Why the fascination with intermittent renewable energy sources?

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Summary
To me, intermittent sources of energy don't make sense in any large portion of grid power.
Maybe I’m missing something, and this thread is to at least try to drill down into this to help me understand what that something might be…

Basically I do not understand the almost cult like fascination with intermittent renewable energy for utility scale electricity production. My current opinion on this is that it is entirely a waste of critical time and resources as I can’t see how it makes any sense to pursue this as a long term energy solution.

While I understand that market forces, subsidies etc drive a lot of decisions, often in counter intuitive ways, I’d like to step back from that and look at the what to me are basics or fundamentals of the problem we need to solve, delivering reliable electricity.

To keep the numbers simple, your goal is to deliver 1kW continuously 24hrs a day (I know actual grid load changes over a day) eg California average daily grid load changes from 20GW to 26GW (2014 numbers, https://www.nrdc.org/experts/sierra-martinez/new-and-improved-electric-grid-california). How would you do it?

Then you are an isolated system, ie you cannot rely on someone else to generate for you while you have no power, IMO it’s easy to hand wave away the storage problem (and importantly its associated cost), but this problem comes back once you get sufficient proportion of intermittent sources.

This link is source for overnight capital number (pg 7) https://www.eia.gov/analysis/studies/powerplants/capitalcost/pdf/capcost_assumption.pdf

Note I am assuming overnight capital is per name plate rating, and does NOT consider capacity factor.

Example 1) Delivering this 1kW with nat gas, lets pick something cool sounding Advance Natural Gas Combined Cycle:

Overnight capital =$1100/kw
Fixed O&M $10/kw-yr (Going to ignore variable O&M since it’s such a small number $2/MWh)
So lets assume you want some redundancy, so you build two 1kw turbines total cost:
$2200 capex, $20/kw-yr O&M
Conclusion: Cheap but makes CO2, basically 100% reliable power.

Example 2) Advanced nuclear:

Overnight capital 6000/kW (although I’ve seen projections as low as 4k/kw for SMR)
Fixed O&M $100/kw-yr
Since nuke plants have very high capacity factors and only really shut down for maint/refuel lets place an Advanced Combustion Turbine next to it as backup during this downtime (+700 capex):
Capex total $4700-$6700, $105/kw-yr O&M
Conclusion: Cost effective, no CO2, basically 100% reliable power.

Now for the fun…

Example 3) Solar PV.

This is where the comparisons need more math. Let’s say you live in a nice sunny place (ie ideal for solar PV), you get 8hrs of good sun a day. So in that 8hrs you must generate your days’ worth of power. So your total required capacity is 24kWhrs/8hrs = 3kW. So you need to install at least 3kW solar PV.

Required capex = $7800, O&M = $70/kw-yr
But that’s not the killer.
You also need to store 16kWhrs.
In that eia link, they list BES (battery electric storage) at $2800/kw, with $40 O&M. I’m going to assume that is $2800 per kw/hr of capacity (please correct if wrong, li ion battery cost is about $200/kwhr, then you need the power electronics, 2800/kwhr feels expensive).
Another example: Tesla 100MWhr battery cost about $90 million, this puts it about $1.1 per W/hr, or $1100/kwhr
Capex for storage = $22000-44800, O&M = $640/kw-yr

Total to deliver 1kW 24hrs a day is:
Capex = $30000-52600
O&M = 710/kw-yr
Conclusion: Outrageously expensive, and with only 16kWhr of storage and 3kW of panel you have no way to handle a cloudy day.



Example 4) Mixed wind and solar:

50/50 mix average generation wind solar, now this is where actual conditions have huge impact and I making some big assumptions.
Lets say this mixing of renewables allows you knock your storage requirements in half. I have no idea if this is reasonable or not!
So you install 1.5kW of solar (total 12kWhrs generated) and 2kW wind at 30% capacity factor (14.4kWhrs)
Total capex = 1.5*2600=$3900(solar), 2*1900=$3800 (wind) total = $7700
8Kwhrs storage = $8800-22400
Total = $17000-30100
Conclusion: Still very expensive, and with only 8kWhr of storage you have no power on a windless night.


So given that just to generate your required 24kWhrs per day, solar is already 1.5-2x capex vs adv nuclear just for generating capacity why are we doing this? It makes no sense to me.

