Solar Cell Technology: Where Is It Now and Where Will It Be?
Solar cells (also called photovoltaic cells) convert sunlight directly into electricity by the photovoltaic effect. Think of a mechanical version of photosynthesis in plants. In this world of ever increasing energy requirements we are looking at every possible alternative energy solution, and solar seems to be the most promising. Of the 1.4 x 10^30 Joules of energy produced by the sun every hour 6.48 x 10^20 J hits the earth. To get a picture of the sheer quantity of energy, that is enough to power the entire United States for over a year. One hour of sunlight > 1 year of powering the USA. Solar power is a completely green energy with no carbon footprint. Solar facilities require minimal maintenance and individual solar panels can run for 50 years after being installed.
Solar is an underutilized means of gathering energy because up until now it simply hasn’t been cost effective. A decade ago solar panels cost more than $5.00/watt. (Comparatively the cost for a coal power plant was around $2.1/watt) Luckily the price of crystalline silicon (the building block of photovoltaic cells) and in turn the price of solar panels themselves, has been in steady decline ever since it was first invented. Since 2011 the cost of installing a solar panel has dropped 60%. Solar panels are currently priced at $0.74/watt. And not only is the cost to purchase solar panels rapidly decreasing, the efficiency of solar panels is going up in leaps and bounds. In September, 2013 the Fraunhofer Institute for Solar Energy Systems set a world record for the efficiency of their latest solar cell at 44.7%. This surpassed their previous record of 43.6% that they had set only months before.
There has been a large increase in usage of solar cell technology across the world. This site has a nice graph of the increase in the top ten countries in the world (Only up to 2012). Germany has been leading the way since 2003. In February, 2014 it reported a PV Capacity of 36 gigawatts. (On an average day Germany can meet nearly 10% of its energy demands through solar alone) Solar cell technology is a very promising area of research and development for the future. It provides a fossil fuel free alternative that will be around for at least a couple billion more years. Due to Swanson’s Law (A trending drop in crystalline silicon photovoltaic cell price) solar panel costs should continue to decrease every year. Due to advances in technology those same solar panels are getting more efficient every year. Hopefully these two trends will allow for the mass implementation of solar cell technology across the earth. The EU (European Union) is leading the way to a renewable future with its Renewables Directive; a promise from all its members to have at least 10% (all the way up to 49% from Sweden) of their energy needs met through renewable sources by 2020. Solar will play a major part in this directive as Germany has shown. The US 2035 Energy Goal is that 80% of electricity will come from green energy sources. More solar power was installed in the US in the past 18 months than in the past 30 years! The US was actually the world’s leader in solar installation in 2013, even beating out Germany. The future is looking bright for solar cell technology.