Will PV cells take over the world?

Solar power is the poster child of the green energy movement. And why wouldn’t it be? Fuel that is entirely free, will be around for billions of years no matter what we as humans do, and doesn’t pump out nasty pollutants when used. Also, as a bonus, there is more solar power available than the world could conceivably use, roughly 89 petawatts of power [1], that’s 89,000,000,000 megawatts.

However, harnessing that power proves to be much more difficult than burning wood for a fire. The most common method used to convert solar radiation to useful energy is the photovoltaic effect, which converts photons from the sun directly to electricity and is utilized by photovoltaic, PV, cells. These cells in general do a fairly poor job of collecting the sun’s energy. Typically efficiencies are of the order 20%. In the laboratory, ie highly controlled conditions, PV cells have reached efficiencies of over 40% [2]. While the public may see these efficiencies in the future, they are not currently realistic.

What is realistic however, is a drop in price of PV cell technology. Last year, Ramaz Naam blogged for Scientific American about a possible Moore’s Law effect for solar PV cells [1]. Moore’s law originally applies to the doubling of computing power every 18 months, a trend followed by the computer industry for decades. It appears that solar power follows a similar curve, with dropping prices following a logarithmic curve from the 1980’s through 2010. Via Naam’s prediction, PV cells would reach $1/W in 2023, and could become cost effective, including installation costs, in 2020 [1].

It seems though that solar power will beat Moore’s Law. Today, 2012, PV cell production costs are already approximately $1/W [3]. That’s 11 years sooner than Naam’s prediction, made only 1 year ago. In addition to dropping to $1/W, improvements in technology and production methods could lead to costs dropping to 50¢/W in the next 10 years. This would put solar power much ahead of the curve, and into the cost effective region for power generation, poised for rapid entry into the energy market.

It is very difficult to predict when a technology is on the edge of explosion due to innovation, and so a year ago it would have been exceedingly difficult to guess that solar power would go through a revolutionary shift in production techniques, enabling PV cells to be produced at greatly reduced prices. However, it seems as if PV technologies have experienced a massive innovation spike with such ideas as new ways to manufacture silicon with less waste, improved stability in silicon wafers that allow for less of the material to be used, and new designs for solar cells themselves [3]. These technologies are emergent, and will be improved upon as kinks are worked out. However, these advances represent a boom for solar power, and it will continue to ride that wave for many years to come as technologies are perfected and production grows.

Will solar power be part of the future? Most definitely. The amount of grid-connected PV installations grew 39% in just the 3rd quarter of 2011 with over 1 GW installed in the first 3 quarters of 2011 [4]. This growth will continue, especially with recent price drops for PV cells. Will solar power take over the energy sector, and the world? Maybe. There are still many hurdles for solar power to face, an intermittent source being the most serious. But the hurdle keeping away the most investors and customers has been lowered, reducing one of the barriers to clean, cheap, accessible energy for all.

Here’s to world domination solar power.

[1] http://blogs.scientificamerican.com/guest-blog/2011/03/16/smaller-cheaper-faster-does-moores-law-apply-to-solar-cells/
[2] http://www.nrel.gov/ncpv/images/efficiency_chart.jpg
[3] http://www.technologyreview.com/energy/39771/page1/
[4] http://www.seia.org/cs/news_detail?pressrelease.id=1793



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9 responses to “Will PV cells take over the world?

  1. Great Blog!
    I found an interesting survey related to solar energy, conducted by ICMA(International City/County Management Association) in 2011. The core aim of this survey is to collect information on what local governments are doing related to the adoption of solar PV.
    According to this survey, approximately a third of local governments face challenges to solar energy development, and of those, nearly two thirds (64.0%) report the high cost of solar. The next challenges are aesthetic impact concerns (28.7%), lack of interest in or awareness about solar energy development (27.1%), and lack of enabling legislation to incentivize solar installations (26.5%).
    However, almost half of local governments said they have already a solar system. I realized that almost one-third of local governments have installed one or more solar PV demonstration projects. Local governments also have their own solar through planning. Zoning ordinances were the most commonly reported to address solar (43.1%), followed by comprehensive plans (34.8%), and green building codes (27.6%). Over half (54%) of local governments responding to the question also say that they have discussed solar energy in the visioning process.
    In addition, regarding incentives for solar, 17.2% of local governments offer financial incentives for installing solar PV.
    Through this survey, I realized that local governments put their energy into making changes to help facilitate the adoption of solar energy technologies.


