The tourism industry is dominated by small and medium-sized companies. 99% have less than two employees, in addition companies with less than 10 employees represent 95% (INE, 2019). Given the competition in the sector and the new needs of customers, companies are forced to evolve towards new business models. In recent years, sustainability has become one of the main institutional objectives. Governments have developed different sustainable plans, such as the 2030 agenda for the countries of the European Union or the measures adopted by the member countries of the United Nations. When we examined the "Google Trends" tool, the searches recorded for terms related to sustainability have grown significantly in recent years (Figure 1). The communication of environmental and social responsibility (Herold & Lee, 2017) and the improvement of organizational performance (Martinez-Martinez, Cegarra-Navarro, Garcia-Perez, & Wensley, 2019) is considered very important to obtain a competitive advantage and improve the corporate image of SMEs companies, otherwise the measures taken could be considered as cost savings and not as a sustainable measure (Manaktola & Jauhari, 2007). Suggests that participation in environmental activities may be driven by both economic and ethical considerations (Tzschentke, Kirk, & Lynch, 2004).

Some researchers have studied the impacts of sustainable development for the small and medium enterprises, giving value to the sustainable management system as a model to obtain competitive advantages in an increasingly demanding market (Côté, Lopez, Marche, Perron, & Wright, 2008; Fotiadis, Vassiliadis, & Rekleitis, 2013; Yu & Bell, 2007), if it is not green washing techniques, it has a significant negative effect on green trust in hotels (Chen, Bernard, & Rahman, 2019; Trang, Lee, & Han, 2019). Lee, Hsu, Han and Kim (2010) defines how guests who select an ecological hotel consider that their purchase decision contributes to saving the planet and leaving a green environment for their children, creating a strong competitive advantage over other products that are not sustainable. Although SMEs managers sometimes feel that implementing green practices generates higher prices for the end user and reduces corporate competitiveness (Porter & van der Linde, 1995; Rosenbaum & Wong, 2015), these strategies can lead to significant cost reductions through improved resource efficiency such as water and energy, as well as an improvement in waste management (Font, Elgammal, & Lamond, 2017). Hotels can focus their green practices on four main categories; energy saving, water conservation, recycling, and waste management (Verma & Chandra, 2018; Han & Hyun, 2018). According to previous researches (Iwanowski & Rushmore, 1994; Singh, Cranage, & Lee, 2014) environmental problems are directly related to your operating costs, and proper management could reduce operating expenses on your property. Reducing waste, energy savings (lighting, heating and air conditioning replacements can be the difference between a SMEs hotel obtaining a higher profitability than its competition and generating great savings, improve the liquidity or invert in sustainable innovations. Furthermore, the more the more advanced sustainable practices in the hotel, the better the impact on consumer satisfaction (Y. Yu, Li, & Jai, 2017).

Han, Moon and Lee (2019) analyses how this sustainable management is more effective if it is supported by certificates with which the guests can verify the measures taken by the company, this is consistent with the research of Goyal, Rahman and Kazmi (2015), Peiró-Signes, Segarra-Oña, Verma, Mondéjar-Jiménez and Vargas-Vargas (2014) and K.-H. Lee, Lee and Gunarathne (2019). We will use TripAdvisor Green Leaders as a reference. The results of using these certificates intend to pay a higher price. The number of eco-hotels is scarce-approximately a 7% according with the Eco-Labelling from TripAdvisor1.

The objective of this study is to test whether the implementation of an ecological management system is an advantage for hotel SMEs in Barcelona. In this sense, we also tested the existence of spatial concentration areas with Ecohotels and specified a Logit model to determine the explanatory factors of the profitability of these hotels based on their operational and internal characteristics. We proposed an empirical model in a sample of SMEs hotels in the city of Barcelona, Spain. With more than 7.2 million international arrivals in 2018, Barcelona is in the Top 20 of the most visited cities in the world, reaching the top 10 on some specific dates (Top Cities Destination Ranking 2017). Thus, to face this situation, traditional hotels seek competitive advantages where the client's preferences are the main objective.

Faced with an increasingly demanding market and with a greater number of companies offering similar products, the competitive advantages for SMEs in the tourism sector are very important for their survival and long-term growth (Iraldo, Testa, Lanzini, & Battaglia, 2017; Özgener & İraz, 2006), adapting business models to new consumer trends of potential customers.

