The electricity blog has moved
Posted by hdk on July 21, 2006,
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Dear Colleagues:
This Blog has moved to http://www.leonardo-energy.org/drupal/eblog - thanks for updating your bookmark.
The rss feed for the new site is http://www.leonardo-energy.org/drupal/taxonomy/term/63/0/feed
The new site, based on drupal, integrates Sustainable Energy Blog and The Electricity Blog with the Leonardo ENERGY website, offering a single information portal for sustainable energy professionals.
All posts will remain accessible through this page, but as of today, new posts will appear only on the new site.
I hope you will follow us to the new site, and that it meets your expectations.
Regards,
Hans
One wind turbine, 13 GWh in 2005
Posted by hdk on July 16, 2006,
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First year of operation of a mega wind turbine
In the past decennium, wind turbines have been growing quickly, both in height and in output power. The most recent generation typically has a tower height of 120 meter, a rotor diameter of 125 meter, and an output power of 5 MW. The first of this “mega turbines� that became operational was the REpower 5M on shore wind turbine in Burnsbüttel near Hamburg (Germany), inaugurated 2 February 2005. In its first year of operation, it produced 13 GWh, which was more than expected. After this test run, the annual production is expected to raise to 17 GWh. Several more mega wind turbines have recently been inaugurated or are being built in Germany (on shore and off shore) and Scotland (off shore).
Why not using DC at residential level?
Posted by hdk on June 26, 2006,
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Reducing energy losses with DC systems
Many residential electrical applications have DC inside, produced by a small rectifier. Bundling those rectifiers into one at the site of the grid interface could reduce energy losses. It also eliminates reactive power, largely reduces stand-by losses, facilitates the improvement of power quality, and makes the integration of small distributed generation units easier. The following paper from KULeuven’s ESAT/Electa group weighs these advantages against the technical complications. It concludes that for one residential unit, it is not recommended since in-house conduction losses are low. But combining DC power in house and DC at the lowest level of the distribution grid could have an interesting future.
Electricity in Spain
Posted by hdk on June 23, 2006,
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Courtesy Pablo Eguia from the University of the Basque Country in Spain, a reference to the map of the Spanish electricity system, published by REE, the national transmission system operator.
Electricity in the Czech Republic
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Courtesy Robert Pinter from the Hungarian Copper Promotion Center, an excellent website of the Czech transmission system operator, showing among other things the daily load profile of the system.
Electricity maps of UK
Posted by hdk on June 22, 2006,
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Courtesy Deloitte & Touche LLP, an electricity map of UK, showing major power stations (>500 MW) and transmission infrastructure.
From the same source, also a renewables map of UK, showing the single offshore wind farm in the UK at North Hoyle, but some more in an advanced stage of construction. However, a lot more seems to be in progress on hydro-power and biomass.
Investing in tomorrow’s transmission grid
Posted by hdk on June 20, 2006,
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Modified circumstances change cost-effectiveness of technology
European transmission grids are evolving to fundamentally different circumstances than they are used to cope with. Cross-border traffic is increasing due to international trade and renewables affect on the predictability of generation. These new circumstances require a new assessment of technologies. While some technologies were not feasible in the past for techno-economic reasons, they now can become viable solutions for enforcing the network. The following paper from KULeuven’s ESAT/Electa group treats the opportunities for underground transmission lines, DC transmission lines, and energy storage systems (batteries, compressed air, superconductors and supercapacitors, …).
The cost of electricity
Posted by hdk on June 19, 2006,
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There is a large difference between the cost of generating electricity and the price of electricity paid by consumers. The difference is the cost of transmission & distribution (including ancillary services) and taxes. To a large extent, the cost of electricity is the cost of distributing it.
In a generic model, L Elder and M. I Beardow demonstrate, a.o. how the unit cost of distribution increases, and reliability decreases with reduced electricity demand per customer. According to the graph, the cost of distribution (not including generation, transmission or taxes) would be around 7 c/kWh for an average European family using 3,500 kWh. It would go up as high as 13 c/kWh for a demand of 2,000 kWh, i.e. a family investing in high efficiency appliances and lighting, and serving heating needs from non-electrical sources. For an all-electric passive house, with 2,000 kWh demand for appliances & lighting, and 3,000 kWh for heating, distribution costs would go down to 5 c/kWh.
This begs the question that for a reduced energy demand, we no longer can afford distribution of multiple energy utilities, and if we select a single utility, electricity is a good candidate. Considering the many methods available to generate electricity, many of which with low or reduced carbon content, an all-electric system, based on high efficiency buildings and appliances, with a high portion of renewable generation, may be one of the most promising, cost effective routes forward.
Energy management on local scale
Posted by hdk on June 18, 2006,
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The optimal placement for distributed generation units
An increasing number of Distributed Generation units, using renewable sources or not, is connected to the distribution grid. That requires new concepts for developing those grids. The influence on grid stability is already well studied. The following paper from KULeuven’s ESAT/Electa group tackles the optimal placement of the DG units on the grid, decision strategies and the correlation with real-time control.
What if new control systems run out of control?
Posted by hdk on June 16, 2006,
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The interdependency of the power grid and its ICT control infrastructure
Due to the increase of distributed generation systems, new control strategies for the distribution grid are being proposed to maintain the desired degree of availability. Those new control systems are often based on ICT infrastructures, causing new or amplifying old dependencies. The following paper from KULeuven’s ESAT/Electa group discusses this topic. It emphasizes the need for making a thorough study of the risks introduced by these interdependencies. Common sense should be used in the first place. A more systematic study can be made with traditional reliability assessment tools, as well as with new multi-agent based models and simulators.