Then to sell solar and wind as being cost effective due to capex per kw name plate rating is at best an oversight, at worst basically fraud.

Labeling plants that deliver consistent power 24hrs a day as “inflexible” and therefore bad is obnoxious, our power needs are steady and “inflexible”, these inflexible sources should be preferred, and the intermittent sources shunned unless they include the cost of 24hr power delivery, not including storage just punts the problem to someone else.

Grid scale battery electric storage for renewable to me is utterly insane, to support California grid for 1 hr with Li ion (Tesla) you need 200 of those "worlds biggest battery", that only gets you one hour of hold up for one state in the US, how much lithium is there on this planet? Power plants that can deliver the required power with NO storage should be the goal.

My current position is that looking at it with the above in mind the only sensible thing is 100% nuclear, give the rivers back, take down the wind farms, take down the solar arrays. Why dam a river when you can fit 300MW capacity in the basement of an average building?

What am I missing?
 
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PhanthomJay

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That’s an impressive set of figures you have put together, although I haven’t focused on them. I felt the same way decades ago about wind and solar power generation. But that’s when wind turbines were putting out a mere 50 kW of intermittent power and solar was powering just a few lighting poles.
Today, some wind farms generate over 600 MW , solar is on the serious move, along with battery storage, and hydropower generates huge amounts of power at the large dams.
That fact of the matter is that in the US , nuclear fission power died in the 1980s, and will likely never be resurrected due to safety issues, unworkable evacuation plans, and fierce opposition. Fusion power? Talk to me in 30 years.
With the focus on the environment and climate change and its introduction to students at a very early age, the fossil fuels like oil and coal are disappearing. Natural Gas is stilll holding its own so far, but not for very long I suspect. The large Percentage of new energy generation in the next five years will, in my region, come from Renewables. They are here to stay.
 
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What am I missing?
Sentiment:wink:

Your numbers are ~ correct in any technical sense: but by any practical sense the costs are assigned as the law says, so what you get (in Europe/Germany) is that wind is cheap, and nuclear must be eliminated to make room to wind.
End user costs are irrelevant: what matters is the occasional negative price on the market, since that's what you can sell as marketing.
 
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@PhanthomJay
I guess that's my issue, solar wind and batteries do work in principle, and its a nice feel good thing you can imagine building for your own house for example. But scale that up from a few kwhrs to TWhrs on a global scale? Pipe dream.

Eg

Summary: if we scale production up as intended for electric cars/renewable storage etc, li ion batteries everywhere, we'd run out of lithium in a few decades...
 

anorlunda

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I believe that it is a subset of the "silver bullet" phenomenon. People are very fond of the idea that some technical silver bullet will alleviate all of our problems without requiring any life style sacrifices on their part.

You are correct that subsidies seriously distort the reality, however:
  • Cleaner energy seems to be a mandate people will support. Cleaner energy costs more. Subsidies are one way to finance some of those costs, even if they need to be permanent.
  • The trends are such that even sober energy analysts say that wind and solar should contribute substantially to our mix, even if the subsidies were to stop. Improvements in solar and wind follow an expotential curve comparable to Moore's Law in the digital world.
 
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I believe that it is a subset of the "silver bullet" phenomenon. People are very fond of the idea that some technical silver bullet will alleviate all of our problems without requiring any life style sacrifices on their part.

You are correct that subsidies seriously distort the reality, however:
  • Cleaner energy seems to be a mandate people will support. Cleaner energy costs more. Subsidies are one way to finance some of those costs, even if they need to be permanent.
  • The trends are such that even sober energy analysts say that wind and solar should contribute substantially to our mix, even if the subsidies were to stop. Improvements in solar and wind follow an expotential curve comparable to Moore's Law in the digital world.
There is a magic silver* bullet, advanced nuclear! No lifestyle changes needed. :-p

I completely agree on clean energy, its just that to me this includes nuclear. Keep in mind there is no such thing as completely "clean" energy, they all cause some sort of environmental degradation, IMO modern nukes cause the least damage.

I disagree that energy harvesting systems can follow Moores law, they may follow it for some technical metrics but fundamentally a solar PV panel for example will never exceed about 1300W/m2 unless you move the sun closer (which will create no shortage of other issues).

