Utility-Scale Thin-Film: Three New Plants in Germany Total Almost 50 MW

Although still lagging behind crystalline silicon in the maximum efficiency stakes, as costs per Wp fall, thin-film technologies are rapidly taking up a significant share of the PV market. Industry figures give a compound annual growth rate of 60% between 2002 and 2007, and production capacity could reach more than 10 GW in 2010 and 16 GW in 2012. Although uncertainty remains over the timescale, the European Photovoltaic Industry Association (EPIA) nonetheless expects about 4 GW of thin-film production capacity to be operational in 2010. Based mainly in Europe, China, Taiwan, the USA and Japan, this will represent about 20% of total PV module production, up from 10% in 2007.

Consequently, the thin-film sector is considered not only a very dynamic market, but one which also benefits from significant potential for development. Scaling factors, efficiency gains and the new production technologies are expected to reduce thin-film module manufacturing costs to €1/Wp (and below) in the near future, EPIA says. Efficiency is anticipated to rise from a current 6%–12% to 10%–15% in the coming years, with a potential of more than 20% in the longer term. Meanwhile, potential material developments include optimization of different technologies (a-Si, a-Si/µc-Si, CI(G)S and CdTe) in addition to the development of new polymers and other types of organic, dye-sensitive solar cells.

A clear signal of growing confidence in the sector was provided by EPIA’s International Thin Film Conference. Held in November 2008, the event was the first EPIA event to focus on thin-film. With over 350 participants in attendance, the conference, held in Munich, Germany, heard that more than 150 companies had already entered the thin-film business, with some 40 of these already in production.

Winfried Hoffmann, EPIA president, explained that while crystalline silicon module prices have shown a 20% decrease with each doubling of installed capacity, in the case of thin-film modules this digression rate may be higher, especially in the wake of the silicon shortage.

Paula Mints, analyst at Navigant Consulting (and occasional REW contributor), presented analytical data on the evolution of the thin-film PV market, showing a spectacular annual growth rate of 126% in 2007, although she also warned that due to the current global financial environment, growth expectations for the next two to three years need to be reduced slightly.

The subtitle of the conference: ‘Thin Film goes Large!’ seemed particularly appropriate, given that Germany is host to a range of thin-film projects that more than illustrate the technology’s potential. With three new large-scale thin-film PV installations recently commissioned, with a combined capacity of some 50 MW, Germany can provide an excellent insight into the real cut and thrust of the thin-film market.

Pitched Roof installation

Located in Moers, near Duisberg, on the site of a former coalmine, the head office of Riedel Recycling has been home to Germany’s largest pitched-roof thin-film plant since October 2008. (See image, below, which shows the vast PV structure which covers nearly 10,000 square metres.)

The PV system has an output of 837 kW and will deliver around 750 MWh per year. Supplied by the American manufacturer First Solar, the black cadmium telluride (CdTe) modules cover the large south-facing roof, covering nearly 10,000 square metres of the former coal mixing hall. Mining at the site was discontinued in the 1990s, and since 2001 Riedel has used the building for recycling construction materials and storing wood.

Installed at a height of up to 30 metres, and at inclinations of 36°, 55° and 75°, the 11,467 modules could only be fitted with an inclined lift and a ladder. In particular, explains Günter Grandjean from system provider Solaxis GmbH, the inclination of the main roof, at 36°, caused problems ‘for the human body, this angle is very unusual.’ Even so, the installation was completed in three months.

The owners, brothers Ludger and Norbert Riedel, explain their reasoning in installing thin-film: ‘Thin-film modules are a good choice at our latitude, since they deliver a good output, even with weak solar irradiation,’ explains Ludger Riedel. The solar plant cost €3.4 million net, which included a new roof covering – the service technicians replaced asbestos-containing corrugated sheets with steel while they installed the solar modules.

Riedel continues, ‘In the best case, the plant will have already paid for itself after 10 years thanks to the increased feed-in remuneration of 44 eurocent/kWh.’ Placing a lot of emphasis on energy efficiency he adds: ‘We want a sustainable investment that pays off and fits well with our company philosophy.’

This philosophy is evident elsewhere at the site too. The two-storey administration building was once a fair-stand of a Japanese computer manufacturer and uses rescued facade coverings, entrance doors and lamps from a bank building before it was demolished. The flooring of the stairs is made out of recycled glass and brick dust, while the windows of the administration building previously saw service in the pithead baths of the Pattberg coalmine.

