P
OLITECNICO DIM
ILANOS
CHOOL OFI
NDUSTRIAL ANDI
NFORMATIONE
NGINEERINGM
ASTER OFS
CIENCE INM
ANAGEMENTE
NGINEERINGE
NERGY ANDE
NVIRONMENTALM
ANAGEMENTAnalysis of the Vehicle-to-grid technology:
European case study review
Master Thesis of:
Sherly Maria Cristina Vergara Diaz
897567
Supervisor:
Prof. Simone Franzò
Tutors:
Martino Bonalumi
Fabiola Bordignon
Lucrezia Sgambaro
Academic Year 2018 – 2019
Content
List of Abbreviations ... 4 List of Figures ... 5 List of Tables ... 7 Abstract ... 8 Sommario ... 9 1. E-mobility ... 10 1.1. Electric Vehicles ... 11 1.1.1. History ... 11 1.1.2. Technology ... 12 1.1.3. Market ... 13 1.2. Charging Infrastructure ... 16 1.2.1. Charging methods ... 16 1.2.2. Connectors ... 171.2.3. Charging stations diffusion ... 21
2. Vehicle-to-Grid ... 28
2.1. Technology ... 28
2.2. Requisites ... 29
2.2.1. Vehicles ... 29
2.2.2. Infrastructure & smart technologies ... 32
2.2.3. Aggregator ... 34
2.3. Strategic Overview ... 35
2.3.1. Main Players ... 35
2.3.2. Business Models ... 37
2.3.3. Opportunities & Barriers ... 41
3. V2G Pilot Projects ... 46
3.1. Global Overview ... 46
3.2. Development Stages ... 48
3.2.1. Early Stage (2008-2011) ... 48
3.2.2. Technical Viability (2012-2015) ... 49
3.2.3. Looking for a BM (2016-actually) ... 50
3.3. European Overview ... 51
3.4. Main European Projects ... 58
3.4.1. Parker (Denmark) ... 58
3.4.2. Aces (Denmark) ... 63
3.4.4. Smart Solar Charging (Netherland) ... 70
3.4.5. Project’s Confrontation ... 74
Conclusions ... 76
List of Abbreviations
AC = Alternating Current BM = Business Model
BMS = Battery Management System DSO = Distribution System Operator ICE = Internal Combustion Engine DC = Direct Current
EV = Electric Vehicle
BEV = Battery Electric Vehicle HV = Hybrid Vehicle
PHEV = Plug-in Hybrid Electric Vehicle RES = Renewable Energy Sources TSO = Transmission System Operator
List of Figures
Figure 1 Types of Vehicles. Source: Leading the Charge (1) ... 11
Figure 2 Series vs Parallel PHEV. Source: Research Gate (2) ... 12
Figure 3 EV Sales by year. Source: Adaptation of EV volumes(4) ... 13
Figure 4 EV Sales by Market (Global Light Vehicles). Source: Adaptation of EV-volumes (4) ... 14
Figure 5 EV Sales and Growth by European Country (European Light Vehicles). Source: Adaptation of EV-volumes (4) ... 14
Figure 6 Global Electric Vehicle Sales Forecast. Source: J.P. Morgan (5) ... 15
Figure 7 EV adoption by region (% of Sales). Source: McKinsey & Company(6) ... 15
Figure 8 Energy Demand for EV by Region. Source: Adaptation of McKinsey (6) ... 16
Figure 9 AC charging Types. Source: EV Expert (10) ... 18
Figure 10 Estimated number of charging units 2018. Source: Adaptation of Dalroad (12) ... 20
Figure 11 DC Charging Types. Source: InsideEVs (13) ... 20
Figure 12 Compatibility of the different Charging Station's Connectors. Source: Charge Hub (11)... 21
Figure 13 Global N° of Light Vehicle’s Charging Stations (2013-2018). Source: Adaptation of IEA 2019 (14) ... 22
Figure 14 Publicly accessible chargers. Source: Adaptation of IEA 2019 (14) ... 22
Figure 15 Number of EV per charging points. European Parliament (15) ... 23
Figure 16 Estimated N° of Chargers and Investment. Source: Adaptation of McKinsey (6) ... 24
Figure 17 Energy Demand by Charging Technology (% of KWh). Source: McKinsey (6) ... 24
Figure 18 N° of Highway Charging Stations and distribution targets. Source: EIA 2018 (17) ... 25
Figure 19 Number of EV and publicly accessible charging points in Europe (2017). ... 26
Figure 20 Evolution of charging infrastructure in EU. Source: Adaptation of European Parliament (15) ... 27
Figure 21 V2G Concept. Source: PSPA (18) ... 28
Figure 22 Schematic of a Battery Management System. Source: ResearchGate (19) ... 29
Figure 23 Bidirectional V2G converter. Source: PSPA (18) ... 30
Figure 24 Schematic of AC/DC Charging. Source: Future of Charging (20) ... 31
Figure 25 Schematic of a CHAdeMO DC Bidirectional EV Charger. Source: Future of Charging (20) ... 31
Figure 26 V2G projects using CHAdeMO connectors. Source: CHAdeMO (21) ... 32
Figure 27 European EVs using CHAdeMO connectors. Source: Adaptation of CHAdeMO (21) ... 32
Figure 28 Communication levels. Source: Science Direct (22) ... 33
Figure 29 Smart Grid System. Source: Science Direct (22) ... 33
Figure 30 BM1 roles & Value System. ... 38
Figure 31 BM2 roles & Value System. ... 38
Figure 32 BM3 roles & Value System. ... 39
Figure 33 BM4 roles & Value System. ... 40
Figure 34 Project’s Global Distribution. Source: Everoze & EVConsult (33) ... 46
Figure 35 Focus of the 50 V2G existing Projects. Source: Adaptation of Everoze & EVConsult (33).... 47
Figure 36 Number of projects each Manufacturer is involved. Source: Everoze & EVConsult (33) ... 47
Figure 37 Type of current (AC or DC). Source: Adaptation of Everoze & EVConsult (33) ... 48
Figure 38 V2G Projects. ... 51
Figure 39 Participation per Country in the total European Projects Deployment. ... 53
Figure 40 Total N° of V2G Chargers per European Country. ... 53
Figure 42. N° of European Projects where Energy Companies are involved. ... 56
Figure 43 Number of European Projects where Service Providers are involved. ... 57
Figure 44 Cooperation between Nissan & Enel. Source: PSPA (18) ... 57
Figure 45 Parker's EVs & Chargers. Source: Parker Project (51) ... 58
Figure 46 Parker Project Partners. ... 59
Figure 47 Parker's roles & Value System FF Case. ... 61
Figure 48 Parker's roles & Value System General Case. ... 62
Figure 49 ACES Project Team. Source: ACES Project (61) ... 63
Figure 50 ACES Project Partners. Source: ACES Project (62) ... 64
Figure 51 ACES' roles & Value System. ... 66
Figure 52 INEES EVs & Chargers. Source: Inside EVs (41) ... 67
Figure 53 INEES Project Partners. ... 67
Figure 54 INEES' roles & Value System. ... 69
Figure 55 Smart Solar Charging EVs & Chargers. Source: Smart Solar Charging (70) ... 70
Figure 56 Smart Solar Charging Project Partners. ... 70
List of Tables
Table 1 Parameters of the most popular EVs. Source: Adaptation of PSPA (18)... 30
Table 2 Main models sold in Europe. Source: Energy Strategy (16) ... 31
Table 3 Main Issues for V2G BM's adoption. ... 40
Table 4 Main Opportunities & Barriers for V2G adoption. ... 42
Table 5. V2G European Projects’ main characteristics. ... 52
Table 6 Reverse Power Flow use cases. ... 54
Table 7 European Projects’ main players & BMs. ... 55
Table 8 Smart Solar Charging 5 pilot areas. ... 72
Abstract
Due to distributed generation, the role of EVs as energy storage facilities is becoming increasingly important giving rise to new mobility concepts and attracting attention worldwide. Technological progress and pilot projects are moving forward showing positive results on the usage of bidirectional flow of electricity between EVs and the power grid. Players involved in the processes of generation, transmission, distribution and consumption of energy can take advantage of this new functionality, especially DSOs & TSOs given that V2G may prove to be effective in balancing the grid while bringing economic benefits. In these sense, V2G technology offers technical possibilities for a deep convergence of the transport and energy sector.
