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Thread: Power shares

  1. #591
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    Electricity 'beamed' to homes could do away with wire transmission cables

    https://www.stuff.co.nz/business/gre...mission-cables

    A great methodology to introduce vast inefficiencies, but still could find some niche market.

  2. #592
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    Quote Originally Posted by fish View Post
    My guess is that after the election the future possibilities and timescale will become clearer.
    Personally I would like to see more Geothermal and Wind generation in the NI which would reduce the massive transmission costs to bring power from the very south to the north.
    Coal needs to be banned and substituted with gas for when nature fails to provide power.
    I read that contact and meridian were going to tip in $5 million each to help fast track the southern transmission lines but at a later date that was put on hold....why I,m not sure......as for huntly on gas sounds good but security of supply will be an issue with no more drilling allowed and also huntly has water temperature issues with regard to discharge back into the waikato river.?..maybe back to meremere and the rubbish boiler to generate electricity

  3. #593
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    Quote Originally Posted by ziggy415 View Post
    I read that contact and meridian were going to tip in $5 million each to help fast track the southern transmission lines but at a later date that was put on hold....why I,m not sure......as for huntly on gas sounds good but security of supply will be an issue with no more drilling allowed and also huntly has water temperature issues with regard to discharge back into the waikato river.?..maybe back to meremere and the rubbish boiler to generate electricity
    Drilling is still allowed (but no new permits-in fact more oil and gas have recently been discovered offshore Taranaki ) and do not forget existing onland pipelines/infrastructure could be used as current gas is depleted .
    If any goverment really wanted to change Huntly to Gas it could be done .
    The new gas baseload generation is highly efficient and should discharge water at lower temperatures.

  4. #594
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    Quote Originally Posted by fish View Post
    Good and essential question.
    Is there a good location?
    Clearly the higher above sea level the more power can be stored .
    North Island is the best place to store power but I guess rainfall patterns and space may make the SI look better but leaves the transmission problems......
    There is only one suitable North Island location, and even that would only be intra day storage, not dry year. That is Lake Otoaira above the Tokaanu Power Station. The permitted usable range is only around 30 cm and that gives 12 hours storage. If it could be permitted to go to 1 m it would then allow for intra day pumped storage.

  5. #595
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    Quote Originally Posted by Jantar View Post
    If Taupo was to be used for dry year back up, then that would mean the loss of generation from the current Waikato stations for most of the time. These stations cannot be retrofitted with reversible (pump) type turbines so it is not a matter of simply pumping water back up the line.
    Actually all Francis Turbines can reverse pump and are most suitable for pump-hydro out of all the turbine designs. Given most of NZ's hydro utilises francis turbines, 'theoretically' any of NZ's francis turbines could be used.

    I'm interested to see if Manapouri gets investigated for pumped hydro as it's already setup for it (has the water source at the bottom and a tunnel to the top). The downfall being that it'd pump salt water back into the Lake and needs a greater capacity in Lake Manapouri but otherwise the bones are all there.

    I suspect a reason the government has started investigating the Lake Onslow scheme is to encourage consented wind projects to be developed without interfering with existing schemes.
    Genesis has been making plans to shut down Huntly for awhile but it's also the biggest piece in the puzzle to get 90% renewable for 2025 (the governments pledge made in 2017). Removing Huntly comes with great risk because we need to install new generation to cover dry years and somewhere to sink that power.

    The issue is, all the consented generation in NZ is primarily wind. With over 2000MW's of consented wind projects and the variability of wind, we need somewhere to store that energy otherwise risk curtailment. Genesis has consent for the 860MW Castle Hill project, which it could be develop as a replacement for Huntly but given that's ~1/10 th of NZ's installed capacity, Genesis needs somewhere to sink that power when the winds blowing and there not demand for it. Otherwise, run the risk of curtailment or unprofitable spot prices. This is where Onslow comes into the picture, with an opportunity to store the energy with relatively good efficiency (round-trip pumped hydro at ~85% efficiency) and with the huge storage capacity it provides some security to go ahead with installing new generation and cover the dark cloud of dry years.

  6. #596
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    Quote Originally Posted by fish View Post
    If any government really wanted to change Huntly to Gas it could be done .
    The new gas baseload generation is highly efficient and should discharge water at lower temperatures.
    The term 'efficiency' can mean different things in different contexts.

    To go back to thermodynamics basics, the thermal efficiency of any thermal power generation unit is determined by the difference between the maximum temperature that can be withstood inside the power generation unit and the discharge temperature of what becomes the waste energy steam at the end of the power generation process. It is the difference between the heat energy you put in and the heat that comes out that determines the electrical energy that you can ultimately take out of such a process. It may be possible to more easily control the burning of natural gas where you know the chemical make up of what you are burning before it goes into the pipe to arrive on site, verses coal where you may not know exactly what you are burning until it is stoked into the boiler furnace. That means a stoicheometrically controlled natural gas input might be able to burn hotter. But ultimately the other gain in natural gas 'efficiency' is that the chemical composition of the waste plume is less damaging to the environment. I think the power turbine efficiency gains of recent years are more due to material improvements allowing higher temperatures in both the combustion and then the power generation processes. I don't think you can do much about the discharge temperature of a combustion process. That tends to be determined by the environment.

    'Unit 5', the base load power generation unit today at Huntly, already runs wholly and solely on natural gas. It is only the older Rankine units that can be used fill gaps in the power supply when lake levels are low that can run on coal or natural gas.

