Darjan Bošnjak

An overview of ancillary services in an open market environment

The worldwide restructuring of the electrical energy industry is followed by processes like deregulation, liberalization and commercialization. These changes introduce new paradigms such as competition in generation and the concept of electricity supply as a commodity market and creates a new set of transactions among utilities and new agents and end users. An important aspect is the role of competitive markets stressed by the new regulation in procurement and remuneration of ancillary services. These services are required to provide stability and security of supply. Ancillary services have a variety of terms used through the world to name them (e.g. system services, support services) and it is not easy to define or classify them. The objective of this paper is to give a possible classification scheme for ancillary services to allow an easier identification of the roles of suppliers and buyers. Also, means by which the costs of various services can be measured, quantified and allocated are discussed and one method for cost allocation is proposed.

Analysis of incentives approach to renewable sources and cogeneration

The current feed-in tariff system for renewable energy sources and cogeneration in Croatia stimulates privileged producers exclusively for electricity delivered into the grid, both on transmission and distribution levels. Hence, the electricity consumed on the power plant site is not stimulated by the current feed-in tariff system. Therefore, most privileged producers, in order to receive incentives for entire electricity generation, have to deliver all of the generated electricity into the grid and separately buy the electricity from the electricity distribution company which requires significant supplementary investments. Furthermore, overall losses in electric grid are increased. This paper analyses the current feed-in tariff system and proposes an enhanced tariff system which allows metering of the generated energy. This, with on-site consumption metering or metering of electricity delivered to the distribution network, enables separate billing of electricity consumed at the plant site and delivered into the power grid. The paper analyzes the power flows and losses in the nearby electric grid in the current and proposed incentive system in three real-case scenarios.

The true inventor of the radio communications

There are more than just a few examples in the history of innovations when it is not so obvious who exactly should be praised as the inventor of a specific device. The invention of radio communications are certainly one of them. This paper is based on historical documentation and describes the battle of Nikola Tesla and Guglielmo Marconi in the USA as well as the parallel and independent work of the Alexander Popov in the Russia. The aim of the paper is to objectively present all available historical facts and to perceive the merits of all three great inventors, as well as conditions in which they delivered their work.