Current status and grand challenges for small wind turbine technology

Abstract

Abstract. While modern wind turbines have become by far the largest rotating machines on Earth with further upscaling planned for the future, a renewed interest in small wind turbines (SWTs) is fostering energy transition and smart grid development. Small machines have traditionally not received the same level of aerodynamic refinement as their larger counterparts, resulting in lower efficiency, lower capacity factors, and therefore a higher cost of energy. In an effort to reduce this gap, research programs are developing worldwide. With this background, the scope of the present study is 2-fold. In the first part of this paper, an overview of the current status of the technology is presented in terms of technical maturity, diffusion, and cost. The second part of the study proposes five grand challenges that are thought to be key to fostering the development of small wind turbine technology in the near future, i.e. (1) improving energy conversion of modern SWTs through better design and control, especially in the case of turbulent wind; (2) better predicting long-term turbine performance with limited resource measurements and proving reliability; (3) improving the economic viability of small wind energy; (4) facilitating the contribution of SWTs to the energy demand and electrical system integration; (5) fostering engagement, social acceptance, and deployment for global distributed wind markets. To tackle these challenges, a series of unknowns and gaps are first identified and discussed. Based on them, improvement areas are suggested, for which 10 key enabling actions are finally proposed.

Selecting the Best Permanent Magnet Synchronous Machine Design for Use in a Small Wind Turbine

“…Small wind turbines and prosumer energy sources face a multitude of challenges themselves [12]. For small wind turbines, the key challenges include improving energy conversion through better design and control, especially in turbulent wind conditions.…”

Impact of turbulence and blade surface degradation on the annual energy production of small‐scale wind turbines

“…Yet, the LSWT sector does not provide the full picture of the wind industry. The small‐scale wind turbine (SSWT) branch has been acquiring an increasing relevance within the wind‐energy sector lately 4 . According to the worldwide‐accepted stipulation by the American Wind Energy Association (AWEA), SSWTs are those turbines with a rated power of up to 100 kW, which, translated into dimensions, corresponds to a maximum rotor diameter of 20 m 5 .…”

“…On the scope of the net‐zero‐emission agreements by 2050 within the LSWT sector, 9 technological investments in favour of the small‐scale industry are justified as a complimentary way of achieving such goals, primarily within urban and isolated environments, where deploying SSWT‐based distributed grids should have a reduced environmental impact 8 . It is on these grounds that the 950 MW of global installed capacity achieves relevance, with the SSWT sector having undergone a growth‐rate far over 50% during 2013–2018 4,7 …”

“…The small-scale wind turbine (SSWT) branch has been acquiring an increasing relevance within the wind-energy sector lately. 4 According to the worldwide-accepted stipulation by the American Wind Energy Association (AWEA), SSWTs are those turbines with a rated power of up to 100 kW, which, translated into dimensions, corresponds to a maximum rotor diameter of 20 m. 5 Compared to the multi-MW output and over 100-m-long diameters of current LSWTs, the capacities of SSWTs may seem negligible, but their recent global increase and widespread use deserves special attention. Especially in the United States and the European countries, policies stimulating the inclusion of electric power from SSWTs have been encouraged by governmental institutions, mainly on the scope of pushing self-sufficient and decentralized power generation systems within the green deal strategy of the European Union.…”

“…8 It is on these grounds that the 950 MW of global installed capacity achieves relevance, with the SSWT sector having undergone a growth-rate far over 50% during 2013-2018. 4,7 1.2 | Scale-effect issues In contrast to LSWTs, which are usually installed in large farms far from the consumers, SSWTs are often installed isolated or in small arrays, mainly in urban areas that constitute the so-called electrical grid islands. Consequently, the operating conditions vary significantly with respect to LSWTs, with two main aspects being worth of mention.…”