The aim of this tesina is to define the characteristics of this emerging V2G ecosystem and, based on data collection, analyze the actual scenario focusing on a European level. The existing V2G projects and results obtained up to now make it possible to understand the technology’s current state of development and have a general idea of its possible future scenario, understanding if and how the adoption of this technology is economically convenient for the players involved.
First, a general overview on the e-mobility concept is given together with a broad description of the different types of propulsion systems. The focus nonetheless, is on EVs (PHEV, BEV) given that these are the ones that can be used for applying the V2G technology. This initial part also provides information about charging infrastructure such as the charging modes and connector types. Issues on the related standardizations, such as compatibility are explained together with a deeper analysis on the charging stations diffusion at a global and European level.
After the introduction of these basic concept, a deep description of the V2G technology and its requirements is given, including the aggregator concept, enabling technologies based on a smart approach and related critical issues. There have been identified the existing EVs V2G enabled as well as the type of connectors they use making an emphasis on CHAdeMO connectors given that these are the only ones V2G enabled commercially available until now. From a strategic point of view, the role of the players involved and the emerging business models have been identified as well as the possible opportunities that this technology brings and the existing barriers that must be overcome.
In order to understand better the evolution of this technology, a global overview of the existing V2G projects with physical deployment is proposed making a general analysis of the main EV manufacturers involved in the technology development worldwide. Moreover, the development stages since the first appearance of the V2G technology are identified and described in detail making an emphasis on the relevance of project’s scale. A deeper analysis is developed on European pilot projects identifying the main players and leading countries.
Finally, some of the European projects are further analyzed in order to evaluate V2G applications focusing on the ones that include an interaction with the TSO. Results show that through V2G, EVs can successfully provide services to the grid, especially frequency regulation services, which are the most lucrative. However, more large scale projects are needed in order to select an adequate BM.
It is important to mention that the idea behind the V2G solution is to optimize the use of renewable energy, which is aligned with the energy and climate policy of the European Union.
Sommario
A causa della generazione distribuita, il ruolo dei veicoli elettrici come strutture di accumulo di energia sta diventando sempre più importante dando vita a nuovi concetti di mobilità e attirando l'attenzione in tutto il mondo. Progressi tecnologici e progetti pilota stanno andando avanti mostrando risultati positivi sull'uso del flusso bidirezionale di elettricità tra veicoli elettrici e rete elettrica. Gli attori coinvolti nei processi di generazione, trasmissione, distribuzione e consumo di energia possono trarre vantaggio da questa nuova funzionalità, in particolare DSO e TSO, dato che la tecnologia V2G può rivelarsi efficace nel bilanciare la rete e apportare vantaggi economici. In questo senso, questa tecnologia offre possibilità tecniche che costituiscono un forte punto di incontro fra il settore dei trasporti e quello dell'energia creando nuovi sbocchi economici.
Lo scopo di questa tesina è definire le caratteristiche di questo emergente sistema V2G e, sulla base della raccolta dei dati, analizzare lo scenario reale concentrandosi a livello europeo. I progetti e i risultati V2G esistenti finora ottenuti consentono di comprendere l'attuale stato di sviluppo della tecnologia e di avere un'idea generale del suo possibile scenario futuro, comprendendo se e come l'adozione di questa tecnologia sia economicamente conveniente per gli attori coinvolti.
In primis, viene definito il conceto di e-mobility descrivendo i diversi tipi di propulsione. L'attenzione, tuttavia, è sui veicoli elettrici (PHEV, BEV) dato che questi sono quelli che possono essere utilizzati per applicare la tecnologia V2G. Questo capitolo fornisce anche informazioni sull'infrastruttura di ricarica come le modalità di ricarica e i tipi di connettore. I problemi relativi alle standardizzazioni correlate, come la compatibilità, sono spiegati insieme a un'analisi più approfondita della diffusione delle stazioni di ricarica a livello globale ed europeo.
Dopo l’introduzione di questi concetti base, verrà descritto in modo approfondito la tecnologia V2G e i suoi requisiti, incluso il concetto di aggregatore, abilitando tecnologie basate su un approccio intelligente e relative criticità. Sono stati identificati gli EVs esistenti V2G abilitati e il tipo di connettori che usano enfatizzando i connettori CHAdeMO dato che questi ultimi sono gli unici abilitati alla tecnologia V2G disponibili in commercio fino ad ora. Da un punto di vista strategico, sono stati identificati il ruolo degli attori coinvolti e i modelli di business emergenti, nonché le possibili opportunità offerte da questa tecnologia e le barriere esistenti che devono essere superate.
Per capire meglio la evoluzione di questa tecnologia viene proposta una panoramica globale dei progetti V2G esistenti con dispiegamento fisico facendo un'analisi generale dei principali produttori di veicoli elettrici coinvolti nello sviluppo tecnologico in tutto il mondo. Inoltre, le fasi di sviluppo dalla prima apparizione della tecnologia V2G sono identificate e descritte in dettaglio ponendo l'accento sulla pertinenza della scala del progetto. Un'analisi più approfondita è sviluppata su progetti pilota europei che identificano i principali attori e paesi leader.
Infine, alcuni dei progetti europei sono ulteriormente analizzati al fine di valutare le applicazioni V2G concentrandosi su quelle che includono un'interazione con il TSO. I risultati mostrano che attraverso V2G, i veicoli elettrici possono fornire con successo servizi alla rete elettrica, in particolare i servizi di regolazione della frequenza, che sono i più redditizi. Tuttavia, sono necessari più progetti su larga scala per selezionare un BM adeguato.
È importante ricordare che l'idea alla base della soluzione V2G è quella di ottimizzare l'uso di energia rinnovabile, in linea con la politica energetica e climatica dell'Unione europea.
1. E-mobility
The concept of e-mobility refers to the electrification of transportation, which not just involves the vehicles that are powered by an electric motor, but also the overall system that makes it possible including in this way, the energy supply side as well as the infrastructure.
At the beginning, governments started to support e-mobility driven by the increasing CO2 emissions that the usage of traditional fuel vehicles generate. Now, further benefits have been identified and governments have started to push even more this concept. Both, non-economic incentives as free circulation, preferential pathways and free parking; as well as economic ones like subsides or VAT exemption are nowadays granted in many countries. It is clear that the electrification of transportation has become a priority.
