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Climate Change: The Megathread - Read Post #1 before posting



  • Registered Users Posts: 18,553 ✭✭✭✭ cnocbui

    I find it equally depressing the schilling solar gets in a country which only sees 14% of the hours in year having actual sunlight. 50% of the hours in a year are darkness, leaving 36% of cloud obstructed gloom. If you look at the production charts the solar hobbyists post, the energy output drops about 70-80% when clouds obscure the panels, which means to get an average of 7 KW, you probably have to put in 14 KW area of panels.

    The pay-back break even point is double that of sunnier countries that actually get some sunlight. Then of course there is the nonsense of solar producing energy when it's least needed and none when it is - which is winter.

    50% of Europe's energy usage goes to heating buildings. Try working out how to heat a building using solar energy in winter. It's possible with a house built to passive specs, but lets get real, 99.99% aren't.

  • Registered Users Posts: 1,287 ✭✭✭ reboot

    Agreed,that's why I personally wouldn't spend serious money on it, some say we are too far north.

    But to mess around and educate myself for a few Euro it's a bit of a hobby,having recently discovered an EV breakers yard,lipo batteries are plentiful.

    A few wee panels on a trolly,on the ground,can track the sun ,you can't turn the house round, starting with 12dc,down to USB,, balancing cells,reusing laptop an phone batteries.

    Recently a 100 watt turbine has been add to supplement photons in the dark days.€200.

    If I resort to flicking the switch in the house,last time I looked it cost around 12 cents/kwhr,from midnight to 8am.

    Sure it's a bit of fun,in Winter.Thanks,points well made.

  • Moderators, Recreation & Hobbies Moderators, Science, Health & Environment Moderators, Technology & Internet Moderators Posts: 85,612 Mod ✭✭✭✭ Capt'n Midnight

    Solar won't be an overnight solution :pac:

    Rooftop solar panels installed on farms and other businesses could generate up to three gigawatts of electricity. (or ~ 1GW in overcast conditions) And in summer they'd be producing power until very late.

    It's low maintenance too, so once the capital cost is covered it's about the cheapest energy you can have. And the cost per watt is falling and will continue to do so for years as new technology and lab proven devices are commercialised. For example in sunnier climates you'd mirror the back of the panel to capture more of the direct sunlight but for climates with diffuse light more of the time a transparent backing could capture 10-20% more light, besides silicon panels are more efficient with lower temperatures.

    In order to provide lots of power to the grid both renewables and nuclear rely on a combination of energy storage , flexible demand , interconnectors and dispatchable plant.

    In winter roughly 1GW more power is used than in summer. Better insulating means it would be easier to shed demand or soak up surplus power in the short term by using a smart control during the longer timescales that buildings and hot water could keep their warmth. On RTE's Eco Eye they said the most of Dublin could be powered by surplus heat from industry and commercial premises. Passivhaus and/or district heating for the future ?

    Certainly we need to up the game on new construction, stuff like common ducts too so people aren't tied to a sub set of providers.

  • Registered Users Posts: 1,287 ✭✭✭ reboot

    Being more of a small scale practical microgrid person, I viewed with interest, Science view programe on NHK out of Japan.

    The roof had an aluminum sheet applied,which is then painted with special paint.

    They worked on the basis that in order to provided a USB 5 volt supply to power and charge devices in the property, 9 volts was enough .

    I work around small supplies of this nature,spending a few hundred Euro over the years.I reflect on the notion that I order for ESB to supply mains to the property and thereby a 5v dc supply, they start out with 44 000 volts 70 miles away. This is necessary of course for various other reasons.Fifty years ago the BBC workshop in Belfast had a 110 v DC, permanent supply .I note a move towards DC distribution in Europe,and away from AC sorry Nikola.

    There's room for everyone but more is not always better or cheaper, Thanks,most interesting.

  • Registered Users Posts: 18,553 ✭✭✭✭ cnocbui

    The real way to measure solar cost is to add the expense of an accompanying energy storage system that allows for 24/7/365 energy output. All over the wolrd, large amounts of solar generated electricity is thrown away because it is generated when demand is low. California, for example. Then you have Ireland's little problem, cloud cover and winter. These little issues mean you probably need at least 10+ times the quoted rating of the panel in area to get that rated output from the system consistently. Renewable like solar and wind are touted as producing 'cheap' electricity, and it's true, but this only applies under optimum conditions, which are rare. If you have to buy 10 hectares of panels in Ireland to match the output of one in Australia or the Sahara, the cost is 10 times what solar proponents say it is. And that's even before adding the cost of storage solutions.

