Intelligent control for energy-positive street lighting

The paper investigates the application of solar energy in public lighting for realizing a street lighting sub-grid with positive yearly energy balance. The focus is given to the central controller, which ensures the adaptive behavior of the overall system and provides smart city services to the end users via its web-based user interface. A functionality of the controller of special interest is the optimization of the energy management of the system, i.e., determining when to sell and buy electricity to/from the grid, in order to minimize the cost of electricity (or to maximize the profit) subject to a given, time-of-use variable energy tariff. This requires precise forecasts of the energy produced and consumed, as well as appropriate robust optimization techniques that guarantee that the system bridges potential power outages of moderate duration in island mode

Carbon footprint of polycrystalline photovoltaic systems

The environmental and energy parameters of Photovoltaic (PV) systems play a very important role when compared to conventional power systems. In the present paper, a typical PV-system is analyzed to its elements and an assessment of the material and energy requirements during the production procedures is attempted. A Life Cycle Analysis (LCA) is being performed on the production system of photovoltaics. Energy and environmental analyses are extended to the production of the primary energy carriers. This allows having a complete picture of the life cycle of all the PV-components described in the present study. Four different scenarios are examined in detail providing every possible aspect of scientific interest involving polycrystalline PV systems. In order to obtain concrete results from this study, the specific working tool used is the Eco-Indicator ’95 (1999) as being reliable and widely applied and accepted within LCA community. A process that relates inventory information with relevant concerns about natural resource usage and potential effects of environmental loadings is attempted. Large-scale PV-systems have many advantages in comparison with a conventional power system (e.g. diesel power station) in electricity production. As a matter of fact, PV-systems become part of the environment and the ecosystems from the moment of their installation. Carbon Footprints of various PV-systems scenarios are greatly smaller than that of a diesel power station operation. Further technological improvements in PV module production and in the manufacture of Balance-of-System components, as well as extended use of renewable energy resources as primary energy resources could make Carbon Footprint of PV-systems even smaller. Extended operational period of time (O.P.T.) of PV-systems determined by system reliability should be given special attention, because it can dramatically mitigate energy resources and raw materials exploitation