The aim of the present paper is to investigate ways of improving the efficiency of a six-bladed Savonius rotor. The efficiency of Savonius machines is low because of the “negative drag” exerted on the convex part of the blades and also because the torque of standard Savonius rotors varies substantially during one rotation and therefore affects the self starting of the rotor at certain wind angles. Improvement of the efficiency of the Savonius rotor is carried out by increasing the number of blades and also by preventing the wind from impinging on the convex parts. The latter can be done by hiding the convex part of the blades behind a shield or a vane. The present paper shows the results of two-dimensional computational fluid dynamics (CFD) computations, indicating a promising increase of the power coefficient from 0.3 to 0.5.

Piezoelectric energy harvesters can scavenge energy from their ambient environment in order to power low-consumption electronic devices. The last two decades have seen a growing interest towards vortex-induced vibration harvesters; most harvesters consist in rigid splitter plates oscillating at higher frequencies. The concept presented here is a low-frequency undulating flexible plate placed in the wake of a square cylinder. Piezoelectric patches can be placed at the plate surface to harvest the strain energy arising when the plate bends. The flapping pattern mimics an anguilliform swimming motion. There is a great need to establish correlation between wake generating bluff body size, plate dimensions and power output. Geometric parameters were investigated using water tunnel experiments, particle image velocimetry and fluid–structure interaction modeling. Results showed that for a given plate length and within a given freestream velocity range, there is a square cylinder diameter and a thickness that optimize the plate–wake interaction. Longer plates yield greater power output but have lower flapping frequencies. Additionally, the more frequent curvature changes occurring can result in charge cancellation among the piezoelectric cells. Consequently, the estimated conversion efficiency from mechanical strain to electricity is higher for shorter plates.

The power demand on the electric grid varies according to the time of the day following users’ needs and so does the cost of electricity supply because the electricity mix is formed using different generators of varying capacities. Demand response (DR) is the modification of the consumption load curve following a signal from the electricity provider; it is mostly used for peak clipping. By reducing the short-term mismatch between generation and consumption, it helps to integrate intermittent renewables and new low-carbon technologies such as energy storage, electric vehicles, and power-to-gas. The present work is a literature survey based on the following keywords: demand response, demand technology, potential, power, and power dispatch, which aims to provide a summary of the state of the art regarding the potential for demand response implementation. Literature is either related to potential assessment or to implementation; less focus is given on non-dispatchable DR than on dispatchable DR. There is a great untapped potential for power demand reallocation in all sectors. Incentivizing users to participate in demand response programs is crucial, as well as education campaigns and smart meters penetration. The barriers to demand response are mostly the investment costs in the absence of an adequate pricing scheme.