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Archive for the category “storage”

TNO & TUE Heat Battery

Dutch video, English subs

TNO and TU/e have developed a brand new device principle and a breakthrough material, in which the heat is stored. Together they form the heat battery. It is so small that it fits into the limited space available in most homes. The breakthrough material is a salt composite, with K2CO3 (potassium carbonate) as the base material.

The heat battery uses a so-called thermochemical principle. The heat battery for the home is based on two components: water and a salt hydrate. As soon as water vapour and salt are added, the water binds to the salt and the salt transforms into a new crystalline form. This reaction that releases heat is reversible. When heat is added to separate the water from the new crystal, the two original components are obtained again. In fact, it is this heat that is stored, and as long as these two components are separated, the stored heat is retained. This makes it a process without heat loss, which in turn is a prerequisite for long-term storage of heat. In this way a lot of heat can be stored in a small volume. Significantly more than water, and considerably more than in so-called phase transition materials.

The battery can store both heat and electricity. It has the size of a small refrigerator, expected consumer price 3,000-6,000 euro. Technical life expectancy 20 year. Storage capacity device: 200-300 MJ (600 MJ/m3). Power: 1-3 kW. The battery has 4 parts: ventilator, heat exchanger, condensor and reactor vessel:


The heat capacity is at least ten times higher than that of water and more than phase-change-based devices.

[] – A Heat Battery For The Home: Compact, Stable, and Affordable
[] – Miljoenensubsidie EU voor innovatieve warmtebatterij
[] – Thermal battery

The European Commission has granted a 7 million euro subsidy for further development of the TNO and TUE heat battery, within the Horizon2020 framework. For that purpose a new European consortium named HEAT-INSYDE, led by TNO and TUE, will develop the heat battery for the consumer market.

[] – Horizon2020

[source] Prototype heat battery

SolidEnergy and Their Hermes Battery Cell

The storage company SolidEnergy has a battery based on Li-Metal. Storage density after 120 cycles: 0.40 kWh/kg. The battery is so light that a glider with solar cells and Hermes batteries can remain in the skies for ever.

[] – Company site
[] – Data sheet Hermes pack
[] – Meet Qichao Hu

Advances in Lithium-Sulfur Batteries

“Lightweight Battery systems using metallic Lithium are known to offer the highest specific energy. Sulfur represents a natural cathode partner for metallic Li and, in contrast with conventional lithium-ion cells, the chemicals processes include dissolution from the anode surface during discharge and reverse lithium plating to the anode while charging. As a consequence, Li-S allows for a theoretical specific energy in excess of 2700Wh/kg, which is nearly 5 times higher than that of Li-ion. OXIS’s next generation lithium technology platform offers the highest energy density among lithium chemistry: 400 Wh/kg already achieved at cell level… Cost Effectiveness Li-S production cost projections are significantly lower than Li-Ion due to lower raw material cost (i.e. Sulfur) and high energy density (less material required for same energy). This cost advantage is expected to be a key driver for widespread adoption of Li-S technology. Full discharge OXIS cells have a 100% available Depth-of-Discharge. This compares with Li-ion batteries which are only used across 80% (or less) of their available discharge range. OXIS cells use all their stored energy – full discharge. Maintenance free OXIS cells have an indefinite shelf-life, with no charging required when left for extended period. Li-ion batteries require a recharge every 3-6 months to prevent failure and often causes significant warranty issues. Eco friendly The OXIS Li-S chemistry is considered to have less environmental impact when compared to other technologies such as Li-ion. The Li-S cell utilises sulfur in place of heavy metals such as cobalt, which have a significant environmental impact, whereas the sulfur used in OXIS manufacture is a recycled material, a by-product of the oil industry.”

[] – Company site
[] – Li-S, Lithium-Sulfur, an energy revolution
[] – Lithium–sulfur battery
[data sheet] – Ultra Light Lithium Sulfur Pouch Cell

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Wind Turbine With Battery Included

Concept: let a wind turbine pump up water from a lower situated basin in times of over-supply of wind energy for storage purposes.
Storage capacity: 70 MWh from 160,000 m3 total water capacity (4 turbines).