Most of the governments of developed countries have a more accurate idea of how are they going to approach e-mobility in terms of market, infrastructure and value chains. However, without doubts, it is a long term path that needs the involvement of many players and a coordinated approach in order to be successfully implemented. The good news is that manufacture enterprises, the energy sector and services enterprises, have now common and clear goals approaching e-mobility in their respective sectors.
Other issues such as reduced autonomy of EVs, long charging periods and high prices, are going to be tackled soon with the new generation of EVs cars. Moreover, the diffusion of renewable energies, the technological advances and smart grids, are contributing in order to foreseen e-mobility as a way to achieve sustainable development.
It is important to highlight that E-mobility will not just deeply impact the future of energy companies, indeed, due to the big economic, political and social changes that it is already generating, together with the technological development, this macro trend will change the way we live. In any case, it is more an opportunity from which everyone can take advantage, for example we can take advantage of e-mobillity in order to transform the grids into smart ones or update the infrastructure, or even introduce the concept of circular economy by recycling batteries. However in order for this to happen, all the actors must cooperate and coordinate their actions strategically in a broader way.
1.1. Electric Vehicles
1.1.1. History
The EVs, or vehicles powered by a battery, was one of the first technologies to be developed. The earliest prototypes were designed during the 1830’s by Sibrandus Stratingh, a dutch professor, and Robert Anderson, a scottish entrepreneur. However, it was not until 1884 when Thomas Parker, an English inventor and engineer, built the first EV. This was mainly achieved thanks to the invention of the lead-acid battery in 1859 and its following improvements that increased the batteries’ power and storage capacity.
By the end of that century, EVs were already being produced in Belgium, France, Germany, UK and USA, achieving its peak during the first decade of the 20th century. However, due to the fact that at the beginning EVs did not achieve high sale quantities, they were easily replaced by the ICE vehicles (Internal Combustion Engine) which are nowadays the most diffused configuration of propulsion system.
The first gasoline powered ICE vehicle, also known as fuel vehicle, was invented in 1870 by the German Siegfried Marcus but it was not commercialized until 1885. Even if this is a mature technology with an on-going working infrastructure, it uses traditional fuels (gasoline, diesel) which are not just characterized by having a high volatility price but also for generating emissions. However, due to the innovations in the technology that increased their efficiency, the introduction of assembly lines and the discoveries of new petrol depots which lowered the fuel prices; overall costs of ICE vehicles ended by being lower than EVs and this fomented their diffusion.
The Hybrid vehicles (HVs) on the other hand, another type of propulsion system, were invented in 1899 by Ferdinand Porsche, a German automotive engineer. This type of vehicles did not become an economic viable solution until the late 90’s with the launch of the Toyota Prius and Honda Insight models. This technology combines a combustion engine and an electric motor with a battery that can be charged by capturing the energy when braking, decreasing the conventional fuel need, without necessarily having to be plugged. Both motors complement each other, while the electric engine works efficiently producing a torque, at low speed, the combustion engine is ideal for maintaining high speed. Actually HVs are the second more diffused configuration and are perceived as a main segment for the future automobile market.
1.1.2. Technology
Nowadays, given the technological advance, it is also possible to develop EV technology in a profitable way. This type of technology is the focus of this report because it refers to the vehicles that have a battery and can be connected to the grid in order to be charged, due to this they could be used for applying the V2G technology. It must be mentioned that they approach sustainability by creating common benefits such as energy efficiency and assessing environmental issues (less or no emissions, less noise pollution). EVs can be of two different types:
1.1.2.1. Plug-in Hybrid EV (PHEV)
PHEV is a type of HVs that have a larger battery which can also be charged by be connecting it to an electrical vehicle charging station or any other suitable electrical outlet. It has two configurations:
Parallel PHEV: Where the engine and the motor can be used individually or in a coupled way being able to change to the ICE mode when it is more convenient like when high speed is needed or the battery is depleted.
Series PHEV: Where just the electric motor is connected to the wheels while the combustion engine generates electricity to power the motor when the battery is discharged acting as a range-extender.
Figure 2 Series vs Parallel PHEV. Source: Research Gate (2)
These vehicles tend to cost more than traditional vehicles due to the additional battery, having also a more complicated maintenance process without getting rid of the noise or emissions completely.
1.1.2.2. Battery Electric Vehicles (BEV)
These vehicles use just electric motors fed by batteries that can be charged using the braking system or by plugging it into an outlet or charging station. The level of autonomy of this solution depends on the battery size, but achieve always longer electric driving ranges than the PHEVs. In terms of energy efficiency, the electric engine efficiency is around 98%, but, considering the overall process, EVs convert about 59%–62% of the electrical energy from the grid to power at the wheels. Otherwise conventional gasoline vehicles only convert about 17%–21% of the energy stored in gasoline to power at the wheels (3). Another advantage is that they do not generate any noise pollution or tailpipe emissions while they are used, however, considering an overall perspective, emissions may be still produced during the generation of electricity used to feed the vehicles, depending on the electricity generation mix. It must also be mentioned that they do produce emissions during their manufacturing
process. This type of vehicles are also more reliable, their drivetrain has low chances of failure and given that the electric motors have fewer parts than the ICE, its maintenance is also simpler.
There is another typology of vehicles that as BEVs, produce no emissions during its usage, they are called Fuel Cell Vehicles (FCV). However, even if they use electricity, they are not considered as EVs due to the fact that they cannot be plugged into the grid. This type of vehicles are similar to the BEVs but their storage system is different, they use hydrogen gas stored in a tank and a fuel cell to produce electricity by an electrochemical reaction. It must be mentioned that this technology is still under development and its market share is not yet significant.
1.1.3. Market
The market of EVs is nowadays in expansion mainly driven by the introduction of more competitive prices and some incentives given by the governments. Its use is increasing not just in the private sector but also in the public transportation. Another fact that is also cooperating to the market expansion is the increasing interest from users to products more environmentally friendly and the infrastructure implementation that are facilitating their usage. However the diffusion is still related to the level of development of each country.
1.1.3.1. Global
The EV market reached 2.1 millions of units sold in 2018 from which 69% are BEVs while the remaining 31% are PHEVs. In Figure 3, as its can be noticed, the market share of EVs among all the new vehicles sold worldwide have always been increasing, reaching the value of 2.2% for last year and achieving the total global fleet of 5.4 million plug-ins light vehicles which is expected to reach the value of 8.5 million at the end of the current year.
