Solar will soon be cheaper than coal fueled power

[NobleSavage]

Work out the numbers. 2000 food calories a day is about 100 watts.

Dumb question, but don't you need a unit of time for the watts? A hard cardio day for me is ~200 watts for an hour, that doesn't burn 2000 calories.

 

[Sarpedon]

I recall there is a train station in Stockholm that harnesses the body heat of all the people who pass through it to warm nearby buildings.

On any human powered energy scheme, there's the problem that there won't be enough energy in one place to justify installing the equipment. But places where there is a constant, predictable, large amount of people, like a train station, can make more sense.

Another scheme I've heard is to install generators in the floor, that would be powered by people walking across it. The numbers never really work out.

 

[Derec]

Work out the numbers. 2000 food calories a day is about 100 watts.

Dumb question, but don't you need a unit of time for the watts? A hard cardio day for me is ~200 watts for an hour, that doesn't burn 2000 calories.

He said "a day". That's your time reference. There are 86,400 seconds in a day, so 100 W*86,400 s=8.64 MJ=2065 kcal so his math works out. However a human body burning 2000 kcal a day would generate an average of 100 W of heat, but that doesn't translate into muscles doing 100 W of work moving exercise equipment. Still, all that work is expanded anyway.

 

[Derec]

As far as grid power is concerned, molten salt could provide the energy storage requirements necessary for turning solar and wind into a base load power supply.

Molten salt stores heat, not electricity. To convert this heat to electricity you need some sort of heat engine. Thus it is only usable for large solar thermal setups. You also need huge tanks to reduce heat loss (the one in the example is ~4100 m³. But the biggest advantage of photovoltaics is that it can be used on a small scale and distributed, rather than huge and concentrated.

But if you combine heat engine efficiency (Carnot (ideal) cycle efficiency with the temperatures given on the wiki page is only 33% - real life efficiency would be significantly less), heat losses from storage and other sources of loss (including power transmission from remote plants to customers) I would doubt very much that the overall efficiency is better than PV + flow battery, even given low efficiency of PV.

 

[Loren Pechtel]

Yup. Battery economics stink.

Lets look at those numbers a bit: 1000 lifetime cycles. 10¢ of electricity needs $100 of battery to store it--that's 1000x. Thus the battery alone costs you 10¢ per kwh even if you didn't have to pay anything for the power you are using to charge it.


In practice solar can cut the fuel used by oil and gas plants and it's good for industrial situations where they can run the machinery when the sun shines. Beyond that it makes no sense other than for off-grid use.

There is nothing wrong with using solar power to reduce the daytime/summertime peaks in demand for air-conditioning and refrigeration in warm and hot climates. It also makes sense, even in temperate climates, to supplement the heating of water for domestic use with direct solar heating - in the topics and sub-tropics this can almost completely eliminate the demand for electricity or gas to generate domestic hot water; An insulated tank can keep the water sufficiently hot overnight to make this a good option.

For solar hot water I agree--it seems to me to be just about a no-brainer in any area where you can use a primary loop through the collectors. My parents home had solar hot water, it worked well. Note, though, that once frost become a threat on winter nights the economics change--you need more complex and less efficient systems to ensure the collector isn't shattered by freezing some winter night. (While there was a very slight frost threat where they lived it was so minor that it was addressed by an additional sensor on the collector that would report they were boiling hot if it hit 36 degrees. The pump would come on for a little bit, warming the collector with tank water.)

We live in such a climate--plenty of summer sun but winter frosts are enough to rule out primary loops--and I have never seen a solar hot water system here. (We do, however, have a lot of solar pool heaters--as they are not part of a pressurized loop you simply don't pump water through them when it's cold and they're not going to blow up.)

In the long term, I can foresee HVDC intercontinental links, allowing solar power from the daylight side of the planet to be supplied to the nighttime side; this seems like it is going to be a cheaper option than local battery storage, although either is likely to be pretty expensive.

That might be possible in the old world. Here they would have to span major oceans.

In the meantime, using nuclear fission to fill the gap is a no-brainer. Sadly, the people influencing the decisions seem determined to use no brains; they see the very small, localised risks of a fairly unpleasant nuclear accident as outweighing the massive non-accidental global disaster that they unwittingly support every time they oppose the expansion of nuclear fission.

By lobbying against nuclear power, the environmentalist movement have placed themselves amongst the most effective supporters of continued burning of coal on the planet. It would be hilarious if I didn't live here.

Agreed. Fission is by far the greenest answer we have.

 

[Loren Pechtel]

Batteries will improve and lithium-ion is not necessarily best fit for storing electricity at night.
Lithium-Ion has high energy density which is what needed for cars and other cases where weight is a factor.
Weight is not a factor for night storage.
Nukes are baseload therefore are not mutually exclusive with solar which coincides with demand (A/C and such) rather well.
People advocating nukes forget that nukes are very long term projects, if you build one now be prepared to live with it for the next 30 years, and chances are, in 10-15 years we will have very decent storage for solar electricity and nukes would have to be expensively shutdown.

There's no battery on the horizon that's suitable.

