What was studied? This report studies the possibilities and challenges of establishing a high-power charging system for battery-electric aircraft (EA) within an operational airport environment, with a particular focus on enabling short turnaround times (TAT). The study integrates perspectives from a diverse group of stakeholders, including an airport owner, a charging equipment solution provider, an aircraft developer, a research institute, an innovation arena, and a testbed operator. The aim is to significantly enhance the common understanding and identify viable pathways for the efficient and safe implementation of EA charging systems. The report addresses the three key subsystems (airport, charging equipment, and aircraft) detailing their specific requirements, including e.g. technical, operational, regulatory, and safety considerations, followed by identification and evaluation of possible power system topologies and conceptual charging solutions. Smart control of EA charging systems is explored and modeled to support adequate system design and optimal utilization of available power capacity. Additionally, the report presents measurement results from an operational airport to better understand the current electromagnetic compatibility (EMC) environment. It also includes a review of aviation cybersecurity and offers initial recommendations for future risk assessments to ensure an efficient and safe deployment of EA charging systems. 

The adoption of electric aircraft (EA) offers notable environmental advantages by mitigating greenhouse gas emissions and enhancing regional accessibility through reduced operational costs. Despite these benefits, EA faces significant challenges, partly in achieving practical operational ranges and developing robust airport charging infrastructures. The infrastructure challenge is compounded by the need for rapid turnaround times (TAT) in regional aviation, requiring high-power charging solutions above 1 MW. This paper explores various topologies for EA power supply systems and discusses pros and cons with those. Furthermore, an optimization model is developed using quadratic programming (QP) to allocate charging power among multiple aircraft, ensuring efficient and reliable operations under different system configurations. Simulations evaluate the performance of these configurations, highlighting the impact of grid power capacity, dimensioning of battery energy storage systems (BESS), and number of charging stands on system feasibility. The findings in this paper provide a foundational framework for designing airport infrastructures capable of supporting a growing demand for electric aviation, ensuring efficient power management and minimal operational disruptions. 

Införandet av elektriska flygplan (EA) erbjuder betydande miljömässiga fördelar genom att minska utsläppen av växthusgaser och förbättra regional tillgänglighet tack vare lägre driftskostnader.

Trots dessa fördelar står EA inför stora utmaningar, delvis när det gäller att uppnå praktiska räckvidder och att utveckla robust infrastruktur för laddning på flygplatser. Infrastrukturutmaningen förvärras av behovet av korta väntetider (TAT) inom regionalflyget, vilket kräver hög-effektsladdningslösningar över 1 MW.

Denna artikel utforskar olika topologier för EA:s kraftförsörjningssystem och diskuterar för- och nackdelar med dessa. Vidare utvecklas en optimeringsmodell med kvadratisk programmering (QP) för att allokera laddningseffekt mellan flera flygplan, vilket säkerställer effektiva och pålitliga operationer under olika systemkonfigurationer.

Simuleringar utvärderar prestandan hos dessa konfigurationer och belyser påverkan från nätets effektkapacitet, dimensionering av batterilagringssystem (BESS) och antalet laddningsstationer på systemets genomförbarhet. Resultaten i denna artikel ger ett grundläggande ramverk för att utforma flygplatsinfrastrukturer som kan stödja en växande efterfrågan på elektrisk flygning, med säkerställd effektiv effektförvaltning och minimala operativa störningar.

En generisk, flexibel simuleringsmodell utvecklas med syftet att kunna bidra till förståelse samt ge möjligheter att enkelt testa vad elektrifiering (batterielektriskt) av önskade flygtrafikflöden kan förväntas innebära i form av krav på laddinfrastruktur vid flygplatserna. Modellen utvecklas i programspråket Python och innehåller ett flertal olika tillvägagångsätt för att testa elektrifiering såväl baserat på inläsning av historiska flygtrafikdata, som skapande av nya, icke-existerande flygtrafikscheman för elflyg. Eftersom det i dagsläget inte finns några elflygplan i kommersiell linjetrafik, och således inte heller någon data eller statistik gällande dess prestanda eller egenskaper, så utvecklas en modell även för detta, vilken tillåter simulering av önskade flygförbindelser, och resulterar i erhållande av energiförbrukning och flygtid på dessa. Projektet utgår ifrån en elflygplansmodell som är parametersatt i enlighet med certifieringsnivå CS/FAR-23 (19 säten och maxvikt 8618 kg). Logiken i modellen är att följa den fullständiga rörelsekedjan för varje flygplansindivid under en given tidsperiod (typiskt ett dygn), där behovet av laddning för respektive flygplan på respektive flygplats i kedjan ges av vilken energinivå batteriet höll vid påbörjad flygning, hur mycket energi som förbrukades under flygningen, när flygplanet anländer till destination, samt när det behöver påbörja nästa flygning. Även in- och uttaxning på flygplatserna påverkar hur mycket tid som finns tillgänglig för laddning. En inbyggd laddningskurva begränsar hur snabbt det är praktiskt lämpligt för batteriet att laddas. Laddningskurvan definieras genom ett förhållande mellan C-rate (Charging-rate) och SoC (State-of-Charge). Dessutom kan laddare i sig begränsas till en viss maxeffekt och styr således hur snabbt energi kan levereras till flygplanets batterier. För att möjliggöra tillräcklig räckvidd förväntas elflygplanen ha relativt stora batterier som dessutom sannolikt ska laddas upp inom korta tidsintervall på flygplatserna (turnaround-tider). Därmed kan behovet av installerad effektkapacitet förväntas öka drastiskt på flygplatserna om flera elflygplan behöver ladda samtidigt. Projektet lägger därför lite extra vikt vid att utveckla smarta algoritmer för styrning av effektuttag över tid med ambitionen att lastbalansera och sänka effekttoppar vid simultan laddning. Till sist diskuterar projektet vilka implikationer elflyg kan medföra ur perspektivet flygtrafikledning, befintliga och framtida luftrumsstrukturer. Ett flertal fallstudier genomförs för att exemplifiera modelleringsprocessen och de resultat som användaren slutligen får. Projektet syftar inte till att skapa något färdigt kommersiellt verktyg, utan snarare en första version, samt lägga grunden för vidareutveckling av ett analysverktyg som är till nytta för flygplatser och andra aktörer inom flygbranschen nu, och i framtida forskning- och utvecklingssamarbeten.