Figure 3 EV Sales by year. Source: Adaptation of EV volumes(4)
Nowadays, the largest market is China, standing for 56 % of the total sales and for 63 % of the overall growth achieved in 2018, reaching almost 1.2 millions of units sold. Europe, on the other hand, increased their sales just in 34% selling near 410 thousands units, however it must be mentioned that sales were held back by supply constraints in larger EV markets, losing the possibility to sale between 20 to 30 thousands of units. In the case of USA, its increase is mainly given by the Tesla Model-3 sales while Japan losses are related to the declination of Toyota Prius plug-in by the arrival of the second generation Leaf. 0.17% 0.25% 0.37% 0.61% 0.83% 1.28% 2.20% 0.0% 0.5% 1.0% 1.5% 2.0% 2.5% 0 500 1000 1500 2000 2500 2012 2013 2014 2015 2016 2017 2018
Figure 4 EV Sales by Market (Global Light Vehicles). Source: Adaptation of EV-volumes (4)
1.1.3.2. Europe
Norway is the Europe's largest EV market, where 26% of the total vehicles are BEV and 14% PHEV, mainly due to government incentives and infrastructure investment, reaching the number of nearly 80 thousands of units sold in 2018. Almost all the European markets showed growth during last year, especially Netherlands and Denmark. In the case of Belgium, the cut of incentives on luxury EVs resulted in a 7% decline, while Italy’s sales are expected to grow even more during the present year due to subsidies and increased taxation for conventional vehicles.
In terms of individual countries Norway has the highest market shares with 40.2% of their light vehicles being EVs, followed by Iceland with 17.5%, Sweden with 7.2% and Netherlands with 5.2%.
% Change +18% +23% +25% +25% +45% +187% -7% +59% +97% +15% +25% +94% +85% +371% +16%
Figure 5 EV Sales and Growth by European Country (European Light Vehicles). Source: Adaptation of EV-volumes (4)
52 200 306 56 663 97 358 409 53 1182 0 200 400 600 800 1000 1200 Other USA Europe Japan China 2018 2017 0 4 3 4 2 1 5 5 18 9 10 12 14 11 0 10 20 30 40 50 60 70 80 Iceland Denmark Finland Portugal Austria Switzerland Italy Spain Belgium Netherlands Sweden France UK Germany Norway (Thousands) 2017 Growth to 2018 Decrease to 2018
About BEV/PHEV mix, PHEVs are still preferred by European customers, however regardless their preferences, the final mix is mostly given by the taxation and incentives differences. Until 2017 the market penetration was almost 50/50%, nevertheless in 2018 BEV sales started to be promoted by some policy changes such as Sweden’s taxation system, the reduction of the Netherlands and Belgium PHEV incentives, the 37.5 % CO2 reduction objective introduced by Europe, between others. At the end all these changes ended up changing the ratio achieving a value of 69/31% in favor of the BEV by the end of the year.
1.1.3.3. The future of EV
The automotive industry is experiencing a huge transformation and will bring changes during the next 10 years that will radically change the future of mobility. To begin with, given the fact that governments are approaching fuel emissions issue, by 2030 BEV, PHEV and other HVs will be more likely to be sold moving out from the ICE era. In 2025, just the EV vehicles sales will rise close to 8.4 million, while HVs sales are forecasted to reach a value higher than 25 million representing the 23% of global sales over the same period. ICE vehicles market share will decrease to the value of 68% in 2025 and continue to fall having just near 41% of the market share by 2030.
Figure 6 Global Electric Vehicle Sales Forecast. Source: J.P. Morgan (5)
The next decade, PHEVs are not going to be so popular in USA and Europe, so other HVs and BEVs will be the ones trying to lead the market. By 2030 In Europe, EV will rise to 31% while in China will represent a market share of 34%. Even if in USA regulation will push manufacturers to increase their EV offer, however its penetration will be just of 14% due to the fact that the urgency level will be lower than in Europe, where there are targets and fines for CO2 emissions. In this sense, by 2030 approximately 120 million EVs could be on the road.
Another point that must be considered is that given the fact that, without doubts, EVs demand will increase, the demand of electricity required for charging the vehicles’ batteries will increase too.
The energy demand for EV across USA, Europe and China may grow dramatically from 18 billion KWh in 2020 to 271 billion KWh in 2030. Its major increase will be given in Europe where the actual demand will be multiplied by 20. However, China will still have the highest demand requiring 139 billion KWh, more than half of the total need. In this sense EVs are expected to add globally near 2,000TWh of new electricity demand by 2040 and 3,414TWh by 2050, accounting for 9% of all the demand (7). As it can be noticed, renewables integration which will help to shift demand to periods when cheap renewables are running, as well as energy efficiency improvements will become essential to be able to cover the future electricity need.
Figure 8 Energy Demand for EV by Region. Source: Adaptation of McKinsey (6)
1.2. Charging Infrastructure
One important aspect to facilitate the development of e-mobility and a broad dissemination of EVs is the deployment of charging infrastructure. The availability and proximity of charging stations is the main reason why potential customers are concerned about buying EVs. In order to assess this issue and involve governments in the process, it is necessary to demonstrate that the EVs other than caring about the ecosystem are capable of creating economic development. Nowadays, there are many projects going on in order to evaluate economic impacts, weak and strong points as well as new business models.
A relevant aspect that must be considered while comparing traditional infrastructure with the charging infrastructure under development is the fact that even if the refueling of petrol or diesel cars has a well-established and already working infrastructure, there is only one way to deliver the fuel, through a fuel pump at a retail petrol station. EVs, on the other hand, can be fueled at different rates of speed and at many different locations, including at home. In this sense, it also represents a key benefit for consumers: EV drivers no longer need to travel to a central location to refuel.
However, the deployment and the adaptation of infrastructure to new mobility patterns is a long process that leads to additional challenges that require new investments and a different approach to networks design and business models, which should be more opened and standardized.
1.2.1. Charging methods
The charging methods describes the speed at which a vehicle is charged, the required voltage and current and defines the level of communication between the vehicle and the power outlet. According to the International Electrotechnical Commission (IEC 61851-1), there exist four charging modes, 3 of them use an Alternating Current supply while the other uses a Direct supply (8):
6 23 53 4 25 79 8 44 139 0 40 80 120 160 200 240 280 2020 2025 2030 Bi lli o n KWh USA EU China
Alternating Current (AC):
Mode 1: It implies a slow charging from a regular electrical socket without exceeding 16A, 250V for single phase and 480V for a three-phase supply source. This mode is nowadays the most immediate option for charging EVs as it is simple and requires a low investment, however its safe operation depends on the presence of adequate protection on the plant side such as protection against overcurrents, contacts and earthing system. It must be mentioned that even if these protections are mandatory by regulation in all the new plants for most of the countries, there are still some old plants without them creating a potential risk for the users. Where it is allowed it may remain, at least for some more years, as the more diffused charging mode for private places such as residential or business parking lots.
Mode 2: This mode also implies a slow charging from regular socket but with a higher current limit set at 32 A. It is equipped with additional protection arrangement having a control unit integrated in the supply cable which also guarantees information transmission. It must be mentioned that even if the control unit protects the downstream cable and the vehicle, it does not protect the plug itself, which is one of the most used components. This mode was initially developed for the US however it has also reached the European market and intends to substitute the mode 1 being considered as a transitory solution while the adequate infrastructure is developed. It can be used in both, public or private places.
Mode 3: This mode can be used for slow charging with a current limit of 16A and 230V or for semi-quick charging with a limit of 63A and 400V. It uses special sockets with control and protection functions. It must be mentioned that in order to connect the vehicle to the supply, specific device is needed.
Direct Current (DC):
Mode 4: This mode implies a fast charging with limits of 200A and 400V being just used for public application. In this case, the current is so powerful that the battery can be usually charged from 0 to 80% in less than half an hour, after that state of charge, charging will slow down significantly. For this charging mode both, the control unit and the battery charger are located inside the charging station. It is important to highlight that high currents produce more heat which reduces the battery life.