    SNOOPY
    Last edited by Snoopy; 03-08-2020 at 10:50 AM.
    Watch out for the most persistent and dangerous version of Covid-19: B.S.24/7

  7. #597
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    Pumping water uphill for hydro entails pumping losses, losses from evaporation (although could be offset by rainfall) and uses large amounts of land area and/or requires dredging and excavation to increase capacity. It's also so last century solution apparently...

    https://www.aresnorthamerica.com/art...s-blm-approval

    Once operational, the 50-megawatt project will encompass 106 acres of public land in Southern Nevada, near Pahrump in Clark and Nye Counties, and help stabilize the electric grid. ARES Nevada will connect to the power western grid via the facilities of Valley Electric Association.

    Utilizing gravity, ARES Nevada will store energy and release it for dispatch when it’s needed. Using a single railroad track sited on a gentle grade, multiple electric locomotive cars can move up the track as they receive excess power from solar and wind power plants during sunny and windy days. The train cars will remain available and, when needed, be dispatched slowly downhill, using their motor-generators to return power to the electricity grid. ARES Nevada will provide a wide range of ancillary services, enabling the grid to adjust to momentary changes in demand and help stabilize grid voltage and frequency.


    So effectively, surplus electricity is used to send electric locomotive cars (usually filled with gravel which isn't affected by evaporation) up a hill on sunny, windy (or in NZ days where hydro wasn't required) days and then parked at the top. When power is required then the cars are sent down the hill and using regenerative braking via the motor to return power back to the grid. You'd have to put it somewhere where pesky humans wouldn't walk on the track or try to cross a bridge when an automated locomotive came up or down a hill and presumably overhead electrification lines. I'm sure there's a few marginal or mothballed railway lines that we could find somewhere to do this to supplement freight (maybe the incline from Canterbury up to Arthurs Pass) - you could even use it say to run coal up the hill from the West Coast to Otira during the early hours of the morning and then run them down to Canterbury during the evening peak which would potentially see a carbon offset from eliminating thermal generation on the transport - imagine the ETS calculation on carbon neutral coal transportation!

  8. #598
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    Quote Originally Posted by Snoopy View Post
    The term 'efficiency' can mean different things in different contexts.

    To go back to thermodynamics basics, the thermal efficiency of any thermal power generation unit is determined by the difference between the maximum temperature that can be withstood inside the power generation unit and the discharge temperature of what becomes the waste energy steam at the end of the power generation process. It is the difference between the heat energy you put in and the heat that comes out that determines the electrical energy that you can ultimately take out of such a process. It may be possible to more easily control the burning of natural gas where you know the chemical make up of what you are burning before it goes into the pipe to arrive on site, verses coal where you may not know exactly what you are burning until it is stoked into the boiler furnace. That means a stoicheometrically controlled natural gas input might be able to burn hotter. But ultimately the other gain in natural gas 'efficiency' is that the chemical composition of the waste plume is less damaging to the environment. I think the power turbine efficiency gains of recent years are more due to material improvements allowing higher temperatures in both the combustion and then the power generation processes. I don't think you can do much about the discharge temperature of a combustion process. That tends to be determined by the environment.

    'Unit 5', the base load power generation unit today at Huntly, already runs wholly and solely on natural gas. It is only the older Rankine units that can be used fill gaps in the power supply when lake levels are low that can run on coal or natural gas.

    SNOOPY
    Hi Snoopy,
    Just to clarify about gas generation
    My understanding is that you have combined cycle and peakers.
    Combined cycle being gas turbine plus steam utilising waste heat so 50% more efficient than the peakers.
    The peakers however reach full efficiency in 10 minutes.
    The older rankine units use a slightly different combined cycle and I would imagine using coal would take some time to operate efficiently.
    The power companies seem to want to use more peakers and less combined cycle.
    To me this may reflect a competitive bidding process rather than making the country more energy efficient.
    In theory hydro could be increased for short periods for peak demand and combined cycle kept continuous generation during times of low inflow.
    I have no expertise in this field-just an interest in energy efficiency.
    Gas is becoming more efficient-https://www.powermag.com/efficiency-improvements-mark-advances-in-gas-turbines/

  9. #599
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    Quote Originally Posted by kiora View Post
    Hows this?
    No power lines?
    https://www.stuff.co.nz/business/gre...mission-cables
    "A Kiwi technology start-up hopes its long-range wireless power transmission system will herald a brighter, cleaner future.

    Emrod has developed a system which converts electricity into electro-magnetic waves that can be sent wirelessly to receivers to be converted back into electricity for use in homes and businesses."
    "If we make sure we don't call it a 'death ray' we might get funding ... then we can TAKE OVER THE WORLD!!!"

  10. #600
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    Quote Originally Posted by ziggy415 View Post
    I read that contact and meridian were going to tip in $5 million each to help fast track the southern transmission lines but at a later date that was put on hold....why I,m not sure......as for huntly on gas sounds good but security of supply will be an issue with no more drilling allowed and also huntly has water temperature issues with regard to discharge back into the waikato river.?..maybe back to meremere and the rubbish boiler to generate electricity
    Meremere closed down. It was falling to bits when I was working there. Every time a panel rusted out or dropped of they would weld on another patch. It was only built to last 20 years but went on for another 20 or so years. I assume most people who worked there when I was there are probably dead by now. Asbestos in the air, every night and every day. What a dump.

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