The new report about solar photovoltaic of Fraunhofer is out!
The new report about solar photovoltaic of Fraunhofer is out!
Battery technologies have undoubtedly become the Holy Grail of the EV industry, just as energy storage is the Holy Grail of renewable power generation/Integration. There are different types of batteries but Lithium-ion batteries are the most popular batteries existing in the market powering our consumer electronics and EVs successfully. The specific energy of a modern lithium-ion battery is about 220-240 Wh/kg which is still not good enough to compete with gasoline powered cars making EVs less viable option for long distance travels. Engineering lighter, more powerful batteries with higher energy density would definitely be a game changing innovation in battery technology systems. One such possibility is to replace modern lithium-ion batteries with so-called lithium-air batteries. Lithium Air battery would be able to accumulate five times more power than lithium-ion technology. This could have a major impact on electric cars market, which now uses lithium-ion batteries.
A new kind of battery systems called Lithium Air battery has created lot of excitement among the battery technology researchers because if lithium air battery works then energy density close to that of gasoline could be achieved. The idea of lithium air battery occurred accidently to chemist K M Abraham while testing a battery cell having a small leak in his laboratory in 1995, which provided the cell with far higher energy content than expected. Rather than try to fix the leak, he investigated and discovered the first rechargeable lithium-air (Li-air) battery. Lithium-air battery comprises of a metal electrode which is lithium in this case, electrolyte which could be either aqueous or non-aqueous, and a bi-functional air electrode. Lithium Air Battery works by electrochemically reducing O2 from air and oxidizing the metal electrode to reversibly form solid lithium-oxides. In this way, both the volume and the weight of the battery can be significantly reduced compared to Li-ion systems.
So far, we have understood how lithium air battery could work and yield five times more energy density than commercial lithium-ion battery technology, but at the moment it's quite challenging to recharge a lithium-air battery more than a few times due to the oxidation of the lithium anode and production of undesirable byproducts on the cathode that result from lithium ions combining with carbon dioxide and water vapor in the air. These byproducts gum up the cathode, which eventually becomes completely coated and unable to function. These experimental batteries have relied on tanks of pure oxygen — which limits their practicality and poses serious safety risks due to the flammability of oxygen.
Successful Customized Lithium Air Cell at University of Illinois at Chicago
When researchers were on the cusp of losing hope of making lithium air battery work for significant number of charge/discharge cycles. Researchers at University of Illinois at Chicago developed a custom-made cell using a MoS2 cathode, a protected lithium anode and an EMIM-BF4/DMSO (25%/75%) electrolyte in the lithium–air experiments. This electrolyte composition provides the maximum oxygen reduction and evolution in a three-electrode electrochemical cell. A custom-made simulated air stream of around 79% N2, around 21% O2, 500 p.p.m. CO2, and a relative humidity of 45% at 25 °C was used for the battery experiments. After longterm discharging and charging profiles up to a capacity of 500 mAh g−1 with a constant current density of 500 mA g−1 were observed. The charge at the first cycle began at 2.92 V, which is very close to the reversible thermodynamic potential of Li2O2 formation (2.96 V versus Li/Li+) and reached a potential of 3.75 V at a capacity of 500 mA g−1. The potential gap for the first cycle of the lithium–air system is 0.88 V, increasing to 1.3 V after 50 cycles, followed by a gradual increase to 1.62 V after 550 cycles. The increase in the potential gap during cycling may be due to slow degradation of the protective anode coating and/or the MoS2 cathode. However, no failure was observed in the battery during testing up to 700 cycles. The results indicate a substantial increase in the number of lithium–air cycles achieved when the anode is protected compared with when it is not; with no coating, the lithium–air cell fails after 11 cycles, whereas up to 700 cycles can be achieved with an anode-protection layer .
Extensive R&D in following areas could make Lithium Air battery a practical reality:
Optimization of Air Cathode Structure
The limiting factor in this system, and nearly all of the metal air batteries, is the air cathode. The performance of the lithium-air battery has been limited by a low rate of oxygen diffusion in the porous cathode. Recognizing that improving the cathode structure is the key to increasing the energy density of the Li air battery.
An effective air electrode would need to present a much shorter diffusion path for oxygen and offer the largest possible surface area for Li2O2 deposition. These requirements call for an open porous conductor structure using nanostructured materials. Materials used as cathode supports comprise porous carbon, graphene, carbon nanotubes (CNT) or carbon nanofibers (CNF) with catalysts such as metal oxides.