    They real kw cost of solar in Ireland is uneconomic, which is why there are sharks currently circling in the water, hoping for a lifetimes supply of taxpayer money in the form of subsidies so they can become very wealthy at taxpayer expense. A third of Scottish wind farm 'owners' are in the Cayman Islands. In Germany, the real retail cost of energy has doubled due to renewables. They have lots of solar, not because it's technically wise to try and generate electricity in Europe from it, but because it's subsidised. Same for wind. German consumers have been paying a massive charge on their power bills to subsidise renewables. If the energy were actually chepaer, their pwer bills, and ours, should have been falling. I know mine hasn't

    This claim of greater solar panel efficiency at Irish temperatures is self-deceit that hobbyist PV enthusiast here engage in. A PV in Algeria generates 3 times as much power as it would in Germany, so likely 4-5 times as much as one in Ireland, despite being probably 7-8 times hotter.

    The greater temperature efficiency of cold PV's doesn't even begin to compensate for the lack of light, which is one reason it's cold. So contrary to the lies, Ireland is not one of the best places in Europe for solar because it's cold, it's one of the worst.

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  • Registered Users Posts: 1,287 ✭✭✭ reboot

    Well said,look out for sharks. It's hard to beat 8p/ unit economy 7.

  • Registered Users Posts: 3,328 ✭✭✭ Banana Republic 1

    Where are you getting those percentage figures from ?

  • Registered Users Posts: 18,553 ✭✭✭✭ cnocbui

  • Registered Users Posts: 3,328 ✭✭✭ Banana Republic 1

  • Registered Users Posts: 18,553 ✭✭✭✭ cnocbui

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  • Moderators, Recreation & Hobbies Moderators, Science, Health & Environment Moderators, Technology & Internet Moderators Posts: 85,612 Mod ✭✭✭✭ Capt'n Midnight

    That's the hours of bright sunshine. The mean cloud amount for each hour is between five and six okta. So even at the worst there is diffuse sunshine ~ 18 hours a day in summer. This is why we use panels rather than mirrors and concentrators. Storing green hydrogen in disused gas fields means grid level storage using mostly existing infrastructure.

    You could install 3GW of solar on farm and similar buildings. So zero extra land used. But solar just keeps getting better and cheaper : Nanowires could could potentially double the efficiency of today's Si solar cells at low cost. That 3GW could be 6GW and even if de-rated to 2GW it would provide a significant part of our summer demand.

  • Registered Users Posts: 1,287 ✭✭✭ reboot

    Interesting,also panels floating on lakes being used.Frequency of light an interesting topic,and NASA rovers on Mars making full use of more of the spectrum. Does seem to cost around $1 million though.

  • Registered Users Posts: 18,553 ✭✭✭✭ cnocbui

    As I have said, Boardsies with PV installations reporting their Oct production results have days of only 1.7kw and sunny days with 23kw. Trying to pretend that actually cloud isn't as bad as I or Met Eireann make out, is dishonest. I have some solar panels I acquired for a remote power project. I was completely shocked by the difference in output between naked exposure to sunlight and that from when they were behind just a double glazed window. They lost nearly 30%. Cloud is much worse. A UK site flogging PV systems claims cloud only reduces output by between 80-90%.

    Here is some local data:

    October Stats - galway

    TOTAL 7.2kWp (4.3 south/2.88 west ) - Total production 420.3 KWH

    4.3 Kwp (3.6 inverter) S/SW array -- 260.3 Kwh

    2,88 Kwp (2.5 inverter) West array -- 160 Kwh

    Mid Oct there are about 10hrs of daylight, for ease, lets imagine there is no dawn or twilight tapering. So a 7.2 Kwh system can in theory produce 31x10x7.2 = 2232kw. 420 is 18%

    If you think cloudcover is insignificant, rather than something that brings the whole system to it's 18% knees, then keep on trucking. As for nanowires and other pie in the sky; fantastic, but it's not real until it is. And becoming real can not be assumed as a given.

    7 years ago materials science researchers at UL announced a Li-ion battery breakthrough, doubling their capacity and increasing cycles to at least 1000.

    Do we have this? No. While research can sound promissing, as with 40% PV cells, using vertically stacked GaAs fibres grown with multi million dollar metal-organic vapor deposition machines, I doubt that process is currently fast or cheap.

    Quoting the latest research as proof of something being industrially or realistically achievable and as a counter argument is juvenile.

    Have you heard of micro LED TVs? Well they are the next big thing in display tech. They are they bees knees - landing any day now. Don't waste your money on a big old fashioned OLED, like I just did. They will be here any day now; just wait.

