SuperGrids - Future of the Electric Systems

During the eclipse - see new - of last Friday March 20th in the morning, no relevant issues were reported or suffered by the European Electric systems, despite of the variation in the solar yield and its consequences for managing the generation and consumption in the European countries, which needs to be balanced every single second - see example in Germany.
Considering the already 35.000 MW of solar energy capacity in Europe, the high voltage European Network needed a great coordination between all European Transmission Systems Operators (TSO's) previously, and during the eclipse.

As a sample of the reinforcing this European Network, Last February 20th, it was inaugurated - Ree new - one Power Electric Interconnection between Spain and France by the 
French Prime Minister, the president of the Spanish government and the presidents of the TSO's from France (RTE) and Spain (REE).

Figure 1_General view of the Converter Station in the Spanish side, in concrete in Santa Llogaia i Baixà, close the city of Figueres. It is possible to see the AC substation (right side) and the Converter Station (left side)_source:J. Sánchez Ríos

The underground Direct Current High Voltage (HVDC) Power Line of 64,5 km (40 miles), has represented an investment of 700 millions €. With that infrastructure, the electric interconnection between Spain and France is now 2,800 MW, from the 1,400 MW installed before the inauguration of this interconnection. With this underground installation, the capacity of interconnection has passed from 3% to 6%, of course when will be in operation in summer this year 2015.
The infrastructure has cost ten times more than it was expected. The opposition of the french farmers who made the obligation for building the underground line, instead of the overhead power line, it made that the cost has been increased in 10 times more, of course, reducing the environmental impact. 
In the same way, it is necessary to remark the cutting edge technology applied to this infrastructure, making it unique in the world for having the capacity to reverse the direction of the energy flow in just 50 milliseconds. 
Similarly, it is necessary to remark other projects which are being implemented in other regions of Europe to reinforce the interconnections of all EU members.

This infrastructure mentioned is linked with the European (EU) directive 20/20/20, to increase the interconnections between European TSO's, increasing interconnections to 10% in 2020, and by 15% in 2030. 
The European Transmission System Operators for Electricity (ENTSO-E), an entity for supporting security of supply, sustainability, and the development of the European internal energy market by EU Regulation EC 714/2009, It is the responsible for the assurance of the coordination of all European TSO's, being a great challenge, understanding which European transmission grid is 300.000 Km of transmission lines, 500.000 Km of distributed lines, with 41 TSO's in 34 countries with 534 millions of citizens.

Figure 2_Map of the Project of Common Interest (PCI) between European members regarding Electric interconnections_source: European Commission


It is well known the challenges for the implementation of a unique European Electric Network, politically; for the necessity to find a common point of understanding of all the energy markets, and technically; with the necessity to implement some solutions in the DC systems, which are going to be the technology for the interconnection to every state of the European Union, for the advantages in transportation of electricity in long distance; losses reduction, possibility to change the power flow of the current, and increasing the power quality, stability and reliability by power electronic systems.

For some professionals in the implementation of this solutions, gathered in a conference of power electronics in the grid, exposed about the main issue for the implementation of this grid, grid called "SuperGrid", see "Friends of Supergrid", is the existing grid, because it needs to be implemented with the high conditioning of having an existing AC power lines.


Regarding the conference mentioned in the previous paragraph; "IX International conference Energy Innovation. Power Electronics in the Grid - HVDC and FACTS", it was exposed the evolution and the state-of-the-art of the power electronic technology applied to HVDC and AC, in concrete to Flexible AC Transmissions Systems (FACTS), and how the technology and investments are helping in its implementation.
HVDC technology is in the market long time ago. In first term applied for connecting islands or Oil & Gas Offshore Rigs. Afterwards, it was implemented in the development of high level of electric yield coming from Wind Offshore Farms to the Mainland transmission lines.
Talking about the history of HVDC, with the first project in Sweden in 1954, by Dr. Uno Lamm, the father of HVDC, by the company ASEA (nowadays ABB: Asea Brown Boberi), which started to connect Gotland island to the Sweden Mainland Electric System. The project of 150 Km of cable of 150 KV, used mercury valves for the power electronic control.
The evolution of the power electronics in those last years have increased rapidly, with the first and second thyristor generation in 1970 and 1980 respectively, and the starting of using Isolated-Gate Bipolar Transistor (IGBT's) in 2000 - see document of ABB of the 60 years of HVDC technology.


It is necessary to mention, the most important challenge for HVDC technology is the Protection Systems. 
Protection systems in HVDC - Think Grid article, are still in development phase, because to date no DC circuit breaker is in the field. With the same philosophy and scheme for AC Power systems, and needing to perform in a short tripping time, of course, without losing selectivity, security and sensibility.
Nevertheless, it is necessary to consider that transmission lines in HVDC are longer than the equivalent in AC, then, the communication time delay is longer. Furthermore, is not possible to use Fourier based algorithm for protection systems used in AC Power Systems, for being a DC current.



On the other hand and making a conclusion, besides the technical and economical challenges for the interconnection of different electric systems. It is necessary to think about to establish systems for controlling all the data generated, from the micro grids; from the smart meters or Advance Metering Infrastructure (AMI) in the Smart Homes, even in both direction, consumption and production, with the Distribution Energy Resources (DER), the Electric Vehicle (EV) Chargers, even in the Vehicle to Grid (V2G) systems, the storage systems, in its different technologies, and regarding the situation of the main Bulk Power Flows in the actual AC Power Systems, which will create a system mixed by AC and DC technologies.