As for solar + nuke: What happens when the sun goes behind a cloud? Unless you give the utility company a way to shut off everybody's ACs when the sun goes behind the cloud the solar adds very little to the system. The nuke plant can't throttle up/down quickly enough to meet the demand, thus it's going to have to be throttled up to meet the load anyway and the solar adds almost nothing.

- - - Updated - - -

As far as grid power is concerned, molten salt could provide the energy storage requirements necessary for turning solar and wind into a base load power supply.

As far as residential electricity is concerned, the potential for independent power generation and storage is exciting news.

We might see viable solar-thermal systems from molten salt. It's not useful for photovoltaic systems. Note that the efficiency of such systems is going to be abysmal, you'll need huge collector areas.

 

[SimpleDon]

There a company here selling 1000 watt starter solar kits for a little over $1800. Four panels, each with built in inverters, and mounting hardware. Easily expandable, just add another panel and plug it into the already installed panel array. You'd still have to pay for the wiring to your home wiring and grounding system.

I have seven panels now on my roof averaging about 220 watts each. Because of the orientation of my house they are pointed southeast (~148°) which means that they have a morning bias, they produce peak power from the morning to the middle of the afternoon. I have a great roof 90° from that one to generate in the afternoon but It is above my side entry garage but Mrs. SimpleDon doesn't want to have panels visible from the street.

I originally had individual inverters on my first two panels. One failed and since then I have cabled the unregulated DC to two larger invertors in the closet in my garage. There are pros and cons to each method but if you want batteries then you want to avoid the dual losses of DC to AC at the panels and then AC to DC at the batteries. Also the temperatures on the roof can reach 40° C in the summer. The garage closet never gets above 30°. The inverters are rated for 45°. Lower is better. The panels are rated for 60 to 85°, why use inverters rated at only 45°? Like everything you get what you pay for, you can buy better inverters, more efficient and rated for higher temperatures but most likely you won't. When I installed the first panels myself I bought directly from China the cheaper components, since I have had to pay to install them I tend to buy better quality. But most installers that have to bid competitively will bid with lower quality components.

 

[Togo]

As for solar + nuke: What happens when the sun goes behind a cloud?

Very little. Solar is viable here in the UK, where the sky is covered in clouds from horizon to horizon, for most of the year.

Unless you give the utility company a way to shut off everybody's ACs when the sun goes behind the cloud the solar adds very little to the system. The nuke plant can't throttle up/down quickly enough to meet the demand, thus it's going to have to be throttled up to meet the load anyway and the solar adds almost nothing.

Why not have extra solar rather than extra nuclear, since it throttles better? And what does the nuclear solution do when demand changes, as it tends to every minute of every day?

 

[Derec]

There's no battery on the horizon that's suitable.

I think flow batteries are promising.

 

[SimpleDon]

Batteries will improve and lithium-ion is not necessarily best fit for storing electricity at night.
Lithium-Ion has high energy density which is what needed for cars and other cases where weight is a factor.
Weight is not a factor for night storage.
Nukes are baseload therefore are not mutually exclusive with solar which coincides with demand (A/C and such) rather well.
People advocating nukes forget that nukes are very long term projects, if you build one now be prepared to live with it for the next 30 years, and chances are, in 10-15 years we will have very decent storage for solar electricity and nukes would have to be expensively shutdown.

No, I don't think that we will have decent storage options in 10 to 15 years. If you can't name the technology it probably can't be in widespread use in 10 to 15 years.

Look at the Tesla battery. I told you that they were most probably shooting for a cost of production of $100 a kWh, down from say $250 today for the LiFePO4 batteries, the best in production and use now. We don't know if they can do it.

Also, I didn't include a section that I wrote, because my posts are longer than most people are willing to read already. In it I pointed out even if Tesla could reduce that $250 number by ten times the battery technology would still be too expensive. A change of this magnitude in 10 to 15 years is utterly impossible. The 2.5 times reduction that they are trying to get now is most probably wishful thinking.

I don't know what technology you are thinking about when you say lithium ion batteries. All of the lithium battery technologies are lithium ion batteries. I agree that most aren't suitable for stationary, deep discharge service. But this is true of any battery technology out there, lead acid, nickel cadmium, etc.

But in the category of deep discharge batteries the lithium ion technology of the LiFePO4 battery is about the best that we have currently in production, whether for a vehicle or a stationary application. The fact that it has a high energy to weight and volume ratio is less of an advantage in stationary applications but it is still an advantage. They take up less room for example.

Compared to lithium cobalt or lithium polymer the LiFePO4 battery maintains its voltage better through the full discharge cycle,d allows for quicker charging and has a longer life. They require more sophisticated controlled charging but this easily accomplished with smarter chargers. They don't require the thin noble metal cathode wires that cause the fires.

 

[ZiprHead]

Batteries will improve and lithium-ion is not necessarily best fit for storing electricity at night.
Lithium-Ion has high energy density which is what needed for cars and other cases where weight is a factor.
Weight is not a factor for night storage.
Nukes are baseload therefore are not mutually exclusive with solar which coincides with demand (A/C and such) rather well.
People advocating nukes forget that nukes are very long term projects, if you build one now be prepared to live with it for the next 30 years, and chances are, in 10-15 years we will have very decent storage for solar electricity and nukes would have to be expensively shutdown.

