Friday, September 30, 2005

What can be Expected from Combined Cycle (Steam and Gas) Power Stations?

In the middle of the 1990’s, very efficient (over 38%) gas turbines with high power output entered the market. Their exhaust gases had a high temperature and could be used to produce steam in a subsequent vaporizer.

Simultaneously, natural gas prices were continuously dropping since the beginning of the 1990’s and had moved close to hard coal prices. Finally, for economical and competitive reasons, big gas turbine manufacturers offered attractive prices.

As a result, it became possible to construct so-called steam-and-gas or combined cycle(CC) power stations with high ratings at low investment costs and operate them with low power generation costs.

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Sustainable, efficient electricity service for one billion people

In the June issue of the 'Energy for Sustainable Development' Journal, a 50 GWe electrification scheme is proposed to provide efficient electricity to a billion people. The scheme would provide a 0.025 kW service per person (0.15 kW per family), providing power for basic energy services such as lighting, refrigeration and infotainment (TV).
Such a scheme would require to be financed 100 B$ over 20 years, to ensure the use of efficient over lowest-first-cost technology. The overall investment would be 4 times higher, and raised by local capital and tariff payment.\sustainableelectricity.pdf

Monday, September 26, 2005

Liberalization and the Performance of the Electricity System

Liberalization has improved the administrative efficiency of the electricity system, but what has been its impact on technical performance? Energy efficiency of the distribution system, its technical quality of supply and environmental performance are issues which where largely conspicuous in their absence in the debate, but maybe it is time to address them now. A discussion paper from Leonardo ENERGY.

Sunday, September 25, 2005

What can be expected from combined-cycle power stations?

This article, by SEAL in partnership with Energie-Fakten gives an overview of the potential conversion efficiency that can be expected from combined-cycle (Steam & Gas) power stations.
If we consider the electricity production system of the future:
  • Renewable electricity, primarily wind and solar PV, with a primary energy equivalent of 1 kWh per kWhe generated - according to an IEA convention
  • Combined cycle power stations with 55-60% efficiency, i.e. up to 1.8 kWh primary energy per unit of generation
  • Coal-fired power stations with 40-45% efficiency, i.e. up to 2.5 kWh primary energy equivalent.
  • Nuclear power plants with 30% efficiency
A system based on the first 3 technologies with the most modern power stations would have an overall primary energy equivalent of 1.7, i.e. requiring 1.7 kWh of primary energy to produce a unit of electricity.

Thursday, September 22, 2005

Ecodesign Glossary

Glossary on the most important ecodesign terminology. Learn to talk like an environmental expert in 23 terms.

Sunday, September 18, 2005

Direct-Current Voltage (DC) in Households

As new technologies are developed in the area of DC voltage, durable local energy sources and storage systems, it becomes technologically possible and energy efficient to provide a portion of the electricity required in homes and offices in the form of direct current. In spite of the higher costs associated with such a 'double' system (direct and alternating current), it is a serious option. Due to the increasing dependence on electricity and our increased need for comfort, sustainability and simplicity, a DC voltage installation offers value for money. Certainly considering the growth of the aging population that places extra focus on the reliability, safety and usability of the electricity supply system.
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Wednesday, September 14, 2005

The Electrical System as a Tandem Bicycle

The system that delivers electricity to private citizens and companies across the country is highly complex. While electricity is an omnipresent and crucial part of our everyday economy, understanding this system and all its associated phenomena is not easy, sometimes even for trained electrical engineers. In such a case, a good analogy often helps to form a better idea of how things work. We have chosen to compare the electrical system with a tandem bicycle to explain a few of its aspects.

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Tuesday, September 06, 2005

Monday, September 05, 2005

Building telecare in England

Telecare offers the promise of enabling thousands of older people to live independently, in control and with dignity for longer. This document provides local authorities and their partners with guidance in developing telecare services for their communities. It sets out the purpose of the Preventative Technology Grant and sets out expectations for the use of the grant.
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Friday, September 02, 2005

High efficiency transformers proven to save 30 tonne CO2 per year

Leonardo ENERGY has worked together with Polish and Czech utilities to equip 15 substations with high efficiency transformers. Each station has power monitoring equipment to measure energy savings, and these savings are converted into emission reductions using national average factors.
Detail results show that these 15 substations, with total rating of 5440 kVA, save on average 30 MWh electricity per year, equivalent to 32 tonne CO2 emissions. Over their economic lifetime of 25 years, these transformers are expected to avoid 814 tonne of CO2 emissions. And given Europe's population of 4 million transformers, the project has the potential to be replicated many times.
On the website 'Supertrafo', daily measurements per substation are being published, showing energy saved and emissions reduced.
Supertrafo website

Thursday, September 01, 2005

Webcast - functional earthing of electronic devices

The growing diffusion of electronic devices imposes new requirements for earthing systems, which are a key element in electrical installations safety requirements. Usually, electronic devices require a connection to earth for safety reasons (protective earthing) and also for functional reasons (functional earthing).
These different requirements result in electromagnetic compatibility problems. The simultaneous need of a connection to earth for both safety and functional reasons, exposes electronic devices to disturbances otherwise not present. It also results in safety hazards due to the steady leakage currens they generate.
These considerations also apply to earthing systems where there isn’t any electronic device connected, but where equipments have similar features, such as:
  • high leakage currents;
  • high frequency leakage currents;
  • steady leakage currents;
  • low resilience.