Figure 3_In the left, Smart Meterings, in the right, a Trafos in a Hydraulic Power Plant_source: J. Sánchez Ríos

Of course the development in DC technology will change the composition of the network, not only in HV Systems, also in low and medium voltage (LV & MV), it is well know the implementation of DC for supplying Data Centers  and other applications, even working in a off-grid solutions. 

The restrictions in the future for the integration of DER in the distribution grid in LV by the owners of this Distribution assets, will create microgrids DC systems; with generation, storage, and EV chargers in parallel with conventional AC infrastructure, normally connected to AC systems.

Likewise, Offshore Wind Power has helped in the development of the HVDC technology, with the increasing of the capacity installed, which have brought investments to the rest of technology requirements; cables, substations and power electronics systems. 
Furthermore, if Offshore Wind Technology overcomes its primary handicap, being able to establish wind farms in emplacements independently of the deep sea, and knowing the high cost of the construction phase in the implementation of the Offshore Wind Farm project, which in some cases is being the two-third of the lifetime. The projects which will bring alternatives to fixed-bottom foundations, will extend the emplacement of this Wind Technology. Some samples from Hitachi or Alstom, open the possibility for installing Wind Offshore Energy in deeper locations - out of North Sea and North East coast of US. 


Other technology which will bring great possibilities in the electricity transmission with applications in cities, despite of the limitation nowadays, in terms of distance, is the superconducting technollogy.  Some projects are yet implemented in Europe - "Ampacity" in Essen, Germany. A project of longest superconducting cable installed in the world, and the first to combine a superconducting cable with a resistive for overload protection restructuring of inner-city networks. 
Superconducting cables are cables cooled by liquid nitrogen at -200ºC. Apart of the project expose, it is possible to find applications in other emplacements, one is in ITER project, the International Nuclear Fusion project - see new about the instrumentation for the system monitoring, and in the Superstation "Tres Amigas" in New Mexico (US), for connecting the three electric systems in US and Canada, from Texas, Western and Eastern coast respectively (WECC, Eastern, ERCOT).



Accordingly, it is possible to think about the great possibilities of the DC systems, not only in HVDC, and the coexistence with the existing AC Power Systems.
The potential for the management of all this enormous network and data, which at the end, can be extended not only in a continental space, having only the geographical limitation, or may be not. 
May be in future, this Supergrid will be bigger than our future expectations nowadays. Some months ago, it was connected by train Beijing and Hamburg, opening the possibility for establishing an electric catenary, which in future brings automated trains, even this catenary can be supplied by Renewable Energies sources in the emplacement or close to the railway, minimizing the greenhouse gas emissions and reducing the cost of the operation. 
If is in construction the project "Keystone XL Pipeline", may be US is able to avoid great damages in the Transmission lines in cases of twister or hurricanes with the implementation of one underground HVDC in parallel with the mentioned project "Keystone XL Pipeline" like is implemented in the West Coast from Oregon to California. 

Knowing the relevance of the Electric Operation in the social and economical activity, with this article, it is opened the possibilities to the interconnection of the Electric Systems, for having a more flexible, reliable and profitable Electric System for the integration of Renewable Energies and Electric Vehicles. 

Notwithstanding having a constant changing perspective in the Electric Systems, which of course, in terms of hardware, is related to great risk for the obsolescence of the technology, in terms of software, with cloud and big data and its possibility for adapting continuously, it opens a great challenge for the companies with are giving services to the control of the complete Electric Systems. Not only for the Utilities or regional markets, also introducing the control of the holistic energy and other resources; Oil & Gas, Telecommunication, Water, etc., and managing this enormous among of data for optimizing and establishing predictive or simulation models for advancing to any situation like the eclipse exposed. As a result, giving better studies of the possible future projects or any possible disaster, and restablishing the resources as soon as possible. 

All of that, in Electric Systems which will be more worried about the complete balance - consumption and generation, which will be the main task of the TSO in future, and with an increasing of DER,  but of course being the quality of the wave also a great challenge.


The electric grid is like a river: step by step rivers are more and more dirties, but we want it, step by step, cleaners... Ramon Comelles (Circutor owner in a interview in Enginyers Bcn) 


Bibliography:
1) Smart Grid: Technology and Applications / Janaka Ednayake, Kithsiri Liyanage, Jianzhong Wu, Akihiko Yokohama, Nich Jenkins
2) IEEE Power & Energy Magazine / Volume 13

Smart City (Air pollution)

Taking in consideration what had happened in Paris and London last summer, and in Barcelona and Madrid the first week of 2015, in terms of high level of air pollution, it is necessary to introduce the main topics which are responsible for pollution in the cities.

Figure 1_Example of a street in Paris, The Champs Elysees, where is able to see the high level of traffic and in consequence, the high level of emissions, reason for what this summer, Paris was in the alarm levels of Air Pollution_Source: Javier Sanchez Rios

Knowing that Humans started living in communities with the discovery of agriculture, being no necessary moving to find food. 
The first communities established, as it is known the actual concept of city, it was located in Western Asia. Nowadays, the 50% of people lives in cities, and it is going to be increasing in the next years, being a necessity a properly management of the cities.

In this blog it is going to be considered an introduction of the situation for two most important topics related to the management of the city, in circunstance of high level of Air Pollution: Energy, including Mobility and Waste Mangement. 
Of course, it is possible to find webs with a different and deeper information regardig the concept of Smart City, e.g.: by City Protocol Organization,  Smart City Business Institute, Smart Cities Council, C40, Ecocity Builders, or from different locations; European Union, Japan, Brazil, etc.

