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Archive for the category “solar”

Photovoltaic Thermal Hybrid Solar Collectors (PVT)

Schematic of a hybrid (PVT) solar collector: 1 – Anti-reflective glass, 2 – EVA-encapsulant, 3 – Solar PV cells, 4 – EVA-encapsulant, 5 – Backsheet (PVF), 6 – Heat exchanger (copper), 7 – Insulation (polyurethane)

Solar panels can convert ca. 20% of the solar radiation into electricity. Solar collectors can convert radiation in warm water or air at much higher efficiencies than those 20%. The tempting idea is to combine these two functions into a single module, a principle known as PVT. There are several construction possibilities: putting a glass cover in front of a black solar panel en pump the heated air away. Disadvantage: one degree Celsius temperature increase of the solar panel decreases the efficiency with about 0,4%. Alternatively, the solar panel can be cooled at the back-side, resulting in less higher temperatures of the panel. In the Summer, with reduced need for warm water, the glass cover could be removed in order to keep temperatures in check.

A little research reveals that in the 2018-2019 the PVT topic is anything but dead. Especially interesting is the prospect of combining PVT with seasonal storage of heat in large volumes of water.

PVT could be a potential solution in areas with high population densities and limited space for separate solar panels and collectors, like in the Netherlands, Flanders or England.

[] – De kansen voor PVT door middel van een analyse volgens Strategic Niche Management (2007)
[] – Evaluation Photovoltaïc-Thermal Solar Panels (PVT, 2008)

[] – Photovoltaic thermal hybrid solar collector (PVT)
[] – Verwarmen zonder gas met het Triple Solar®-systeem
[] – Ecovat PVT module

[] – Systematic testing of hybrid PV-thermal (PVT) solar collectors in steady-state and dynamic outdoor conditions
[] – PVT and seasonal storage: innovative technologies in Spain
[] – Photovoltaic Thermal /Solar (PVT) Collector (PVT) System Based on Fluid Absorber Design: A Review
[] – Numerical investigation of a solar PVT air collector used for preheating the ventilating air in tertiary building under the climatic conditions of Fez, Morocco
[] – New taskforce on PVT collectors to starting its work (2019)
[] – Thermal energy storage: a Spanish start-up achieves high solar fractions
[] – Energy performance analysis of a novel solar PVT loop heat pipe employing a microchannel heat pipe evaporator and a PCM triple heat exchanger
[] – Photovoltaic Thermal (PV/T) Hybrid Solar Panel
[] – PVT: het dak als warmtepompbron
[] – Analysis of a Residential Photovoltaic-Thermal (PVT) System in Two Similar Climate Conditions (2019)

Huge Returns For Agricultural Solar

Ever more farmers (and governments) are finding out that farmers with their huge stables and corresponding large roofs can realize huge return-on-investment with solar panels. Think 240% in 15 years.

The Dutch state of North-Holland, the one with Amsterdam within its borders, basically wants to identify every single suitable agricultural roof and stimulate the owner to cover these roofs with solar panels, in an effort to speed up the energy transition and realize a financial quick win.

[] – Jaarlijks 109 procent rendement op investering zonnepanelen
[] – Noord-Holland kiest voor zonnepanelen op boerendak

LONGi 166 mm Wafers Becoming the New Norm

Many regular solar panels are based on mono-crystalline silicon wafers. The solar PV industry is moving towards larger wafers, from 125 to 156 mm, that reduce production cost. Further increase towards 166 mm has now been realized by wafer producer LONGi, realizing a wafer price of $0.49. This is the largest wafer size than can be realized with currently available production tools.

[] – Why are monocrystalline wafers increasing in size?
[] – How LONGi’s M6 wafer boosted module output ten years ahead of schedule
[] – Longi will 166-Millimeter-Wafer zum Industriestandard machen
[] – LONGi: 2 gigawattpiek orders voor zonnepaneel met wafer van 166 millimeter


Solar Team Eindhoven Wins World Solar Challenge in Australia

The World Solar Challenge has resulted in a broadly supported startup called “Lightyear One“, that has begun producing solar powered cars for the market. Perhaps this car can participate as a non-competing guest in WSC-2021?

Solar Team Eindhoven won for the fourth time in a row the World Solar Challenge in Australia in the cruiser class (family car). The Low Countries dominated anyway, with Team Agoria of the the University of Leuven winning the speed racing class, when Delft University had to abandon at 90% of race at pole position when their vehicle burned out completely.

Dutch PM Mark Rutte congratulates Solar Team Eindhoven

The 2019 innovation was the autonomous driving aspect, enabling the car to find a sunny spot all by itself.

