The Power of Sun

The major obstacle for spreading solar energy is the low conversion efficiency into electrical power (at the present 10-15%). This together with high energetics cost to build solar systems makes Solar Energy an option with low EROEI and high costs pro KWh.

But the sector is booming for R&D and the convinience of solar power will probably increase in the next 5 years. The target is an increase in efficiency up to 30/40% and EROEI about 10:1

I report here some interesting and promising projects around the world:

- Concentrated Solar Power (CSP) Plants -
"CSP plants use different kinds of mirror configurations to convert the sun's energy into high-temperature heat. The heat energy is then used to generate electricity in a steam generator" -USA Department of Energy
three types of CSP technologies are currently being developed:

CSP 1- Trough Systems - the most successful and cost-effective CSP system design at present.
Take a look at the SEGS system a 330 MW thermal CSP plant based in California:
http://www.fplenergy.com/portfolio/contents/segs_viii.shtml

CSP 2 -dish/engine systems,


CSP3 - power towers/heliostat - array of flat, moveable mirrors to focus the sun's rays upon a collector tower. Energy trasnferred via Liquid Sodium (metal with a high heat capacity, allowing that energy to be stored and drawn off throughout the evening).
A 100 MW Solar Power Tower in South Africa: http://www.solarpaces.org/CSP_ESKOM.HTM

- CSP units for direct conversion into electricity (without steam generation)
They concetrate solar energy reflecting it on a small PV cell. The most advanced version used 2 PV cells (one with silicium , one with InGaP) adsorbing diacroic separated radiatiation from the mirror improving efficiency (each PV cell is optimazed for a given spectrum of the source radiation). This project is carried on from Univ. of Ferrara / Physics Dep. and SGS-Future
[http://www.enel.it/attivita/novita_eventi/archivio/doc/Ricca... - this source is in Italian]


[Pictures: 1.cristinevadai (USA), 2 ips-solar (USA),3 monsterdesign (korea), 4 sgs-future(Italy)]