It is important to mention that at the end of 2017, almost 600 thousands public charging points were installed globally, 53% of them in China (9). However, from the overall quantity, just 20% were able to offer fast charging which means that most of them use AC.
A faster charge would be preferred by the drivers, but higher power chargers cost more and may require electrical upgrades, so different power levels are appropriate for different locations. Moreover, it makes sense to match the power level of the charger to the amount of time an EV is expected to be parked to minimize the burden on the grid. It is therefore expected that different charging modes will remain relevant in the future.
1.2.2. Connectors
The connectors are the plug that connects the vehicle with the charging point, which are used for power transfer and information exchange. They can vary according to the power supply range and the EV inlet port. There exist different shapes and standards for the connectors related mostly to the
geographical location, being Tesla the exception, offering a complete line of all global charging standards.
There is a big issue in terms of standardization, not just related to the physical plugs and sockets, but also for the charging protocols and payment systems. For manufacturers it is important in order to provide a clearer overview and allow economies of scale while for costumers, it guarantees interoperability which is essential specially in order to be able to use EVs for cross-border traveling. Given that there were no clear and common standards, many different connector designs were developed. Fortunately, given that local governments of different countries pushed producers to design a connecter system according to guidelines that were set across different regions, just some types are currently used. The main EV connector manufacturers are Yazaki, Fujikura and Sumitomo from Japan; Bosch, Siemens AG and Schneider Electric from Europe and Tesla from US.
1.2.2.1. Type of connectors
The charging type is related to the kind of connectors that are used. It must be mentioned that mode 1 connectors are not being mentioned because this mode is not relevant in the EV context, moreover it is prohibited in some countries such as the USA. The connectors currently used can be divided in 2 big groups according to the charging current they use:
Conventional Charging:
This type of charging uses alternative current with charging mode 2 or 3. The existing connector types are basically three:
Figure 9 AC charging Types. Source: EV Expert (10)
Type 1: Is a Japanese standard adopted by the USA and accepted by EU. It complies with the IEC 62196 and SAE J1772 standards and it is used by EV models such as Opel Ampera, Nissan Leaf, Nissan ENV200, Mitsubishi Outlander, Mitsubishi iMiev, Peugeot iON, Citröen C-Zero, Ford Focus electric, Toyota Prius Plug in and KIA SOUL EV.
It is designed for single-phase current connection: phase, neutral and ground with a rate up to 250 V and 32 A. It has two pins and extra protection to lock the connector.
Type 2: Also known as “Mennekes” due to the first brand that commercialized them. It is mainly diffused is Europe where, in accordance with IEC 62196, it is considered to be the
standard model. It is used by EV such as BMW i3, i8, BYD E6, Renault Zoe, Tesla Model S, Volvo V60 plug-in hybrid, VW Golf plug-in hybrid, VW E-up, Audi A3 E-tron, Mercedes S500 plug-in, Porsche Panamera and Renault Kangoo ZE.
It is similar to type 1, but it has two more pins that correspond to the extra phases, allowing 1-phase or 3-phase charging with a rate up to 480V and 32A. Most public charging stations have a type 2 socket and all mode 3 charging cables can be used with it.
GB/T AC: China has its own recommended standard which is only used by Chinese manufacturers. It works according to the 20234.2-2015, allowing a single or three-phase charging in charging mode 3. Its rated values are up to 480V and 32A.
Fast charging:
This type of charging uses direct current and it is used for charging stations in mode 4. The chargers can be installed in different public places such as supermarkets, drug stores, shopping malls, restaurants etc.; but are specially needed along major roads and highway service area for long distance driving across cities. In this category 3 different types of connectors are distinguished (11):
CHAdeMO: This standard was developed by a J apanese association and was the first and only DC charging option until the emergence of CCS. It is used by different Asian EV manufacturers such as Nissan with its model Leaf and ENV200, Mitsubishi with iMiev and Outlander, Peugeot with iON, between others.
Combined Charging System (CCS): The CCS started in 2011 as a collaboration between the SAE, a mainly US technical standards organization and the European Automobile Manufacturers Association. It allows conventional and fast charging, so both AC and DC vehicle connectors fit into the CCS vehicle inlet.it is diffused in the American market as CCS type 1 and in the European market as CCS type 2 complying with the above mentioned standards. It is used by models such as Chevrolet Bolt and Spark, BMW i3, Mercedes, Volkswagen, etc.
GB/T DC: It is the fast charging version of GB/T AC. Its rated values are up to 750V and 125A and works according to the according to the 20234.3-2015 standard.
Tesla Super Charger: Tesla provides fast charging to drivers of its vehicles using a modified version of the type 2 plug. This connector allows the Model S to recharge up to 80% in less than half an hour. Moreover, this system can charge at 120kW providing a range of 300+ miles with an hour charge higher than CCS or CHAdeMO with 120 miles range (12). It must be mentioned that even if the charging is given for free, it is impossible for vehicles of other brands to be charged with Tesla superchargers.
CHAdeMO, with 16 500 charging units, and GB/T, with 125 000, share near 90% of the global fast-charging market, however in the long term, they can be overcome by the CCS due to the fact that it is supported by major players. It is thought that driven by this, CHAdeMO signed an agreement with the China Electricity Council (CEC) in August 2018 in order to develop a common fast-charging standard with up to 900 kW charging power.
Figure 10 Estimated number of charging units 2018. Source: Adaptation of Dalroad (12)
The new GB/T charging standard, will be released in 2020 with the name of ChaoJi. This joint development should lead to a next-generation Ultra-Fast charging technology that is safe and versatile. It aims to ensure interoperability with existing CHAdeMO and GB/T fast charging standards and is also expected to be adopted not only in Japan and China but also in many other EV markets worldwide (13).
In Figure 11, there can be appreciated some characteristics of the different fast charging connectors including the new standard previously mentioned:
Figure 11 DC Charging Types. Source: InsideEVs (13)
The most relevant change is that the maximum power of the new standard reaches 900kW, more than twice the actual maximum power available in the market. In terms of the communication system, it keeps using the Controller Area Network (CAN) which is a robust vehicle bus standard designed to allow microcontrollers and devices to communicate with each other in applications without a host computer. It is a message-based protocol, designed originally for multiplex electrical wiring within
10.5% 4.8% 5.4% 79.4% CHAdeMO CSS
Tesla Super Charger GB/T
automobiles to save on copper. The SAE J1939, on the other hand, refers to a Society of Automotive Engineers standard recommended practice originated in USA. It is used for communication and diagnostics among vehicle components.
1.2.2.2. Compatibility
It is possible to find charging stations with more than one type of connectors and there are also some adaptors that can be used, however compatibility is still a relevant issue. Tesla is compatible with almost all the other existing connectors through the usage of adaptors, even if it is the only brand that has its own connector type. On the other hand, the models that do not use the Tesla standard are not compatible with it.