[] – Lightyear One company site
[] – It’s Cruise Control All The Way From Solar Team Eindhoven
[] – Bridgestone guarantees another decade of WSC sponsorship
[] – Dutch company develops partly solar powered car

Solar Park Midden Groningen

Largest solar park “Midden Groningen” in the Benelux completed. Size: 140 soccer fields. Capacity: 103 MW. Location, surprise, surprise, in the middle of the Groningen province.

Yesterday on the Dutch news it was reported that some 40 large solar parks are under construction or in the planning phase in the Netherlands.

A point of criticism is that these solar arrays occupy a lot of valuable agricultural land. Yet it is estimated that by 2050, after completion of the renewable energy transition, merely 0.5% of all arable land will be covered with solar panels. Lots of farmers are interested in solar panels on their land, because they have higher returns than crops in many cases. Yet it is urged to aim at dual-use of land, by lifting the panels, so that life stock can graze below them.

Grid-operator TenneT has warned that the grid in its current state is hardly coping with all these new renewable energy projects and that it is forced to invest 12 billion euro in the coming 10 years to prepare the grid for 7 million new solar panels, for every Dutch household one panel. Several solar parks cannot be connected to the grid because of capacity limitations.

[] – Project site
[] – Detailed solar project overview in the Netherlands
[] – Werken aan een duurzame toekomst met zonneparken
[] – Tennet breidt stroomnet uit voor 7 miljoen zonnepanelen
[] – Zonnepark 103 MWp Midden Groningen is eind 2019 gereed
[] – Vermogen zonnepanelen meer dan de helft toegenomen

In 2018 total installed solar capacity in the Netherlands increased with 1.5 GW to 4.4 GW peak.
Total average electricity consumption: 13 GW.
Total installed electricity capacity from all sources: 29 GW.

Under Dutch circumstances the peak-Watt number needs to be divided by 10 to arrive at 24/7/365 average power.
In other words, the currently installed 4.4 GW peak means 0.44 GW average power. If we assume a renewable energy base of 50-50 wind-solar by 2050 and additionally assume a doubling of the electricity production to cover for all energy requirements, including transport and space heating, than the Netherlands will need 26 GW electricity on average. That would be 13 GW solar on average or 130 GW peak. Spread out over 30 years that would be 4.3 GW peak increase per year, rather than the 1.5 GW the Netherlands had in 2018.

It remains to be seen if it is not cheaper for the densely populated Netherlands to be satisfied with, say, 50% local solar production and import the rest from desert areas, where labor and soil are cheap and abundant and solar conditions far better than in the Netherlands. For that to happen, the energy storage problem needs to be solved first, before large quantities of hydrogen or one of its many derivatives, will arrive by oil-tanker, err… make that hydrogen-tanker in Rotterdam harbor and fuel retrofitted conventional fossil fuel power stations.

Michael Grätzel at GYSS 2019 – Molecular Photovoltaics and Perovskite Solar Cells

[] – Dye-sensitized or Grätzel solar cell
[] – Perovskite solar cell

Everybody Loves Perovskite

When people talk about solar cells, they typically think of silicon wafers, produced in a non-trivial process. But do we really need silicon to harvest solar energy? Actually not. Far cheaper alternatives do exist, keyword perovskite:

A perovskite solar cell (PSC) is a type of solar cell which includes a perovskite structured compound, most commonly a hybrid organic-inorganic lead or tin halide-based material, as the light-harvesting active layer. Perovskite materials, such as methylammonium lead halides and all-inorganic cesium lead halide, are cheap to produce and simple to manufacture.

Solar cell efficiencies of devices using these materials have increased from 3.8% in 2009 to 25.2% in 2019 in single-junction architectures, and, in silicon-based tandem cells, to 28.0%, exceeding the maximum efficiency achieved in single-junction silicon solar cells. Perovskite solar cells are therefore currently the fastest-advancing solar technology. With the potential of achieving even higher efficiencies and very low production costs, perovskite solar cells have become commercially attractive.

Meanwhile the EU has discovered perovskite and started a massive development program, where everybody and his mother in Europe joined in, see list at the bottom.

Price erosion potential: from 75 cent for silicon to 10-20 cent per installed Watt for perovskite. Think 300 Watt panels for 45 euro or dollar. If this will materialize, the most expensive aspect of solar will not be the panel but the space it occupies, certainly in over-crowded Europe.

[] – Potential of Perovskite Solar for Lower Cost Energy
[] – Perovskite Solar Cell Fever Reaches Fever Pitch
[] – Perovskite solar cell

Jumpers onto the EU perovskite bandwagon:

Solliance Solar Research (NL, BE, DE), TNO (NL), including:

Read more…

18.1% – New Perovskite Solar Record

An international team of scientists claim to have developed perovskite solar cells with an efficiency of 18.1% by using a new configuration of cesium lead iodide perovskite CsPbI3, which has the narrowest band gap – 1.73 eV – of all inorganic lead halide perovskites.

