Dressing the power lines to bring more renewables into cities

February 12, 2016 by Sorina Buzatu, Youris.com

A higher volume of electricity delivered to the grid requires adaptation of existing transmission lines and improvement of the system's security. To this end, innovative materials and geometries of components are being designed and tested

To date, European consumers pay more for energy from renewables than for energy from conventional resources.

One of the reasons is the immaturity of the technology used for harnessing and distributing renewable energy. In addition, some power stations are far away from consumption centres. Such is the case of the wind farms, many of which are located on offshore sites, in the North and Baltic Seas.

To transport the electricity over long distances, the existing alternating current (AC) must be upgraded or new lines built.

"Using innovative materials and geometries for pylons, conductors and insulators helps to keep within the space already used, while allowing for a higher electrical capacity," says Vanessa Gombert, project manager at 50Hertz, a power transmission operator, in Berlin, Germany.

Insulated cross arms can reduce the pylon widths, and high-temperature, low-sag conductors can transmit higher electrical capacity without having to increase pylon height. "Nevertheless, we need to make sure that the and geometries of the line components are reliable throughout their planned lifetime and that they don't interfere with any of the other components," says Gombert.

Other scientists agree. Changes in the design of the lines can lead to a higher volume of electricity carried.

"For example, we use aluminium conductors and add steel in the middle of the conductor for mechanical reasons. Researchers are looking into conductors capable of carrying more electricity because land for building new pylons comes at a high price," notes Nicolae Golovanov, professor at the power engineering faculty, Polytechnic University of Bucharest, Romania.

New power lines will remain expensive until new energy producers come in and redraw the areas of consumption, according to Nicolae Mogoreanu, Ph.D. in technical science at the Technical University in Chisinau, Republic of Moldova.

That's why the structural adjustments in power line components are key to connecting "green" energy to the national grid.

"We would go forward with redimensioning the existing networks, partially reshaping the grid geography to fit the new conditions of electricity generation and with upgrading where necessary," explains Mogoreanu.

Repowering of the AC transmission lines faces other challenges, namely their dependence on the availability and intensity of the respective renewable energies: sun, wind and water.

"We need good weather forecasting for . This will enable us to precisely plan the feed-in to the grid," says Vanessa Gombert. She adds that part of her team's work is the development of a low-cost sensor to assess the prevailing conditions correctly and to secure a safe line operation.

The downtime could be reduced if the maintenance work was conducted during the operation of the line. It implies working on a "live" high-voltage line.

The experts are also looking at ways to increase flexibility: "Our main goal is to use our grid in the most efficient way, working also on the distribution systems: transformers, intelligent breakers, etc." notes Federico Caleno, head of New Technology and Global Infrastructure and Networks Innovation at the Enel Group, in Rome, Italy.

Optimisation of the transmission capacity on existing lines is suitable for reducing the overall investment costs, conclude the experts working on the European Best Paths research project, whose partner is 50 Herz. According to Vanessa Gombert, they expect a reduction in downtime of the lines by the end of the project in 2018.

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11 comments

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gkam
1.7 / 5 (6) Feb 12, 2016
Distributed solar does not require transmission lines, because it supports the system from inside.
WillieWard
3 / 5 (2) Feb 12, 2016
Distributed solar does not require transmission lines, because it supports the system from inside.
It is needed just a fossil-fuel power plant to compensate intermittency, mutually beneficial.
Lord_jag
2.3 / 5 (3) Feb 12, 2016
Exactly, Willie! Just look at how many days the sun failed to come up. What will we do for power on ALL those days??
gkam
2.6 / 5 (5) Feb 12, 2016
We have some high clouds today, but my PV system is generating power, . . . and I have not a single 400-foot stack.

Imagine that!
WillieWard
3 / 5 (2) Feb 12, 2016
We have some high clouds today, but my PV system is generating power, . . .
So disconnect it from the grid, it is easy to go off-grid: batteries$ or a small fossil-fueled electrical generator or stop taking warm bath and keep your aircon off as well other electrical appliances, mainly during the night, and welcome back to the cave ages!
gkam
1.8 / 5 (5) Feb 13, 2016
The world is in a drought, it seems. Perhaps more of the technology which needs no water, let alone tremendous amounts, is to be required of all new powerplants.

The least thermally-efficient are the nukes, kept at relatively lower operating temperatures so they do not kill us.
gkam
1 / 5 (5) Feb 13, 2016
Releasing ourselves from the need for gross amounts of water, alternative power systems can be put in places not suited for thermal plants such as nukes and coal and gas. And we will find these places:

http://www.utilit.../413441/

"A Deloitte study finds 'alternative energy's shift to the mainstream is largely complete and likely irreversible'"
gkam
1 / 5 (4) Feb 13, 2016
And we had better get started, say the bankers, because if we wait and try to save ourselves all at once, it can ruin markets and result in gross inefficiencies.

Oh, . . . and it can kill us.

http://www.thegua...arns?utm
gkam
1 / 5 (5) Feb 13, 2016
Speaking of water, . . .

http://www.nydail....2526779

Perhaps it is time we ended our Faustian Bargain with Nuclear Power.
gkam
1 / 5 (4) Feb 13, 2016
double-post
WillieWard
3 / 5 (2) Feb 13, 2016
Speaking of water, . . .
"water is used to manufacture solar PV components."
"The PV cell manufacturing process includes a number of hazardous materials, most of which are used to clean and purify the semiconductor surface ... include hydrochloric acid, sulfuric acid, nitric acid, hydrogen fluoride, 1,1,1-trichloroethane, and acetone. The amount and type of chemicals used depends on the type of cell, the amount of cleaning that is needed, and the size of silicon wafer. Workers also face risks associated with inhaling silicon dust."
"Thin-film PV cells contain a number of more toxic materials than those used in traditional silicon photovoltaic cells, including gallium arsenide, copper-indium-gallium-diselenide"
http://www.ucsusa...GgUBLuBU

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