C02 of one beef dinner in comparison to a flight.

joe sod

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That's 3 kWm⁻² of rotor disc. But then you need spacing between turbines of 10 to15 times the rotor diameter ... which could be more than two kilometres in the case of the GE behemoths!
Thats another thing people dont understand, they think advances in technology can solve everything, unfortunately no advance in technology can create energy out of nothing or harvest energy thats not there in the first place.
 

Purple

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The solution is simply to suspend a doughnut of plasma at 100 million degrees Kelvin in a magnetic containment field (or electrostatically confine it...somehow) and generate nuclear fusion. Nuclear is the only viable form of green energy and fusion is the only version of nuclear which doesn't generate waste and is intrinsically safer than fission in that once the fuel source is removed the reaction stops.
 

joe sod

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The solution is simply to suspend a doughnut of plasma at 100 million degrees Kelvin in a magnetic containment field (or electrostatically confine it...somehow) and generate nuclear fusion. Nuclear is the only viable form of green energy and fusion is the only version of nuclear which doesn't generate waste and is intrinsically safer than fission in that once the fuel source is removed the reaction stops.
in reality fusion exist in theory (sun and stars excluded of course) and no real hard advances have been made in decades. In fact no advances have been made in conventional nuclear energy since the 1980s, the number of nuclear reactors has remained more or less unchanged since 1985. It now only provides 10% of global energy demand , it was alot higher in the 80s so we are going backwards in terms of nuclear energy. All of the brain power and research seems to be on the consumer end of energy and not on the production end. The big car companies and the googles et al are spending billions on research into electic cars, nobody is spending billions on nuclear energy. If everyone migrates to electric cars, where is the power going to come from? There seems to be a suspension of reality that this can be met by renewables and remember as dub_nerd has pointed out the world population has increased by 40% since 1990.
 

Purple

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I agree Joe. It's over 40 years since the American government ordered a nuclear power plant and nearly 25 since one was commissioned.
The technology around small fission reactors is exciting, as is producing hydrogen for fuel cells from nuclear energy.
 

joe sod

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There was a program on BBC 1 last night about a family trying to get their c02 production down to 1 ton each per year. So they reared their own chickens and grew their own vegetables etc etc. It was sort of doable with a lot of effort and they had land in the country. However there came a big dilemma they were invited on a skiing trip to France by friends, they really wanted to go and were all excited and everything. However that one flight to France would blow all their co2 savings for 2 years. So doing everything else does not count in comparison to flying.
Also the clearing of forests in developing countries to grow cash crops is a massive contributor and this is accelerating. We need to concentrate on the really big stuff first.
 
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Purple

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Yeah, renewable energy tends to be fairly diffuse. 1.3 kWm⁻² is not bad for solar, but at 15-22% efficiency and the sun not overhead, you could be easily talking about 0.1 kWm⁻² of land use. Wind turbines can produce a lot of energy per unit area of the rotor disc. General Electric are creating the current largest -- 12 MW with 107 m blades. That's 3 kWm⁻² of rotor disc. But then you need spacing between turbines of 10 to15 times the rotor diameter ... which could be more than two kilometres in the case of the GE behemoths!
Can you explain what the total electricity usage is globally? I see wildly differing figures. The figure of 18.0 terawatt-hours comes up. Is that the correct anual measure?
 

cremeegg

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Can you explain what the total electricity usage is globally?
Amount of energy used is not the meaningful measure.

The grid has to maintain an energy output per hour which is high enough to meet the demand plus any losses, at all times. The maximum output of the Irish electricity generating capacity is just under 8 giga watts AFAIK.

As most power stations cannot be turned on and off at short notice, and wind power which comes and goes based on the wind, the system produces at this level continuously (aside from the pumper storage facility at Turlough Hill).
 

Purple

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Amount of energy used is not the meaningful measure.

The grid has to maintain an energy output per hour which is high enough to meet the demand plus any losses, at all times. The maximum output of the Irish electricity generating capacity is just under 8 giga watts AFAIK.