For having in consideration Energy, it is necessary to understand what is the mix generation of energy which the city is supplied, of course being the challenge to have a 100% renewable energy supplied city. Analyzing the 100% of the resources, it is possible to know what is really the greenhouse emissions just in the energy supplying.

In this blog, is going to be taken the example of Barcelona, being the first Smart City in Spain, 4th in Europe and number 10th in the world.

If it is taken energy, it is necessary to understand that Barcelona receives electricity from different sources; nuclear plant in southern Catalonia, thermal power plants located in the same city, co-generation plants, some hydraulic and wind energy which are located in south and north Catalonia, being far from the city, and having the necessity to transport this electricty. In terms of fuel and gas, the port of Barcelona is the hub for this supplying.
For getting more details about energy supply in Barcelona, please go to Barcelona Energy Agency.

Figure 2_Map of Electric Transmission and Distribution Systems and the Power Stations for producing electricity to Barcelona Metropolitan Area. Being the main supplying station Vandellos - nuclear power plant - in southern Catalonia_source:
Mapas de la Red Ree  by the Spanish Transmission System Operation (TSO) - Click on the picture to enlarge.

Of course, when is proposed the idea of Smart City, the main topic is, the reduction of pollution. Knowing this pollution mainly is created by waste management, and energy consumption, including mobility by fossil fuels, it is necessary to take a view about this situation.

For achievement this self-sufficient cities, energy and waste treatment it has to be considered such as most important issues. It is possible to give examples in small scale, in terms of Zero-energy Buildings, which the energy demand is covered by renewable energies and energy efficiency, e.g.: Honda House, and at the same time, policies which follow the rule of three R: Reduce, Reuse and Recycle, in terms of recycling policy, considering the great amount of waste generated by the population. 

For reducing the air pollution in the cities, new Mobility will play an important role. First action is reducing vehicles in the center of the cities, like it was implemented in London, with the payment to enter in Central London, but being supported by alternatives, mostly in public transport, car sharing, bycicle etc., and giving preference to vehicles of zero-emissions and the charging infrastructure in its different technologies, e.g.: EV and FCV. 

The put in motion the European law, it is necessary to create incentives for buying zero-emissions vehicles and proposals for EV charging systems supplied by renewable energies, for closing the complete life-cycle of zero-emissions. Similarly, the implementation of Fuel Cells systems for supplying Fuel Cell Vehicles (FCV), by electrolysis systems or by natural gas, taking the actual Natural Gas (NG) grid.
This web showns examples taken in Germany with the "Schaufenster elektromobilität projekt", which englobes electromobility project around different "Landes".
At the same time, other great possibility for implementing the EV, is reducing the electric tariff during nights for leveling the demand during off-peaks, from 1 to 5 night, in times of recharging EV.

Similarly, the zero-emissions buildings supplied by Photovoltaic (PV) energy and other systems - see Figure 5 - letter B as example of small wind energy- in areas with no great sun irradiation, small wind energy or geothermal energy, will be a great solution,  of course, considering energy efficiency. For supplying the energy which is not able to cover the energy demand in buildings, it is necessary to support by renewable energies, if is possible in the cities, or if not, out of the cities. For being able to do that, storage systems will be the most important solution, even with batteries, in a lot of cases coming from EV and the hydrogen coming from electrolysis, mostly in wind farms, because Wind and PV Power has issues of intermittency.

Figure 3_Example, ride side, of parkings in Barcelona City, where is possible to see the high number of motorcycles. Just as information, Barcelona is after Rome, the second city with more number of motorcycles in Europe. This is able to give an idea of the reduction in the emissions if this motorcycles are zero-emissions motorcycles. On the left of the picture, it is possible to see one scooter waiting for having the complete load in a Charging station in Mode 1 in Center of Barcelona._Source: Javier Sanchez Rios

Figure 4_Example of Electric Motorcycle made by the students by UPC, and connected to the program MotoStudent. Also it is enclose some proposals of Electric Vehicles exposition in Barcelona, and motorcycles in the market: Bultaco, Yamaha, Zero-Motorcycles, BMW.

Figure 5_In the top, an example of Electric bicycle, saw during the 2014 Smart City Expo in Barcelona. In the bottom, example of parking full of bicycles of the program of bicycle mobility in Barcelona. It must to be considered, this program has implemented the Electric bicycle due to the geografic situation of Barcelona, being a city which is closed by mountains and sea, for users is very usefull the program to go down from the top of the city to the places close to the center, and close to the sea, but the problem is, when users want to come back, in this case, are using public transport, e.g.: underground, bus, etc., and the management of the system must to carry the bicycles from the center of the city to the places closer to the mountains, being a system not profitable. For that reason, the system is implementing the electric bicycle, for reducing this impact and being more useful to come back to all locations in the city.

Figure 6_Examples of sustainability in the Smart Cities. 
A: example of Photovoltaic system in a parking of the town train station in the Metropolitan Area. B:  example in the same town of a small wind energy. C: example of post for indicating the time arrival of buses with a small photovoltaic panel on the top in Barcelona City, in concrete in Avinguda Diagonal.
D: example of train which communicates Barcelona city with other close cities, in this case Girona or Figueres, in northern Catalonia, and operated by the National Rail Company, see Renfe. E: example of train which communicates the Metropolitan Area of Barcelona. F: example of bin with TV screen, the system is supplied by photovoltaic panel on the top, system exposed on 2014 Smart City Expo, this micro-grid system opens the possibility to have a communication system for indicating when the bin is full in off-grid system, of course with storage system included. 
G: example of hybrid bus in Barcelona city from the Metropolitan transport company, logo shown in letter I. See also examples of 100% battery Electric Coach Bus. H: example of tram which operates in Barcelona.
I: logo of TMB, in catalan: "Transports Metropolitans de Barcelona". J: example of hybrid taxi. K: example of electric vehicle. F: example of generator which uses biodiesel fuel.

