Innovative contracting in infrastructure design and maintenance
This paper describes the results of research into the contract arrangements and design processes for contractors in the road infrastructure industry. The changing institutional environment has led the industry to believe that more opportunities can be realised to the benefit of society (lower cost, higher quality, more efficient design and design process) when contractors are allowed more 'design freedom' in their contracts with governments. We have explored the technical design space, and developed a framework to structure this space. Next, we identified, through many indepth interviews and case studies, a number of technical, organisational and institutional opportunities, threats and barriers for granting more design space. Finally, the paper discusses the conclusions that could be drawn from the mapping of the opportunities onto the bottlenecks, and it shows that much can indeed be gained, but that many of these opportunities for cost reduction or value improvement are hampered by large, inert institutional settings.
New regulation on strategic behaviour in network-based industries
This paper starts by establishing that change processes like liberalization and privatization in the world of network-based utilities have been accompanied by considerable and harmful strategic behaviour. In many cases, regulators have been set up to counter this strategic behaviour. It is doubtful whether regulators would manage to do so if they actually have to operate on the basis of widely accepted concepts, such as independence, ride-guided behaviour and transparency. This work presents a new interpretation of independence, rule-guided behaviour and transparency that would enhance the regulator's effectiveness without too many adverse consequences.
Simulation and control of hybrid renewable energy system connected to the grid
This paper presents a control and simulation of hybrid renewable energy system connected to the grid. The studied system includes a photovoltaic panel, synchronous permanent magnet generator based wind turbine, and a battery for storage energy. The PV array and wind systems are connected to the common DC bus by a boost converter. The battery is connected by a bi-directional DC/DC converter, and then integrated into the AC utility grid via a common DC/AC inverter. In order to extract the maximum energy, a simulation study has been carried out according to the meteorological conditions (wind speed and variable solar irradiance) while maintaining power quality at a satisfactory level. In order to capture the maximum power, a MPPT algorithm is applied for both wind turbine and photovoltaic panel. The modeling and simulation of the whole system has been performed under Matlab/Simulink environment. The obtained results show that the current and the voltage of grid side are sinusoidal and alternative forms, and the power injected to the grid is around the power produced by the hybrid system.