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Power

France Decrees New Rooftops Must Be Covered In Plants Or Solar Panels 247

An anonymous reader writes: A law approved in France Thursday now requires all new rooftops in commercial zones to be covered in plants or solar panels. "Green roofs have an isolating effect, helping reduce the amount of energy needed to heat a building in winter and cool it in summer. They also retain rainwater, thus helping reduce problems with runoff, while favoring biodiversity and giving birds a place to nest in the urban jungle, ecologists say." The law was actually watered down from its original version — businesses only have to cover part of their roof. In other solar power news, reader SpzToid notes that despite earlier worries, the European power grid handled the solar eclipse just fine
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France Decrees New Rooftops Must Be Covered In Plants Or Solar Panels

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  • by Dan1701 ( 1563427 ) on Friday March 20, 2015 @03:17PM (#49304085)

    A couple of hours of no power input from solar power is not, and never has been a problem for the European power grid. This sort of thing happens extremely regularly, every night. We're used to it, and can cope. Thanks for worrying about us, though; it really was extremely kind of you.

    • by MickyTheIdiot ( 1032226 ) on Friday March 20, 2015 @03:22PM (#49304127) Homepage Journal

      This remind me of "sun sets, wind dies" billboards that get placed in coal mining towns. Only affective if you choose not believe in things like batteries and/or you have pushed the argument to full false dilemma status.

      • Only affective if you choose not believe in things like batteries

        You also have to not believe in markets. If the supply of electricity goes down, just raise the spot price, and marginal users drop off. My electric company (PG&E) gives me a 20% discount on my summer electricity bill for letting them put an automatic switch on my A/C compressor, so they can shave off demand peaks.

        • by itzly ( 3699663 )

          My electric company (PG&E) gives me a 20% discount on my summer electricity bill for letting them put an automatic switch on my A/C compressor, so they can shave off demand peaks.

          And the same thing can be done with electric cars. It's possible to make the charging software smart, and have it look at the spot price graph, user desired charge levels, and determine whether to charge the battery, wait, or even sell some power back to the grid.

      • by zlives ( 2009072 )

        but solar wind lives forever!!! :)

        you will always need a backup power source just in case of extreme outage cases for solar and wind... nuclear?

        • by itzly ( 3699663 )

          You can calculate risk of extreme outages, and aim for an acceptable value.

        • "you will always need a backup power source just in case of extreme outage cases for solar and wind... nuclear?"

          No, nuclear is out in the winter because the river is frozen and in summer it's because there's not enough cooling water in it.
          Nukes got hit by climate change as well. During those times, France has to rely on the coastal reactors alone.

          But the wind blows day and night.

          • In Arizona, the heat sink for nuclear is dry desert air, not water. This would also work in other dry parts of the world, such as Australia or Chile.

        • Nuclear has a poor ramp time. You can't just turn up the power output when the wind stops. It takes days to adjust. Same for goal.

          If you're looking for non-renewable power source that can be turned on an off as demand changes, you want gas. It's quite expensive, but it's also very quick to change power output, so it's commonly used to meet demand peaks.

      • Grid storage technology is currently cost prohibitive. What does that mean? Glad you asked. If it costs ~$0.06 kW to burn natural gas/coal to generate electricity that then can be sold for ~$0.13 kW any storage medium needs to have an amortized/maintenance cost less than the difference between the generation/sell price ($0.07 kW in this example) to be cost effective. Otherwise the power company is just wasting money. Wind farms frequently generate electricity they just pump into the ground rather than store
      • by dougmc ( 70836 )

        Batteries aren't really cost effective for storing the amount of energy that we'd need to power the electrical grid from sunset to sunrise [wikipedia.org].

        That said, even if we we ignore the possibility of storing energy or transporting it long distances to handle the moving (east to west) peak sunlight hours ... even if we can can only get half of our energy from the sun, that's still half of our energy that we didn't have to burn fossil fuels for.

        We don't need batteries for that to be a false dilemma.

      • Any power that renewable tech generates is good, so long as the grid can supply power when:

        1. The wind isn't blowing or the sun isn't shining
        2. You need more energy in one place than sun and wind can provide. This doesn't just mean steel mills; it also means high-rise apartment buildings with small roof areas.
        3. The renewable tech in your area is not one of the forms favored by Greens, so your dam or tidal lagoon got canceled.

    • by itzly ( 3699663 )

      The expected problems had to do with the rate of change, which was 3 times as high as the normal maximum.

    • by GroeFaZ ( 850443 )
      It is NOT bleedingly obvious. For once, the dropoff was much sharper than a normal sunset. Also, it came at a time of peak solar power production, early afternoon on a clear, sunny spring day. Real preparations and plans had to be made. If that makes it easier for the IT crowd to understand, compare it to the Y2K bug. The reason why nothing major happened back then was not because the threat was exaggerated, but because actual code fixing has happened.
    • A couple of hours of no power input from solar power is not, and never has been a problem for the European power grid. This sort of thing happens extremely regularly, every night. We're used to it, and can cope. Thanks for worrying about us, though; it really was extremely kind of you.

      You did forget to mention the coal-fired and nuclear plants that feed that same grid at night, and don't ask about Eastern Europe. ;)

  • by ArcadeMan ( 2766669 ) on Friday March 20, 2015 @03:18PM (#49304089)

    It better be a minimum percentage of the roof otherwise the law will be useless.

