Energy and sustainability in Chilesimulation modelling of low-carbon technologies and energy in buildings

Resumen

Fossil fuels reserves are diminishing rapidly across the world, intensifying the stress on existing reserves due to increased demand. Moreover, the production of greenhouse gas (GHG) emissions driven by human activities, in particular the combustion of fossil fuels, presently contributing to 81% of the world primary energy, inflict disastrous impacts on human health, economics and environment of the planet. Increase in GHG concentrations is directly responsible for the rise in the earth average temperature and its associated climate change implications. The Chilean economy grew at a rate of 4% between 2003 and 2015 and is forecast to continue to grow over the coming years. As for most developing countries, pressures from economic and population growth have traditionally forced governments to look at cost-effective options, mainly those exploiting fossil fuel sources, to cope with the increased demand for electricity from households and industry. However, besides the serious concerns on whether the actual strategy is environmentally sustainable, the lack of fossil fuel sources in Chile makes also the country vulnerable to supply disruptions of foreign fossil fuel and energy price volatility, and thus raises concerns over satisfying the country energy demand. Therefore, there is an urgent need to look at sustainable options for energy production and energy saving in Chile, especially since the Chilean government pledged to reduce the country GHG emissions by 30% below 2007 levels by 2030 at the latest Paris climate negotiations in December 2015. The present work is aimed to demonstrate that sustainability in the field of energy can be achieved in a cost effective manner in Chile, through clean energy generation from renewable sources and efficient use of energy in buildings. The energy sector has a key role in the production of environmentally harmful substances. It has thus become crucial for the sustainability of modern societies to switch over of energy systems from conventional to renewables. Solar energy represents an attractive alternative to conventional fossil energy, as it is freely available in abundant and inexhaustible quantity and can make an important contribution towards a sustainable future. The study explores the economic viability of large scale solar technologies for clean electricity generation, in terms of levelised cost of electricity (LCOE) on the Atacama Solar Platform (PSDA) for a solar-solar hybrid energy mix with the objective of evaluating new options for continuous solar electricity delivery. For this purpose, a simulation model was built to predict LCOE evolutions until 2050 of three different types of 50 MW solar power plants, a photovoltaic (PV), a concentrating solar power (CSP) plant with 15 hours thermal energy storage (TES), and a hybrid PV-CSP plant with 15 hours TES. Calculations present two scenario projections (Blue Map and Roadmap) until 2050 for each type of plant. Due to the huge solar resource available in northern Chile, the PV-CSP hybrid plant results to be a feasible option for electricity generation, as well as being effectively able to meet electricity demand profile of the mining industry present in the area. This type of energy could mitigate long-term energy costs for the heavy mining activity, as well as the country CO2 emissions. Findings point out that PV-CSP plants are a feasible option able to contribute to the continuous delivery of sustainable electricity in northern Chile. Moreover, this option can also contribute towards electricity price stabilization, thus benefiting the mining industry, as well as reducing Chile's carbon footprint. The building sector contributes to approximately 40% of the global energy consumption and more than a third of the global GHG emissions. Therefore, there is a need to seek adequate solutions to minimize energy consumption and deploy the renewable energy technologies, with the objective of “low-energy building”. In order to achieve this objective, buildings must combine two main requirements: (1) being energy efficient as to have a low energy demand, and (2) being able to generate electricity, or other energy carriers, from renewable sources in order to compensate for its demand. Ground source heat-pump (GSHP) is one of the energy saving technologies available for building applications. With high efficiency characteristics, such technology has a great potential in reducing energy use and consequently carbon emissions from buildings. The performance of GSHP, often expressed as Power drawn and/or the COP, depends on several operating parameters. Manufacturers usually publish such data in tables for certain discrete values of the operating fluid temperatures and flow rates conditions. In actual applications, such as in dynamic simulations of heat pump system integrated to buildings, there is a need to determine equipment performance under operating conditions other than those listed. The investigation describes a simplified methodology for predicting the performance of GSHPs using multiple regression (MR) models as applicable to manufacturer data. It is found that fitting second-order MR models with eight statistically significant x-variables from 36 observations appropriately selected in the manufacturer catalogue can predict the system global behaviour with good accuracy. For the three studied GSHPs, the external prediction error of the MR models identified following the methodology are 0.2%, 0.9% and 1% for heating capacity (HC) predictions and 2.6%, 4.9% and 3.2% for COP predictions. No correlation is found between residuals and the response, thus validating the models. The operational approach appears to be a reliable tool to be integrated in dynamic simulation codes, as the method is applicable to any GSHP catalogue data. Energy efficiency in buildings, by means of energy saving design is the most economically viable short-term solution to rapidly reduce energy usage and mitigate the repercussions of carbon emissions in buildings. In order to reduce the energy consumption in homes, there is a demand for tools that identify significant parameters of building energy performance. The work presents such a methodology, based on a simulation model and graphical figures, for the interactive investigation of energy performance in different climatic regions in Chile. The simulation tool (called MEEDI) is based on the ISO 13790 monthly calculation method of building heating and cooling energy use with two additional procedures for the calculation of the heat transfer through the floor and the solar heat gains. The graphical figures are illustrating the effects of the climate conditions, the different envelope components and the size and the orientation of windows on the energy consumption. The MEEDI program can contribute to find the best solution to increase energy efficiency in residential buildings. It can be adapted for various parameters, making it useful for future projects. The economic viability of different specific measures for building envelope materials are analysed as a function of their payback periods. Payback periods range from 6 to 31 years depending on location and the source of primary energy scenario. The study illustrates how decisions in the early stages of building design can have a significant impact on final energy performance. With simple building envelope components modification, valuable energy gains and carbon emission reductions can be achieved in a cost effective manner in Chile.