Four Sputnik Engineering SolarMax central inverters are installed at the facility, two at 300 kW, together with one at 100 kW and 30 kW respectively. In another example of clever thinking and maximizing efficiency, heat generated by the SolarMax C Series central inverters, which have a maximum efficiency of 96%, is used for space heating. In Moers this amounts to around 45 kW. ‘We transfer the waste heat to the air conditioning system with heat exchangers and into the administration building,’ explains Grandjean of the system which supplys the complete heating needs of about 30 employees.

Further installations are also planned. In addition to the hall roofs, the roof of the former fair-stand could also supply electricity. ‘We are considering installing tracking solar plants on the outer columns,’ reports Norbert Riedel. A further possibility would be to mount solar modules on the old watertower, which lies to the south of the processing hall.

Utility-scale play

On a somewhat larger scale comes one of the world’s largest thin-film solar parks, recently commissioned by Conergy Deutschland GmbH in Trier, near Germany’s border with Luxembourg.

Developed on behalf of local utility group Stadtwerke Trier (SWT), Conergy built the 8.4 MWp thin-film installation over a period of six months. The installation includes more than 112,500 thin-film modules, again supplied by First Solar, over an area of 250,000 square metres. These modules are mounted on 40,000 Conergy Solar Linea model mounting systems, and are linked to 28 Conergy IPG 300K series inverters. Capital expenditure for the grid-connected project amounted to around €30 million, and the output from the facility is sold at the lucrative feed-in tariff of 35.49 eurocents/kWh – a rate that the operators will enjoy for over 20 years. The plant is expected to produce over 9 GWh annually, enough to supply over 2400 four-person homes all-year around, the company claims.

‘We’re very happy about the project’s quick realization, and we’re proud that our plant is immediately producing environmentally friendly electricity for homes in Trier,’ said Rudolf Schöller, the project manager at SWT responsible for the solar park. ‘Considering the great demand, we hadn’t expected to obtain all the modules by the year’s end,’ added Schöller.

‘The project shows that power supply companies have now discovered photovoltaics for themselves,’ says Conergy Deutschland managing director Jochen Kirmaier. He goes on to explain: ‘In light of the current capital market crisis, solar energy has now become a safe and sought-after investment.’

IPP development

Meanwhile, with its final phase of commissioning, the Waldpolenz energy park in Brandis, near Leipzig, has now become the world’s biggest thin-film solar PV power plant.

The juwi group – based in Bolanden, south-western Germany– built the 40 MW thin-film solar park, completing the installation the end of 2008. The solar power station, located in the eastern German state of Saxony, is expected to generate approximately 40 GWh annually, displacing about 25,000 tonnes of carbon dioxide a year. (See image of the project, below.)

Construction at the site, a former military airbase, began in February 2007. In August that year the first building phase was completed and the official inauguration of some 6 MW of capacity took place. Built on half of the 220 hectare site, in the townships of Brandis and Bennewitz, the surface area of the installation is approximately one kilometre wide by two kilometres long.

Indeed, one key to the development was the site itself. ‘In Brandis we’re building on an area of more than a million square metres. By contrast, most house roofs are only 40 to 50 square metres,’ says Matthias Willenbacher, co-head of the juwi group, adding: ‘There are very few contiguous areas of this kind and size in Germany.’

Investment in the Waldpolenz solar park amounts to some €130 million and when juwi announced the 40 MW solar project they stated an installed project cost of €3.25/W.

Working jointly with the Sachsen LB Group, the juwi group has structured a professional equity capital and external financing scheme. SachsenFonds GmbH – a subsidiary of the Sachsen LB Group – has been offering to interested investors owner’s equity of the project in the form of closed-end funds since late summer 2007. The move allows inhabitants of the region to have the opportunity to participate in the project with investments starting at €5000.

‘We are proud to have been able to implement such a unique, forward-looking project of this scale together with juwi and SachsenFonds,’ says Sachsen LB board member Werner Eckert.

In addition, Germany’s legislation – the Renewable Energy Sources Act (EEG) – stipulates payment of approximately 35 eurocents/kWh, making installations that use innovative technology, such as thin-film, commercially cost-effective.

‘The Sachsen LB Group’s long track record in project financing renewable energy projects clinched our financing decision,’ says Fred Jung, co-CEO and co-founder of the juwi group.