It must to be considered that the EV implementation is able to be a solution worldwide, not just for air pollution reductions, at the same time, in some countries, like in case of Spain and Australia, cases which the crisis made the demand of electricity decreased, leaving a great number of electric generation systems out of the pool, for being non competitive in terms of cost-of-energy. With the implementation of EV, the demand will be higher, and this electric generation systems which right now are out of the Electric Market pool, it will be again in the pool. 

Regarding waste treatment, it is necessary to consider Germany as example, in terms of reusing; glass, plastic bottles and aluminum cans, with a program which is paying for bottles, cans, etc., in the supermarkets, and then, having no necessity for recycling at 100% of waste, for reusing, with the energy consumption and pollution it represents. This solution is reducing the plastic bags, metal and glass bottles in the environment, which in other systems get great consequence in the wildlife. 
In the recycling process, it is necessary to get technological systems with less level of environmental impact - reducing or eliminating greenhouse gas emissions - or creating biodegradable or organic materials.
Of course, also is important that the rubbish collection is made by zero-emission vehicles, because is well known the high level of distance which is covered by this vehicles.

Figure 7_Example of different kind of containers in Barcelona Metropolitan area. On the top, in brown colour, containers for organic material, in yellow for packaging, green for glass and blue for paper, the grey are used for all with exception of organic, of course, it needs to be separated in the waste treatment plant, increasing the cost. In the bottom, the rectangular green is for clothes, normally for use those clothes such as second hand clothes or used like trags to use in the industry.

Regarding waste management, is important to give training to the population for reducing the level of waste, in terms of buying product which reduce the volume of packagings, buying in bulk, like our fathers did, even using the packaging for a high number of times. In Europe, it is well known, that is wasted a great amount of food, knowing in countries like Spain, some part of the population has serius problems for having a properly feeding.

Figure 8_Example of Electric Vehicles for waste collection_source: Javier Sanchez Rios

On the other hand, it is necessary to think about the systems which will control all the processes in this Smart City.

For getting the complete control of all the infrastructure of the city, not just energy, sustainable mobility and waste treatement, IT solutions, will communicate all the processes, operating in all kind of communication system - optical, wired, wireless, Power Line Communication (PLC), etc.,  will play a role in this Smart City.

Figure 9_Picture of the telecomunication tower in the olimpic village in Barcelona_source: Javier Sanchez Rios

Similarly, other important question is what systems will operate all the topics of the city, which software and big data systems, including IoT - which is spected to have a great economic growth - not only for managing the exposed in this blog, all systems which is able to be in a city, which will be increasing and changing day by day, e.g.: Wonderware of Schneider Electric, SAP, Cisco, Abertis, Telefonica, Oracle, GDF Suez, Thales. 

Connecting to this last point, one project which is necessary to consider, and is able to expose what is really this Smart City is and will be, is a project which is involving a lot of different partners and public institutions, in this case companies - Schneider Electric and Cisco Systems - and Barcelona City Council, the project is called Ca l'Alier. 

Figure 10_Domestic Data Streamers in the Smart City Expo in Barcelona in novembre 2014_source: Javier Sanchez Rios


PS: It must to be considered, the Smart City envolves a great number of topics which is impossible to describe in detail in one blog. The intention of this blog is just getting the introduction to the main points which must to manage the policy makers and the city population in general, for mitigating pollution, and the great possibilities which offers Smart Cities, and considering which will be a particulary case of study in every city, for different particularities.


Javier Sanchez Rios
javiersanchezrios@gmail.com

Energy Storage

Last 18^th December I attended to one IEEE webinar regarding “Enabling Smart Grids: Energy Storage Technologies Opportunities and Challenges”.

The webinar got an introduction of the different energy storage technologies:

1. Mechanical: pumped hydro, compressed air (CAES), flywheels
2. Electromechanical: secondary bateries, flow batteries
3. Chemical: hydrogen
4. Electrical: doble layer capacitor, superconducting magnetics (SMES)
5. Thermal: heat storage, molten salts

This blog tries to introduce the state-of-the-art of the Energy Storage Systems and to expose very interesting example (also energy projects Wiki) and discussions in internet to try to introduce in the topic and show the big possibilities for this emerging technology which is in engineering more time than we know: 

Mechanicals:

Pumped hydro: Pumped-storage hydro electricity (PSH) is a hydroelectric energy storage used by electric power systems for load balancing in the Electric System using gravitational potential energy of water,  pumped from a lower elevation researvoir to a higher elevation during low-cost off-peak electric power, normally during night, depending of the load.

Figure 1_ Picture of Hydroelectric Plant of Susqueda (Northern Barcelona: Hydroelectric Plant which supply to Barcelona City Water and Electricity - See web in Spanish)_Source: Javier Sanchez Rios.

