By P Kadel

Low-voltage-networks operate with a nominal voltage charged with a tolerance range. Consumer’s installations (CI) are feeded with different supply-voltages which depend on the location of the CI within the LV-grid and the load flow. At the feeding point of the CI no additional regulating device is foreseen. Local-Energy-Controllers can decrease the supply-voltage and influence the energy consumption of the CI. This paper shows when LECs operate properly and which preconditions have to be fulfilled for the energy-saving. Different consumer categories and the calculation algorithm for the amount of the energy saving will be introduced. At the end the algorithm will be compared with results of real LEC-installations. The properly engineered operation of an LEC saves energy, energy costs and reduce CO2, without affecting the power-quality negatively.

By J Rozenkrons et al

Rapid growth of Latvian economy resulted in rapid growth of electricity demand in cities and rural regions. Consumers’ reliability requirements are increasing, but improvement of reliability is directly related to electricity supply reservation possibilities in case of one or more network components failure. This article describes conditions for independent operation of decentralized renewable power supply sources, evaluates its exploitation possibilities and feasibility for local consumers’ reservation. JSC “Latvenergo” distribution network has used this work for network long-term development planning.

The UK got one of the tougher tasks when Europe distributed the shares for renewables within the 20% target for 2020. They were tasked to reach 15%, coming from 1.5 %, in only a few years. Considering that many other countries with better deals and coming from better starting points screamed to high heaven over their misfortune, it was anticipated that the British would just say no, it can’t be done. So much greater is the surprise when their recently launched consultation shows the possibilities based on work from their Renewables Advisory Board (RAB).

At the "Cogen Europe Annual Meeting", which took place in Brussels, Belgium on 22 May 2008, Mr. Nobuo Tanaka, Executive Director of the International Energy Agency intervened with a presentation titled Today’s Energy Challenges: The Role of Combined Heat and Power (CHP).

Mr Tanaka highlighted that improved efficiency and decarbonising the power sector could bring emissions back to current levels by 2050.

In particular, policy messages coming from the presentation can be summarized as follows:

• Deep emissions cuts are technically achievable
• Cooperation with developing nations is essential
• The task is urgent, capital stock turnover is low, technology deployment needs time
• Start with existing opportunities, governments should identify and pursue all cost-effective CHP today

Wasted Energy Is a huge opportunity, statistics show thas 2/3 of the fuel we use to produce power is wasted. CHP can more than double this efficiency.

So Why Are We at 9% of CHP generation? Mr Tanaka identifies the following barriers:

• Difficulties connecting CHP to the electricity grid
• CHP benefits are not recognised in GHG regulation
• Lack of information about cost savings, other benefits
• Developing countries only now beginning to see potential

In this framework, IEA created the International Combined Heat and Power (CHP)/District Heating and Cooling (DHC) Collaborative.

The IEA International Combined Heat and Power (CHP)/District Heating and Cooling (DHC) Collaborative is designed to help evaluate global lessons learned and guide the G8 and other efforts. The CHP/DHC Collaborative assesses global markets and policies for these important technologies. It is also producing data on current installations, assessing technology growth potentials for key markets, and documenting best practice policies — offering insights to policymakers and industry seeking to advance these low-carbon solutions.

By J Arbi et al

In this paper, the authors study a variable speed wind generation system based on Doubly Fed Induction Generator (DFIG) in case of large balanced voltage dip and analyzed a remedial solution that allows for the turbine to stay connected and helps grid recovery through reactive power injection, by supplying the grid with reactive power during faults. Simulation results show the effectiveness of the solution in different operating points of the four working regions of the power-speed turbine characteristic.

By T Pfajfar et al

Rapidly increasing share of distributed generation (DG) in distribution networks introduced the need for active distribution network operation. As current distribution networks were not designed to integrate the power generation, the DG introduced many technical challenges in sense of power quality, network planning, protection schemes, voltage stability…. This paper presents the advantages of active approach in distribution network operation. The paper focuses on a voltage quality problem and introduces the coordinated voltage control technique to increase the share of DG in distribution networks and at the same time supply the customers with the required voltage quality.

Power supply systems and power industry in contemporary world are significant, if not the most important, sectors of any company, each country and the entire world economy.

The continuity of power delivery is of fundamental importance for all customers, particularly for the industry and public sector.That's why the issue of on-line monitoring and measuring of power consumption, electric power consumption, and selected power quality parameters becomes more and more important. The information and characteristics contained in this paper depict the capabilities of intelligent building systems.