A generic, flexible simulation model is developed with the aim of increasing our understanding as well as provide opportunities to easily test what the requirements for charging infrastructure at airports could become when transitioning to battery electric aviation. The model is developed in the programming language Python and contains several different approaches for testing electrification based on historical air traffic data, as well as the creation of new, non-existent air traffic schedules for electric aviation. Since there are currently no electric aircraft in commercial scheduled traffic, and thus no data or statistics regarding its performance or properties, a model is also developed for this, which allows simulation of desired flight connections, resulting in estimates for energy consumption and flight duration. The project is based on an electric aircraft model that is parameterized in accordance with certification level CS/FAR-23 (19 seats and maximum weight 8618 kg). The logic of the model is to follow the complete chain of movements for each aircraft individual during a given period (typically one day), where charging required for each aircraft at each airport in the chain is given by what energy level the battery held at the start of flight, how much energy was consumed during the flight, time of arrival at destination, and when the next departure is due. Taxi-in and taxi-out at the airports also affect how much time is available for charging. A built-in charge curve limits how fast it is practically convenient for the aircraft’s batteries to charge, which is defined as the ratio between C-rate (Charging-rate) and SoC (State-of-Charge). In addition, the charger itself can be limited to a certain maximum power and thus controls how fast energy can be delivered to the aircraft's batteries. To enable sufficient range, the electric aircrafts are expected to have relatively large batteries that are also likely to be charged within short time intervals at the airports (turnaround-times). Thus, the need to install power capacity may be expected to increase drastically at the airports if several aircraft’s need to charge simultaneously. The project therefore places extra emphasis on developing smart algorithms for controlling charger power output over time with the ambition to balance the load and lower power peaks at the airports. Finally, the project discusses what implications electric aviation can have from the perspective of air traffic control, existing and future airspace structures. Further, several case studies are conducted to exemplify the modeling process and the result that the user ultimately gets. The project does not aim to create a commercial tool, but rather a first version, and create the basis for further development of an analysis tool that is useful for airports and other stakeholders in the aviation industry now, and in future research and development collaborations.

The Swedish government has prioritized achieving a fossil fuel-independent vehicle fleet by 2030 which will require radical transformation of the transport industry. Electrifying the vehicle fleet forms an important part of this transformation. For light vehicles, electrification using batteries and charging during parking is already well advanced. For city buses, charging at bus stops and bus depots is being developed, but for heavy, long-distance road transport, batteries with enough capacity to provide sufficient range would be too cumbersome and too much time would have to be spent stationary for charging.

One solution might be the introduction of electric roads, supplying the moving vehicle with electricity both to power running and for charging. In the longer term, this approach could also be used for light vehicles and buses.

The objective of the Research and Innovation Platform for Electric Roads was to enhance Swedish and Nordic research and innovation in this field, this has been done by developing a joint knowledge base through collaboration with research institutions, universities, public authorities, regions, and industries.

The work of the Research and Innovation Platform was intended to create clarity concerning the socioeconomic conditions, benefits, and other effects associated with electric roads. We have investigated the benefits from the perspectives of various actors, implementation strategies, operation and maintenance standards, proposed regulatory systems, and factors conducive of the acceptance and development of international collaborative activities.

The project commenced in the autumn of 2016 and the main research continued until December 2019, the work during year 2020 has been focused on knowledge spread and coordination with the Swedish-Germany research collaboration on ERS (CollERS). The results of the Research and Innovation Platform have been disseminated through information meetings, seminars, and four annual international conferences. Reports have been published in the participating partners’ ordinary publication series and on www.electricroads.org. The project was funded by Strategic Vehicle Research and Innovation (FFI) and the Swedish Transport Administration.