*not actually magic, or silver.
 

f95toli

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One problem with that analysis is that no energy source is running 24/7 365 days per year. Most power plants are designed to be turned on/off (or at least throttled) depending on the load and even nuclear power plants require maintenance shutdowns every now and then; the amount of power needed in a given region tends to vary a LOT; both of over a 24 hour cycle and over a year.
The best way around this is to have a good mix of energy sources and a well functioning grid which can shuttle power around to wherever it is needed.

Also, nuclear power is very, very expensive (Hinkley Point C which is currently being built will cost over £20B) and currently it is not profitable without significant government subsidies (which typically come in the form of guaranteed prices); the UK government has been trying to persuade the private sector to build several new reactors but haven't had much luck. At least in the UK we are now at a point where wind is very competitive and certainty often way cheaper than the guaranteed energy prices the government has had to offer companies to get them interested (the strike price for Hinkley C is £92.50/MWh; off shore wind around £60MWh).
 

anorlunda

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I look at it as a former power system planner and grid operator. I say bring it on; every form of power production/storage/delivery that investors are willing to build. It is conceivable that we might get too much of one kind, but it is more likely that before we reach that point that things change again. There are few regrets to having more resources of all types.

The key point is that it is not the public, not the utilities, not the government, not the tech companies, that determine the future mix; it is private investors. Even publicly owned facilities depend on selling bonds to private investors. Private investors have no obligations to invest in power infrastructure at all. They are free to invest in .com companies or CBD oil instead.

From the investor's point of view, the most significant negative event in the history of the power industry was not any blackout, not a nuclear meltdown, not any law or regulation, but rather the Whoops disaster from 1982. That bell can never be un-rung.

 
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One problem with that analysis is that no energy source is running 24/7 365 days per year. Most power plants are designed to be turned on/off (or at least throttled) depending on the load and even nuclear power plants require maintenance shutdowns every now and then; the amount of power needed in a given region tends to vary a LOT; both of over a 24 hour cycle and over a year.
The best way around this is to have a good mix of energy sources and a well functioning grid which can shuttle power around to wherever it is needed.

Also, nuclear power is very, very expensive (Hinkley Point C which is currently being built will cost over £20B) and currently it is not profitable without significant government subsidies (which typically come in the form of guaranteed prices); the UK government has been trying to persuade the private sector to build several new reactors but haven't had much luck. At least in the UK we are now at a point where wind is very competitive and certainty often way cheaper than the guaranteed energy prices the government has had to offer companies to get them interested (the strike price for Hinkley C is £92.50/MWh; off shore wind around £60MWh).
IMO its a little disingenuous to just say its expensive because it cost 20B pound. What does that 20B pound buy you? And why is it so expensive?

Hinkley C contains 2 3rd gen PWR reactors (still disappointed they didn't go with the GE PRISM), and is rated at 3200MWe. To be able to compare that capacity with other sources, you might want to work out how much it costs to deliver a similar amount of power with other methods. Today 1GBP buys you about 1.22USD, so that 20B GBP = ~24B USD. This works out to 24e9/3.2e9 = 7200 $/kw over night capital.

Based on the over night cap for solar, assuming you get 8 hrs of sun in the UK (lol) this is basically the same as it would cost to build equivalent in solar. So actually not expensive if you are ok with the cost of solar, keeping in mind you have no way to make the solar give you power at night, where as Hinkley C would quite happily deliver that 3.2GW at night, or on a windless day.

Then Hinkley C is made of two 1.6GW PWR reactors.

Economies of scale are a thing, as I'm sure you'd agree.

Any time we build a one off custom something its expensive, over runs budgets and typically doesn't work right on the first shot. For example in my world a prototype Al heatsink costs about 8k when we make one with a CNC machine, that drops to about $100 a piece off a soft tool, and that drops to about $3.7 each (345g Al) once at full manufacturing volume (1+Mpcs/yr). Hinkley C (and most hydro) are in the CNC machined price territory. Wind is likely at the soft tool level (ie we are mass producing them, but not in the millions per year), solar is at the full production volume level.

GW scale reactors require huge forgings for the reactor vessels, not many people can do that globally. You can achieve 1.6GW with one large reactor, or for example, 6 Nuscale/Terrestrial energy SMR reactors (~300MWe ea). So now you have more smaller forgings, which are much easier to make, and you are now moving from custom one off, to making 12 of them (to get you total 3.2GWe), this is already big difference.