    Micro LEDs were invented in 2000; 21 years later and even Samsung hasn't managed to mass produce displays using them.

  • Moderators, Recreation & Hobbies Moderators, Science, Health & Environment Moderators, Technology & Internet Moderators Posts: 85,612 Mod ✭✭✭✭ Capt'n Midnight

    The top line is solar radiation outside the atmosphere. Similar to surface of Mars but only as bright as an overcast day on Earth. In fairness $1m is peanuts compared to the cost of putting a rover on the surface of Mars. We've been using solar power since 1958 when the Vanguard 1 satellite used it for seven years.

    A 500nm photon has twice the energy of a 1000nm one but still only moves one electron in a silicon panel so the excess energy is wasted. Below 900nm there isn't enough energy to move an electron in silicon so no power there.

    By using panels with different band-gaps you can reduce the wasted energy, in the same way a triple expansion steam engine has different sized cylinders optimised to use different steam pressures.

    Note : the voltages are a property of the semiconductor material rather than the actual voltage per layer.

    Transparent panels that harvested UV or Near IR could be used for windows or greenhouses. And in the case of greenhouses or fields the action spectrum of photosynthesis means that plants survive on blue and red light and don't use green-yellow much so you could harvest most of the spectrum with transparent panels.

  • Registered Users Posts: 1,287 ✭✭✭ reboot

    Most interesting, I concentrate on small scale ,but avoided going from 20 v dc up to 230 ac and back down again,inverters and all that.Also avoiding the use of pulse mode power supplies to get back from 230 ac to USB, 5v dc. Some say possible cause of "Dirty electricity", a big problem in the States,if you look at sales of filters.

    I suppose I'm talking Elon Musks Power wall idea,but staying DC, supplying the property only with 12v and 5v dc. Its just an educational hobby,costs virtually nothing,and is now supplemented with a 100 w turbine 20v off load.

    It's interesting how many of our devices only require a small dc voltage,at reasonable current draw.

    Moving from 12v lead acid to lipo EV batteries has reduced size and weight but complicates battery cell balancing.

    It occurs to me , that when I see the awful scenes of power lines coming down during storms in the US, if they were 220v and not 110v,then the heavy cables would be half as thick, but it's not as simple as that ,when you take current and wattage requirements etc.

  • Registered Users Posts: 1,287 ✭✭✭ reboot

    Your also right $1 million not much to NASA. Some say they spent that on a ballpoint pen to write in space,while the Russians used a pencil.

  • Registered Users Posts: 3,376 ✭✭✭ Funsterdelux

    With all the PV talk here I thought I should share this with ye.

  • Moderators, Recreation & Hobbies Moderators, Science, Health & Environment Moderators, Technology & Internet Moderators Posts: 85,612 Mod ✭✭✭✭ Capt'n Midnight

    The space pen was developed without govt money by a private company. Nobody used pencils because bits of carbon floating around the space craft causing short circuits is the stuff of nightmares. Russians used wax pencils and then like NASA they bought the space-pens when they became available.

    Probably a discussion for another thread on the merits of using power banks vs. their sunk costs.

    BTW Power lines are much higher voltages, the lines from Moneypoint to Dublin are 400,000 Volts. Weight isn't an issue for local lines on wooden poles as the steel cores are under a lot of tension to stop the wires drooping. In the US they use split phase so the cables from the sub-station wouldn't be twice as thick.

    Moving the grid from AC to DC would reduce the amount of power lost to resistance in the lines. It would also reduce the need for frequency stability and make it easier to hook up capacitors or batteries. But then you'd have issues with switchgear and providing DC to AC convertors for legacy equipment like large synchronous motors.

  • Registered Users Posts: 1,287 ✭✭✭ reboot

    Brilliant,well researched and not much has changed. Good to keep a sense of humour,and beware the arrogance of the Engineer,thanks.

  • Registered Users Posts: 1,287 ✭✭✭ reboot

    I did ask if a separate thread would be of value,but no support was indicated.

    Your quite right on the pen,bit of an urban myth .

    Point I was trying to make on cable size was relating to current,but no matter,

    As pointed out elsewhere,BBC electronic workshop in Belfast had a dc supply, some forty years ago,some say it came from the shipyard.

    Agreed on high voltage powerlines, if I didn't supply my own 5v USB supply from solar,at an outlay of around €50, I'd be using ESBs supply which is 44,000v from 70 miles away. Obviously its needed for other reasons,but in this specific case,not by me,for device charging.

    Supplies coming into UK,increasingly DC,as new components now available,which Nikola wouldnt5have had access to.Good to talk continue to keep me right,thanks.

