The work presented in this paper aims to analyze the efficiency of using optimum tilt angles defined for several time intervals to maximize the incident solar irradiation on a certain surface deployed in Europe. Such a technique would improve the solar energy harvesting process, both for photovoltaic panels and solar thermal collectors, while not investing in the more expensive sun-tracking devices. The optimum tilt angles have been determined for the yearly, bi-annual, seasonal, and monthly time intervals, which were delimited on a calendar and astronomical base, respectively, considering multiple locations from Europe, and using various mathematical models based on empirical equations and solar irradiation estimation. The total incident solar irradiation provided by adjusting the tilt angle multiple times per year was calculated and compared to that obtained when using the yearly optimum tilt angle. The gains for each type of adjustment were investigated, and the monthly optimization of the tilt angle is obviously the most effective one, ensuring gains of up to 7%, depending on the considered latitude. Otherwise, an optimization twice per year, using the bi-annual optimum tilt angles determined for the astronomical-defined warm and cold seasons, would be the next best solution.

In the deregulated electricity markets, trading prices are determined by the offer-demand mechanism, and retail consumers can negotiate tariffs with their supplier of choice. For classic wholesale suppliers, the tariffs are determined by the prices of transactions performed on the wholesale market. In parallel with becoming eligible for participating in the market, the consumers use increasingly local generation sources based mostly on renewable electricity generation equipment such as Photovoltaic (PV) panels, and become prosumers. They want to be able to sell back to the market the generation surplus, in order to obtain the maximum benefits from their initial investment. This paper proposes a two-tier local market model oriented for prosumers and consumers connected in microgrids, based on the blockchain technologies and other technologies and concepts such as smart grids, crowdsourcing and energy poverty. Its goals are to improve the possibilities of local prosumers to sell electricity to local consumers and to increase their profitability, compared to the trading model often used in developing markets, of selling the surplus back to the grid via aggregators. The research aims to contribute to the sustainable development of the electricity sector using new and renewable sources of energy, state-of the art technologies and smart contracts, leading to prosumer proliferation and electricity cost reduction for consumers.

This study aims to improve power law extrapolation accuracy by proposing a new methodology for wind shear coefficient calculation. Real wind speed profiles, measured with a LIDAR remote sensor at two different sites, were extrapolated according to the power law at heights up to 200 m. Two different definitions of the wind shear coefficient are proposed considering wind speed profiles measured at three, four, and five different heights using either the first height as a reference or all of the heights successively. These two definitions were tested, along with the generally accepted constant values of 1/7, 0.25 at the first site, and 0.2 at the second site, to identify the most efficient one. The extrapolated wind profiles were compared with those measured using LIDAR. The results show that the computed wind shear coefficients provide more accurate results compared with constant wind shear coefficients, as the mean absolute errors at 200 m were reduced from 1.396 m/s to 0.437 m/s at the first site and from 1.203 m/s to 0.411 m/s at the second site.

The deregulated markets have replaced the traditional way of trading electricity from the producers to the consumer, via government-owned organizations and regulated tariffs. Nowadays, electricity prices are determined by the offer-demand mechanism and consumers can negotiate tariffs with their supplier of choice. For classic wholesale suppliers, the tariffs are a result of the transactions performed on the wholesale market and the energy mix available in certain geographical regions. In parallel with becoming eligible and participating in retail electricity markets, the consumers use increasingly local generation sources based mostly on renewable energy technologies such as PV panels, and become prosumers. They want to be able to sell back to the market the generation surplus, in order to obtain the maximum benefits from their initial investment. Currently, several trading mechanisms for prosumers are available, ranging from the simplest, selling back the surplus to an aggregator at fixed tariffs, to more complex market schemes. This paper proposed a two-tier local market model for prosumers and consumers connected in microgrids, based on the blockchain technologies and other technologies and concepts such as remote sensing, smart grids, crowdsourcing and energy poverty.

Solar photovoltaic (PV) generation suffers from multiple serious issues, for example shading effects directly affect the performance of installed PV arrays. By studying these issues, it can play a key role in improving the limitations and performance of PV panels. The study of PV arrays under partial shading conditions is mentioned in many papers as a part of other studies and as an independent phenomenon. Therefore, it is essential to improve these studies and update them with new research and study this problem in detail to know how to limit the effects of partial shading irradiance conditions on PV arrays performances, including economical aspects. This paper proposes to study the effects of different partial shading irradiance conditions for a PV array in various configurations. The analysis is proved in detail through the simulation of the proposed PV array in the Matlab/Simulink environment. The obtained results show the performances of interconnected PV arrays under different partial shading irradiance and temperature conditions, including the solar array I-V and P-V characteristics. In addition, different PV array configurations with and without bypass and blocking protection diodes improve and minimize the effect of partial shading conditions and avoid the reductions in output power.