Daily Archives: August 11, 2008

Bravo – Ms. Vivienne Cox, head BP Alternative Energy unit

Posted on August 11, 2008 | 1 Comment

By Tom Bergin

 LONDON (Reuters) – Oil major BP (BP.L: Quote, Profile, Research) has decided against spinning off its investments in green and alternative energy and will instead try and boost the impact of the investments on its shares by giving analysts more data.

In February, Chief Executive Tony Hayward said BP’s shares had received little, if any, uplift from its investments in renewable energy, while these would be worth between $5 billion and $7 billion if they existed on a standalone basis.

“We’ve looked at IPO options and we’ve looked at partner options, we’ve looked at other options, but at this point we’ve decided to keep these businesses within BP,” Vivienne Cox, head of the Alternative Energy unit, told a conference call with analysts.

 Cox said further data on the units would be provided to investors and analysts in February next year, which she hoped would give greater financial transparency on the units.

 Some energy companies, mainly utilities, have partially floated their wind energy units to take advantage of strong investor interest and high stockmarket valuations for green energy assets.

 (Editing by Will Waterman)

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Posted in Europe, Politics

highly efficient process for storing energy is the bottle neck for deploying renewable energy [1]

Posted on August 11, 2008 | Leave a comment

 

The latest demand for renewable energy sources in general, solar & wind in particular, raised again the need for feasible energy storage solutions. Solar power is currently a daytime-only energy source because storing extra solar energy for later use is prohibitively expensive and grossly inefficient. Wind energy is also dependent of sufficient wind power, which exists in many areas mainly at night time only.

 

Various storage solutions for solar power plants were and are being developed; most of them are based on thermal storage. Much effort is invested for developing storage for trough technology (since it requires lower temperatures, up to 400ºC). Usually phaze changes materials (PCM) are being used, since it enables higher density in the storage and minimal temperature losses between charge and discharge. The main problem is the low heat transfer (due to low thermal conductivity of the salts), and this affects directly the amount of power that could be extracted from the storage. 

Several research is being executed for developing enhanced solutions, mainly by enhancing the heat transfer between the salt and the heat transfer fluid (in the molten salt receiver/hot storage tank), reducing transient effects, optimization of the storage materials.

 

Various solar tower electricity generation systems were developed and the most advanced of them was installed and tested in California. This system, Solar Two, generated 10MW electricity using an eutectic molten nitrate salts mixture pumped and piped from a ground-based cold tank to a receiver mounted on the top of a tower. The hot salt from the receiver is then piped to a second, hot tank on the ground. In a secondary loop, the hot salt flows through a heat exchanger to generate steam and returns to the cold tank. The third loop includes the steam generator, which supplies steam to a steam turbine electricity generator. This plant was closed on 1999. Now Sener is trying to do something similar in Spain.

For the trough, – in Acciona’s Nevada plant, for example, there is no storage (only for about 30 minutes, that is achieved by the fluid that is in the pipes). On the other hand, at Andasol, – Flagsol (Solar Millenium’s subsidiary) together with ACS Cobra are developing thermal storage based on molten salt.

 

A simple, inexpensive, highly efficient process for storing energy is the bottle neck for deploying renewable energy for electricity base and peak load demands.

 

Later on we’ll discuss possible other energy storage options.

 

 

 

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Posted in Technologies