[] – Max Bögl Wind puts turbine on THE tallest tower, 178m. Blade tip to 246.5m
[] – Naturstromspeicher Gaildorf (Germany)
[Google Maps] – Gaildorf

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Liquid Air Energy Storage (LAES)

British research club reports the results of their analysis of a liquid air storage system (LAES). The idea is to use renewable electricity to liquefy air for energy storage purposes. Result: storage cost 11 euro cent/kWh for a 20MW/800 MWh storage installation at a round-trip efficiency of ca. 50%. Storage pressure ambient. Recuperation by boiling the liquid and drive a turbine in a Rankine cycle. Efficiency could be increased by combining solar of waste heat, thus increasing the temperature at the expansion phase. Storage of liquid air in large volumes is fairly easy with an energy density of 83 kWh/m3.

To really solve the renewable energy storage problem, as a rule-of-thumb, a country needs to be able to store ca. 41% of its annual energy consumption, in order to reasonably guarantee energy supply security. Let’s apply this to a country like the Netherlands, with an average power need of 13 GW. Given the energy density of 83 kWh/m3, a storage volume of 562 km3 would be required, which is unrealistic. Liguid air storage is a short term storage possibility (think in a range of hours, not months).

The real solution of the long term storage problem doesn’t lie in gravity batteries or even phase change solutions, like the one presented her, but in combustible material, reduced with renewable means: hydrogen, iron powder, borohydride, ammonia, methanol, formic acid and a wide range of other possibilities.

[] – An analysis of a large-scale liquid air energy storage system
[] – Rankine Cycle

Lithium-ion Storage Price Development


Cheap storage is a necessary requirement for a successful renewable energy transition. It looks like that the short-term storage problem is going to be solved with price levels of below $100/kWh in 2024. For less than $1.000,- an average household can supply for its own energy during the evening and morning hours autonomously, provided of course that sufficient sunshine was available during the previous day.

Sodium-Ion Batteries

Lithium (Li) and Sodium (Na) have comparable positions in the periodic table and hence similar chemical properties.

Lithium is relatively rare and expensive and its mining environmentally problematic, where sodium is cheap and abundant. Combined with the fact that they have similar chemical properties, sodium is considered to be a potential alternative for lithium-ion batteries. New Korean research suggests that copper-sulfide electrodes could play a role in boosting this form of storing electricity in chemical energy, offering a life-span of up to five years, based on a single charge-cycle per day.

Advantages: cheap, abundant, rapid charging, drainable to 0% without damage (Li-ion must keep 30%), safe storage and shipping, “excellent electrochemical features in terms of charge-discharge, reversibility, coulombic efficiency and high specific discharge capacity”.
Disadvantages: less energy density, heavier.

Less suitable for e-vehicles, but potentially very suitable for grid-or home-storage purposes.

[] – High-performance sodium ion batteries using copper sulfide
[] – Sodium-Ion Battery Research Shows Promising Results
[] – Sodium-Ion Battery
[] – Are sodium-ion batteries worth their salt?
[] – Sodium is the new lithium

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Key Efficiency Hydrogen Electrolysis is in Electrode Oxide-Layer

[] – Leids onderzoek biedt nieuw inzicht in elektrolyse van water

Air Compression Example Projects

As of 2017, only 2 CAES installations are operational world-wide, one in Germany, one in the US.

Huntorf, Germany. Operational since 1978, output 290 MW daily or 321 MW max for 2 hours, thanks to storage, consisting of 2 135,000 m3 large underground cavities, at a depth of 650-800 meter, with air pressures of up to 50-70 bar. Efficiency at 42% if compression heat is not used (adiabatic compression). For the future, efficiencies of up to 70% are to be expected.

