Renewable Energy

[Bob Wallace]

Audi has their first plant operational making methane out of electricity.  Combined with methane fuel cells, that could be an easy answer.  We already have lots of methane storage and distribution infrastructure.

I was worried about that plant because what we generally see with these 'surplus electricity' + CO2 = fuel plants is that they are snuggled up to a coal plant and using smokestack CO2.  That, unfortunately, could lead to us burning coal longer rather than closing coal plants down as quickly as possible.

This plant is wise-sourcing its CO2 -

"The CO2 used in the plant is a waste byproduct from a nearby biogas plant operated by utility EWE. "

This is good.  Perhaps we could grab the CO2 again as it exits a fuel cell or turbine and turn it back into more methane.

[crandles]

This plant is wise-sourcing its CO2 -

"The CO2 used in the plant is a waste byproduct from a nearby biogas plant operated by utility EWE. "

This is good.  Perhaps we could grab the CO2 again as it exits a fuel cell or turbine and turn it back into more methane.

http://www.virginearth.com/2014/09/zero-carbon-fuels-in-sight-as-climeworks-unveils-industrial-direct-air-capture-system/

Audi already have a small e-gas plant operating in Werlte, Saxony, which uses waste CO2 from a nearby biogas plant. But there are limits to how much biogas-derived CO2 will be available in future and scaling up would require a lot of biomass to be grown and transported to the plant, so Audi are keen to cut out the biogas middleman. Now they want to replace the biogas feed with Climeworks’ industrial system in 2015.

Wise-sourcing but already moving on to even better? air capture.

[Bob Wallace]

Air capture would be great.  But watch carefully when you see an article about syn-fuel.  I think the Audi plant is about the only one that isn't sucking on a coal smokestack.

[Sigmetnow]

Why haven't I heard of this before?  Tie in major U.S. power grids, with renewables -- using superconducting wires.

The Tres Amigas SuperStation

The Tres Amigas SuperStation is a planned project to unite North America’s two major power grids (the Eastern Interconnection and the Western Interconnection) and one minor grid (the Texas Interconnection), with the goal to enable faster adoption of renewable energy and increase the reliability of the U.S. grid.[1] The project will use superconducting wires from Massachusetts-based American Superconductor Corp for electrical distribution and to interconvert alternating current (AC) and direct current (DC) power.

Proposed by Tres Amigas, LLC in 2009, the project is in the process of finalizing funding. Permits and construction contracts are in place.[2] CEO Phillip G. Harris is the former CEO of PJM Interconnection, an East Coast regional transmission organization (RTO

http://en.m.wikipedia.org/wiki/Tres_Amigas_SuperStation
 
http://www.tresamigasllc.com

[Bob Wallace]

Tres Amigas is likely ahead of its time.  They've been trying to get this project off the ground for several years but continue to have funding problems.

Apparently the market doesn't want to invest for profits that could be several years off in the future.

[sidd]

Superconducting transmission is tough. You got to maintain a liquid N2 jacket around the conductor(s). Coolant failure and quench (superconductor goes normal at a defect, resulting in thermal runaway and loss of coolant via boiling) are very difficult to deal with. Replacement takes a long time, since the failure mode is explosive (800 expansion as LN2 flashes to vapor)

sidd

[Bob Wallace]

Superconducting transmission is tough. You got to maintain a liquid N2 jacket around the conductor(s). Coolant failure and quench (superconductor goes normal at a defect, resulting in thermal runaway and loss of coolant via boiling) are very difficult to deal with. Replacement takes a long time, since the failure mode is explosive (800 expansion as LN2 flashes to vapor)

sidd

Developed over the course of the past decade, superconductor cable technology will be utilized to carry gigawatts of power with 100 percent efficiency between each of the SuperStation’s three converter stations. The cable will be contained in a three-foot underground pipeline similar to those used in the oil and natural gas industries. Superconductor cables are more power dense and more efficient than any other transmission option available. Their underground nature also significantly enhances system security and reliability.

http://www.tresamigasllc.com/technology.php

[Sigmetnow]

Sustainable solar panels, and a bunch of other new solar technology.

Cradle to cradle solar panels
Solar panels are usually considered a clean way of generating power, and this development makes them even more sustainable. The world’s first and only Cradle to Cradle (C2C) certified solar panels were launched last month by the US-based SunPower Corporation. All panels produced at its plant in Mexicali, Mexico, have achieved the silver level award, which requires proof of a fully sustainable manufacturing process.

