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Perspective: “System output must improve”

Joyce Laird

Following SPI2011, four experts – including Argonne National Laboratory’s Mark Petrie and Dr. Seth B. Darling - volunteer their insight on the state of play in solar.

First up is Mark Petrie – technology development director – Energy Sciences and Engineering at Argonne National Laboratory. Petrie has recently been involved with the Intergovernmental Panel on Climate Change (IPCC) that has been researching the ability of renewable energy to contribute to climate change mitigation. And he believes we need to exercise caution when speculating about solar's place in the future energy mix:

“There is good potential”, he begins, “but there are a number of technical and economic barriers that will need to be overcome…to really make a dent in the true energy portfolio. You need to remember that when talking about energy generation and plants of Gigawatts (GW) and so forth, solar people always talk about how much capacity has been put out into the marketplace. I don't care about capacity. How much actual energy is coming off of those solar cells? I have something open on my desk right now that says the cumulative installed capacity worldwide is about 22 GW. But here's the problem. With 22 GW of installed solar, you are not getting 22 GW back out. If that efficiency factor is 25%, then in reality it is more like 5 GW.”

Petrie says he is supportive of all the renewable technologies. “I don't think we can ever solve all the climate issues and energy demand issues with a single technology. What gets your attention with solar is that there is so much solar energy hitting the earth. It is such an incredible, renewable resource. There is far more energy hitting the earth from the sun than you could ever imagine getting from wind or waves or tidal power or geothermal or any other resource. Think of what it would mean if there was a system that had 100% capacity and was 100% efficient. If I could just tap into that, I could solve all the energy problems of the world. How can I trap all those photons and transform them into something useable?”

LCOE is all important

Petrie's scientific colleague at Argonne, scientist Dr. Seth B. Darling, is hard at work on many levels trying to not only find the golden fleece that will trap those photons and turn them into useable electricity, but more importantly, accurately track them to lift the veil from power auditors' eyes: “The levelised cost of electricity (LCOE) is a drum we have to keep beating. It is really important that people need to understand the true cost of an installed solar system on any level,” he says. “Only LCOE can truly tell you what you are getting for the long term.”

He says that the only way to do accurate calculations of cost is to have real systems out in every geographical location, calculating data in true technology-agnostic facilities.

“We are working on it here”, he adds, “but there needs to be a network of facilities collecting not just data on the performance of PV modules, but also all of the ancillary equipment such as the inverters for example – under real life conditions for each area.

“Universities, private businesses, Governments – even the big testing facilities like Fraunhofer ISE and NREL should all be involved. Each provides a unique advantage. For industry, you want them involved because they need ways to benchmark their specific products against everything else that's already out there.”

Further consolidation likely

Headquartered in Charlotte, NC, U.S., Providence Solar is a new entrant to the solar market but ceo Tom Kepper has a track record in semiconductors. And he sees a parallel between that market and what is happening with solar around the world today.

Providence Solar is part of a fast-growing new business set; a developer, an IPP firm, and an independent power producer. The company finds sites and brings investors in. Then it sources the capital and negotiates with the power companies: “We build the sites and get the interconnection agreements and then we operate them,” Kepper says.

So with such a wide perspective on the process of building solar projects, what does he see as the current trends?

“There is a lot going on in the area of supply and demand out there today. I think what you are going to see is a consolidation of the industry. Companies are coming out with fully integrated solar kits. Developers like us will no longer need to go out and find racking systems or inverter systems and match them all up to the panels we select. We will be able to choose the best total kit with the technology that fits the area we want to install in. I think that has to be the growing trend in the industry.

“This will occur naturally as larger companies partner with – or buy up – companies that complement what they make or sell. It's a natural progression of smart business. It will happen more as the giant energy companies step into the solar business [think of the recent deal between Total and SunPower – Ed]. I see this as positive for the industry as a whole because when you have the Siemens', the GE's, the Schneider Electric's, and the AREVA's of this world involved in renewable energy in a big way, it adds to the validity of the technology”.

The importance of manufacturing

Rensselaer Polytechnic Institute (RPI) is private engineering school, founded close to 200 years ago in Troy, NY, US. Professor Jian Sun is the Director of RPI's Center for Future Energy Systems (CFES). His focus is on power electronics and power conversion for all types of renewables. He offers a very objective view.