Figure 2_Electricity Demand in real time in Spain during January 5th of 2015. As it has been exposed in the present point, normally the pumped system is working in the low demand, in the case of Spain from 2 to 6 in the night, when the price of electricity and the demand are lower. Source_Ree -Electricity Demand in real time 

Compressed air: Compressed air energy storage (CAES). Small scale systems is normally used as propulsion of mine locomotives. Large scale applications must conserve the heat energy associated with compressed air; dissipating heat there is a decreasing of the performance in the energy efficiency of the storage systems, but for some companies, CAES opens new possibilities in storage systems.

Flywheels: Flywheels is a rotating mechanical device that is used to storage rotational energy. Flywheels have a significant moment of inertia and thus resist changes in rotational speed. Energy is transformed to a flywheel by applying torque to it, thereby increasing its rotational speed, and hence its storage energy.

The common uses of flywheels are:

• For providing continuous energy when the energy source is discontinuous, in cases of reciprocating engines (piston engine, e.g.; compressor for cooling systems), when the energy source is intermittent, such as torque of the engine.
• Delivering energy at rates beyond the ability of a continuous energy source. This is achieved by collecting energy in the flywheel over time and then releasing the energy quickly, at rates that exceed the abilities of the energy source.
• Controlling the orientation of a mechanical system. In such applications, the angular momentum of a flywheel is purposely transferred to a load when energy is transferred to or from the flywheel.
• For providing stability in the Electric Systems in terms of voltage and frequency, overall, in small or isolated Electric Systems (e.g.: Ree in the Canary Island of Lanzarote)

Electromechanical

Batteries: Composed by Electrodes, Electrolyte and separators.

Secondary batteries: Also called reachargable battery, storage battery, secondary battery or accumulative is a type of electrical battery. Rechargable batteries have a lower total cost of use and environmental impact then disposal batteries. It comprises one or more electrochemical cells because its electrochemical reactions are electrically reversible. Rechargable batteries come in many different shapes and sizes, ranging from button cells to megawat systems connected to stabilize an electrical distribution network. Several different combinations of chemicals are commonly used, including: lead-acid, nickel cadmium (NiCd), nickel metal hydride (NiNH), and lithium ion (Li-ion), and lithium ion polumer (Li-ion polymer) used in second application for grid applications energy storage, most of them coming form Electric Vehicles, enlarging the End-of-life (EOL).

Figure 3_ Nissan Leaf charging Li-ion arranged laminarly batteries during the 2014 Smart City Expo in Barcelona_source: Javier Sanchez Rios

At the same time, it is possible to describe some of the main secondary batteries in use:

Flow batteries:Batteries where the active material is out of the tanks (power and energy independently) and made by Vanadium, being safer batteries.

Sodium (Na) based batteries: Technology which performs at 200ºC by molten salts and sulphur which gives the possibility to work with cheap materials and long life-cycles. The drawback is the corrosive reactions and the consequence of leakage and the cost in maintenace.

Zn-air: Batteries composed by one metal (anode), and O2 from air as cathode which is able to perform at high temperatures. This technology has great maturity and potential for high energy densities, is stable and less dangerous than other technologies.

Chemical: The chemical energy storage is the storage of hydrogen. There are different kind of hydrogen storage; high pressure, cryogenics, and chemical compounds that reversibly H2 upon heating. Underground hydrogen storage is used for grid energy storage for minimizing intermittent in renewable energy sources (solar PV, Wind etc.), as well as providing fuel for fuell cell vehicles (FCV), see example of project in sustainable urban transport by Fuel Cells in Europe and new concept car by hydrogen.

Liquid hydrogen is used in Space Shuttle. However liquid hydrogen requires cryogenic storage (-252,882ºC). Hence, its liquefaction imposes a large energy loss (energy needed to cool it down to the temperature of -252ºC). The tanks must also be well isulated to prevent boil off, but adding isolation increased cost. Liquid hydrogen has less energy density by volume than hydrocarbons fuels such as gasoline by aproximately a factor of four. This highlights the density issue for pure hydrogen: there is actually about 64% more hydrogen in a liter of gasoline (116 grams of hydrogen) than there is in a liter of pure liquid hydrogen (71 grams of hydrogen). The carbon in the gasoline also contributes to the energy of combustion.

On the other hand, compressed hydrogen is stored in a different way. Hydrogen gas has good energy density by weight, but poor energy density by volume versus hydrocarbons, hence it requires a larger tank to store. A larger hydrogen tank will be heavier than the small hydrocarbon tank used to store the same amount of energy. All other factors remaining equal, increasing gas pressure would improve the energy density by volume, making for smaller, but not lighter container tanks. Compressed hydrogen cost 2,1% of the energy content to power to compressor. Higher compression without energy recovery will mean more energy lost to the compression step. Compressed hydrogen storage can exhibit very low permeation.
The applications are increasing but most common: aerospace industry (not only for rocket launches), chemical, automotive, Smart Grids applications (for wind or solar farms) and in new applications like superconducting.

Electrical: Electrical doble-layer capacitor, superconducting magnetics (SMES).

Electrical double-layer capacitors (EDLC), or also called supercapacitors or ultracapacitors, part of a new type of electrochemical capacitors. This kind of capacitors have no the conventional solid dielectric, the capacitance value of an electrochemical capacitor is determined by two storage principels:

• Double-layer capacitance: electrostatic storage of the electrical energy achieved by separation of charge in a Helmholtz double layer at the interface between the surface of a conduct electrode and an electrolytic solution electrolyte. The separation of charge distance in a double-layer is on the order of a few Angströms (0.3 – 0.8 nm) and is static in origin.