C2C is a set of principles that measures product quality in terms of material health, material reuse, renewable energy, water stewardship and social fairness. SunPower does not use cadmium chloride or cadmium chemicals, which are known to be harmful and are used in some solar panels. The company has a reuse and recycling programme to deal with panels at the end of their life and ensure that parts that can’t be reused are handled by certified recyclers.

http://www.theguardian.com/sustainable-business/2014/dec/09/we-want-the-black-hole-of-sunlight-solar-power-breaks-new-frontiers

[Sigmetnow]

U.S. solar power generation up 100% over same period last year.

Through September, utility-scale solar had sent 12,303 gigawatt-hours of electricity to the U.S. grid (actually a collection of grids), compared to 6,048 GWh in the same period in 2013, according to the U.S. Energy Information Administration. That was enough to meet the electricity needs of 1,513,703 average U.S. homes, and represented about 0.4 percent of the nation’s electricity. With continued growth and adding in commercial and residential PV as well as concentrating solar power, solar electricity could easily account for 1 percent of U.S. generation by the end of this year.
...
“Given the growth of solar over the last few years, getting to 10 percent of U.S. electricity from solar should happen far sooner than 2030,” SunEdison founder and clean energy entrepreneur Jigar Shah said in a statement released with the report.

http://breakingenergy.com/2014/12/01/solar-powers-stunning-growth-u-s-generation-up-100-percent-this-year/

[MOwens]

I think some of you may be interested to read my new book - which is currently available for free as an e-book through Dec 14th from Amazon.

The title is Traps: A New Theory on the Origins of Civilization and Modern Economic and Climate Traps

After examining the trajectory of natural resource use since the last glacial period, I explain how the world can stop using fossil fuels while simultaneously enhancing economic growth.

I've also posted an excerpt here discussing some of the physical components needed for a global energy overhual: http://www.fairfaxclimatewatch.com/blog/2014/12/the-way-out.html

[viddaloo]

I think some of you may be interested to read my new book - which is currently available for free as an e-book through Dec 14th from Amazon.

The title is Traps: A New Theory on the Origins of Civilization and Modern Economic and Climate Traps

Thanks! Looks very interesting, MOwens. Reading it now. 

[Bob Wallace]

U.S. solar power generation up 100% over same period last year.

Through September, utility-scale solar had sent 12,303 gigawatt-hours of electricity to the U.S. grid (actually a collection of grids), compared to 6,048 GWh in the same period in 2013, according to the U.S. Energy Information Administration. That was enough to meet the electricity needs of 1,513,703 average U.S. homes, and represented about 0.4 percent of the nation’s electricity. With continued growth and adding in commercial and residential PV as well as concentrating solar power, solar electricity could easily account for 1 percent of U.S. generation by the end of this year.
...
“Given the growth of solar over the last few years, getting to 10 percent of U.S. electricity from solar should happen far sooner than 2030,” SunEdison founder and clean energy entrepreneur Jigar Shah said in a statement released with the report.

http://breakingenergy.com/2014/12/01/solar-powers-stunning-growth-u-s-generation-up-100-percent-this-year/

Non-utility solar electricity needs to be added in.



The blue line, EIA, is only the electricity fed into the grid from utility scale solar farms.  The green line, NREL, includes residential and commercial production.  Solar is coming on stronger than some of the measurements tell.

The NREL data may or may not include the electricity which is used 'behind the meter'.  If behind the meter isn't included then the green line would be even higher.

[Bob Wallace]

I think some of you may be interested to read my new book - which is currently available for free as an e-book through Dec 14th from Amazon.

The title is Traps: A New Theory on the Origins of Civilization and Modern Economic and Climate Traps

After examining the trajectory of natural resource use since the last glacial period, I explain how the world can stop using fossil fuels while simultaneously enhancing economic growth.

I've also posted an excerpt here discussing some of the physical components needed for a global energy overhual: http://www.fairfaxclimatewatch.com/blog/2014/12/the-way-out.html

Well written, very readable - some niggling criticism.

RE: your excerpt.  You start with flawed data.  The EIA 2019 projections are not connected to reality.