Selection of Appropriate Electrolyte
The requirements for the electrolyte in the lithium– air system are as follows:
Construction of Laboratory Cell Prototype
The main problem lies in making a system that is sufficiently shielded from the external while ensuring an oxygen flow in and out of the device at the same time.
The first design by Abraham and Jiang consisted of a pouch cell where a small aperture on the cathode side allowed for uniform oxygen flow. Others have resorted to a modified CR coin-cell design, by perforating the cathode metallic cover with a series of pinholes and then enclosing the cell in an oxygen-filled plastic bag. A similar concept has been applied to Swagelok cells, where oxygen is provided into the system by flowing it through a perforated cathode. The first problem with such designs is the volatility of the electrolyte, which is free to evaporate during cycling and storage. Secondly, the use of such electrolytes brings up the safety hazard posed by the coexistence of reactive lithium and a pure oxygen atmosphere in contact with a flammable organic electrolyte.
There is no doubt that the lithium Air battery technology is quite promising but at the same time this technology has lot of challenges which need to be overcome before it becomes a viable and commercial reality. It would be too early to say now whether lithium-air batteries will be cheaper or more expensive than lithium-ion ones. We could assume that they will be cheaper. But the problem is often wrapped in details. It could be possible that in order to solve rechargeability problem, we'd have to add some very expensive additives. Many experts believe that we won't get any prototypes till between 2020 and 2025.
AI is starting to get into PV reasearch through trials and errors based on results provided in other people's papers.
IN organic solar cells, polymers are so difficult to understand and to prepare that this kind of topic is growing bigger in the next years: https://www.pv-magazine.com/2018/05/31/organic-photovoltaics-designed-by-ai-at-osaka-university/
Julio Quintana doesn't this remind you what we listen to at the EIT Connect? What was the name of the company researching organic pharmaceutical molecules through mathematical computation?
Imagine if Melisandre could bring Alexander Graham Bell back to life in 21st century, the inventor of telephone, like she brought John Snow back to life in Game of Thrones. Bell would definitely be surprised because he would have never thought in his wildest imagination that communication technologies would be radically disrupted so fast to such an extent that people would even forget one of the greatest inventions of 19th century. Many prominent industries have gone through similar paradigm shifts except energy industry which is still working same as described in blueprint devised by Nikola Tesla in 19th century, starting from generation of electricity from centralized energy grid, and transmission of electricity to passive consumers. There are many reasons to believe that this centralized energy system needs a serious overdue overhaul in order to meet today’s electricity demand in consumer centric manner. I strongly believe that there’s never been a more exciting time to work in the energy industry as its galloping towards decarbonisation, decentralization, digitization and democratization.
Decentralized micro grids offer many benefits over centralized energy systems; centralized energy grid is designed for one directional flows of electricity which is not capable of harnessing full potential of integration of renewable energy technologies; centralized grid is more vulnerable to natural calamities like extreme floods and earth quakes which could lead to power breakouts with no alternatives at hand but creating micro grids would always have some alternative ready to bring life back to normal even if something goes wrong.
If we look at energy transition from fossil fuels to renewables, we could see that something very exciting is happening. It’s not only the way we produce energy is changing but also consumer habits are changing, consumers are becoming prosumers left with extra energy after consumption which brings little or no value at all for them in centralized grid systems; making our present day centralized grids quite ineffective because they were not designed for bi-directional flows of electricity. The idea of decentralized smart grids looks promising for solving this problem but their full potential could only be unlocked if combined with blockchain technology by allowing producers to trade energy in a decentralized peer-to-peer network of energy producers and consumers without the need of intermediaries. Peer-to-Peer trading and electric vehicle charging are few of the myriad use cases of blockchain being deployed in energy sector at the moment, if explored rigorously blockchain has tremendous untapped potential of creating new business markets within energy sector by connecting energy suppliers and energy consumers in ways never possible before.
We have got a vivid roadmap and a compass. Opportunities are limitless because a lot need to be fixed which has not been taken care of, for many decades. Let’s show some proper respect to the generations which are not here yet and our fellow creatures by contributing our part in shaping energy system of the future which ideally should be decarbonised, decentralized, digitized and democratized.