• Pseudocapacitance: Electrochemical storage of the electrical energy, achieved by redox reactions electrosorption or intercalation on the surface of the electrode by specifically absorbed ions that results in a reversible faradaic charge-transfer on the electrode.

• Double-layer capacitance and pseudocapacitance both contribute to the total capacitance value of a supercapacitor. However the ratio of the two can vary greatly, depending on the design of the electrodes and the composition of the electrolyte.

Pseudocapacitance can increase the capacitance value by as much as an order of magnitude over that of the double-layer by itself.

Supercapacitors are divided into three families, based on the design of the electrodes:

• Doble-layer capacitors: with carbon electrodes or derivatives with much higher static double-layer capacitance than the faradaic pseudocapacitance.
• Pseudocapacitors: with electrodes made of metal oxides or conducting polymers with much higher faradaic pseudocapacitance than the static double-layer capacitance.
• Hybrid capacitors: capacitors with special electrodes that exhibit both significant double-layer capacitance and pseudocapacitance, such as lithium-ion capacitors.

Supercapacitors have the highest available capacitance values per unit volume and the greatest energy density of all capacitors. They can have capacitance values of 10,000 times that of electrolytic capacitors; up to 12,000 F at working voltages of 1.2 V.

Supercapacitors bridge the gat between capacitors and rechargeable batteries. In terms of specific energy, as well as in terms of specific power, this gap covers several orders of magnitude. However batteries still have about ten times the capacity of supercapacitors. While existing supercapacitors have energy densities that are approximately 10% of a conventional battery, their power density is generally 10 to 100 times as great. This makes charge and discharge cycles of supercapacitors much faster than batteries. Additionally, they will tolerate many more charge and discharge cycles than batteries.

In these electrochemical capacitors, the electrolyte is the conductive connection between the two active electrodes. This distinguishes them from electrolytic capacitors, in which the electrolyte is the cathode and thus forms the second electrode.

Supercapacitors are polarized and must operate with the correct polarity. Polarity is controlled by design with asymmetric electrodes, or, for symmetric electrodes, by a potential applied during manufacture.

Supercapacitors support a broad spectrum of applications for power and energy requirements, including:

• Long duration low current for memory back up in (SRAMs)
• Power electronics that require very short, high current, as in the KERS system in Formula 1 cars
• Recovery of braking energy in vehicles

Supercapacitors have longer life-cycle than electrochemical batteries, which includes lower maintenance and is made by materials easy to recycle.

One example of company which produce supercapacitors is Maxwell

Superconducting magnetics energy storage (SMES): is a energy storage by magnetic field made by the flow of a direct current in a superconducting coil which is cooled by a temperature lower than the critical temperature of superconducting.

The structure is based in three components: one superconducting coil, one power electronics system and one cryogenic cooling system.

Regarding the functionality, once the superconducting coil is under the magnetic field effects, the current is not decreasing, and the magnetic energy is possible to storage indefinitely. The energy storage is able to be managed. For extracting this energy, the current is switched (ON/OFF) quickly by a power electronic control. On the other hand, by the high inductance, the coil behaviour is like a current source which is able to use for loading a capacitor which gives a voltage to a inverter which produces the AC voltage required with only 2-3% of energy losses, being this superconducting with high efficiency.

Thermal: Molten salts

Molten salts: can be employed as a thermal energy storage method to retain thermal energy collected by Solar Power and after used to generate electricity when there is no sunshine or at night.

The molten salts mixtures vary, the most extended mixture contains sodium nitrate, potassium nitrate and calcium nitrate, being those, non-flammable and nontoxic, and has already been used in the chemical and metals industries as a heat-transport fluid.
The salts melts at 131 ºC (268 ºF). It is kept liquid at 288 ºC (550 ºF) in an insulated storage tank. The liquid salt is pumped through panels in a solar collector where the focused sun heats to 566 ºC (1.051 ºF). It is then sent to a hot storage tank. 
This is so well insulated that the thermal energy can be usefully stored for up to a week.

Regarding the opportunities and challenges for energy storage, it is possible to mention the applications in Renewable Energies penetration for reducing or avoiding the “intermittent” issue in this sustainable generation. Such as Renewable Energies needs to get a better maturity, in terms of technology and the consequence in cost-of-energy, energy storage needs as well a certain improvement in technology maturity and cost reduction, for getting better comercial availability, but on the other hand, it needs greater support for developing this technology, from the regulators and institutions, not only economically, also in the awareness for exposing the benefits and value of this technology in the achievement of sustainable global target, knowing the consequence in the energetic plans for being a topic which concern a lot of different technologies (chemical, electrical, thermal) and then, having application in all the technologies which affects energy and its energy management: Energy Efficiency.

From customer point of view, it is necessary to explain the main contributions for customers;

1. with the possibility for managing the Demand Response, in first term to flatten the peak demand, using the energy storaged for this peaks,
2. Time-of-use (TOU): giving the possibility to the customer for managing the energy consumption in relation with maximum cost, and then having the possibility to save energy and money to the customer having the needs required at lower cost.
3. Following with point 2, even giving the possibility to the customer for storage energy when it is at lower cost and selling this energy during high cost, increasing the Return on Investment (ROI).
4. Possibility for frequency regulation, over all for Transmission System Operators (TSO), but also for customer which requires high frequency regulation for its control systems.
5. Demand Response: the possibility for having a reserve of capacity to be dispatched when in whatever unexpected event.