The presented applications of intelligent building systems have an opportunity of significant development particularly with prospects connecting them with local networks in buildings or industrial facilities (Ethernet network) and global Internet web. That way the data on building power supply can be remotely analyzed, practically throughout the world.

RETScreen is a unique decision support tool developed with the contribution of numerous experts from government, industry, and academia. Over the coming months, Leonardo ENERGY will be publishing a series of webcasts on energy project analysis using RETSCreen.

Register here if you wish to be informed when we make additions to this page.

This module introduces wind energy project analysis. It has three objectives. These are first, to review the basics of wind energy systems; second, to illustrate key considerations in wind energy project analysis; and third, to introduce the RETScreen Wind Energy Project Model. View webcast (35 minutes)

And what must be done to ensure the future security of supply?

Experts seem to agree on the fact that the current U.S. electric grid has room for improvement. The rise in the number of blackouts in the US over the last twelve years clearly demonstrates this fact (see my post of 2 June.) However, opinions differ on how dramatic the situation really is.

In an opinion article in the Energy Bulletin, Gail Tverberg paints a very dark picture. If a major upgrade of the grid is not undertaken, it will be necessary to seriously downscale expectations concerning the free trade of electric power, renewable energy, and plug-in vehicles. She even foresees a situation in which some areas of the country may be forced into planned blackouts. In my experience, things are rarely as bad as they may seem at first, but consider this an interesting thought experiment from her pessimistic point of view. It reminds us of the fact that we should not take the high reliability of electric supply for granted, neither in the US, Europe, nor any developed region.

A company specialized in uninterruptible power supply systems developed and manufactured in 2006 a system comprising a 400kVA UPS unit.

The system was installed in a production facility manufacturing food packaging equipment and foil, located in northern Poland.

Frequent voltage dips and fluctuations were severely impairing the production process, causing downtimes of several-hour duration, which generated substantial losses. Restarting the production caused another losses resulting from the process specifi city.

Typically about 200 kg of material was lost until final product was compliant with standards.

Discover how the design engineers managed to find a solution for this process production line !

Leonardo ENERGY has launched a new publication for electrical design engineers called “Guide for electrical design engineers”. Each chapter will study an electrical design case and present its methodical step-by-step calculation method. To view the different chapters, click on their title below.

Please register if you would like to receive an email each time we add a new chapter to this guide.

At semiconductor manufacturing plants, Power Quality (PQ) solutions can be the deciding factor in maintaining competitiveness.

Semiconductor production lines are designed to print an ever higher number of integrated circuits on one chip. However, increasing production complexity also increases the sensitivity to irregularities in the power supply. The semiconductor industry has adopted various mitigatory solutions, but nevertheless poor Power Quality generated production stoppages still happen, resulting in costly process failures.

A European Copper Institute (ECI) Survey has identified that poor Power Quality (PQ) costs semiconductor manufacturing companies up to 10 per cent of their pre-tax profits (EBITDA). Consequently, making production lines immune to irregularities in the power supply can be a decisive factor in maintaining the competitiveness of a semiconductor manufacturer.

This ebook can be downloaded as pdf.

The influence of electricity and transmitters on our health

The term ‘electrosmog’ is being used more and more often. Questions have been raised as to whether this phenomenon is the cause of certain diseases and perhaps even some types of cancer. Should we be concerned? Are there ways to reduce the influence of electrosmog? And what exactly is electrosmog?

The possible effects of electromagnetic fields on our health are currently the subject of a very lively debate. Not only in the media, but also among responsible scientific and government bodies. For example, the Flemish government, acting on the principle that prevention is better than cure (see below), recently took the precaution of distributing a folder aimed at reducing mobile phone use by children. In Germany, the Ministry for the Environment has warned against the harmful effects of using Wi-Fi. Some people prefer to banish all electronic equipment from their lives, while others think that the situation is not all that serious. The debate seems far from over.

This briefing paper attempts to provide candid and unbiased answers and sketch the current state of knowledge. Legislation and possible preventive measures are also discussed.

The Romans claimed that sailing was necessary, and it certainly was for them in order to build and maintain an empire, but how about us? Are travelling and transportation as necessary with telecommunications expanding?

In a global word, nothing has changed since Roman times. We need to meet and move things, maybe even more so. The question is how we do it.

In the past week there have been two reports launched with the same basic message: IT will enable us to be much smarter. The keyword, though, is 'enable'. Will we rise to this ability?

Graphics from article in The Economist