As most power stations cannot be turned on and off at short notice, and wind power which comes and goes based on the wind, the system produces at this level continuously (aside from the pumper storage facility at Turlough Hill).
My question relates to the proportion of total electrical generation capacity which existing renewables can realistically handle. That is before we account for the massive amount of energy generated in vehicles using internal combustion engines which will, hopefully, one day be replaced by electric cars. Those cars will be powered from the Grid.
 

dub_nerd

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Can you explain what the total electricity usage is globally? I see wildly differing figures. The figure of 18.0 terawatt-hours comes up. Is that the correct anual measure?
No, that figure is off by a factor of a thousand. World electricity consumption is over 20,000 TWh, projected to double in the next 20 years. World total primary energy consumption is over 160,000 TWh, of which half goes to heating and a quarter to transport. Electricity sounds like a smaller fraction but because much electricity generation is from heat engines which are typically 35% efficient, it actually accounts for most of the remaining quarter.

86% of primary energy comes from fossil fuels. 12% comes from nuclear and hydro, neither of which is increasing their market share. Just 2% comes from all other sources. In electricity generation, two thirds comes from fossil fuels, but another quarter from nuclear and hydro, leaving only 6% for all other sources.
 

dub_nerd

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And just to bring it back to the thread topic of beef dinners versus air travel:

Globally, the primary sources of greenhouse gas emissions are energy and transport (74%), agriculture (11%), land use change and forestry (6%), industrial processes (6%), waste (3%).

The three quarters of CO2 from energy and transport break down further as: electricity and heat (31%), manufacturing and construction (12%), transportation (15%), other fuel combustion (8%), fugitive emissions from energy production (5%), bunker fuels, i.e. shipping (2%).

The combustion of fossil fuels spans most of these categories, and accounts for over 90% of human CO2 emissions. Almost 40% is produced by just one particularly carbon-rich fuel -- coal. If you want to see why global CO2 emissions will be rising into the foreseeable future, just follow coal use.

The USA is still by far the biggest emitter of CO2 per capita, but its total output is less than half that of China. North America's coal consumption has dropped by 40% in 15 years (because of the cheapness of natural gas, not any altruism!), while China's has doubled. Consider that India now uses more coal than the US and the EU combined, and China uses five times more than India! And Chinese and Indian consumption are growing at 3% and 5% per annum respectively. Nothing the West does to curb CO2 emissions will be effective in the face of such growth, though there's an argument for making the problem worse as slowly as possible.
 

joe sod

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The USA is still by far the biggest emitter of CO2 per capita, but its total output is less than half that of China. North America's coal consumption has dropped by 40% in 15 years (because of the cheapness of natural gas, not any altruism!), while China's has doubled. Consider that India now uses more coal than the US and the EU combined, and China uses five times more than India! And Chinese and Indian consumption are growing at 3% and 5% per annum respectively. Nothing the West does to curb CO2 emissions will be effective in the face of such growth, though there's an argument for making the problem worse as slowly as possible.
very sobering. I remember hearing about the "fermi paradox" in university back in the 90s, the famous question by acclaimed physicist enrico fermi, paraphrasing,

if there is intelligent life elsewhere in the universe, then why have we not heard from them?

by the law of averages , because of the sheer size of the universe and its supposed existence of billions of years, there should be many more intelligent civilizations elsewhere and further advanced than humans, and therefore we should have heard from them.
One explanation is that civilization gets to a certain level of development, uses all of the resources on its planet but cannot get to the next level and consequently wipes itself out. it looks like thats where we are now?
another sort of ridiculous theory is that there is intelligent life out there but they are choosing to stay silent and leave us alone. That would be like columbus and the spanish knowing about the americas but choosing not to go there and to leave the natives alone, not really plausible.
 

RichInSpirit

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Can CO2 be captured at point of creation, eg. From the chimney of a coal burning power station and recycled.
Convert it into methane and burn it again.
Maybe it is impossible to do ?
 

joe sod

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Can CO2 be captured at point of creation, eg. From the chimney of a coal burning power station and recycled.
Convert it into methane and burn it again.
Maybe it is impossible to do ?
well the reason we burn fossil fuels is to obtain the energy, but carbon dioxide is released. To reverse the process or to create methane requires you input energy back in. That is what plants do, they take carbon dioxide from the air and convert it into carbon compounds and O2, but they need energy to do this which they get from the sun. Unfortunately to create a gallon of petrol requires alot of sunshine and alot of plants , basically petroleum is condensed sunshine that shone for millions of years before mankind even existed.
 
