Contents lists available at ScienceDirect Sustainable Energy Technologies and Assessments journal homepage: www.elsevier.com/locate/seta Design of a bus shelter based on green energy technologies for extreme weather conditions in Nur-Sultan, Kazakhstan Arailym Alikhanova, Aldiyar Kakimzhan, Anuarbek Mukhanov, Luis Rojas-Solórzano ⁎ School of Engineering, Nazarbayev University, 53 Kabanbay batyr Ave., Nur-Sultan city 010000, Kazakhstan ARTICLE INFO Keywords: Nur-Sultan Bus shelter Design Geothermal energy Green energy ABSTRACT Green energy technologies in combination with conventional technologies can result in viable solutions in many applications within the fundamental areas of the economy, including the transportation segment. This sector has recently experienced rapid development in Nur-Sultan, capital of the Republic of Kazakhstan and one of the popular projects in the city is the construction of “warm” bus shelters. Nevertheless, current bus shelters have insufficient space for passengers and use grid electricity, which is mostly generated in heavily polluting coal- fired power plants. Thus, this paper proposes the modernization of the shelter at “Cardiac Surgery Center” bus stop by using an optimal combination of clean and conventional energy sources. The technical and financial viability analyses were performed using RETScreen 4 and HOMER LEGACY state-of-the-art software platforms, which permitted to model the energetic system and determine its technical and economic viability within given financial and market conditions. Simulations demonstrated that including a geothermal heat pump unit in the system would be a profitable solution with relatively short payback period. However, possible combinations of grid electricity with wind and solar energy technologies resulted in higher net present cost than the conventional only-grid connected system. Introduction Renewable energy sources such as solar, wind, marine, hydropower, geothermal, and biomass have recently gained a lot of attention as al- ternatives for electricity generation. Overall, they contribute to 15–20% of the worldwide energy demand. This figure is expected to increase to 30% by 2020 and to 50% in 2050 [15]. Likewise, Republic of Ka- zakhstan is also concerned with the development of the renewable energy sector. This is evident from the main theme of EXPO-2017 AS- TANA, which is development of “green energy” [8]. In addition, the transportation sector has been one of the fastest developing segments in Nur-Sultan, the capital city of Kazakhstan, since the establishment of “Astana Transportation Authority” in 2011. The green shelter challenge One of the popular projects in this sector is the construction of “warm” bus shelters. However, there are still several problems like the lack of space in the bus shelter for passengers and the use of grid power. In addition, transition to renewable energy sources would be a logical next step within the framework of EXPO-2017. Therefore, our paper proposes modernization of the bus shelter at “Cardiac Surgery Center” bus stop (in front of “Asia Park” shopping mall) with clean energy sources, particularly solar and wind for electricity supply, and geo- thermal unit for heat generation. Nevertheless, the viability must be firstly assessed through the simulation of multiple technologies and financial scenarios to determine the best suiting hybrid clean energy system. Therefore, the proposed systems correspond to combinations of conventional grid, solar panels, wind turbines, and a geothermal unit. These hybrid systems will be properly dimensioned and afterwards, compared economically against the conventional system (i.e., use of the grid) in terms of their net present costs (NPC). The system with the lowest NPC will be chosen for construction. Another objective to be achieved in the project is to expand the overall area of the bus shelter in order to accommodate a larger number (more realistic) number of passengers needing that service during a regular day. Existing technology Accessibility and protection from weather conditions of public bus stops has been found to increase ridership while moderating harsh ambient effects on ground passengers waiting for a bus [17]. Therefore, closed bus shelters emerged as a mean to increase public transport usage in areas subject to severe ambient conditions, which if managed https://doi.org/10.1016/j.seta.2019.100544 Received 2 November 2018; Received in revised form 15 June 2019; Accepted 12 September 2019 ⁎ Corresponding author. E-mail address: luis.rojas@nu.edu.kz (L. Rojas-Solórzano). Sustainable Energy Technologies and Assessments 36 (2019) 100544 2213-1388/ © 2019 Published by Elsevier Ltd. T