You might want to switch to the most current Lazard LCOE numbers.



http://www.lazard.com/PDF/Levelized%20Cost%20of%20Energy%20-%20Version%208.0.pdf
--

I think you might want to talk about the number of hours per year the wind does blow in windy places.  People who don't live in the sorts of places where the "wind drives you crazy" don't appreciate what a regular source of energy the wind actually is.    Wind is our cheapest source of electricity and provides grid electricity a lot of the time.
--

The EIA has consistently not factored in the rapidly falling price of solar.  And the EIA is predicting that coal holds roughly the same market penetration going forward even though we are in the process of closing about 25% of our coal plants.
--

The cost of solar is now driven by balance of system (BoS) costs, not panel costs.
--

Thermal solar is not likely to be competitive with PV solar.  It's questionable whether thermal solar with storage will be cost competitive.

 

[Sigmetnow]

17% Of Household Energy Comes From Rooftop Solar In Queensland
http://cleantechnica.com/2014/12/12/17-household-energy-comes-rooftop-solar-queensland/

[MOwens]

Thanks viddaloo and Bob Wallace!

Someone actually just showed me the Lazard figures Wednesday. The EIA report was the most recent set of figures I could get when putting this all together several months ago. If I'm able to publish a second edition I'll definitely aim to use the Lazard numbers or newer ones. Those other points are all good too, I'll definitely take them into consideration.

[viddaloo]

I particularly liked the part about how hunting & gathering ended and agriculture started because megafauna was hunted to decimation, so that agriculture/civilization had to begin because we had already 'left the Garden of Eden', so to speak, so that civilization was a strategy of last resorts to survive when we'd become so many by eating so many of the animals.

Is this the thing from the book title that's 'new' in your book, and (presumably) not to be found in too many other books?

[SATire]

And that there is not much potential left - that is also stated in the link you posted above. There maybe some places where they could cut a mountain to make an artificial lake - but people loved that mountain and they prevented that pump power storage. Maybe there is a chance for additional 5-10 GWh pump hydro more -

The link you supposedly quote reports 1,380 GWh theoretical and 818 GWh realizable pump-up hydro storage for Germany.

Of that 818 GWh realizable, 98% of the potential consists of two already built/existing reservoirs/lakes.

Bob - I see, that we probably used different meanings of the word "capacity". The 40 GWh capacity I was talking about is the energy, which can be stored in the built/existing hydro storage plants. This "capacity" is the equates to the capacity of a rechargeable battery and can be used frequently again by numerous charging/discharging cycles. Another number important in this context is the power those plants can deliver/receive: 7 GW. So in average you may use that charged "hydro battery" for 6 hours to take 7 GW until it is empty and then you may charge it again. Please consider, that these numbers are for Germany and that the average electricity consumption is about 40 GW - 50 GW here (1 TWh/day, 8 TWh /week, 400 TWh/year) - so this battery can deliver maximum 17% of our consumption for maximum 7 hours and then need a recharge. No way this can help us for a complete day nor a week or two.

There is some other possible usage of the word "capacity" I have seen in US studies in this context: How much energy can be generated in average by the installed plants in a given time - so this is some accumulation of numerous discharging cycles e.g. in a year. This value is much larger but it does not help in the 2 dark winter weeks without wind the article you disagreed on was talking about. For this occasion we need the fossil back-up to deliver close to 100% demand also in future. At least until the grid is good enough for long-range and high power transmission or the power-2-gas storage (see e.g. the small Audi prototype http://www.etogas.com/ ) is scaled >1000x and is installed several times.

[SATire]

There's an optimal horizontal line that one can draw across that graph (let's assume it to be 1.25 TWh) that minimizes the amount of storage, over-building, and even deep fossil fuel backup.

Bob, that horizontal line is to low for Germany - we need about 8 TWh per week to keep the things running.

If you ask yourself now why PV and wind is so little in average while renewables should be >25 % in Germany, then you should consider, that biogas is "conventional" in this figures from Fraunhofer ISE. From today's perspective this consideration is right - but back in year 2000 it was far from clear that PV would scale that nice so they fostered biogas and now biogas gives about 10% of our electricity (PV and wind together about 16%). This latter 16% will be increased in future so the problem I tried to explain to you for so long will get more and more severe. I know that you still did not understand that problem. It would help me to explain you better if you could tell me, which parts are not clear to you instead of only denying the observations. How could you know that if you did not understand what I was talking about? That is the reason, why I thought you were kidding. Not understanding the problem and then denying it or formulating "solutions" for this problem is usually foolish.

