficient energy transport mechanism across thousands of kilometers. Waves generated by a storm in mid-Atlantic will travel all the way to the coast of Europe without significant loss of energy.

All of the energy is concentrated near the water surface with little wave action below 50 meters depth. This makes wave power a highly concentrated energy source with much smaller hourly and day-to-day variations than other renewable resources such as wind or solar. Conveniently, the seasonal variation of wave power closely follows the trend for electricity consumption in Western Europe.

One technology that makes use of the this wave energy is the Pelamis wave energy converter. The Pelamis is a semi-submerged, articulated structure composed of cylindrical sections linked by hinged joints. The wave-induced motion of these joints is resisted by hydraulic rams, which pump high-pressure oil through hydraulic motors via smoothing accumulators. The hydraulic motors drive electrical generators to produce electricity. Power from all the joints is fed down a single umbilical cable to a junction on the sea bed. Several devices can be connected together and linked to shore through a single seabed cable.

Have a look at the YouTube video below and to this animation to see how it works !