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Science Forum

  1. 20 Mar '14 20:29 / 2 edits
    At the moment, according to this link, this seems more true for wind than solar power although, because the cost of manufacturing solar panels is steadily going down all the time, the prospects for both having extremely rapid cost-effective growth is looking good. It may not be very long before 99% of all our energy will comes from renewables!

    http://phys.org/news/2014-03-farms-society-surplus-reliable-energy.html

    "...The worldwide demand for solar and wind power continues to skyrocket. Since 2009, global solar photovoltaic installations have increased about 40 percent a year on average, and the installed capacity of wind turbines has doubled.

    ...

    At issue is whether renewable energy supplies, such as wind power and solar photovoltaics, produce enough energy to fuel both their own growth and the growth of the necessary energy storage industry.

    "Whenever you build a new technology, you have to invest a large amount of energy up front," said Michael Dale, a research associate at Stanford. "Studies show that wind turbines and solar photovoltaic installations now produce more energy than they consume. The question is, how much additional grid-scale storage can the wind and solar industries afford and still remain net energy providers to the electrical grid?"

    ...
    from an energetic perspective, the wind industry can easily afford lots of storage, enough to provide more than three days of uninterrupted power. However, the study also revealed that the solar industry can afford only about 24 hours of energy storage. That's because it takes more energy to manufacture solar panels than wind turbines.

    ....

    "Within a few months, a wind turbine generates enough electricity to pay back all of the energy it took to build it,"

    ...
    "
  2. 20 Mar '14 20:50 / 2 edits
    I just also found this:

    http://phys.org/news/2014-03-spanish-island-eyes-world-power.html
    "....
    A Spanish island hopes to become the first in the world fully powered by renewable energy later this year when it launches a new wind and water energy plant, a spokeswoman said Thursday.

    The Gorona de Viento plant is due to launch in June on El Hierro, the smallest of the Canary Islands off the Atlantic coast of Africa, project spokeswoman Cristina Morales told AFP.

    "It will introduce energy into the system gradually. By the end of this year, if all goes well, we will be able to reach 100 percent" of the power used by the island's 11,000 inhabitants.

    The two sets of turbines, one powered by wind and one by water currents, have a capacity of 11.5 megawatts each, far exceeding the total eight megawatts used at peak times on the island.

    To test a system of 100 percent renewable energy, the volcanic island of 278 square kilometres (107 square miles) "is the ideal place because it is so small," Morales added.

    The plant cost 80 million euros ($110 million) to build and Morales said the local government hopes to save the same amount over 20 years by using this cheaper renewable energy.

    The island is also expected to cut carbon dioxide emissions by 18,700 tonnes and diesel consumption by 6,000 tonnes...."

    If they can do this, why cannot we achieve something similar?
  3. Standard member sonhouse
    Fast and Curious
    21 Mar '14 07:28 / 2 edits
    Originally posted by humy
    I just also found this:

    http://phys.org/news/2014-03-spanish-island-eyes-world-power.html
    "....
    A Spanish island hopes to become the first in the world fully powered by renewable energy later this year when it launches a new wind and water energy plant, a spokeswoman said Thursday.

    The Gorona de Viento plant is due to launch in June on El Hierro, the sm ...[text shortened]... onsumption by 6,000 tonnes...."

    If they can do this, why cannot we achieve something similar?
    I just listened to a piece on NPR, a Dutch company just came out with a gearless rotor system for wind turbines. It does away with the transmission which has its own set of costs but manufacturing and maintenance wise.

    The normal method is to take the wind blades which turn at something like 10 to 12 RPM and rev up through the transmission to 1800 or so RPM for efficient generation of electricity through normal generators.

    This new device uses extremely powerful magnets to generate electricity directly at 11 to 12 RPM without the need to rev up to 1800 or so.

    This is a great development, the process is at least as efficient as the units with transmissions but is much more reliable since there is almost zero friction in these new units.

    They said it adds only a couple of percent to the cost of the units so it is a win win situation.

    http://www.ewtdirectwind.com/technology/direct-drive-technology.html
  4. 21 Mar '14 08:15
    Originally posted by humy
    At the moment, according to this link, this seems more true for wind than solar power although, because the cost of manufacturing solar panels is steadily going down all the time, the prospects for both having extremely rapid cost-effective growth is looking good.
    Solar is already cost effective. However it is taking a while for politics to catch up. Also, the prices have come down so rapidly that many people do not realise that it is now cost effective.
    The political problem is that solar tends to be owned by the individual rather than large utility companies - so of course there is significant resistance to the change by the utility companies.
    Here in Cape Town, you may put solar panels on your roof. However, if you want to connect them up to your mains supply, there are some approval processes you have to go through. The ideal is a situation where the utility company will buy your power during the day and sell you power at night. However, that option is currently not available - because the municipalities here in Cape Town derive significant income from selling electricity so there is strong political motivation to stop this scheme from ever happening.
    Germany implemented this scheme (after a political battle) and the solar industry there is booming.
    Here in South Africa we are currently short of power to the extent that we have occasionally had to resort to 'load shedding' which means turning some people off for a while - so we should be encouraging solar not discouraging it. We also already have two power storage facilities in the country - which helps with renewables.
    What is quite common in cape town is solar water heaters - and there is some political assistance in rolling these out.
  5. 21 Mar '14 08:44 / 1 edit
    Originally posted by sonhouse
    I just listened to a piece on NPR, a Dutch company just came out with a gearless rotor system for wind turbines. It does away with the transmission which has its own set of costs but manufacturing and maintenance wise.

