This work evaluates the biogas production potential of the Ceibales landfill for feeding a power plant in the southern region of Ecuador. Biogas production is estimated through mathematical models that consider energy generation and technologies available to supply electricity plants. Characteristic landfill data are accounted for to analyze and develop these mathematical models. Once the generation capability of each source is identified, a decision can be made on the most suitable electricity generation technology. A local model (Ecuadorian model) is applied to calculate the potential of biogas and is compared with other models commonly used for evaluating this type of project. This type of renewable energy is attractive because it produces electricity from waste; however, it is not an attractive option unless its application is encouraged, as hydro has been encouraged through the investment of taxpayer resources. Technologies require a boost to become profitable, and even more so if they compete with traditional technologies.

Cities are human creations requiring large amounts of materials and energy. Constant consumption of resources exerts pressure on the environment not only due to its exploitation, but also because once processed, the resources produce waste, emissions or effluents. Cities are responsible for more than three quarters of the emissions of greenhouse gases. It is anticipated that the urban population will increase by up to 80% by the mid-21st century, which will make the current energy model unsustainable, as it is based on the intensive use of fossil resources. A change in urban planning is required to meet the energy requirements of cities. Several studies mention that renewable energy must be used in cities, but they do not identify the resources and technologies that can be used to promote circular urban metabolism. A review of the literature establishes that there are eleven renewable technologies with different degrees of maturity that could reduce the import of energy resources, which would contribute to changing the metabolic linear model into a circular model. However, the applicability of the different possibilities is conditional upon the availability of resources, costs, policies and community acceptance.

Installing photovoltaic systems (PVs) on building rooftops is a viable and sustainable alternative to meet the growing demand for electricity in cities. This work develops a methodology that uses LiDAR (laser imaging detection and ranging) technology and roof footprints to obtain a three-dimensional representation of the rooftops in the urban centre of Santa Isabel (Azuay, Ecuador). This allowed the determination of characteristics such as area, slope, orientation, and received solar radiation, making it possible to calculate the rooftop's theoretical, technical, and economic photovoltaic potential. It was found that 68.8 % of the total roof surface is suitable for PV capture, with which a theoretical photovoltaic potential of 62.39 GWh can be achieved. The annual technical photovoltaic potential using silicon panels was calculated at 4.85 GWh, which could supply 4.97 times the demand of the analyzed neighbourhood. To determine the economic potential, the peak power of a solar project was calculated to match the electricity demand of the analysis area, with a levelized cost of energy of 12.37 c$/kWh. This project could prevent the emission of 6805 tons of CO₂ into the environment during its useful life. The methodology developed in this study can be replicated in other areas to determine their photovoltaic potential and contribute to the diversification and decentralization of electricity generation systems, as well as transform Ecuador's energy matrix.

Previous research has assessed the potential of solar energy against possible demand; however, the sustainability issues associated with the use of large-scale photovoltaic deployment in urban areas have not been jointly established. In this paper, the impact of photovoltaic energy in the total urban energy mix is estimated using a series of indicators that consider the economic, environmental and social dimensions. These indicators have been previously applied at the country level; the main contribution of this research is applying them at the urban level to the city of Cuenca, Ecuador. Cuenca is close to the equatorial line and at a high altitude, enabling this area to reach the maximum self-supply index because of the high irradiation levels and reduced demand. The solar potential was estimated using a simple methodology that applies several indexes that were proven reliable in a local context considering this particular sun path. The results demonstrate that the solar potential can meet the electric power demand of this city, and only the indicator related to employment is positive and substantially affected. The indicators related to the price of energy, emissions and fossil fuel dependency do not change significantly, unless a fuel-to-electricity transport system conversions take place.