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Laughahalla

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I see people knocking solar PV here. If everyone in this country had solar PV we could substantially reduce our requirements on imported gas and oil.

In my own case , I put in solar PV and my consumption of electricity from the grid will reduce by almost 2/3rds in a full year.

Multiply my example by every house in the country and you will see how small changes will add up. Even if they reduced their electricity use from the grid by 1/3rd or 50% that would be a substantial reduction.

So people can do a number of things including..
1: Reducing their meat and dairy consumption.
2. Take less flights
3. Walk or cycle where possible
4. Use renewables
5. Insulate their homes

Some of these will also have health benefits i.e. walking/cycling/reducing the amount of saturated fat we consume.

The options are not binary. For most people taking less flights is obvious and has been for years. People may not have been aware that the emmisons from animal agriculture is massive so it's good that people are made aware that their choices have effects on climate.
 
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Purple

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I see people knocking solar PV here. If everyone in this country had solar PV we could substantially reduce our requirements on imported gas and oil.

In my own case , I put in solar PV and my consumption of electricity from the grid will reduce by almost 2/3rds in a full year.

Multiply my example by every house in the country and you will see how small changes will add up. Even if they reduced their electricity use from the grid by 1/3rd or 50% that would be a substantial reduction.

So people can do a number of things including..
1: Reducing their meat and dairy consumption.
2. Take less flights
3. Walk or cycle where possible
4. Use renewables
5. Insulate their homes

Some of these will also have health benefits i.e. walking/cycling/reducing the amount of saturated fat we consume.

The options are not binary. For most people taking less flights is obvious and has been for years. People may not have been aware that the emmisons from animal agriculture is massive so it's good that people are made aware that their choices have effects on climate.
All true but in reality it all makes very little overall difference. The statistics for emissions from beef production are wrong in that they are calculated based on feedlot production rather than grass fed beef. Removing antibiotics from beef would greatly reduce their net CO2 emissions as their manure would then attract far more soil aerating insects which in turn increases plant growth and biodiversity.
 

dub_nerd

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When I look at the proportion of my electricity bill that is standing charges and levies, knocking off a third of the basic electricity unit cost wouldn't be worth it. I reckon payback time for a solar PV installation would be thirty years, even without taking the cost of money into consideration. You also have to consider the effect if large numbers of people installed PV. Unless you go totally off grid the electricity network operator still has to provide all the same infrastructure, but spread over a smaller revenue base. We would get the same situation as in the southwestern USA, where some utilities have gone from paying feed-in tariffs to domestic solar PV producers to charging for low grid usage.
 

joe sod

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meanwhile for all the talk of electric cars and reducing plastics etc etc, global oil demand continues to rise uninterrupted it is now at 100 million barrels per day, it barely dipped in 2009 at the height of the recession. Therefore the statistic of world oil demand makes a laughing stock of our so called efforts to "decarbonise".
Maybe donald trump with his sabre rattling with iran could cut the oil coming out of the middle east drastically like what happened in the 1970s.
 

Betsy Og

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One thing re electric cars, I think the theory is you'd be incentivised to charge at night, and even add to the grid on arrival home (peak demand). The thing with generation being you need to meet peak demand, but a lot of the rest of the time there's spare capacity, so cars could act like a national battery stock. I'm wondering will we run out of lithium, but the likes of Trinners may develop the tech to solve that. China & India though..., while we should do the right things, one suspects are are urinating against the prevailing air movement.
 

Purple

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One thing re electric cars, I think the theory is you'd be incentivised to charge at night, and even add to the grid on arrival home (peak demand). The thing with generation being you need to meet peak demand, but a lot of the rest of the time there's spare capacity, so cars could act like a national battery stock. I'm wondering will we run out of lithium, but the likes of Trinners may develop the tech to solve that. China & India though..., while we should do the right things, one suspects are are urinating against the prevailing air movement.
Who are Trinners?
 

john luc

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How do you know when a student goes to trinity college instead of another college, they tell you.
 
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