  2. For a normal PV panel, the efficiency is about 10%, instead of 20%. Besides, I don’t think improving efficiency is the trend of solar energy. Since we have a lot of spaces for those PV panels, what we do care is the efficiencies divided by the construction costs. For instance, if we now have a PV panel with 10% of efficiency and with construction cost of 10 dollars, we prefer a 6% efficency and 5 dollars than a 12% efficiency and 15 dollars in the future. And increasing the efficiency will indeed cost a lot of money. So, what we will see in the near future is just the decreasing prices with nearly the same or droped efficiency. But PV panel efficiencies for a electrical vehicle is another story.

  3. yuxia1234

    Thanks for the topic first, I strongly agree with you that our world will be dominated by solar power in the future just as the scenes described in scientific fiction. However, based on the current technology, we still have such a long way to go. Just as the author said, the huge cost of solar is the most largest problem. Even the cost of PV cell production is already approximately $1/W, solar power still accounts for only 1 percent of electricity use in the United States(Based on a lecture I heard recently).

    Technology breakthrough will be a solution to this problem, such innovation can decrease the cost even faster than the predicted time. Government subsidy could also be an important method to boost the development of solar energy. China is example which government subsidies played a significant role in solar energy development. Loans at very low rates from state-owned banks in Beijing, cheap or free land from local and provincial governments across China, huge economies of scale and other cost advantages have transformed China from a minor player in the solar power industry into the main producer of an increasingly competitive source of electricity. (New York Times, Sep 14, 2011)

    Solar energy has many problems, but is still the one with most bright future to take place fossil fuel. We should do everything we can to make it easily used as fossil fuel.

    [1] New York Times, Sep 14, 2011

  4. techreviewseast

    Reblogged this on Tech Reviews East and commented:
    I’m not surprised the mainstream media is paying 0 attention to this right now! And actually, the graph looks a little off. I was under the impression that January 2012 saw prices below 1/watt: http://www.renewableenergyworld.com/rea/news/article/2012/02/chinese-tier-2-modules-offered-below-1w

    • bradystoll

      The graph is actually a projection from last year, so the numbers for this year are off from true values. As you point out and I mentioned in the post, the current price is approximately 1$/W.

      • techreviewseast

        Still, having a graph that is off by ten years kind of defeats the purpose of including it in the first place

      • techreviewseast

        People that just scan the first paragraph or two will not be aware of how close we are to utter solar revolution. Probably this year.

  5. yuki451

    I hope sollar would dominate in the future, but I agree with the comment that it would take a long time. Besides its manufacturing cost, I think its intermittency is one of the major problem. Generally grid operators forecast demand and supply capacity of electricity everyday but solar and wind made them difficult. If they overestimate solar generation, they need to balance frequency by other power resources (mostly coal or LNG). The solution for this would be adding batteries to solar pannels to compensate intermittency, but batteries are too expensive. Moreover, when solar generates electricity and exceeds the demand of home use, the electricity flows backward to grid. This will seriously affect to voltage (utility has a obligation to keep the voltage in a certain level) and require grid owner to bear cost of transformers. I think we should take these facts into account when we consider solars.

  6. twilliamson9

    Solar power clearly has a bright future based on the current trends of increased efficiency and reduced cost of solar mentioned in the post. I agree, however, that the biggest barrier to PV’s domination of the energy market is its inherent trait of being intermittent. Improvements in efficiency and production costs alone will certainly boost PV’s current role of shaving peak loads, but for it to truly dominate the energy market, developments in energy storage will be the deciding factor. If the production cost of PV dropped to $0.10/watt overnight, we would still be years away from being able to economically store the energy in a way that would let us rely on it around the clock.

    Of course, such improvements to production costs and efficiency will put more pressure on and resources into developing improved energy storage, accelerating progress. For now, the best we can hope for for solar in the near future is to continue adding more and more to our mix of energy sources. The sudden drop in production cost is certainly a huge step in the right direction, and hopefully one day it will dominate the market. There is still a lot of work to be done before that day comes. Until then, it’s critically important that we don’t put all of our eggs in one basket, but rather think carefully about which mix of energy sources make the most sense on a case by case basis.

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