19 July 2021


Solar PV Europe Netherlands

Why Bigger is Better when it comes to Solar Panels

Author: Solarplaza

A move to larger panels is good news for the Dutch solar industry—so it makes sense to adapt as soon as possible.

It pays to think big in the solar industry. Vaster projects can help to optimize balance-of-plant costs. Larger portfolios can deliver economies of scale in capital expenditure and operations and maintenance. Bigger companies can attract more investment and get better component prices. And the same goes for solar panels. The average module power output has been creeping up since 2009 when 290 W was the standard. Last year, that figure was 550 W. And in 2021 we have breached the 600 W level. At 210 mm, the new silicon wafers used by these higher-rated panels are larger than ever before.

The increase in average wafer size in the industry has been recent, and significant. A mere five years ago, most large solar projects were still using panels made from 125 mm wafers, a format that has been around since the mid-2000s. This size grew to 156 mm, 158 mm, 163 mm, 166mm, 182 mm, and most recently 210 mm in just a few years, based on manufacturers’ ability to work with larger wafers, cells, and modules. Why is this important? In a nutshell: larger wafers mean larger and more powerful panels. And larger panels mean more solar power for less amount of equipment per module and reduced costs per Wp. 

More power per string for ground-mounted projects

As an example, a Trina Vertex DEG21C.20 bifacial module for ground-mounted projects can deliver up to 660 W of power, compared to 585 W for a reference model. Additionally, besides higher power, with a low open-circuit voltage design at 45.9 V, developers can get 29 Vertex modules per string, compared to 25 as standard. That equates to more than 19 kW of total power per string, compared to less than 14 kW for the reference module.

Vertex 660 W modules can thus offer 4.5 kW of extra power output per string, a 31% gain compared to traditional setups. To put the benefits further in context, consider the example of a 110 MWp solar plant in Seville, Spain, with string inverters, bifacial modules and single-axis trackers. Compared to a traditional setup with 25 modules per string, equipping the plant with Vertex 660 W products would result in 11% fewer panels, 12% less DC cabling, 22% less AC cabling, and 24% fewer trackers. 

This reduction in components would cut balance-of-plant costs by almost 4.7%, from €0.28 to €0.27 per watt. Across the entire plant, that is equivalent to almost €1.5 million in savings. These savings translate to a 2% cut in levelized cost of energy, from €34.10 to €33.40 per MWh—just by a change in module size. Having fewer modules also means plants can be built more quickly, with a knock-on impact on contractor costs.

Unsurprisingly, analysts predict 210 mm wafers will soon dominate the market. InfoLink, for instance, forecasts wafers of at least 210 mm will make up 56% of module production by 2025, up from 19% at present.

High installed capacity for rooftop projects in the Netherlands

Indeed, Dutch solar developers will likely be keen to see the industry standardize around 210 mm for some time to come. With the SDE ++ subsidies being trimmed down more and more, the Dutch solar industry welcomes every possibility for increasing energy yield and saving costs. Not only are the subsidies being phased out, but the Netherlands also still faces the common challenge of land scarcity. Traditional large-scale ground-mounted PV projects are unlikely to help the country achieve its renewable energy targets on their own, which has been causing a strong call for large-scale rooftop projects, such as recently emphasized by a group of experts (quoted in the national newspaper De Volkskrant). Not only do the 210 mm wafer panels help with saving costs, but they also offer flexibility and efficiency in a reduced space. 

If we take a closer look at another successful Spanish example, a recent 1MW project on a 9600m2 flat factory roof shows how one of Trina’s modules, the Vertex DE18M.08(II), can offer efficiency and significantly reduced costs. Such an application can lead up to 21.2% efficiency, and provide an installed capacity of 1152 kWp. When compared  to 166mm silicon cell panels, this represents a power yield increase of 11% and a higher power generation along the project lifetime. Considering the increased installed capacity for each module, projects can see a decreased cost per watt in several of the plant components, such as inverters, cables, grid-connected cabinets (boxes), and installation accessories.

The emergence of a new standard

Although there are clear benefits in moving up to larger panel sizes, the transition from one size to another also requires a fair amount of adaptation. Particularly in the early stages, developers may be rightly concerned about finding plant components, such as mounting structures and inverters, that are compatible with larger panels. Fortunately, the solar industry has already taken the initiative in embracing 210 mm wafers and ultra-high power panels.

July 2020 saw Trina Solar launching the 600W+ Open Innovation Ecological Alliance, an industry group committed to supporting the deployment of ultra-high-power modules. By August, the Alliance had pulled in 57 members, including organizations as diverse as the DNV, Huawei, Nextracker, SMA Solar Technology, Sungrow, Solaredge, UL, TÜV Rheinland and Trinatracker.

Thanks to this wave of industry support, Dutch engineering, procurement and construction firms can specify 600 W+ panels confident in the knowledge that they are fully compatible with components from a wide range of manufacturers. On the inverter front, for example, GoodWe, Growatt, Huawei, SMA, SolarEdge, Solis and Sungrow all support the larger format. And the same goes for eight of the world’s leading tracker suppliers: Arctech Solar, Array Technologies, GameChange Solar, Ideematec, Nextracker, PVH, Soltec and TrinaTracker.

This broad industry backing points to 210 mm wafer based solar panels becoming the new standard for Dutch solar in the coming years. And given the wide industry support that already exists and the clear benefits of using this larger format, there is no reason why developers should not start specifying the technology today.

This article was created in preparation for Solarplaza Summit The Netherlands. Be the first to know when the new edition will be held by signing up for updates.