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Solar energy faces up to a challenge

Published Oct 13, 2010

Better feeds to the electricity grid, energy storage and smart grids in combination with solar cells and less expensive solar equipment. These are a few of the items on the agenda to ensure that solar energy will become an energy solution to be reckoned with in the future.

Staffan Norrga is a researcher working in the Department of Electrical Machines and Power Electronics at KTH. He is also project manager for an absolutely fresh photovoltaic facility at the university and has a range of ideas as to how solar energy can play a larger role on the electricity market.

For example, there has been considerable progress in research into the energy losses in solar cells’ inverters. The efficiency of these is up to around 97 percent. This is good. What is now needed is further research in other areas as regards solar cells.

“The use of energy storage and smart grids with solar cells is a good solution. But is it mainly large or small energy storage that is needed? This is where we need to conduct further research,” Staffan Norrga says.

A stronger penetration of solar energy also involves further, new challenges. What happens when the power fails? Under current regulations the photovoltaic system, for safety reasons, would disengage automatically when the power fails, but if solar cells become a more vital part of the grid, it also becomes a problem if they suddenly stop delivering power. For wind turbines, we already have solutions where the electricity is not disconnected. What we need here is more research on the solar front for a similar solution.

Another prerequisite for large-scale facilities for many gigawatts is that the price of equipment goes down. This is because solar energy is dependent on various countries’ subsidies; subsidies that are slowly shrinking in size.

“The price of solar equipment must be reduced in the future so that solar cells will become profitable. In addition, research is required on the technical work needed to be able to have a significantly higher proportion of solar electricity,” Staffan Norrga says.

He also adds that there are current applications for research funding submitted for solar cell research at KTH, which is most opportune considering that a new solar cell facility has just opened.

“We will be able to use the facility for research on how best to feed solar energy into the grid. It is hoped that it will lead to plants becoming cheaper and more efficient,” Staffan Norrga says.

He goes on to say that there are many countries where the development of solar energy has come a lot further than in Sweden.

“Solar energy is more valuable than other forms of electricity generation, because you get paid more for it. Spain and Germany receive feed-in tariffs (“Feed-in tariffs” - FIT), representing about SEK 3 per kWh, in contrast to other electricity generation which rarely provides more than SEK 1 per kWh.

The major market for solar cells is therefore in countries with this feed-in tariff, and in addition to Spain and Germany, this also includes France, Italy and Britain. It opens up new export opportunities in terms of solar energy for Sweden. Both in terms of equipment and expertise.

For more information, contact Staffan Norrga on 070 - 560 15 84 or norrga@kth.se.

Peter Larsson