[domen_]

Satire, it will be very hard to run electrolysis on wind and solar PV because of intermittency. Utilization would be low. It would work for nuclear because it's 24/7, but not for wind and PV. Other types of storage will have to be developed. Biofuels would probably be better.

[SATire]

Satire, it will be very hard to run electrolysis on wind and solar PV because of intermittency. Utilization would be low. It would work for nuclear because it's 24/7, but not for wind and PV. Other types of storage will have to be developed. Biofuels would probably be better.

domen_, this storage like power-2-gas will be essential in future, if we want to have 100% renewables in the grid. While batteries could be paired nicely with PV for short-term storage (day-night cycle) we need a lot of storage to prepare for the winter. Since we can store a lot of methane in our big tanks it makes a lot of sense to overbuild wind and to store the excess energy e.g. in form of methan in tanks. See e.g. this study for 100% renewables in 2050 here: http://www.ise.fraunhofer.de/de/veroeffentlichungen/veroeffentlichungen-pdf-dateien/studien-und-konzeptpapiere/studie-100-erneuerbare-energien-in-deutschland.pdf

It makles absolutely no sense to build anything which needs electricity for 24/7 since we probably will not have such a source in future. You know, we are exiting nuclear now and want to exit lignite as soon as possible by forcing it out despite lowest costs...

But I agree that it is far from sure if power-2-gas will be used in future. It is one of many ideas and very far from being usable in the necessary scale. Next generation biofuels could do the job better, perhaps. In that case we could store the excess wind power also as heat for the winter. Because wind is so cheap it could make some sense to build 200% wind and to do even such heat storage...

[MOwens]

Is this the thing from the book title that's 'new'

Yes.

Additionally, the large-scale social organization required for the roundup-hunts/encircling-hunts laid the foundations for the institutions of civilization we are familiar with today. Also, the extreme reduction in numbers of wild animals at local scales forced rapid genetic and behavioral selection for docility in those localities. Ergo, the process of extinction via circle-hunts inherently led to domestication. But the newly domesticated animals only spread to new areas once wild animal resources in those new areas were mostly wiped out too.

Notably, domesticated farm animals are a renewable resource because they provide sustainable/reliable/predictable outputs of meat, wool, milk, eggs, etc.

In the book, I argue that the same tipping points that caused animal domestication and civilization to form are at play now with renewable energy versus fossil fuels, and, that fossil fuels must be driven extinct for renewables to flourish. However, if we let the extinction of fossil fuels happen on its own, or if we let the allegedly "free" market take care of it, then we will be forced to deplete fossil fuels to an extremely ugly level which will lead to all kinds of uncivilized consequences, like, for example: excessively-high unemployment, ever-bloodier wars, and general hardship.

[Bob Wallace]

And that there is not much potential left - that is also stated in the link you posted above. There maybe some places where they could cut a mountain to make an artificial lake - but people loved that mountain and they prevented that pump power storage. Maybe there is a chance for additional 5-10 GWh pump hydro more -

The link you supposedly quote reports 1,380 GWh theoretical and 818 GWh realizable pump-up hydro storage for Germany.

Of that 818 GWh realizable, 98% of the potential consists of two already built/existing reservoirs/lakes.

Bob - I see, that we probably used different meanings of the word "capacity". The 40 GWh capacity I was talking about is the energy, which can be stored in the built/existing hydro storage plants. This "capacity" is the equates to the capacity of a rechargeable battery and can be used frequently again by numerous charging/discharging cycles. Another number important in this context is the power those plants can deliver/receive: 7 GW. So in average you may use that charged "hydro battery" for 6 hours to take 7 GW until it is empty and then you may charge it again. Please consider, that these numbers are for Germany and that the average electricity consumption is about 40 GW - 50 GW here (1 TWh/day, 8 TWh /week, 400 TWh/year) - so this battery can deliver maximum 17% of our consumption for maximum 7 hours and then need a recharge. No way this can help us for a complete day nor a week or two.

There is some other possible usage of the word "capacity" I have seen in US studies in this context: How much energy can be generated in average by the installed plants in a given time - so this is some accumulation of numerous discharging cycles e.g. in a year. This value is much larger but it does not help in the 2 dark winter weeks without wind the article you disagreed on was talking about. For this occasion we need the fossil back-up to deliver close to 100% demand also in future. At least until the grid is good enough for long-range and high power transmission or the power-2-gas storage (see e.g. the small Audi prototype http://www.etogas.com/ ) is scaled >1000x and is installed several times.