In the following image we have a list of the compatibility of the more commonly used connectors. It must be mentioned that the level column refers to the level of power, being level 1 used for the standard wall outlet, level 2 for the typical EV plug and level 3 for the fast DC chargers:
Figure 12 Compatibility of the different Charging Station's Connectors. Source: Charge Hub (11)
1.2.3. Charging stations diffusion
The EV charging stations, together with the EV supply equipment, are part of the infrastructure that supply electric energy to recharge the EVs. In developed countries the new infrastructure requirement is not that much compared to other alternative fuels, however the main challenge is to level the demand.
For charging at home some EVs may come with converters that can be plugged into a standard electrical outlet or a high-capacity appliance outlet. Public charging stations, on the other hand, are able to provide electrical conversion, monitoring and safety functionalities. These kind of stations are also needed when traveling, and many of them allow fast charging. They are typically on-street facilities installed by public authorities, commercial enterprises and some major employers in order to stimulate the EV’s market. Due to this, many charging stations are for free or activated by a free "membership card" or "day code".
1.2.3.1. Global
As it is known, e-mobility is still in its initial stage of market development. In Figure 13 it can be appreciated how both, public and private stations installation have been increasing over the years. In 2018, private installations were near 4.66 million worldwide, while just about 0.54 million were publicly accessible, making a total of 5.2 million, 44% more than the year before.
Figure 13 Global N° of Light Vehicle’s Charging Stations (2013-2018). Source: Adaptation of IEA 2019 (14)
In terms of public available charging points, it must be mentioned that China has a major part of the slow chargers and more than three quarters of the fast chargers global stock as it can be appreciated in Figure 14. This could be explained by its huge population and also by the high utilization rate of non-private vehicles which are more dependent on fast charging.
Figure 14 Publicly accessible chargers. Source: Adaptation of IEA 2019 (14)
0 1,000 2,000 3,000 4,000 5,000 6,000 2013 2014 2015 2016 2017 2018 C h ar gi n g Stati o n s (Th o u san d s)
Private slow Chargers Publicly available Slow Chargers Publicly available Fast Chargers
78% 5% 3% 2% 2% 1% 1%0.6% 7.4%
Publicly accessible fast
chargers (144,000 chargers)
41% 5% 13% 4% 6% 6% 3% 9% 13%Publicly accessible slow
chargers (395,000 chargers)
China Japan USA UK Germany France Norway Netherlands OtherIt must also be mentioned that most of the frontrunner countries have applied a demand-oriented approach for charging infrastructure deployment which says that charging infrastructure should be constructed where existing and future demand can be determined. On the other hand, USA has applied the coverage-oriented approach which is based on the fact that public infrastructure should minimize the distance between the charging points in order to be able to guarantee a minimum standard of service providing a safety network for emergency situations.
To increase the market penetration, a shift towards a coverage-oriented approach is needed. However this is a delicate issue because it won’t be a profitable business for the operators if the number of charging points is too high compared to the number of EVs.
Figure 15 Number of EV per charging points. European Parliament (15)
All over the world, there are many ideas for operating charging infrastructure, however the profitability of most remains limited due to the high capital costs for charging stations, the cost of electricity and uncertainty of utilization of some charging points. Nevertheless, the market is expected to grow at a significant rate thanks to the increasing initiatives set by governments all over the world together with the expected increase on fuel prices. The mix of these two aspects will push consumers to perceive EV as a better and energy efficient alternative. In this way, also the number of charging stations will increase. By 2030, EU will experience the highest growth reaching 15 million units followed by China with 14 million and USA with 13 million. The industry may need to invest more than EUR 40 billion in these regions in order to meet the chargers need.
In Figure 15 we can appreciate the ratio of EVs per charging point, ideally in order to foment the EV technology adoption it should vary between 10 and 16, however long-term oriented it will not be convenient to remain with this ratio. It can notice that nowadays just Norway and USA are within this range. In the other cases, the existing public charging points are more than the ones needed. It is important to mention that the geographical distribution of the charging points is not taken into account, nevertheless, it should be considered by policymakers in order to be able to set a more accurate value of the public charging stations needed.
Figure 16 Estimated N° of Chargers and Investment. Source: Adaptation of McKinsey (6)
Nowadays, there exist more AC charging stations than DC. However even if AC is expected to remain dominant in the near future, it can be noticed that DC charging will experience a considerable growth in terms of energy demand. While AC level 1 will reduce its market share being replaced by AC level 2, DC will increase its penetration. This can be noticed especially in EU where DC will pass from representing the 6% of the region’s EVs energy demand in 2020 to represent the 32% in just a decade. China, on the other hand, will have the highest numbers on DC penetration, covering 44% of its total energy demanded by EVs in 2030.
Figure 17 Energy Demand by Charging Technology (% of KWh). Source: McKinsey (6)
It must be mentioned that even if a DC charging station costs significantly more than an AC one, it provides a charge in much less time.On average, a level 2 charger used in a home costs less than EUR 1,000; while one used in a workplace or in public can cost on average EUR 7,500. A DC charger on the other side, costs about EUR 40,000 varying according its power capacity (16). It is important to mention that there is currently a push towards DC chargers at 100–150kW power levels up to 400kW, to serve the next generation of EVs with much bigger batteries.
The highway charging stations must also be taken into consideration. As it is known, the availability of charging installations along major road networks is a relevant issue because it enables long distance driving for BEVs. In this sense, China, EU and USA have put special attention on this issue targeting to install fast charging facilities along highways. In Figure 18 it can be appreciated the goals of each
2 6 13 1 8 15 1 5 14 0 5 10 15 20 25 30 35 40 45 2020 2025 2030 Esti mated N ° o f C h ar ge rs (mi lli o n s) USA EU China 10 15.4 17.2 USA EU China
region. In the case of China, the values refer to a governmental target (2020), for EU they refer to the targets set in the AFI Directive (2020) while for USA they refer to the targets set by the Electrify America Project (2030). As it can be seen the target deployment of EV charging infrastructure along major highways is in a range of 45-115km.
Figure 18 N° of Highway Charging Stations and distribution targets. Source: EIA 2018 (17)
1.2.3.2. European
The charging infrastructure in the EU has been increasing similarly to the overall EV’s stock. It is mainly coordinated at regional level having no specific targets related to charging infrastructure at EU level, however, there are many supporting measures that aim at increasing the number of charging points and EVs across Europe. The most important one is Directive 2014/94/EU which promotes the deployment of infrastructure for both refueling and charging with alternative fuels such as electricity, hydrogen and natural gas. This directive tackles economies of scale and operability setting some specific requirements such as:
Set national target on the appropriate number of public charging points Define common technical specifications for charging points for EVs
Ensure that charging stations use charging Type 2 for AC and CCS Combo 2 for DC.
Each EU Member State is obliged to submit a national strategy. In this way, the EU will not just facilitate e-mobility but also will reduce their dependence on oil.
In terms of home charging the European Commission is proposing that construction of charging stations in new residential buildings with over 10 parking spaces from 2025. The TEN-T regulation is also facilitating the low carbon transport infrastructure deployment, while the CEF is financing it. Also the industry is increasing their participation by creating partnerships such as Ionity, which aims to build a network of high power charging stations across Europe.