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  • Registered Users Posts: 26,141 ✭✭✭✭ looksee

    I don't know whether this anecdote is of any interest but at the bottom end of the scale of solar panels we briefly owned an above ground, outdoor swimming pool - about 4m x 5 or 6m and just over a meter deep (probably 4 ft). While we were deciding whether it was worth restoring and maintaining (it wasn't) we found the heating system. It was a length of very basic black plastic 'mat' about 3m long and a probably 80cm wide which was unrolled to rest against a south facing bank near the pool. Water was fed in at one end , travelled through a series of channels and returned to the pool. We set it up on a sunny but not exceptional day and it raised the temperature of the entire pool by about 2-3 degrees over a period of about an hour. It was of course being pumped through by electricity (the same pump that was on for filtration purposes anyway) so not entirely the 'free heat' that it appeared to be, but the speed of heating that volume of water in a short time was interesting.

  • Registered Users Posts: 26,141 ✭✭✭✭ looksee

    Moving on to the reason why I called in here, I found this article on the BBC website which I thought was interesting. I am not sure whether this is the correct thread or if it should have been in a new one, if I am in the wrong place perhaps it could be moved?

    The article suggest that by creating a massive Jurassic Park type place in the Siberian Arctic and populating it with large animals - which is already being done to a limited extent - but specifically introducing an elephant/mammoth animal (mamephant? elemoth?) would improve the climate balance for the earth.

    Some of the arguments seem reasonable enough to my unscientific mind, but a couple of points puzzled me. Firstly the vast herds envisioned would surely produce such huge amounts of manure that it would negate a lot of what they are proposing, given the arguments about cows and methane. Secondly they are proposing that the animals would gradually knock back the forests that cover the area and create more grassland which would be a better carbon sink than forest. Which again seems to contradict the usual message of woodland good/grassland bad.

    Presumably I am missing some vital scientific points here but I would be interested to hear other thoughts on it.

  • Registered Users Posts: 3,376 ✭✭✭ Funsterdelux

    I watched an episode of Lives in the Wild? with Ben Fogle, where he was staying with a scientist in Siberia who was trying to do something like that. Getting bison to create grassland, as the forests were expanding, but their reason was that the forests are a darker green so warmed more than grassland (albedo).

    Its horses for courses, different parts of the planet would require different ecosystems.

  • Registered Users Posts: 6,405 ✭✭✭ sporina

    walked by 2 restaurants in Cork City today and I was stunned by the amount of xmas lights they both have streaming down the front of their premises.. think of the amount of electricity its taking to keep those lit.. beggars belief... and all the talk about reducing global warming.. like, are they on another planet??!! i've a mind to send them both an email.. its ridiculous,..

  • Registered Users Posts: 6,405 ✭✭✭ sporina

  • Moderators, Recreation & Hobbies Moderators, Science, Health & Environment Moderators, Technology & Internet Moderators Posts: 85,612 Mod ✭✭✭✭ Capt'n Midnight

    Before the mid-eighteenth century, most people lived in near-complete darkness except in the presence of sunlight and moonlight. Since then, the provision of artificial light has been revolutionised by a series of innovations in appliances, fuels, infrastructures and institutions that have enabled the growing demands of economic development for artificial light to be met at dramatically lower costs: by the year 2000, while United Kingdom GDP per capita was 15 times its 1800 value, lighting services cost less than one three thousandth of their 1800 value, per capita use was 6,500 times greater and total lighting consumption was 25,000 times higher than in 1800

    From 2000 , before LED lights took over -

    Humans like light. And roughly speaking the % of GDP spent on artificial light hasn't changed much in centuries across different cultures in different parts of the world.

    LED Christmas lights use very little power nowadays, even less if they are flashing. And if you've ever had to use a 9 Volt battery to go through all of the bulbs on a set of Christmas tree lights you'll appreciate how much more reliable they are now and less likely to cause house fires.

    The big change already happened when we stopped using incandescent lights for most lighting. That frees up more electricity than is generated by nuclear power.

  • Registered Users Posts: 6,405 ✭✭✭ sporina

    @Capt'n Midnight thats a bit out of date..

    never the less.. its not exactly supporting the message/movement/change is it!

  • Registered Users Posts: 18,553 ✭✭✭✭ cnocbui

    The power consumption of LEDs is utterly insignificant:

    If you are that worried, stop eating cooked food and shower with cold water.

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  • Registered Users Posts: 3,376 ✭✭✭ Funsterdelux

    If anything light pollution probably causes more ecological damage (esp moths) and the light that LEDs produces has an affect on our brain, which can be detrimental to sleep.

    For every improvement theres always some disimprovement.