As general contractor, juwi was in charge of the planning, logistics and construction site management, and says that the project is creating impetus for the regional and national labour market. juwi, whose own employees are responsible for the operational management, service and maintenance of the park, adds that projects such as this one also create jobs in related supplier sectors, such as the module, inverter and metal construction industries. Most of the 550,000 First Solar modules for this project, for instance, are being produced in Frankfurt (Oder) in eastern Germany where one of the world’s biggest and most modern production facility for thin-film modules was opened in July, 2008 – creating 400 jobs. The inverters from SMA and sub-structures are also made in Germany, juwi says.

In addition, juwi solar GmbH, the group’s solar arm, plans to set up a base on the grounds in Brandis and steadily add personnel in the coming years. ‘Particularly with [a] view to more projects in the region,’ says Lars Falck, managing director of juwi solar GmbH.

Willenbacher explains further: ‘At a time when the whole world is discussing climate change we are demonstrating the capabilities of renewable energies. Solar electricity is not only good for the environment, it also builds independence from expensive energy imports and creates new jobs. Freestanding installations are an affordable segment of photovoltaics and contribute greatly to that success.’ Willenbacher points out that, ‘with this installation in Brandis and Bennewitz, we are demonstrating that photovoltaics no longer faces any limits. Very soon everyone will be able to actively contribute towards withdrawal from nuclear energy and a climate-changing, fossil-based power supply – by simply switching to solar energy.’ He adds: ‘That fosters independence, secures local jobs, preserves the environment, and is easy on your wallet.’

Due to its size, which in turn means savings potential across all the system costs, the Brandis plant is a demonstration of the progress being made on cost-cutting in the photovoltaic industry. Thus, with a price of approximately €3250/kW, the installation is around 20%–40% cheaper than the going German market price. ‘Our thin-film modules can be produced cost-effectively, meet the highest quality standards and generate superior energy yields,’ says Stephan Hansen, managing director of the German subsidiary First Solar GmbH. ‘Large-scale projects such as these make a huge contribution to making solar electricity more competitive,’ comments Willenbacher. ‘No other solar power plant in the world is as big and as cost-effective as the juwi project in Brandis,’ he adds, saying: ‘Within just a few years the price of solar electricity produced on your own rooftop will be cheaper than the power supplied by the energy utilities. Photovoltaics will then reach completely new dimensions because everyone will want their own installation. That will launch an unprecedented boom.’ The solar industry anticipates that in just eight to 10 years solar electricity will have achieved wide spread grid parity.

‘Thin-film modules have long since reached series maturity, are cheaper to produce than crystalline modules, are higher-yielding, and above all are not affected by scarcities of and dependency on raw material,’ emphasises Falck.

For example, to supply 10% of Saxony state’s (an 18,000 km2 area of eastern Germany) annual power demand by PV installations, some 2 TWh of solar power a year would have to be produced. The area needed to generate this would be around 4000 hectares. That corresponds to just 2% of the developed and traffic area of Saxony. ‘These figures show that solar power can make a big contribution to generating climate-friendly energy,’ says Falck.

The future for thin-film

Although there has been a rapid ramp up in the number of companies within the thin-film sector, it’s noteworthy that all three of these projects use modules manufactured by First Solar; speaking at the EPIA thin-film event, that company’s Benny Buller argued that their cadmium telluride (CdTe) modules have the lowest module production cost in the sector, allowing for the lowest module price in the current market. This echoes comments from Mike Ahearn, chairman and CEO of First Solar, who in December said: ’Looking ahead to the next 2-4 years, First Solar will be in a position to produce power from the sun at costs competitive with conventional electricity generated from fossil fuels.’

With a strong policy for cost reduction (glass loss reduction, tellurium cadmium oxide (TCO) loss reduction, low cost encapsulants, faster TCO deposition rates and such like), efficiency increases and economies of scale, in its latest earnings announcement, released in late October, First Solar announced a manufacturing cost of $1.08/W, a figure which includes a $0.04/W ramping up cost associated with factories under construction in Malaysia.

It is clear that with a range of large-scale projects already in operation (where the appropriate support mechanisms are in place), thin-film is rapidly establishing itself as a market force to be reckoned with, both in Germany and around the world. Conference chairman Bernhard Dimmler of Würth Solar GmbH & Co KG summed up the prospects for the technology by asking not if thin-film was competitive with crystalline technologies but rather: ‘Will c-Si be able to compete with thin-film PV in 10 years time?’ He argues that if thin-film PV producers are able to reach their targets, the answer is ‘no’.

David Appleyard is associate editor of Renewable Energy World magazine.

With thanks to Iris Krampitz for original research on the Riedel Recycling case study.

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