Researchers from China’s Shanghai Jiao Tong University, Switzerland’s Ecole Polytechnique Fédérale de Lausanne and the Okinawa Institute of Science and Technology Graduate University in Japan observed CsPbI3 cystals in their more stable beta phase. Previous research focused on the crystals in their alpha, or dark phase.

[] – New configuration gives perovskite cells 18% efficiency
[] – Perovskite solar cell
[] – Why perovskite solar cells are so efficient

Solar Team Eindhoven and the 2019 World Solar Challenge

Solar Team Eindhoven and their brainchild Stella Era

The Technical University of Eindhoven will once again participate in the Bridgestone World Solar Challenge in Australia, a race over more than 3,000 km with cars that are propelled by solar power and batteries only.

[] – Solar Team Eindhoven Presenteert Stella Era
[] – World Solar Challenge 2019
[] – Lightyear Electric Car With Solar Power Goes For Test Drive

Read more…

Stefan Reichelstein: Solar Energy’s Bright Future

[] – Stefan Reichelstein

[] – Economics of converting renewable power to hydrogen

The recent sharp decline in the cost of renewable energy suggests that the production of hydrogen from renewable power through a power-to-gas process might become more economical. Here we examine this alternative from the perspective of an investor who considers a hybrid energy system that combines renewable power with an efficiently sized power-to-gas facility. The available capacity can be optimized in real time to take advantage of fluctuations in electricity prices and intermittent renewable power generation. We apply our model to the current environment in both Germany and Texas and find that renewable hydrogen is already cost competitive in niche applications (€3.23 kg⁻¹), although not yet for industrial-scale supply. This conclusion, however, is projected to change within a decade (€2.50 kg⁻¹) provided recent market trends continue in the coming years.

[] – Hydrogen Economy

World’s First Solar Car Presented in the Netherlands

Lightyear One is a Dutch startup, emerging from the Technical University Eindhoven-based Solar Team Eindhoven, that very successfully participated in several editions of the Australian World Solar Challenge, see links below. The company presented today their first “solar car”, a car that in sunny climates can drive for months without having to be recharged, provided it is parked in the sun and not under trees or under carports. With this condition fulfilled the car can drive ca. 20,000 km in sunny climates, like in most parts of the US or southern Europe, 10,000 km in cloudy Holland, without external charging. Note that in Holland average annual distance driven is ca. 13,000 km.

Data sheet:

– 5 m2 solar cells
– Max range with charged batteries and additional sun: 725 km
– No rear window, camera’s only
– CW-value: less than 0.20
– 4 electric motors in the wheels
– Weight ca. 1000 kg
– 2021 small scale production
– End 2022 1500/year production
– 2024-2025 mass production in Helmond
– Design Lowie Vermeersch (Ferrari e.o., #12 in world car designers ranking)
– Initial price low volume production: 119,000 euro

[] – Lowie Vermeersch
[] – Production site
[] – Eerste zonneauto van Helmondse Lightyear onthuld
[deepresource] – LightYear Solar Car – Update
[deepresource] – Solar Driving – State of the Art
[deepresource] – TU-Eindhoven Presents Stella Vie
[deepresource] – TU Eindhoven Wins Solar Challenge 2013 (Cruisers)
[deepresource] – Stella Lux (2015)
[] – 2019 edition

D66 Wants Solar Panel Fields in the IJsselmeer

The very EU-friendly Dutch left-liberal party Democrats-1966 (D66) proposes to install in the inland sea IJsselmeer, 4000 hectare worth of “solar islands”, enough to supply 1 million households with electricity (year-to-year, ignoring storage). That would amount to 4% of the IJsselmeer area. The Netherlands btw has 8 million households, so 32% of this relatively calm water body would suffice to cover the entire Dutch private electricity needs, assuming adequate efficient storage would be in place. The far less calm North Sea could easily provide the rest with wind turbines. A mixture of the solar and wind is desirable because it more or less compensates for seasonal fluctuations (solar in the summer and wind in the winter) and thus reduces the need for storage.

The timing of the launching of the plan could have something to do with the upcoming EU-elections, on the other hand, the Dutch are far behind with the implementation of the EU renewable energy policy and something has to be done. Money could for a large part come from private investors and pension funds, who will see this as a safe investment opportunity with predictable returns, exactly like every German farmer in the north could cash in from the wind energy Bonanza.

Other parties have not yet reacted.