Secondly is redundancy, if one reactor shuts down at hinkley you loose 1.6GW (or 50% of the plant capacity), which would be hard to replace temporarily, vs SMR where you shut one down for service, and you drop 300MW, or 8% plant capacity, probably won't even notice that on the grid.

So to me, single large one off anythings don't make sense for power generation regardless of technology.

We need to mass produce, hence to me the nuclear solution is not "traditional nuclear", but "advanced modular nuclear", ie lets not build any more 3rd gen reactors, we need to build 4th gen SMR that can burn our existing waste stock pile and be factory built. If we do that, solar and wind don't have a leg to stand on IMO.
 

f95toli

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A few points
*I just mentioned the cost of Hinkley to illustrate that nuclear is in no way a "cheap" way to generate electricity; it requires massive investments. Ultimately, it is the wholesale cost of electricity that matters and right now it looks like the price of electricity from Hinkley is going to be significantly higher than the cost from wind; we know this since we know the strike price the government had to agree with EDF to convince them to build the power plant. The only way the way this is going to change is if the price of power from alternative sources went up which is highly unlikely.

*The UK government and (as well as governments from a number of other countries have spent the past few years) trying to convince industry to build new reactors without much success. I am sure it is possible to make improvements to reactor designs etc that would reduce the price; but so far no one seems to think that you can actually make a profit doing so.

*No one has argued that large scale solar is necessarily a good idea in the UK; it has its place in the mix and as the price of PVs drops they will become more common on the roof of building.
However, what the UK does have is wind and lots of it...and it works 24/7.

Hence. when people talk about alternative energy in the UK (and in most of northern Europe) we are mostly talking about wind power; not solar. The situation is obviously very different in e.g. southern Europe where solar works well; or in countries where you have a large amount of hydroelectric power.
 
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Interesting article relevant to this:
 
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Ran across this on the you tubes, I am not alone!

 

sophiecentaur

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To keep the numbers simple, your goal is to deliver 1kW continuously 24hrs a day
In fact, this simple goal does not necessarily apply. There are many uses for electrical power that do not actually need to be continuous. Rather than using energy storage, the actual usage of energy can be resticted to when it's available. By having a high enough peak capacity manufacturing facility, the annual rate of production can be as high as required if the product itself can be stored. We take for granted that sunlight is only available for less than 12hrs per day for farming but we just accept that and enough food can easily be produced with a system that's only 'on' for half the time.
I remember a recent thread on PF about a proposed system using wind or solar (I can't remember which) to charge batteries for running a continuous water pump system. In many or even most cases, it's possible to store water, output from mechanical wind pumps, cuttting out the Electrical part of the energy chain completely. Just changing the basic approach can eliminate the perceived problems of irregular supply.
We use far too much energy for heating and air con in the so called 'advanced' countries. There is actually very little need for large amounts of heating load from the Grid where houses are designed or even converted appropriately.
My comments only apply to a proportion of our energy (perceived) needs but that proportion could actually be massive. Solar, wind and tidal sources do not peak at the same times over the year and the gaps in availability tend follow a multiplicative probability law, rather than an additive law.
There are many vested interests in keeping the status quo in the Energy industry and all surveys on that industry need to be read in that context.
Bottom line is that the best solution, in many ways, would be just to REDUCE energy use. That's an awkward fact to deal with in a culture for which the concept of GROWTH is regarded as essential but this may need to be the way forward.
 

anorlunda

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Bottom line is that the best solution, in many ways, would be just to REDUCE energy use.
I agree. In fact, the first step in every renewable energy product should be to reduce demand.

Alas, it sometimes seems that many people are eager to be green if it means writing a (reasonably small) check. But don't ask them to change their lifestyle or standard of living.

An exception to that seems to be sweeping Europe this year. I am thinking about public shaming of people who use airplane travel.
 

sophiecentaur

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I agree. In fact, the first step in every renewable energy product should be to reduce demand.

IMO the want/need for sustainability, reduction of energy use etc and renewable energy production are intrinsically linked. I think this is because either consciously or subconsciously people realize renewable cannot meet what we do today or what we could be doing in the future, so the only way renewables are even remotely plausible is if its combined with reducing our consumption, and what we do consume must be at the whim of the intermittent sources.