    The normal method is to take the wind blades which turn at something like 10 to 12 RPM and rev up through the transmission to 1800 or so ...[text shortened]... is a win win situation.

    http://www.ewtdirectwind.com/technology/direct-drive-technology.html
    I have just looked at your link and this is fantastic news!
    Making it gearless not only reduces costs but reduces noise pollution; -all-round-good-news for wind power!
  6. 21 Mar '14 08:46 / 1 edit
    Originally posted by twhitehead
    Solar is already cost effective. However it is taking a while for politics to catch up. Also, the prices have come down so rapidly that many people do not realise that it is now cost effective.
    The political problem is that solar tends to be owned by the individual rather than large utility companies - so of course there is significant resistance to the ...[text shortened]... cape town is solar water heaters - and there is some political assistance in rolling these out.
    Solar is already cost effective. However it is taking a while for politics to catch up. Also, the prices have come down so rapidly that many people do not realise that it is now cost effective.
    The political problem is that solar tends to be owned by the individual rather than large utility companies - so of course there is significant resistance to the change by the utility companies.

    Yes, I total agreement with you with all of the above
    I think governments should be generally taking much more action to counter these problems by having policies that really push extremely hard to put solar panels on every roof top -perhaps by even forcing it my making it legally mandatory in law that you legally MUST have a solar panel that covers the sunniest side of your roof unless you have got a good reason or excuse not to.
  7. Standard member sonhouse
    Fast and Curious
    21 Mar '14 09:59
    Originally posted by humy
    I have just looked at your link and this is fantastic news!
    Making it gearless not only reduces costs but reduces noise pollution; -all-round-good-news for wind power!
    I would never have thought you could generate power very efficiently at a speed of 12 RPM! It takes some VERY powerful magnets however and in the story about them, they are only magnetized at the last second to minimize the dangers of getting fingers chopped off and so forth, and inserted in place by robots so no human gets close to them.

    It kind of reminds me of the story of the little 5 year old boy who was killed by having an MRI where a fire extinguisher had been left in the room, was about 12 feet from the MRI machine when they activated the magnets inside and the fire extinguisher shot across the room and hit the little boy on the head killing him instantly.

    Magnets of that power are not safe, besides the issue of erasing credit card data, that would be the least of the worries about such powerful magnets.

    Of course once installed, there is very little external field so they are totally safe from a magnetic field POV. They can still break and fall on your ass but that is another story
  8. 21 Mar '14 17:59
    Originally posted by sonhouse
    Magnets of that power are not safe,
    Video warning of the danger of such magnets:
    https://www.youtube.com/watch?v=0t8yDnyOaQ8

    ..besides the issue of erasing credit card data,
    I once bought what are known as 'rattle snake eggs' a toy consisting of two strong magnets. I put them in the same pocket as my parking ticket which subsequently wouldn't work any more.
  9. Standard member sonhouse
    Fast and Curious
    21 Mar '14 18:16
    Originally posted by twhitehead
    Video warning of the danger of such magnets:
    https://www.youtube.com/watch?v=0t8yDnyOaQ8

    [b]..besides the issue of erasing credit card data,

    I once bought what are known as 'rattle snake eggs' a toy consisting of two strong magnets. I put them in the same pocket as my parking ticket which subsequently wouldn't work any more.[/b]
    The ticket or the magnet?
  10. 22 Mar '14 09:07
    Originally posted by sonhouse
    The ticket or the magnet?
    The ticket wouldn't work. Since then I have been very careful to keep magnets away from cards with magnetic strips. My latest bank card has a chip as well as the magnetic strip and most machines now use that.
  11. 27 Mar '14 20:28 / 1 edit
    http://phys.org/news/2014-03-power-competitive-natural-gas.html

    "...Wind power cost competitive with natural gas, study finds

    (Phys.org) —The costs of using wind energy and natural gas for electricity are virtually equal when accounting for the full private and social costs of each, making wind a competitive energy source for the United States, according to a new study on the federal tax credit for wind energy.

    Just released by researchers at Syracuse University and the University of California, the analysis shows that wind energy comes within .35 cents per kWh when levelized over the 20-year life of a typical wind contract, compared on an equivalent basis to the full costs for natural gas-fired energy, according to Jason Dedrick, associate professor at Syracuse University's School of Information Studies (iSchool).

    "The true cost of electricity from wind power and natural gas are effectively indistinguishable, yet because the cost of carbon emissions is not included in the market price of gas, wind has not been a competitive form of energy use in most of the United States, without government pricingsupport," Dedrick said.

    The analysis starts from the U.S. Department of Energy (DOE) estimates of the lifetime "levelized" cost of electricity from a new wind farm, and also from an advanced combined cycle gas plant. The analysis develops a new metric that incorporates long-term factors which are not included in the DOE numbers. Accordingly, the study also reveals that the recently-expired Production Tax Credit for wind makes up for the lack of any mechanism to make fossil fuel generators pay for the cost of carbon emissions, Dedrick noted.

    ...
    ...
    ..."

    If you look at the top bar chart of that link, this message is made very clear.