I would like to share here this post from a colleague of mine on the role and trajectory of concentrating solar power in our electricity systems. Here is the reference to our publication: Lilliestam J, Labordena M, Patt A, & Pfenninger S (2017) Empirically observed learning rates for concentrating solar power and their responses to regime change. Nature Energy 2:17094.
Author: Johan Lilliestam. Assistant professor of renewable energy policy, ETH Zurich.
Concentrating solar power (CSP) has the potential to play a key role in balancing renewable energy production, but today the technology is living in the shadow of photovoltaics. A closer look at the cost trends and the history of the industry may give new hope for CSP.
Lilliestam J, Labordena M, Patt A, & Pfenninger S (2017) Empirically observed learning rates for concentrating solar power and their responses to regime change. Nature Energy 2:17094.
Lacey S (2017) SolarReserve inks deal with South Australia to supply solar thermal power with storage for 6 cents.(Greentechmedia, London).
Recently I encountered a some news where photovoltaic modules are applied to solar glasses and with more research also to smart lenses.
Here's the link to the work done at KIT, in Karlsruhe: KIT - KIT - Media - Press Releases - PI 2017 - Solar Glasses Generate Solar Power
What do you think about this technologies? Where do you see applications?
Massive photovoltaic power station put into operation in Zhejiang
China’s largest photovoltaic (PV) power station built on a fish farm officially began operation on Jan. 11, People.cn reported. Located in Cixi, Zhejiang province, the project cost 1.8 million RMB ($259,927) and covers an area of 300 hectares, with a total installed capacity of 200MW. Its average annual production capacity is expected to reach 220 million kilowatt-hours.
The new mode of power generation features PV panels installed above the pond, which serve to provide shade and facilitate fish farming under the water. The power generated by the station will be connected to the state grid, yielding an annual income of 240 million RMB. In addition, another 13 million will be earned through the fishery. The station can meet the power demand of 100,000 households, potentially replacing 7.4 tons of coal.
The end of coal is near: China just scrapped 103 power plants (120GW)
China has announced plans to cancel more than 100 coal plants currently in development, scrapping what would amount to a massive 120 gigawatts (GW) of coal-fired electricity capacity if the plants were completed.
For a bit of context, the entire US has approximately 305 GW gigawatts of coal capacity in total, and this massive adjustment leaves room for China to advance its development of clean, renewable energy.
Despite China's much-publicised pollution problems, the reason for the cancellations is because the country was actually vastly exceeding its planned coal capacity for the future.
Per China's five-year-plan for its power sector, it's targeting a coal-fired capacity of 1,100 GW in 2020 – a sizeable increase from its existing 920 GW.
But if all 103 plants in development were to be completed, China's capacity would reach 1,250 GW, creating a huge, unnecessary surplus of coal power – which is why the Chinese government is putting on the brakes.
In a directive issued this week, the country's National Energy Administration cancelled planning and construction on 85 new coal plants, in addition to 18 facilities canned last year.
The 103 cancelled plants span 13 Chinese provinces, and were worth about 430 billion yuan (US$62 billion). Of the 120 GW of cancelled capacity, some 54 GW would have come from projects already under construction.
While suspending so much infrastructure will hurt China economically, creating an energy surplus in the future wouldn't be a smart play either.
In any case, environmental groups are welcoming the decision to shut down so much planned capacity for one of Earth's most polluting fossil fuels.
"Stopping under-construction projects seems wasteful and costly, but spending money and resources to finish these completely unneeded plants would be even more wasteful," Greenpeace told Reuters.
While China has come under fire for being evasive about its carbon emissions and has attracted a lot of unwanted attention for a series of local pollution crises, the country is the world's biggest investor in renewable energy.
While China is clearly not abandoning coal, its uptake of clean energy saw it account for about 40 percent of global renewable capacity increases in 2015 – building almost 20,000 new wind turbines in that year alone.
"The key thing is that yes, China has a long way to go, but in the past few years China has come a very long way," Greenpeace researcher Lauri Myllyvirta told Michael Forsythe at The New York Times.
But despite the national directive to pull back on coal infrastructure, some think that actually enforcing the suspension in the provinces affected might be a harder thing to accomplish.
According to energy policy researcher Lin Boqiang from China's Xiamen University, overcoming local resistance to halting construction on projects worth billions and employing huge numbers of workers will be a battle in itself.
"Some projects might have been ongoing for 10 years, and now there's an order to stop them," he told The New York Times.
"It's difficult to persuade the local governments to give up on them."