On June 21 the northern hemisphere will celebrate a read letter day for me – the summer solstice. This is the longest day of the year, when the sun’s position in the sky reaches its northernmost extreme. I’ve been an advocate for solar power for more than 35 years, so I’m also an advocate for a day dedicated to celebrating the sun. Simply stated: look up in the sky and see the solution to our energy needs. Most of our time is spent looking down at the ground for oil, gas or coal.
It’s been a common rule in the solar power industry that for each cumulative doubling of installed photovoltaic (PV) solar power (the type of panel commonly seen on the roofs of homes and businesses) the price of solar modules decreases by 18%.
Look up in the sky and see the solution to our energy needs. Most of our time is spent looking down at the ground for oil, gas or coal.
This “learning curve” is a characteristic of all manufactured goods and makes it possible to predict the future with great confidence. Transistors, displays, and wind turbines all represent things that are produced every day. And every day that passes, we get smarter, faster and less expensive. We have now reached a critical inflection point in the cost reduction of solar. The price of solar modules has dropped from $4 per watt in 2008 to $1.35 per watt this year, and is expected to drop below $1 per watt in the next couple years.
Many are unaware that electricity produced by PV will cost the same in 2011 as traditional sources of residential power in 19 countries, including Italy, Spain and the Caribbean. Experts have calculated and we forecast that costs will continue to decrease, at such a rate that by 2020, more than 100 countries, representing 98% of world population; 99.7% of world GDP; 99.2% of energy related CO2 emissions; and 99.5% of global residential electricity consumption, will have access to solar power that is equal to electricity costs from traditional sources of power.
A significant factor driving the affordability of PV solar panels is the price reduction of silicon – a raw material for the majority of solar cells. Just three years ago silicon used to account for as much as half of the solar module cost. Supply shortages in 2008 drove the price up to more than U.S. $300 per kilogram. Since then, silicon supply has caught up with the solar industry’s growth, reducing prices to less than U.S. $50 per kilogram. These reductions have helped drive panel costs down more than 50% since the first quarter of 2008.
Advances in solar technology are also pushing down costs and increasing capacity. In the past 35 years, five primary innovations were introduced to make the panel manufacturing more efficient and longer lived. In the next two years, the industry will be adopting five major innovations that will continue the pace of cost reduction, increase module life beyond the current 25 year warranty period and most importantly, increase efficiency of converting light to electricity.
To produce higher efficiency cells, manufacturers are using selective emitter technology, fine line metallization-such as double printing-or combinations of selective emitter and fine-line metallization to create a more efficient circuitry.
As silicon wafers get thinner and move much more rapidly through manufacturing plants than those used in typical integrated circuit fabs, improvements have been made in wafer cutting using a simple twist on today’s wire – structured wire that can dramatically increase the speed of transforming blocks of silicon into thin wafers.
As demand for panels increases, the industry is adapting automation methods from other high-volume manufacturing industries like integrated circuits and automotive production, leap-frogging the pace of development followed by these pioneering examples of mass production. Manufacturing processes are also becoming more complex – growing from 7 to more than 10 steps – and automation helps increase throughput, yield, and lower overall operating costs.
With these exciting technologies on the horizon, the costs of solar power will continue to become more competitive with traditional sources of power. That’s a trend we can all get behind.
Today is the longest day of the year, let’s celebrate our momentum and take this extra time to see PV’s potential to transform the global energy supply in just the next 10 years.
Picture: In this handout from NASA/Solar Dynamics Observatory, a solar large flare erupts off the sun June 7, 2011 in space. A large cloud of particles flew up and then was pulled back down to the sun’s surface.