New photovoltaic technologies: a chance for the planet

More solar energy to tackle climate change

As global climate change is showing larger proportions than predicted and energy demand will likely grow massively, renewable energies can be a key resource for the next decades. Photovoltaic power generation (PV, i.e. solar electric) could become crucial: its market is growing by 35% annually and the price of PV modules decreased by more than 60% since the early 1990s1. Solar power already avoids 90% of greenhouse gases emissions compared to fossil sources of electricity generation (18-37 gCO2eq/kWh vs 400-900 gCO2eq/kWh) and if PV systems are produced using renewable energies CO2 emissions can be eliminated completely2. Moreover PV modules can be recycled, the pay-back time is now 1.5-3 years and the maintenance required is very low. In 2007 the global cumulative capacity of PV systems exceeded 9 GWp, about 50% of them being in the European Union where 75.000 jobs were created in the last few years (Germany and Spain leading the way). In an advanced scenario in 2030 over 1,000 GWp could be generated worldwide via photovoltaic installations, together with 2 million new jobs3.

Advanced options for electricity production

According to the U.S. Department Of Energy a gap must be bridged between the basic and applied solar research: as a result new more efficient PV approaches could change the solar market’s paradigm. Prototype cells and/or processes can be produced by 2015, with full commercialization in 2020-20304.

The solutions proposed are essentially:

• Nanoarchitecture: 1-100 nanometer long solar cells using materials or structures as photon absorbers or exciton transporters
• Multiple Exciton Generation: the single-junction solar cell efficiency can be raised from 34% to 44% by the generation of multiple excitons5 for each photon of sufficient energy absorbed by the photovoltaic cell
• Plasmonics: an emerging branch of photonics using nanostructured materials that can enable more light to enter the absorber via plasmons6
• Tandems: multijunction cells with cells of different bandgaps.

Developing these options on a large scale in Europe as well as in the United States many new qualified jobs can be created, representing an important co-benefit of addressing the climate change challenge. With equally valuable capacity building actions in the developing countries the solar energy will be best exploited there given higher land availability and increasing energy demands of growing populations.

Written by Luca Marazzi on behalf of RTCC

1. http://www.rtcc.org/2009/html/renew-solar-1.html
2. Source: PV Environmental Research Centre (Brookhaven National Laboratory in Upton, New York)
3. European Photovoltaic Industry Association - http://www.epia.org/
4. United States Department Of Energy (US-DOE) Solar Energy Technologies Program - http://www1.eere.energy.gov/solar/solar_america/pdfs/next_generation_pv_prospectus.pdf
5. An exciton is a bound state of an electron and an imaginary particle called an electron hole in an insulator or semiconductor and such is a Coulomb-correlated electron-hole pair. The exciton results from the binding of the electron with its hole.
6. A plasmon is a quantum of plasma oscillation.

To watch videos regarding Climate Change please visit:
www.climate-change.tv