[] – Kraftwerk Huntorf
[] – Compressed air energy storage

McIntosh power plant in Alabama, operational since 1990. Output from CAES storage 110 MW over 26 hours, with heat recuperation, leading to an efficiency of 54%. The 2015 video confirms that until 2015 there were only two CAES plants in the world and only one in the US (the other Huntorf in Germany)

[] – Compressed air energy storage
[] – List of energy storage projects
[deepresource] – Liquid Air Energy Storage

Currently underway is a project in Northern Ireland, funded by the EU and hopefully survives the Brexit drama; 330 MW from storage for 6 hours:

[deepresource] – Europe Chases CAES GWh Energy Storage

Electricity Storage Costs

Global energy storage power capacity shares by main-use case and technology group, mid-2017

2017 IRENA report about storage cost projections 2017-2030.

Electricity storage will play a crucial role in enabling the next phase of the energy transition. Along with boosting solar and wind power generation, it will allow sharp
decarbonisation in key segments of the energy market…

As variable renewables grow to substantial levels, electricity systems will require greater flexibility. At very high shares of VRE, electricity will need to be stored over days, weeks or months. By providing these essential services, electricity storage can drive serious electricity decarbonisation and help transform the whole energy sector.

[] – Electricity Storage and Renewables – Costs and Markets to 2030
[] – International Renewable Energy Agency (IRENA)

Electricity storage energy capacity growth by source, 2017-2030

Siemens-Gamesa Electric Thermal Energy Storage

Siemens Gamesa Renewable Energy (SGRE) has commissioned a pilot electric thermal energy storage system (ETES) in Hamburg-Altenwerder, Germany.

– Storage capacity: 130 MWh for a week. Scaling into the GWh range is possible.
– Storage material: 1,000 ton volcanic rock.
– Storage temperature: 750°C/1382 °F.
– Efficiency: up to 50% (25% total cycle efficiency Hamburg pilot).
– Capital expenditure is up to ten times lower than batteries.

Efficiency is lower than with pumped hydro-storage, the trade-off is lower installation cost.

[] – World first: Siemens Gamesa begins operation of its innovative electrothermal energy storage system
[] – Electric Thermal Energy Storage (ETES)
[] – ETES Energy storage to the next level
[] – Siemens Gamesa Unveils World First Electrothermal Energy Storage System

CO2 –> CO/C –> CO2 Fuel Cycle?

Renewable energy has won once science can come up with a method to effectively store intermittent renewable electricity in some chemical form or another. Many candidates have been proposed: hydrogen (H2), methane (CH4), ammonia (NH3), methanol (CH3OH), metal powders like iron (Fe), formic acid (HCO2H), sodium borohydride (NaBH4),

Scientists from the EPFL in Lausanne, Switzerland, have found a method to reduce CO2 into CO, where an iron catalyst is used instead of a golden one, with high efficiency (90% at low currents).

[] – Carbon-neutral fuels move a step closer (6-2019)
[] – The first low-cost system for splitting carbon dioxide (6-2017)
[] – Catalyzing carbon dioxide: System can transform CO2 into CO for use in industry (12-2017)
[] – Improved carbon capture turns CO2 into energy storage material
[] – This Low-Cost Carbon Dioxide Splitter Just Changed The Game For Solar-Powered CO2 Reduction (6-2017)

Fraunhofer Sodium-Ion Dry Film Battery Breakthrough

The renowned German Fraunhofer research institute has developed a new way to produce lithium-ion batteries, with potentially important implications for the German e-vehicle industry. The essence is that the old toxic way of working with paste electrolyte is replaced by a new production process, working with dry films instead.

The result is cheaper batteries, with higher storage energy density, less hazardous production process and less embedded energy. Advantages only.

The Finnish battery producer BroadBit is already producing the battery on a small scale. German and European car companies could become less reliant on expensive batteries produced overseas.

[] – Economical energy storage for the electric car of tomorrow
[] – BroadBit project events and news
[] – Battery Breakthrough Solves Major Electric Car Problem

Ecovat bij BNR en TUE

[] – Company site
[] – Energy Day TU/e bespreekt Ecovat-systeem

Chemical and Sorptive Thermal Storage Methods

Space heating is an important slice of the total energy consumption pie and storage of thermal heat is as important as storage of electricity. The German Fraunhofer institute has an innovation program for “chemical and sorptive thermal storage methods”.