“I think the whole industry globally right now lives on incentives and Government subsidies to make any installations possible. We saw this in Europe, where there was a peak in Spain because the incentive program was about to run out, so everybody rushed to buy solar panels. While that caused a huge spike, I have heard rumours that this year many of the companies may not survive because of the downturn after that peak, with the loss of the incentive program”.

From that perspective, Sun points to the importance of reducing the cost of making panels, and cites as an example the U.S. Department of Energy (DoE)'s SunShot programme: “If they can get solar down to a dollar per watt in the U.S. without Government support to artificially hold up the market, that would be phenomenal,” he says. This is the kind of program that the global solar market needs to aspire to in order to become cost competitive with other forms of energy.

Sun adds that he sees one area missing from the DoE plan however. This is how to grow the manufacturing sector of the industry, especially in places like the U.S. “On the solar panel side there is a lot of funding for R&D, new ideas and starting up small companies. But I look at a lot of the industries, and when technology moves to the manufacturing stage and is mature enough to be mass produced, it moves offshore”.

This is a major theme in the industry as a whole today, with countries in Asia such as China having gained a foothold in the manufacturing of solar panels. Even Germany is struggling to compete with China for the supply of modules and Chinese companies like Trina Solar and Suntech continue to make impressive strides forward at the expense of countries like the U.S. and Germany.

“I don't see enough emphasis on how we grow that part of the business and keep it here,” continues Sun, and though he is speaking specifically about the U.S. market, this is a challenge that many other countries now face too. “If the DoE [in the U.S.] doesn't look at this, the solar program won't turn into a true grid economy. We will become first the inventor and then the end user…but we miss the big manufacturing section in the middle.”

Systems growing in size

Tim Keating of Skyline Solar outlines a trend that sees larger solar systems being built, something that is changing the dynamics of the industry considerably.

He believes that the key to making the technology more competitive is a combination of three things: firstly, improving the efficiency of the overall system; secondly, developing a total systems approach; and finally, the all important scale. “When I say efficient, it's great to have a whiz bang 40% cell, but nobody can actually deploy 40% without concentration. In fact even a company like SunPower is having difficulty deploying 22%–23% cells, because the cost of making those cells is so much. So many are now talking about a concentration – even for silicon cells.”

Joyce Laird was asking the questions.


Joyce Laird has an extensive background writing about the electronics industry; semiconductor development, R&D, wafer/foundry/IP and device integration into high density circuit designs.

Renewable Energy Focus, May/June 2011.

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Photovoltaics (PV)  •  Solar electricity



Geoff Thomas said

17 November 2011
It is a pity to ask folk like Mark Petrie, no doubt fine in his normal working area of expertise, about something he has no experience of at all, eg his comment that Solar cells are 25% efficient so there is only 1/4 the world output, - does that mean that an automobile which is 10% efficient, (normal) can only go 1 tenth the speed?
One needs to know the actual meaning of the word efficient in the situation, - in cars it is how well they use their petrol, (not how fast they go) in Solar it is how well they use the sun, not how much an individual panel or group of panels puts out, - a 100 watt panel is a 100 watt panel, - it puts out, given certain conditions, ie full sun, not too hot, wires connected to load, 100 watts.
If it is 1% efficient it will need to be huge, ie 25 times larger than a 25% efficient panel.
Normal Solar panels are getting up to the 20% efficiency range, they will do this, in the right conditions, for approximately 4 hours per day, whilst the sun shines straight on the panel and considerably less for the morning and afternoon unless they are on a tracking frame which follows the sun when depending on latitude they can out out up to 50% more per day. So thats what the 22 gig capacity means, 22 gigs for every hour of full sun less efficiency loss through heat plus lesser quantities of gigs for lower light times.
Usually they (the owners of the solar panels) get paid for what they actually produce, so have excellent meters and recording equipment.
Geoff Thomas.

Del Bennett said

15 November 2011
I have been looking at PV systems for a number of years now. The manufacturers claims vary considerably and it is difficult to know exactly the level of output they can provide. At the moment I estimate that the efficiency of the cells is around 19/20% and the best output, midday is 1000watts/sq.metre, could someone confirm or correct my figures?

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