You claimed that Germany had no places to install PuHS. 

I demonstrated to you that you were incorrect.  I'm not going to get involved in exactly how much Germany needs, mainly because I think PuHS is not likely to be our main storage technology.  PuHS is our safety net in the event a better technology does not prevail.

[Bob Wallace]

There's an optimal horizontal line that one can draw across that graph (let's assume it to be 1.25 TWh) that minimizes the amount of storage, over-building, and even deep fossil fuel backup.

Bob, that horizontal line is to low for Germany - we need about 8 TWh per week to keep the things running.

If you ask yourself now why PV and wind is so little in average while renewables should be >25 % in Germany, then you should consider, that biogas is "conventional" in this figures from Fraunhofer ISE. From today's perspective this consideration is right - but back in year 2000 it was far from clear that PV would scale that nice so they fostered biogas and now biogas gives about 10% of our electricity (PV and wind together about 16%). This latter 16% will be increased in future so the problem I tried to explain to you for so long will get more and more severe. I know that you still did not understand that problem. It would help me to explain you better if you could tell me, which parts are not clear to you instead of only denying the observations. How could you know that if you did not understand what I was talking about? That is the reason, why I thought you were kidding. Not understanding the problem and then denying it or formulating "solutions" for this problem is usually foolish.

I said absolutely nothing.   Absolutely nothing. Absolutely nothing about Germany needing only 1.25 TWh or any other amount of electricity. 

You totally missed my point.

(I didn't even bother reading past your first sentence.)

[crandles]

There's an optimal horizontal line that one can draw across that graph (let's assume it to be 1.25 TWh) that minimizes the amount of storage, over-building, and even deep fossil fuel backup.

Bob, that horizontal line is to low for Germany - we need about 8 TWh per week to keep the things running.

By setting the line at 1TW when the typical production from wind and solar is some 50% higher Bob is proposing that we need to overbuild capacity to the tune of 50%. If the cost of renewables is less than 2/3 of the cost of ff then this isn't a high cost route. At todays prices, subsidies are still required i.e. a guaranteed price for electric that is above cost is still needed. Subsidies today and in near future can be much smaller than in the past. Overbuilding capacity will definitely lead to large price differentials between when it is windy and when it isn't, but this isn't a problem if you get a fixed price that is above costs. Subsidies may have to stay for longer but if the subsidy rates are low that isn't such a problem.

I assume land and storage of electricity would be needed in large amounts. Adding some biomass that could be powered up when electric demand is high would help reduce both of these.

[SATire]

There's an optimal horizontal line that one can draw across that graph (let's assume it to be 1.25 TWh) that minimizes the amount of storage, over-building, and even deep fossil fuel backup.

Bob, that horizontal line is to low for Germany - we need about 8 TWh per week to keep the things running.

By setting the line at 1TW when the typical production from wind and solar is some 50% higher Bob is proposing that we need to overbuild capacity to the tune of 50%. If the cost of renewables is less than 2/3 of the cost of ff then this isn't a high cost route. At todays prices, subsidies are still required i.e. a guaranteed price for electric that is above cost is still needed. Subsidies today and in near future can be much smaller than in the past. Overbuilding capacity will definitely lead to large price differentials between when it is windy and when it isn't, but this isn't a problem if you get a fixed price that is above costs. Subsidies may have to stay for longer but if the subsidy rates are low that isn't such a problem.

I assume land and storage of electricity would be needed in large amounts. Adding some biomass that could be powered up when electric demand is high would help reduce both of these.

crandles, I have got your point. However, that picture you were refering to is today's situation with 16% PV and wind in the grid and we are going to push that towards 100% in the next decades. And even with 16% fluctuating PV and wind today we have some days with 80% of demand delivered by PV and wind and many other hours with close to 0%. So talking about averages like in that picture is like overlooking the issues. Overbuilding capacity will be necessary to reach the 100% renewables in future. That would be 6x more wind and PV than today here before we would start overbuilding it on average. Even that results in days with wind exceeding 5x the demand and that should be stored in power-2-gas or must be transmitted to regions without wind. Overbuilding that e.g. another factor of 2 makes even more storage necessary/reasonable. Storage in form of heat is another valuable possibility, therefore.