Nowadays, most charging stations exist only in urban areas of West Europe and vary between countries. Even if the number of charging stations increases with the increasing adoption of EV, it still depends on the national context and the policy instruments promoting their deployment. For example in Netherlands, the European country with highest number of publicly accessible charging points, a 1,000 euro subsidy is given for the installation of a semi-public charging point in the cities of Utrecht and Amsterdam. In Norway, the scenario is pretty similar, the city of Oslo counts with grants that cover up to the 60% of the charging point installation cost. Another example can be London, located in UK, where there exist charging points planning requirements for all the new real estate developments and moreover, residents may request the installation of charging stations on the road in front of their
0 20 40 60 80 100 120 0 200 400 600 800 1,000 China EU US Km / Cha rg in g S ta ti o n Targ e t N ° o f C h ar gi n g S tati o n
homes. In Copenhagen, capital of Denmark a target have been set which aims to reach 500-1,000 publicly available charging stations and 5,000 semi-public ones by 2025 (17).
Sweden 49,387 EVs (1%) & 4,733 CP Finland 5,910 EVs (0.2%) & 947 CP Norway 209,122 EVs (7.7%) & 10,350 CP Estonia 1,237 EVs (0.2%) & 384 CP Denmark 10,393 EVs (0.4%) & 2,582 CP Latvia 369 EVs (<0.1%) & 73 CP United Kingdom 137,680 EVs (0.4%) & 14,256 CP Lithuania 212 EVs (<0.1%) & 102 CP Netherlands 119,332 EVs (1.4%) & 32,875 CP Poland 976 EVs (<0.1%) & 552 CP Ireland 2,687 EVs (0.1%) & 1,009 CP Czech Republic 1,721 EVs (<0.1%) & 684 CP Germany 124,191 EVs (0.3%) & 10,878 CP Slovakia 568 EVs (<0.1%) & 443 CP Belgium 31,984 EVs (0.6%) & 1,765 CP Slovenia 1,085 EVs (<0.1%) & 495 CP Luxemburg 2,183 EVs (0.6%) & 337 CP Hungary 567 EVs (<0.1%) & 272 CP Austria 14,854 EVs (0.3%) & 4,088 CP Croatia 436 EVs (<0.1%) & 436 CP France 123,639 EVs (0.4%) & 16,311 CP Romania 669 EVs (<0.1%) & 114 CP Portugal 8,260 EVs (0.2%) & 1,545 CP Bulgaria 118 EVs (<0.1%) & 94 CP Spain 17,063 EVs (<0.1%) & 4,974 CP Greece 341 EVs (<0.1%) & 38 CP Italy 13,530 EVs (<0.1%) & 2,741 CP Cyprus 171 EVs (<0.1%) & 36 CP Malta 153 EVs (<0.1%) & 97 CP EU 28 669,716 EVs (0.3%) & 102, 861 CP Figure 19 Number of EV and publicly accessible charging points in Europe (2017).
Source: Adaptation of the Eropean Parliament (15)
As it can be noticed, countries and even cities are using different measures to promote the development of charging infrastructure, however, even if infrastructure is necessary, it is not sufficient, other factors may influence the EV uptake, such as model availability, EV incentives, urban density, etc.
Without taking into account some frontrunner countries, the development of e-mobility infrastructure in the EU has been slow. As it can be seen in Figure 20, by the end of 2017 the total public charging points were more or less 90 000 for normal power and 12 500 high power. It must be mentioned that normal charging speeds are mostly given by AC charging power, while fast charging are given by DC charging power. Currently there are not so many fast charging stations, but EU is working on increasing their availability and moreover, push power levels up to 400kW.
Figure 20 Evolution of charging infrastructure in EU. Source: Adaptation of European Parliament (15) 0 20,000 40,000 60,000 80,000 100,000 120,000 2013 2014 2015 2016 2017
2. Vehicle-to-Grid
2.1. Technology
The concept of Vehicle-to-grid (V2G) was based in the idea that vehicles spend almost all their useful life parked; in this sense, it is possible to use them as an asset in the energy management sector. In other words, while EVs are not being used, they can provide services to the grid.
V2G is a technology that enables bidirectional energy transfer between the grid and the EVs, this means that it allows not just to get energy from the grid to charge the EV but also the other way around according to the demand, taking advantage of the storage potential of the EV’s batteries. Its scope is to better integrate EVs while offering other forms of flexibility.
The potential of this innovation is really high because with the adequate infrastructure deployment, it will be possible to have millions of EVs acting as mobile energy assets which will not just support local networks, but also contribute to the national transmission system.
Figure 21 V2G Concept. Source: PSPA (18)
However, in order to achieve maturity, this technology must follow a difficult path. There are still significant technical challenges such as the development of more affordable bi-directional chargers. Electricity networks, on the other hand, also need to evolve in order to be able to guarantee a smart charge. In this sense, smart grids will be needed, distributed meters must be installed along the grid and used to communicate with a Demand Response Management System improving the quality and reliability of the network as well as avoiding overloads. This two way communication and closer interaction between assets and players on the grid will allow smarter interactions which are needed for better exploding the V2G technology.
It can be noticed that most of the governments of developed countries are committed to this technology based on the interest given to their pilot projects. The industry as well is increasing their participation by forming partnerships and developing new business models. However, EV owners will play a key role in driving the change, as they will become an essential part of the energy system.
2.2. Requisites
2.2.1. Vehicles
EVs need specific characteristics in order to be able to operate in V2G service modes, starting from their storage system:
Figure 22 Schematic of a Battery Management System. Source: ResearchGate (19)
Power management of the batteries must be integrated into a control scheme, also called Battery Management system. Charging and discharging processes should be controlled remotely depending mainly on the battery discharging level and the power grid load. The technical condition of the battery and the power grid as well as the grid type (smart or traditional) should also be taken into consideration. Other factors that may influence this process are the provisions of the contract between the EV owner and the utility company as well as the time and distance of the journey planned by the EV user.
Batteries must be able to act as a grid or a building-connected power source, being enabled for bidirectional charge.
The storage system must have the capacity of balancing resource supplying and receiving power in a real time response mode.
About the type of EVs, it is important to mention that between BEVs and PHEVs, PHEVs often have quite smaller batteries, so they may have less to offer in V2G systems. However, they also consume less energy so this should also be taken into account. Table 1 shows the main parameters of the most popular EVs:
Table 1 Parameters of the most popular EVs. Source: Adaptation of PSPA (18)
In terms of type of current, it must be highlighted that for allowing V2G using AC, EVs are equipped with an "onboard" charger with a bidirectional inverter inside given that bidirectional electricity flow between the EV and the power system requires special charging converters. This bidirectional charger takes incoming AC and transforms it into DC, which is then sent into the battery pack and vice versa to be able to fed it into grid. The power of the on-board charger is in this case a key parameter because it defines and limits how fast EVs can be charged on much cheaper and much more widespread AC charging stations.
Figure 23 Bidirectional V2G converter. Source: PSPA (18)
In the case of using DC charging stations, they can transform AC to DC by themselves because this enabler is located in the charging point. In this sense, the energy is directly introduced in the battery without passing through an internal charger. This process is precisely controlled by the instructions and parameters of charging and the BMS. Charging in this case is not limited by the performance of an onboard charger so it is possible to charge at significantly faster rates. However, these charging stations are technologically much more complex and many times more expensive than AC ones. Due to this and the fact that they require a high powered electric supply point their diffusion is low compared to the AC Charging stations diffusion (10).