"The energy put into mining, processing, and shipping uranium, plant construction, operation, and decommissioning is roughly equal to the energy a nuclear plant can produce in its lifetime. In other words, nuclear energy does not add any net energy."

http://www.globalresearch.ca/germany-ending-nuclear-power-has-contributed-to-reducing-carbon-dioxide-co2/5329583

 

[RVonse]

Forget batteries. Batteries suck and they will always suck. The future for our energy is flywheel storage and solar/wind: http://en.wikipedia.org/wiki/Flywheel_energy_storage

Flywheel storage lasts forever. It is something we can learn to mass produce cheap.

 

[SimpleDon]

The unpalatable (for many) truth is that nuclear power is still the best option for cutting CO2 emissions in the long term.

We should be researching newer, safer reactor designs such as thorium and pebble bed. However government funds that could be directed at these projects are currently being frittered away on solar and wind subsidies.

I agree. But there is another factor discouraging research into fusion which produces its own fuel, alternative fuels like thorium and even uranium based fission reactors like molten metal that burn more than the 2% of the fuel that the current fuel rod, water reactor designs burn. We have an entrenched, politically powerful commercial uranium fuel industry that opposes all of the alternatives because it will cost them money.

This is an example of an industry that is not well suited to being a private for profit business for this reason.

 

[Bomb#20]

"The energy put into mining, processing, and shipping uranium, plant construction, operation, and decommissioning is roughly equal to the energy a nuclear plant can produce in its lifetime. In other words, nuclear energy does not add any net energy."

It would add net energy if government regulatory agencies didn't order nuclear reactor operators to throw away their fuel rods as soon as the rods' remaining uranium content drops to 99.28% of its original level.

 

[ZiprHead]

"The energy put into mining, processing, and shipping uranium, plant construction, operation, and decommissioning is roughly equal to the energy a nuclear plant can produce in its lifetime. In other words, nuclear energy does not add any net energy."

It would add net energy if government regulatory agencies didn't order nuclear reactor operators to throw away their fuel rods as soon as the rods' remaining uranium content drops to 99.28% of its original level.

Citation?

 

[Bomb#20]

It would add net energy if government regulatory agencies didn't order nuclear reactor operators to throw away their fuel rods as soon as the rods' remaining uranium content drops to 99.28% of its original level.

Citation?

That's the fraction of U-238 in natural uranium. I was sarcastically complaining about the government policies that have locked nuclear power generation into conventional reactors, which use only the U-235 that makes up 0.72% of natural uranium, even though we've known how to build breeder reactors for seventy years.

 

[bilby]

Work out the numbers. 2000 food calories a day is about 100 watts.

Dumb question, but don't you need a unit of time for the watts? A hard cardio day for me is ~200 watts for an hour, that doesn't burn 2000 calories.

Mixing SI units such as the Watt with weird American units such as the 'food calorie' (aka Calorie, not to be mistaken for the calorie - one Calorie = 1,000 calories, so no confusion there) is completely bizarre.

But not as bizarre as not recognising the 'day' as a unit of time.

 

[Juma]

Yeah, that's what they said 30 years ago too.

I don't recall them saying that 30 years ago.

I do. When sweden voted about nuclear power....

 

[bilby]

Batteries will improve and lithium-ion is not necessarily best fit for storing electricity at night.
Lithium-Ion has high energy density which is what needed for cars and other cases where weight is a factor.
Weight is not a factor for night storage.
Nukes are baseload therefore are not mutually exclusive with solar which coincides with demand (A/C and such) rather well.
People advocating nukes forget that nukes are very long term projects, if you build one now be prepared to live with it for the next 30 years, and chances are, in 10-15 years we will have very decent storage for solar electricity and nukes would have to be expensively shutdown.

"The energy put into mining, processing, and shipping uranium, plant construction, operation, and decommissioning is roughly equal to the energy a nuclear plant can produce in its lifetime. In other words, nuclear energy does not add any net energy."

http://www.globalresearch.ca/germany-ending-nuclear-power-has-contributed-to-reducing-carbon-dioxide-co2/5329583

Wow.

That has to be just about the stupidest thing I have ever read.

And I have read a LOT. Most of it very stupid indeed.

Shit, I have even read British tabloid newspapers.

Wow.

 

[beero1000]

"The energy put into mining, processing, and shipping uranium, plant construction, operation, and decommissioning is roughly equal to the energy a nuclear plant can produce in its lifetime. In other words, nuclear energy does not add any net energy."

http://www.globalresearch.ca/german...ibuted-to-reducing-carbon-dioxide-co2/5329583

Wow.

That has to be just about the stupidest thing I have ever read.

And I have read a LOT. Most of it very stupid indeed.

Shit, I have even read British tabloid newspapers.

Wow.

Lol.



10 kg of atomic fuel.



140,000 kg of atomic fuel.