And as I explained above: That will not be possible without subsidies, a lot of new transmission lines or a new market scheme. Because at 6x of todays production the value at the grid will be exactly 0ct/kWh for wind or PV in times with wind or sun. But we need to make it possible so we have to do that anyway. That makes no economical sense for an individual investor but for the society in general. So we will have to tune the rules accordingly, to make that happen.

The reason for all the new efforts is to make the transition also an economical success. Technologically or in respect to the costs or EROI or such renewables are allready tipped. But to be successful renewables must also make some sense from economical perspective and that is yet an unsolved problem we are addressing these days here. That could be done with subsidies, if poeple are able to accept that. If for some ideological reasons that would not be acceptable the market must be changed in such a way, that the poeple would agree to that. Anyway we have to do that transition with the poeple so ignoring their needs or concerns would render all our efforts useless and civilization would be doomed.

What is not possible here is to blow another bubble: Poeple are very aware of that after the new market bubble and are able to see such things in advance. Poeple here are not following those kind of inversed arguments which may still be working in the US. Poeple here know that they will have to pay for both renewables and for the fossil back-up now or storage later, once a scaled solution might be available. And e.g. PuHS is ready installed here - not much more possible to do in this point.

You are also right that our current biomass set-up is not optimal - it is 10% steady state and not load-following today. That evolution must be changed now. But biomass is anyway at its limits here and all future growth will come from PV and wind on-shore and maybe in future a bit wind off-shore, too.

[wehappyfew]

If I may make a few observations and ask a few questions:

...even with 16% fluctuating PV and wind today we have some days with 80% of demand delivered by PV and wind...

...at 6x of todays production the value at the grid will be exactly 0ct/kWh for wind or PV in times with wind or sun...

These two points together are, I think, making some assumptions that are too static, and not realistic in the future scenario we are talking about.

Because... currently the PV and wind are subsidized, so they will continue to produce even when the marginal value of their output falls to zero cents/kWh. Thus forcing other producers to curtail output, or even accept negative rates.

In the future, unsubsidized, scenario with 6x PV+wind, wind producers will have no incentive to produce at negative reimbursement, so they will feather their turbines to reduce wearing out their capital for no gain. They will make a cost-benefit calculation about revenue needed to cover their marginal maintenance and replacement costs due to producing power at a given spot revenue rate. This will put a floor under the spot price.

So the consequences of overbuilding wind in order to reduce the need for storage...
1. reduced output vs theoretical capacity during high wind (wind producers produce at a small loss, but recoup operating costs);
2. 100% of demand met by wind at some intermediate average wind speed (with highly reactive producer control to avoid negative prices);
3. and less than 100% of demand met by wind at some much lower average wind speed - requiring backup, storage, or variable demand.

Variable demand greatly reduces the need for backup and storage, does it not?

For PV, the mid-day peak in output needs to be broadened by aligning half of the panels to the southeast, and half to the southwest. Is anyone doing this in Europe to compensate for the oversupply at noon?

For PV's seasonality, what options would they have? There is no cost effective way to reduce output to follow demand. They would need, ideally, some seasonal storage since the biggest surplus in output is in summer, and the demand (in Europe) is in winter, right?

Seasonal storage must be hundreds of times more expensive than daily storage, as it cycles only once per year. So the only option I can see is resistive heating underground, like an artificial geothermal source for space heating - still seems expensive... Is there any other way?

[SATire]

wehappyfew, you are right - I oversimplified the situation to make it more clear but reality is dynamic.

Should wind switch off because production is higher than demand? (In case of PV there is no wear so that is not the question.) From individual perspective that could be a good idea. But marginal costs are very low once you installed the turbine. So from larger perspective it could make some sense to pay a small amount to the wind producer (thus subsidies will not stop in future), because there could be someone making some use of that by tuned demand or because he can store that.

Variable demand is key in a 100% renewable world, I like to agree 100%.

The point to build PV with not perfect conditions for the individual roof-top producer but with better condition for the system (e.g. east or west direction to optimize output in the more demanding morning/evening hours) is a topic for the next iteration of the EEG subsidies due in 2016/2017. I think that will come since it makes some sense. Again that will be done by some sort of subsidies to make that happen. If the subsidies are spend to help all the people they are usually considered to be well-spend money here.