BEV PHEV
Renault
Zoe Nissan Leaf
Hyundai IONIQ Electric Volkswagen e-Golf Volkswagen Golf GTE Mitsubishi Outlander BMW 740e Battery Capacity (kWh) 41/41/41 40 28 35.8 8.7 12 9.2 Max. Speed (km/h) 135 144 165 150 222 170 250 Energy Consumption 133/133/161 Wh/km 194 Wh/km 11.5 kWh/100km 12.7 kWh/100 km 12-11.4 kWh/100 km No data 12.5 kWh/100 km Distance (km) 400/400/370 378 280 300 50 54 40
Figure 24 Schematic of AC/DC Charging. Source: Future of Charging (20)
Nowadays, just few models involved in V2G technology and not all are commercially available. In the following table it can be found the models with highest sales within Europe:
Model DC connector Implementation State
Nissan Leaf CHAdeMO Already implemented
Mitsubishi Outlander CHAdeMO Already implemented
Tesla Model S Tesla Super Charger In development
BMW i3 CCS Pilot project
Renault Zoe - Pilot project
Table 2 Main models sold in Europe. Source: Energy Strategy (16)
Among the EVs in the market, the only ones that are enabled for bidirectional charging are the ones that allow DC charging using CHAdeMO connectors.
Figure 25 Schematic of a CHAdeMO DC Bidirectional EV Charger. Source: Future of Charging (20)
In Figure 26 it can be appreciated all the V2G projects where CHAdeMO connectors are involved, it must be mentioned that the “Parker” project is the only one commercially available until now. This project uses both already implemented models: Nissan Leaf and Mitsubishi Outlander.
Figure 26 V2G projects using CHAdeMO connectors. Source: CHAdeMO (21)
It must be mention that both V2G enabled models are in the largest users of the CHAdeMO connectors, Nissan Leaf in the BEV’s category, while Mitsubishi Outlander in the PHEV’s.
Figure 27 European EVs using CHAdeMO connectors. Source: Adaptation of CHAdeMO (21)
2.2.2. Infrastructure & smart technologies
In order to be able to adopt the V2G technology, a communication system between the BMS and the grid is needed. This system will be useful to modulate the charges and discharges according to grid needs. Depending on the level of communication 4 types of charging can be identified:
Dumb charging: No communication system between the BMS and the grid and no possibility to modulate the charging.
Delayed charging: No communication system between the BMS and the grid, however, it is possible to program the charging and postpone the start.
Price-based charging: Communication system between the BMS and the grid exists making it possible to modulate the charging and take advantage of the hours when the electricity price is low.
RES/Load-based charging: Communication system between the BMS and the grid exists making it possible to modulate the charge and discharge based on non-programmable RES availability or based on the grid load. This involves a high level of smartness that allows to take advantage of the RES peak production and also to charge the EVs when the demand is low.
21.7% 18.3% 10.2% 9.8% 9.1% 30.9%
Top 5 BEVs
Nissan Leaf Rennault Zoe Volkswagen e-golf BMWi3 Tesla Model S Others 10.3% 7.3% 6.3% 6.0% 6.0% 64.1%Top 5 PHEVs
Mitsubishi Outlander Volkswagen Passat GTE Volvo XC60BMW 225xe Acive Tourer Volkswagen Golf GTE Others
Tariff Information
Charging Process information Value-added Services
Capability information User Authentication Grid information
Dynamic ampacity control Local ampacity limit Safety monitoring
Figure 28 Communication levels. Source: Science Direct (22)
It must be mentioned that the adoption of these communication and control systems increase the cost of the charging points’ installation, however grid modifications are necessary to allow this bi-directional power flow. Moreover, in order to achieve the maximum benefits, the existing grid must be upgraded and become a technologically advanced grid system with the help of smart technologies. A smart grid is a system that enables connection, two-way communication and best management of the dispersed power infrastructure. It is convenient for both, power generators and consumers making it possible to exchange and analyze information which leads to an optimal operation of the energy system, improving its efficiency, reliability and the quality of the energy supplied.
As it can be noticed, the development and deployment of a smart grid is an important enabler for the adoption of the V2G technology. It involves smart metering, dynamic pricing, automated control and real-time information exchange. In order to be able to implement it, some additional elements are necessary and must be taken into account (23):
Figure 29 Smart Grid System. Source: Science Direct (22)
Utility/grid operator control signal: The grid operator broadcast control signals through mobile network, direct internet connection or a power line carrier being capable of issuing automatic generation control signals to address the ancillary services from EVs (24).
Communication required for remote billing and dynamic grid
load control Minimal communication
with pilot function
User Convenience
Utility/ grid operator communication network: A communication network enables higher data transfer rates and quality of service for the network users, while in heterogeneous systems there could be packet drops or delays that increase with long distance communication (24). Utility/ grid operator billing system: A system that allows to capture billing information
computing real time tariffs and accurate measurements of the energy exchanged.
EVSE control application interface: For bidirectional charging the EV is connected to the infrastructure side (EVSE) and the information communicated between them is gathered to control application interface. This interface manages the charge and discharge functions, based on the control pilot signal and state of charge (SOC) information of the onboard battery (25).
Premise-based net metering: A meter data management system has the functions of collect the data, manage it (validate, edit and estimate) and provide a meter data warehouse allowing to handle interval data of thousands of meters (26).
Grid-tie inverter: A grid-tie inverter converts DC stored in the battery into AC suitable for injecting into an electrical power grid. It must be mentioned that it is not part of a standard vehicle battery charging station (27).
It is important to highlight that according to the depth of system integration and the level of smartness extra elements might need to be considered.
2.2.3. Aggregator
From a cost-effectiveness perspective focused on providing V2G services, it is justified to combine as many EVs as possible within just one actor participating in the market. In this sense, the adoption of V2G enables a new and relevant role in the system: the aggregator. This actor represents the contact point between the grid operator and the EV owner. Its participation is essential in order to avoid direct relation with each of the EV owners and due to regulation issues.
The aggregator is in charge of a huge group of EVs, having to know their availability at every moment in which they are connected to the grid. In other words, the aggregator must track the usage of every single EV of its fleet in order to be able to manage them acting as a virtual power plant. Its aim is to communicate to the grid operator the services that can be offered by the fleet by charging/discharging their batteries. This can be done by provisional algorithms or direct communication, which even if it is more expensive, it is also more accurate. However, it must be considered that uncertainty and information gaps are always present.
The aggregator concept is not totally new, indeed it already exists for distributed generation, where utilities buy energy for a huge number of clients through market bids. However, for the EVs usage, this is more complicated due to the fact that costumer’s charging behaviours must be taken into consideration. It must exist a balance between the flexibility of the service and the EV owners’ need of mobility, issues such as a minimum stage of charge, schedules, charging duration and energy cost should be managed. Commercially and technically speaking it is also a more complex concept. Different actors can be the aggregator, depending on the business model the aggregator can be:
Fleet manager: The aggregator can be a delivery company, car sharing, a corporate fleet or any enterprise involved in transportation that offers mobility services to customers. It manages the availability of the fleet and sells its services to the market or to an operator. As the aggregator owns the fleet, it can decide to charge the EVs during off peak hours and sell it to the market during peak hours. It must be mentioned that in this case the fleet is connected to just one single network point.
