Economic Comparison Between a Stand-Alone and a Grid Connected PV System vs. Grid Distance

Abstract

The limitation of fossil fuel uses and GHG (greenhouse gases) emissions reduction are two of the main objectives of the European energy policy and global agreements that aim to contain climate changes. To this end, the building sector, responsible for important energy consumption rates, requires a significant improvement of its energetic performance, an obtainable increase of its energy efficiency and the use of renewable sources. Within this framework, in this study, we analysed the economic feasibility of a stand-alone photovoltaic (PV) plant, dimensioned in two configurations with decreasing autonomy. Their Net Present Value at the end of their life span was compared with that of the same plant in both grid-connected and storage-on-grid configurations, as well as being compared with a grid connection without PV. The analysis confirms that currently, for short distances from the grid, the most suitable PV configuration is the grid-connected one, but also that the additional use of a battery with a limited capacity (storage on grid configuration) would provide interesting savings to the user, guaranteeing a fairly energetic autonomy. Stand-alone PV systems are only convenient for the analysed site from distances of the order of 5 km, and it is worth noting that such a configuration is neither energetically nor economically sustainable due to the necessary over-dimensioning of both its generators and batteries, which generates a surplus of energy production that cannot be used elsewhere and implies a dramatic cost increase and no corresponding benefits. The results have been tested for different latitudes, confirming what we found. A future drop of both batteries’ and PV generators’ prices would let the economic side of PV stand-alone systems be reconsidered, but not their energetic one, so that their use, allowing energy exchanges, results in being more appropriate for district networks. For all PV systems, avoided emissions of both local and GHG gases (CO2) have been estimated.

Solar Energy: Applications, Trends Analysis, Bibliometric Analysis and Research Contribution to Sustainable Development Goals (SDGs)

“…The advantage of these systems lies in their ability to use them in the nighttime when solar panels do not generate any power. However, stand-alone PV systems are often more expensive than grid-connected PV systems due to the high cost of batteries [64,65]. Until now, the most popular kind of batteries for residential PV has been lead-acid batteries, which are a form of electro-chemical storage [66].…”

“…stand-alone PV systems are often more expensive than grid-connected PV systems due to the high cost of batteries [64,65]. Until now, the most popular kind of batteries for residential PV has been lead-acid batteries, which are a form of electro-chemical storage [66].…”

Days of autonomy for optimal Battery Sizing in Stand-alone Photovoltaic Systems

“…Stand-alone systems are not always beneficial, especially since they generate investment costs as the batteries and PV systems are oversized to meet the consumer demand, the battery is only charged to its maximum during certain periods and a surplus is lost. This type of system can be suitable when the considered site has a high distance to 5 km from the grid [12].…”

Systematic Review on Impact of Different Irradiance Forecasting Techniques for Solar Energy Prediction

“…Many PV investors and producers are participating directly in electricity markets, minimizing financial penalties for any imbalance between generation, production, and supply. These problems are quite common in renewable energy source integration into the grid, i.e., because of stand-alone and grid-connected systems [4]. At any particular time, the generated electricity should be balanced with load usage.…”