The problem is that this is just not realistic. Even if the energy hungry populations reduced they usage by 50%, all the populations in the developing countries that presumably want to increase their quality of life means that no way around it we need to not just replace our current energy generation, we need to double or triple it at minimum. You have to remember we are not just replacing electricity production, we want to use electricity to power all our heat sources, all our transportation etc because those are all causing carbon emissions. For example in Canada, per capita average electricity consumption is ~1700W, however total energy consumption per capita is nearly 10kW.

To me it just doesn't make sense to advocate a solution that is very expensive, forces us to take a massive hit in how we live, all for what?

Why would we not just continue advancing? Embrace the ultimate prime mover (nuclear), master it, and head for the stars?
 

Svein

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Anybody remember this stanza from Kiplings "Road Song of the Bandar-log":

Here we sit in a branchy row,
Thinking of beautiful things we know;
Dreaming of deeds that we mean to do,
All complete, in a minute or two --
Something noble and grand and good,
Won by merely wishing we could.
 

anorlunda

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[Edit, missing quote added.]
Why would we not just continue advancing? Embrace the ultimate prime mover (nuclear), master it, and head for the stars?
If you look at PF archives about home solar/wind projects, they almost always begin with the requirement of producing at least as much energy and power as they already consume. Very few begin by reducing their own demand.


In fact, continuing to advance, both in energy consumption and in population, leads to the SF planet Trantor. If I remember right, Trantor glowed cherry red as seen from space. The 40 billion people lived below ground in air conditioned comfort.

I do have to admire your persistence in advocating for nuclear power. I too like nuclear. But I am not optimistic about nuclear's comeback chances in this century.

The root cause, global population, is almost never discussed. I do not advocate conservation as much as I do population reduction. That famous "hockey stick" turned upward when Earth's population was about 1 billion so 1 billion makes a first guess for the sustainable population.

To emphasize, let me exaggerate a bit. How many Earth environment or resource problems would we have if the global population of humans had been capped at 7 million instead of 7 billion? The 7 million could live as lavishly as they please and not have a significant impact. To me that proves the point that population is the root cause, and the only viable solution.

Unfortunately, population is considered off-topic in energy threads.
 

phyzguy

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My current position is that looking at it with the above in mind the only sensible thing is 100% nuclear, give the rivers back, take down the wind farms, take down the solar arrays. Why dam a river when you can fit 300MW capacity in the basement of an average building?

What am I missing?
I agree completely. You're missing nothing. It's all very sad when you think about what might be. Let me know when you convince people that this is the way to go. While you're working on that, I'd rather have expensive power from intermittent sources than sit around shivering in the dark.
 
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The problem is we're burning money on a solution that wont solve the problem, and by money I really mean resources. Germany is a great example of how absurd/futile this is.

Germany currently has an installed capacity of 200GW (2017 numbers from: https://en.wikipedia.org/wiki/Electricity_sector_in_Germany)

It expects to have spent 1.4T EUR (thats 1.8T USD) to achieve 30-50% renewable (they give target of 30% in 2020, unfortunately the year they give the dollar value for does not have a renewable target. source: https://en.wikipedia.org/wiki/Renewable_energy_in_Germany)

If they spent that 1.8T USD on advanced nuclear at $4k per KW, that 1.8trillion dollars gets you an installed capacity of 450GW. Thats more than twice their current capacity, 100% carbon free, 100% stable, they would be well on the way to having 100% carbon free transportation energy. I mean you could justify hydrogen production at that point.

Instead they have this:

 
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I do have to admire your persistence in advocating for nuclear power. I too like nuclear. But I am not optimistic about nuclear's comeback chances in this century.
Heh, the funny thing is I wasn't till fairly recently, last few years maybe. I was bored and ran some numbers one night...
 
the effective management strategy will ultimately be to utilize every significant source of energy and improve implementation. as one of the other commentators pointed out the sources of energy that you are promoting come with some very tough problems such as limited supply, strong public resistance due to safety and environmental effect. new developments in CO-2 catalytic conversion show promise for the production of ethanol and other products. these can be attached directly to intermittent sources as a method of energy storage. one factor of intermittent power generation that is not being implemented as far as I am aware is the fact that solar and wind often occur in the same location but not at the same time. wind farms in Idaho are very large and successful, however despite the fact that Idaho has plenty of sunshine these wind farms are not taking advantage of the intermittent energy overlap. nuclear has a chance of coming back, only when plants can be designed with far greater disaster resilience and better management. on Mars and the Moon Nuclear will be a major source of power in the next century.
 

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