[] – Als het aan D66 ligt, drijven er binnenkort zonnepaneeleilanden op het IJsselmeer
[] – Predictable objections from the “not-in-my-backyard” crowd
[] – D66

Morocco Turns Sahara Into Solar Energy Oasis

Organic Solar Cells

Most people associate solar cells with silicium. There are however other materials with which the photo-voltaic effect can be achieved, materials like conductive organic polymers or small organic molecules. The energy conversion process has some resemblance with natural photosynthesis. Maximum reported efficiency is ca. 15%.


The molecules used in organic solar cells are solution-processable at high throughput and are cheap, resulting in low production costs to fabricate a large volume. Combined with the flexibility of organic molecules, organic solar cells are potentially cost-effective for photovoltaic applications. Molecular engineering (e.g. changing the length and functional group of polymers) can change the band gap, allowing for electronic tunability. The optical absorption coefficient of organic molecules is high, so a large amount of light can be absorbed with a small amount of materials, usually on the order of hundreds of nanometers. The main disadvantages associated with organic photovoltaic cells are low efficiency, low stability and low strength compared to inorganic photovoltaic cells such as silicon solar cells.

Compared to silicon-based devices, polymer solar cells are lightweight (which is important for small autonomous sensors), potentially disposable and inexpensive to fabricate (sometimes using printed electronics), flexible, customizable on the molecular level and potentially have less adverse environmental impact. Polymer solar cells also have the potential to exhibit transparency, suggesting applications in windows, walls, flexible electronics, etc. An example device is shown in Fig. 1. The disadvantages of polymer solar cells are also serious: they offer about 1/3 of the efficiency of hard materials, and experience substantial photochemical degradation.

Polymer solar cells inefficiency and stability problems, combined with their promise of low costs[5] and increased efficiency made them a popular field in solar cell research. As of 2015, polymer solar cells were able to achieve over 10% efficiency via a tandem structure. In 2018, a record breaking efficiency for organic photovoltaics of 17.3% was reached via tandem structure.

[] – Molecular Materials and Nanosystems (M2N)
[] – Research group site
[] – Organic solar cell
[] – Zonnecelonderzoeker René Janssen wint Spinozapremie

English language presentation by prof. Rene Janssen of the Technological University of Eindhoven on the topic of organic solar cells:

Read more…

SolaRoad Update 2019

Portfolio of current SolaRoad projects

The road-dual purpose project SolaRoad in the Netherlands still exists. The idea is to combine the traditional transport function of the road with generating solar energy from panels on top of the road structure. The panel is the road, so to speak. It began with a bicycle path, now bus lanes are next. The glass cover layer has been replaced by synthetic material. The rationale behind this project is that in the Netherlands, space is rare and expensive. Hence the idea that dual use of road surface could be economical.

Dutch language video

[] – Project site
[] – Nieuwe fase SolaRoad: ook autoweg gaat elektriciteit opwekken
[deepresource] – SolaRoad Followup Project (2018)
[deepresource] – SolaRoad Project Still Alive (2017)
[deepresource] – SolaRoad Project Update (2016)
[deepresource] – SolaRoad Operational (2014)
[deepresource] – SolaRoad Finally Launched (2014)
[deepresource] – SolaRoad (2013)

Merger of Photo-Voltaics and Nano-Technology

Dutch language videos

25% of the cost of a conventional solar cell is in producing the required silicium. Most of that silicium is not used other than for providing mechanical stability, but has no electronic of photo-voltaic function. The idea is to get rid of 90% or more of the conventional amount of silicium used in a solar cell and aim at “printing” a super-thin layer of silicium onto some cheap substratum. Think of printing a newspaper. Five of those printing machines, operating for 10 years on end, would suffice to provide the entire world with low-cost solar energy.

[] – Goedkopere zonnecellen door nanotechnologie
[] – Nano zonnepanelen
[] – Nanodeeltjes kleuren zonnepanelen groen
[] – Nanodeeltjes vangen licht voor zonnecel

How do Solar Cells Work?

Giant Solar CSP and PV Projects in Dubai

[] – $13.6B record-breaking solar park rises from Dubai desert

Renewable Energy is Going to Win on Price Alone

Dutch language video

No need to fence with debatable arguments like “fossil fuel depletion” or “climate change” or “clean energy” or “silent energy” in order to push renewable energy.
Prospects are that renewable energy is going to beat the competition on price alone.
Prof. Dave Blank argues that solar panels will be very cheap soon.

2018 – 50% Increase Installed Solar Power in the Netherlands

The Dutch national statistics office CBS says that in 2018, installed PV-solar power increased with 50%, or 1500 MW, increasing the total from 3000 to 4500 MW. This means that additional 460,000 households were covered with renewable energy, of a total of 7 million households.

[] – Vermogen zonnepanelen meer dan de helft toegenomen

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