Competitive advantage can help to position a company in a market in different ways, making it a differentiated service and difficult to imitate in the short term. According to Rangone (1999) we found three ways to competitive advantages for SMEs: innovation, service optimization through management improvements (cost reduction and hotel management improvement) and reputation of brand through market management (where we could include the green image that we represent for clients, such as true certificates and make our sustainable measures known to them). Bohdanowicz (2006), estimates in his study that about 80% of hotel environmental impacts are due to mismanagement of resources, unnecessarily increasing operating costs. In addition to this competitive advantage, taking green measures by evolving the business model towards sustainable management can have benefits in SMEs in customer satisfaction and the motivation of the organization's own employees (Iraldo et al., 2017; Berezan, Millar, & Raab, 2014).

However, investment in eco-innovation practices also faces some limitations related to barriers to innovation, such as higher costs in its implementation (Hojnik & Ruzzier, 2016). García-Pozo, Sánchez-Ollero and Marchante-Lara (2015) and García-Pozo, Sánchez-Ollero and Ons-Cappa (2016) study the impact of eco-innovation on the labour productivity on a sample of hotels in Spain with positive and significant results. But previous studies do not consider characterising elements of SMEs Eco-Hotels. To fill this gap in the literature we examine to identify the internal elements that characterize ecological hotels, and these management systems are being effective for SMEs in Barcelona (Spain). To do that we focus on the SMEs hotels that obtained the TripAdvisor Green Leaders Certificate –an award based on the ecological practices of the property. We study the characteristics of the hotels to explain the rating and reputation in two different periods.

Therefore, we analyze in this paper whether the hotels that have adopted the option of having management systems based on sustainability have had an improvement in their results at a financial level, compared to conventional hotels. Specifically, as the studies of Ghisetti and Rennings (2014) and Kapiki (2012), we try to check if the innovations in energy efficiency and resources lead to win-win situations, in which reducing the environmental impact of production is contextually improving performance, economic growth of companies and a general improvement in society.

In recent years, the demand for hotels with sustainable management has increased and customers are increasingly informed about the advantages that this type of business provides at environmental and social levels. SMEs have the opportunity to focus their hotel strategy and management based on these business models, creating competitive advantages over competing hotels. These types of models improve the image of the brand, reduce emissions, and optimize resources and organizational performance (Chang, 2011; Gürlek & Tuna, 2018). This research studies the behavior of SMEs hotels in the city of Barcelona, looking for differential effects on the factors that affect the reputation and valuation of customers to hotels with sustainable management models and traditional hotels. In our model we found significant differences in some variables.

Our findings indicate, at an exploratory level, that Eco Hotels have a significant improvement at the profitability level in the period 2012 to 2017, going from having a lower average profitability than the hotels with a traditional management to surpass them. This improvement in profitability leads us to propose the model in search of which factors have improved the reputation and number of reservations of SMEs hotels with this management model. On the one hand, the regression points that guests value more than a popular SMEs hotel in the area if it is sustainably managed. Therefore, for customers it is an extra recognition that it has a sustainable management if it is a hotel with a good position on TripAdvisor, obtaining more reservations and with it an increase in profitability. On the other hand, we also found evidence that it is important for hotels to inform customers about their sustainable measures, through certificates or accreditations such as TripAdvisor Leaders or directly to guests. If not, a higher average price can be considered by customers as a savings policy and not as a competitive advantage (Manaktola & Jauhari, 2007). This effect is considerably reduced in the regression of 2017 with respect to that of 2012 and may be due to the increase in certificates and more information from clients. Lastly, we also found a relationship between the Eco Hotels with the best reputations and the highest indebtedness. The limitations of the database prevent us from knowing exactly if these hotels have a higher indebtedness due to the investment in sustainable innovations, but this would be consistent with the research by Y. Yu et al. (2017).

Finally, this research has limitations that could be considered in future research. This study does not consider the characterization of these ecological hotels based on external environmental factors, nor does it consider the spatially localized contagion effects. Furthermore, the information in our database is limited, given the lack of regulation on the sustainable certificate in the hotel sector and also a growing management model, we have used a certificate that, although reliable, is not a standard. Finally, the study only studies the specific case of Barcelona, the study of alternative locations could corroborate our results.

The author acknowledges the financial support from Fundación Banco Santander.