    • Re: (Score:2, Funny)

      by Anonymous Coward
      "Our 3 square acre factory is totally legit under this law, because we've got a potted geranium on the roof."
    • Re: (Score:2, Insightful)

      by Anonymous Coward

      And how do you define "covered in plants"? How much space between plants? Any kind of plant? What happens when your plants suddenly die?? Sounds like all the same nightmare as living in a homeowners association. "Your lawn is brown, here's a fine and it better be green next week!"

  • Summer cooling? (Score:5, Interesting)

    by DoofusOfDeath ( 636671 ) on Friday March 20, 2015 @03:25PM (#49304163)

    Here's something I've been curious about. I would expect that if there's a between the solar panels and the roof, this would lead the attic to stay a lot cooler in the summer. Because the sun would be mostly heating up the panels and not the roof. Anyone know if that can significantly reduce the temperature of a home's living spaces?

    • Sigh...

      I would expect that if there's a gap between the solar panels and the roof, ...

      • Isn't space a synonym for "gap" ?

        A-Hur-Hur! See what I did there? ;p
      • Which is why attics are ventilated and ceilings are insulated. If a second cover over the roof made much difference most buildings would already have one.
        • by bws111 ( 1216812 )

          How do you figure? A second cover isn't free, in fact it could be quite expensive. However, if the second cover is doing something else, like generating electricity, that offsets the cost. Then you have two benefits, electricity and a cooler house. My house was shaded by a large tree. When we lost the tree the second story was much hotter. That tree was our second cover, and it made a lot of difference.

          • by tomhath ( 637240 )
            You assume solar panels (without subsidies since they don't reduce the total cost) will generate enough electricity to make up for the much higher cost. I doubt that's the case in France. Anyway, a canvas cover would be a lot cheaper than a rooftop garden which is also acceptable.
    • Re:Summer cooling? (Score:5, Interesting)

      by Nemyst ( 1383049 ) on Friday March 20, 2015 @03:47PM (#49304357) Homepage
      The EPA has a page [epa.gov] on the very subject, claiming that green roofs not only help with cooling, but also heating, since they act as insulators. They also reduce pollutants in the air and combat the heat island effect present in many large cities. I am not aware of many negatives for them, aside from the maintenance required for the more elaborate ones.
      • I am not aware of many negatives for them, aside from the maintenance required for the more elaborate ones.

        Cost. Green roofs are heavy, so you have to build the structure (significantly) stronger to hold them up.

      • Another negative would seem to be that it would be hard to find a material that could last for long periods of time with damp earth pressed against it... it's a lot harder to replace a roof with growing material on it.

        It's much better protected against hail damage. Possibly there are potential mud-slide issues??!

        One other strong negative consideration would be that grass-thatch roofs are known to carry diseases that can affect people living within. That's for primitive roofs with no underside though.

        • Re:Summer cooling? (Score:5, Informative)

          by St.Creed ( 853824 ) on Friday March 20, 2015 @05:25PM (#49305145)

          Actually there's quite a lot of experience with this type of roof nowadays.

          Standard roofs locally are covered with bitumen waterproof covering. THis is affected mostly by UV light, which is countered by layering it over with earth and having vegetation on top of it. This can double the lifespan of the waterproof covering.

          The weight of a light covering with Sedum (very small, fatty ground-covering foliage that is very robust) will weigh between 50 and 60 kilograms per square meter. If your roof can't hold that, it will have serious trouble with a big snowlayer. Roofs are mandated to hold at least 100 kg/m^2 over 10m^2, and roofs meant to be used as terrace or walked upon for inspection have to be able to hold 250 kg/m^2.

          See also: http://en.wikipedia.org/wiki/G... [wikipedia.org]

    • Re: (Score:2, Informative)

      by Anonymous Coward

      Solar Installer here.

      There are two effects at work:
      - 15-20% of the solar energy will be converted to electricity and not to heat.
      - the air between the solar modules and the roof will transport most of the heat away. This depends on the distance module-roof and airflow.

      The effect will be in most cases very noticeable. A first order approximitation is, that normally a roof is 20-30C hotter than the surounding air. With solar modules the roof will be almost the same temperature as the air. On u

    • Re: (Score:2, Insightful)

      by Anonymous Coward

      I live in Maryland where 90 degree sunny days would regularly see 140 and sometimes 150 degree temperatures in my attic. After I put solar panels on my house the highest temp recorded in the attic was 110 degrees. This reduced the summer cooling requirements by about 1/3. My results might be slightly higher than normal though since the air return for the house runs through the attic and only has a few inches of insulation on it.

  • by ArcadeMan ( 2766669 ) on Friday March 20, 2015 @03:25PM (#49304175)

    2017-08-12 - A man fell to his death today while mowing the lawn on the roof of Les Olympiades. Witnesses claim to have heard him shout "Putain d'écureuils de bordel de merde!" while he fell down.

  • by SuperKendall ( 25149 ) on Friday March 20, 2015 @03:28PM (#49304195)

    I'm going to take broken / very old solar panels from all over, and sell them to businesses in France.

    After all, the law didn't state the solar panels had to be hooked up to anything...

    You probably don't want to know about my new plan to get ride of discarded trees and other vegetation.

  • That all new solar panels must have a house on them.

  • by PPH ( 736903 )

    Does moss count?

  • by Snufu ( 1049644 ) on Friday March 20, 2015 @05:04PM (#49305009)

    Because the bible tells us the French are a bunch of devil worshiping socialists, our only recourse is mandated "Freedom Roofs", each with eternal flames fed by coal, used electronics, hippies, and any stray French we catch at the borders.

    Better dead than green.

  • excellent

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