[] – Chemical and sorptive thermal storage methods
[] – Sorptive Heat Storage
[] – Sorption thermal storage for solar energy (pdf, 26p)

In a sorption process, heat is stored by breaking the binding force between the sorbent and the sorbate in terms of chemical potential.

State-of-the-Art Electric Energy Storage Technologies


Abstract (2014)

Electrical power generation is changing dramatically across the world because of the need to reduce greenhouse gas emissions and to introduce mixed energy sources. The power network faces great challenges in transmission and distribution to meet demand with unpredictable daily and seasonal variations. Electrical Energy Storage (EES) is recognized as underpinning technologies to have great potential in meeting these challenges, whereby energy is stored in a certain state, according to the technology used, and is converted to electrical energy when needed. However, the wide variety of options and complex characteristic matrices make it difficult to appraise a specific EES technology for a particular application. This paper intends to mitigate this problem by providing a comprehensive and clear picture of the state-of-the-art technologies available, and where they would be suited for integration into a power generation and distribution system. The paper starts with an overview of the operation principles, technical and economic performance features and the current research and development of important EES technologies, sorted into six main categories based on the types of energy stored. Following this, a comprehensive comparison and an application potential analysis of the reviewed technologies are presented.

[] – Overview of current development in electrical energy storage technologies and the application potential in power system operation
[pdf] – 26 pages

Li-ion Battery, How Does It Work?

Large Lithium Reserves in Saxony-Germany

96.000 Tonn Lithium is hidden in the soil near Zinnwald in Germany. A new mine is to build in 2019, production start 2021. Market value: ca. 6 billion euro.

[] – Sachsen träumt vom Lithium-Wunder
[] – Unter Dorf in Sachsen liegt Milliarden-Schatz – den jahrzehntelang keiner wollte
[] – Zinnwaldit

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Solid State Battery Breakthrough

Japan’s Tohoku University and the High Energy Accelerator Research Organization have announced that they accomplished a breakthrough with a new complex hydride lithium superionic conductor, with a record high energy density.

Keywords: hydrogen clusters (complex anions), high ionic conductivity, resulting in the ideal anode material for all-solid-state batteries.

Lithium is the most promising solid state battery material because of its very high theoretical energy density:

Lithium consumption required for a ~90kWh battery (size of useful car battery):

• Li -> Li+ + e- (3860 mAh/g-1)
• 1 kWh = 270,000 mAh ≈ 70 g of Li
• 90 kWh ≈ 6.3 kg of Li

[] – Highest energy density all-solid-state batteries now possible
[] – Awesome Solid State Battery Breakthrough News

Supercapacitors as Competitors for Hydrogen and Batteries

Currently the batteries seem to win the race for powering the e-vehicle, despite the facts that the majority of automotive brains say that they prefer hydrogen.

However, there is potentially a third competitor looming at the horizon: super-capacitors. The storage of electricity in Coulomb, rather than chemical form. Charging proceeds in seconds, rather than hours. No need for batteries of 400 kg. They have no degradation and go on and on. The only disadvantage: leaking. A full charge will largely disappear after a month. Driving a car with a charged super-capacitor is like consuming an ice-cream on a sunny day: you gotta lick it immediately.

Nothing is decided yet, though. Breakthrough new materials are required to live up to the theoretical promise. Candidate material: graphene.

[] – Supercapacitors: A new source of power for electric cars?

[] – Energy storage leap could slash electric car charging times
[] – Fancy charging up your electric car in 10 minutes?
[] – In 2011 Elon Musk bets on capacitors rather than batteries
[] – Supercapacitor
[] – Graphene
[] – Coulomb
[] – Graphene-Based Supercapacitors Could Lead To Battery-Free Electric Cars Within 5 Years
[] – Could Ultracapacitors Replace Batteries In Future Electric Vehicles?
[] – Cars that run on supercapacitors could be charged in minutes
[] – A fluke breakthrough could be the missing link for an electric car age

Read more…

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