Grid Side:

• Bulk energy service: Arbitrage, storage during low cost periods and sell this energy when increase the price
• Ancillary services: Frequency regulations: supports system during loss of generation or transmission
• Support renewable energies: short term intermittency, PV, Wind generation
• T&D deferral: Use energy storage to support feaders or transformers during avercharge.

The challenges which Energy Storage needs a human-centered approach, having a technical feasability for improving economic revenue in this energy storage investments, at the same time, it is necessary a holistic approach; technically (e.g: batteries: higher energy density), economic, social and environtmentally, considering the safety and energy trends and one worldwide regulation.

Bibliography:

Energy Storage Wikipedia

Hydrogenstorage Wikipedia

El Vehículo Eléctrico – Sociedad de Técnicos de Automoción
Thermal Energy Storage Wikipedia

Synchrotron Alba

Last 9th April, it was possible to visit the Synchrotron Alba, located close Barcelona city. Engineers Association of Barcelona organized one visit to the center, and fortunately for us, the Synchrotron was not in functionality, due to maintenance tasks, being possible to visit the tunnel inside, which normally is not possible due to the risk of radiation.

One Synchrotron is used to make experimental test, mainly for R&D. With one Synchrotron it is possible to get X-Rays. There are two ways for getting X-Rays; a) accelerating the electrons and make it breaks suddenly or, b) changing the trajectory of the electrons from the old or previous trajectory.

X-Rays are used for getting some features and test of material and elements which is not possible to get by other way. 

For example, for determined the years of the ink from one antique book, this X-Rays are able to give the properly information. 

Figure 1_Synchrotron Building (by InkScape)_Source: Javier Sanchez Rios

How does it work?

Electrons emitted by an electron injection system are first accelerated in a linear accelerator (linac, point 1 of Figure 2), and then transmitted to a circular accelerator (booster synchrotron, point 2 in Figure 2)), where it is accelerated to reach a high energy level. These high-energy electrons are then injected into a circular storage ring (big ring indicated as point 3, in Figure 2). In this storage, ring the electrons are circulating in a vacuum environment, at a constant energy for many hours.

Figure 2_ Structure and functionality of the Synchrotron Alba. See the description of every point (1 to 7 in the explanation after figure 2)_source: InkScape by Javier Sanchez Rios from Synchrotron Alba website.

Figure 3_General overview of Synchrotron (180 meters of diameter) , where is possible to see (on the right) 3 of the 37 corners where is finishing the X-Rays of the Synchrotron, but in that case with no application for experimental applications. It is necessary to consider, the block of high-density concrete of 1.5 meters of the structure of the tunnel in this side, because in the inner side, there is no risk of radiation and the block is not with this features_source: Javier Sanchez Rios.

Figure 4_Inside the tunnel of the Synchrotron, on the right, the accelerator ring, on the left, the storage ring of the Synchrotron, with the different magnets. Normally it is not possible to enter in this place due to the possible radiation. In the visit, the Synchrotron was in maintenance process, and there was no risk of radiation. The radiation of X-Rays disappears after some hours_Source: Javier Sanchez Rios

1_Electron production:
Electrons are generated like in a television tube. In that case, the electrons are pre-accelerated by electric fields in a Linear Accelerator
2_Acceleration:
In a Booster Ring, the electrons are further accelerated with the aid of powerful magnetic (20,000 times greater than the magnetic field of the Earth), and electric fields, until they reach velocities greater than 99,999% of the speed of light.
3_Storage:
The electrons are then injected into a Storage Ring, where they are maintained in a circular orbit by strong magnetic fields. Velocity is kept constant by compensating for the energy lost as light emissions with electric fields from a radio-frequency source.
Magnets in a Storage Ring:
- Bending Magnets: essentially dipoles that bend the electron trajectory.
- Quadrupoles: focus the electron beam onto a nominal orbit.
- Sextupoles: reduce the energy dispersion (chromaticity) of the electrons in the ring.
- Correctors: smalls dipoles that correct the electron trajectory in real time.
- Dipoles, Quadrupoes and Sextupoles are activated when the electrons are injected.
- Pulsed Magnets (Septums, Kickers and Bumpers) are used to transfer electrons between accelerators. They produce strong magnetic field in a short period of time. They are built from highly specialized magnetic materials.

Figure 5_ Storage Magnet in Storage Ring, it is possible to see the cables of electric supplying (on the left) and the cooling system by the orange hose (in the right). This kind of magnets are supplied by 600A, therefore, this magnets need the cooling systems by water (cooling jacket)._source: Javier Sanchez Rios

Figure 6_ Sextupole magnet, being possible to see the 6 magnets distributed in the properly way in 360º_source: Javier Sanchez Rios

For getting compensation of the energy lost (due to the impossibility to have 100% vacuum in the ring), and different trajectory to drive the electrons into the beam-lines and out of the storage ring, it is necessary to help the electrons by one system of Radio Frequency, which in the positive half cycle is addressing the electrons to the beam-lines.

Figure 7_Radio Frequency system used for Synchronization of the electrons to change the trajectory ("similarly switch points in the railway"). After this process, the X-Rays are going for the different applications. RF waves are generated by 500MHz in three stations like it is shown in the figure 7, which a consumption of 160MW_source: Javier Sanchez Rios.


4_Beam-lines:
Synchrotron Light is propagated through a Beam-Line, placed tangentially to the ring. There are two types of beam-lines, depending on the Insertion Devices or Bending Magnets are used for light production.
In the Insertion Devices, Synchrotron Light is generated when the electrons are accelerated into a sinusoidal trajectory by a periodic magnetic structure. The light thus obtained is very intense and collimated.
The light then generated is with polychromatic, albeit less collimated and intense than that from the Insertion Devices.

