When I was in elementary school, the cafeteria switched to disposable plastic trays because the paper ones hurt trees. Stupid, I know… but are today’s initiatives any better?

  • Hugohase
    link
    fedilink
    11 year ago

    One cannot prove a negative. Can you prove that god does not exist? Typically the burden of proof lies with the one making any positive claims such as you are.

    Of course it would be possible to proof that something isn’t economicly viable exept in this case, because it is.

    Here is a model of an economicly viable stand-alone system.

    https://www.sciencedirect.com/science/article/abs/pii/S2352152X22007836

    The link above was about how insanely expensive Nuclear is compared to, well, everything else.

    • JasSmith
      link
      fedilink
      11 year ago

      Thanks for the study. Super interesting. So they used Grand Canary Island as a proof of concept for the study. The two proposed storage mechanisms were li-ion batteries and hydro. They propose 5.82GWh, which is the equivalent of 108,000 of the cheaper 54KWh Tesla batteries. Hydro works well there because of their 2,000m elevation over a short distance. Their daily energy production is around 17.5GWh, and their proposed storage solution appears sufficient given the variability in predicted wind.

      It looks like a good use case for this location, but I’m not convinced this can be scaled to entire continents. Let’s take Europe (because I’m familiar with the data in Europe). Much of the continent is very flat. Denmark, Southern Sweden, Netherlands, and Northern Germany, for example, cannot take advantage of hydro storage, and this comprised the largest storage component of the proposed solution. In fact, given the elevation requirements, hydro would comprise a much lower proportion of storage than batteries, if scaled across Europe.

      This leads to the second problem. Even if we assumed all of Europe had as high an elevation gradient as the Grand Canaries, the power requirements are on a complete different scale. Using the same ratios, with 37% of storage coming from batteries, and 89% of daily storage required to smooth variance, Europe would require 106.8 million Tesla batteries. For reference, Tesla has only ever produced around three million batteries in its entire existence. In reality, Europe would require far more batteries than this, as hydro storage is not possible in many locations, and economical line transmission distances cap out at around 500km.

      We need new battery technologies or other means of economical storage to make such a grid work in Europe. I suspect the numbers are similar in the U.S. Biomass and geothermal help close the gap, but not nearly enough.

      For posterity, I’m not proposing that at present, renewables can’t comprise an even larger share of the existing mix. I’m arguing that renewables cannot comprise the entire mix at present.

      • Hugohase
        link
        fedilink
        11 year ago

        Let’s take Europe (because I’m familiar with the data in Europe). Much of the continent is very flat. Denmark, Southern Sweden, Netherlands, and Northern Germany, for example, cannot take advantage of hydro storage, and this comprised the largest storage component of the proposed solution.

        But an additional effect you have when considering the whole of europe is interconnection. The geographic spread of renewables lowers storage requirements.

        We need new battery technologies or other means of economical storage to make such a grid work in Europe. I suspect the numbers are similar in the U.S. Biomass and geothermal help close the gap, but not nearly enough.

        The EU will use hydrogen, I am not a huge fan of that but it is what it is…

        https://energy.ec.europa.eu/topics/energy-systems-integration/hydrogen_en

        As a sidenote, I don’t expect batteries to play a huge role in energy storage. Propably more frequency regulation and peak shifting and basically no long term storage.

        But we will see…

        • JasSmith
          link
          fedilink
          11 year ago

          But an additional effect you have when considering the whole of europe is interconnection. The geographic spread of renewables lowers storage requirements.

          Yes I reference this when I explain that, “economical line transmission distances cap out at around 500km.” In other words, hydro storage can’t be utilised all over Europe. Hydro storage in the Alps, for example, cannot power Danish homes.

          https://energy.ec.europa.eu/topics/energy-systems-integration/hydrogen_en

          Thanks for the link! I hadn’t considered hydrogen as viable yet but technology is improving rapidly. I think the major barrier at present is the conversion loss. Between 60-70% of energy input is lost, but I am optimistic this will improve in time. Further, perhaps at scale, close to areas of high variable energy output, this technology makes sense today.

          I agree with you on batteries. Tesla made a huge impact on the world energy market when they proved their battery farm concept in South Australia. It’s only used to reduce spot pricing (demand spikes which last milliseconds to minutes), but producers were bilking the public out of millions in those moments, and Tesla significantly cut their profits.