Figure 8_Two different example of beam-line (being out of the storage ring and out of the tunnel). This is the last procedure, 5, 6 and 7 from the Figure 2. Pay attention of the chamber (on the right) which is connecting the beam-line and the tunnel, this is one chamber of lead for avoiding radiation. In terms of test, of course, it depends of the definition of the proposal_source: Javier Sanchez Rios.

For being able to get this X-Rays, it is necessary to get vacuum in the electrons conduction. For that, the system is using one turbine and RF systems for making the vacuum, but at the same time, the system is using one Titan Ion pump for getting the Gamma-Ray. After that, the system is making a light condition, explained in next point 5.

Figure 9_ On the left, the Gamma Vacuum Titan Ion Pump, used for the absorption of particles which are able to interact with electrons and then make it disappear from the beam (energy lost). On the right, the photon beam, systems for helping to concentrate the beam of the X-Ray for a better experimental applications_source: Javier Sanchez Rios.

5_Light Condition:
In an optical "hutch", it gets selected certain wavelenghts, i.e., a small portion of the white electromagnetic spectrum, by means of a monochromator. These photons are transported and focused onto the sample by, for example, bent X-Ray mirrors.
6_Detection:
In an experimental "hutch", the sample is positioned and a detector system collects the experimental data. There are many types of detectors systems, each specialized for a particular application.
7_Data reduction and analysis:
In the control "hutch" the experimental set-up and data collection is under computer control. Data are extracted, reduced, processed and prepared for analysis and/or storage.
The electrons are accelerated and deviated in the storage ring by different magnetics components:
- Bending magnets: they allow to deviate the electrons by several degrees. This deviation results in an tangential emissions of X-Rays by the electrons.
- Undulators: they force the electrons to follow an undulating trajectory. The X-Ray emitted by this undulation will contribute to generate a much more intense beam of light than that generated by the bending magnets.

Figure 10_Undulator Magnet in Alba Synchrotron_source: Javier Sanchez Rios

- Focusing magnets: they allow to keep the electron beam small and well-defined. Smaller and well-defined the electron beam will be, brighter the X-Ray. These magnets are placed in the straight sections of the storage ring.

The X-RAys emitted by the electrons are directed towards the beamlines situated tangentially to the storage ring in the experimental hall. Each beamline is designed to use with a specific technique or for a specific type of research. Experiments run throughout the day and night.

Figure 11_Part of the Facility system, which is supplied by Power district cooling system coming from Gas Co-generation Power plant for supplying all the processes of the Synchrotron; which includes: Hot Water at 40ºC, Compressed Air, Ionized Cold Water, Water for cooling systems at 23ºC, Water for the HVAC at 6ºC, and nitrogen in liquid and gas. On the top left; Facility room, on the top right; Data Center Network for controlling and for Data Aqusition of the process, on bottom left; water pump for the cooling and HVAC systems, on the bottom right; three way-valve for mixing the cooling water coming from the magnets (hot water) with the cold water for different applications_source: Javier Sanchez Rios

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Applications of X-Rays in Synchrotron of Barcelona and area of investigation:
1_Chemistry: X-Ray analysis of chemical elements allows improvement of production processes for adhesives and lubricants, anti corrosion coating, surfaces electrochemical preparations, hydrophobic coating, etc.
2_Material Science: With X-Rays is possible to establish the three dimensional structure of non-crystalline materials, being this behaviour determined by pressure of nano-crystalline phases or chemical impurities (doping) which is not possible determined by traditional means. By this experimental test, it is possible to know the material's performance.
On the other hand, the beam is used in the study of special alloys for using in Aerospace technology; the electronic and atomic structure of catalysts: semiconductors, superconductors, and how these properties depend on high pressure or temperature.
3_Magnetism: soft X-Ray magnetic circular dichroism, are used to image the magnetic domains in thin films and mono-layers. These are essential in sensors and data storage devices. In addiction, Synchrotron Light is used for "in situ" detection of magnetic micro structures.
4_Life Science: X-Ray diffraction is used to study the structural/functional changes undergone by; DNA, proteins and macromolecules, hormones, enzymes and viruses.
As example: muscles, and other biological systems, convert chemical energy into force or motion. Muscle molecules undergo subtle and rapid conformational changes that only Synchrotron Light is capable of detecting. It is thanks to such techniques which provides sequences of molecular events responsible for molecular contraction.
5_Macromolecular Crystallography: After the completion of Human Genome Project, it is possible to crystallize many biological macromolecules intimately involved in a given biological target. Synchrotron Light has solved the atomic structure of many biological macromolecules and will continue to do so until all the proteins structures (in excess of 50,000) derived from the knowledge acquired in the Human Genome Project are solved. One important recent example is the atomic structure of the biological protein manufacturing machinery.
6_Industry: In the past, many industrial processes such as polymer and ceramics production, depended on the skills of the experts and on chance. Great control and predictability has now carried out with Synchrotron Light.
Other Industrial applications are in areas such as electronics (e.g.: chip manufacturing), micro-mechanics (e.g.: manufacture of sub-micron devices used in medical or sensors applications), Aerospace Industry (e.g.: detector, calibration), Environmental Industry (e.g.: analysis of contaminated soils and/or plants)

PS: For getting information of the current status of the Synchrotron, please visit this website.

Bibliography:
Synchrotron Alba