For seasonal storage next to heat storage this power-2-gas is an idea, which is in prototype state today (http://www.etogas.com/ ). We have large storage capacity for natural gas here since the cold war times (you know, we in Germany get that natural gas from Russia since a long time). So storage of a few month's demand would be easy once we manage to produce the gas efficiently in large quantity from surplus wind electricity. But that is still far away from today's prototype plants (6 MW today - we would need plenty of GW...). A problem is also to get that CO2 in efficient way, which is needed to make CH4 from that electrolysis H2. So CCS is dead for sure ;-)

Another benefit from power-2-gas could also be, that it could be used also for methanol or even kerosene and thus could be a way to make the transport 100% renewable. But those are science fiction dreams today with no practical prove of principle. Only lab things or small marketing plants like that Audi plant fed by biogas-CO2 are here today...

Today's known best solution are still the transmission lines to get the power to places without wind and tomorrow back - like NorNed or NorGer and such. That kind of direct usage is much more cost effective than any other storage.

[Bob Wallace]

Variable demand greatly reduces the need for backup and storage, does it not?

Yes.  EVs should play a major role here.  There is already work done in the industry that would allow remote charging operation which means (with the owner's permission) the grid could start and stop charging in order to eat up oversupply and, at other times, lower demand.

For PV, the mid-day peak in output needs to be broadened by aligning half of the panels to the southeast, and half to the southwest. Is anyone doing this in Europe to compensate for the oversupply at noon?

I'm not aware that this has yet been done.  I remember talking about this a couple years ago but it's only in the last few months that the idea has been openly discussed in the industry.

For PV's seasonality, what options would they have?

In Germany's case the times of year when there's less sunshine there is more wind.  That will vary from places to places around the world.  Each area will have to work out their best mix.

Seasonal storage must be hundreds of times more expensive than daily storage, as it cycles only once per year. So the only option I can see is resistive heating underground, like an artificial geothermal source for space heating - still seems expensive... Is there any other way?

First, seasonal storage is likely a misconception.  We may have no place that needs to store away massive amounts of energy to be used three, six months later.  Let's bring in the German wind/solar graph once more.



In this case Germany would need to move some Week 1 and 2 energy into Week 3 and 4.  Some 6-7 into 8-9-10, etc.

The issue is, how long/large are the storage needs?  As you can see from the graph, in Germany inputs do not stop (at least on a weekly level), they just slow below the level of demand. 

Here's what I think happens.  Several years from now we will have reached the point at which peak wind/solar output starts to exceed demand enough that we are starting to "toss energy away" by curtailing turbines and panels.  While we work our way there we will have added more storage to our grids than we now have (and we do have storage).  Plus we will create more dispatchable loads (and we do currently have and use dispatchable loads).

From that point we will make economic and practical decisions whether to build more capacity (over-build and curtail), build more capacity and store, or bring in dispatchable generation.

We have some cleantech dispatchable generation options.  Biomass - wood pellets burned in converted coal plants.  Biogas - methane from sewage, landfills and feedlots burned in combined cycle gas plants.  Hydrogen extracted from water using electricity and used in fuel cells.  (I may have forgotten others.)

[Bob Wallace]

By setting the line at 1TW when the typical production from wind and solar is some 50% higher Bob is proposing that we need to overbuild capacity to the tune of 50%. If the cost of renewables is less than 2/3 of the cost of ff then this isn't a high cost route. At todays prices, subsidies are still required i.e. a guaranteed price for electric that is above cost is still needed. Subsidies today and in near future can be much smaller than in the past. Overbuilding capacity will definitely lead to large price differentials between when it is windy and when it isn't, but this isn't a problem if you get a fixed price that is above costs. Subsidies may have to stay for longer but if the subsidy rates are low that isn't such a problem.

First, I'm not talking in terms of absolute numbers.  I'm trying to talk about the concept of overbuilding and curtailing.

Some people seem to be uncomfortable with the idea of curtailing (not aiming this at you, Crandles, more at some people in general) so let's take a look at that a bit.  I'm going to us US numbers.

Wind right now is selling for 4 cents/kWh - without subsidies.  DOE/NREL.

Natural gas costs range from 6.2 cents/kWh (and upward - peaker power can be very expensive).  Coal-electricity costs about 6.6 cents/kWh.

http://www.nytimes.com/2014/11/24/business/energy-environment/solar-and-wind-energy-start-to-win-on-price-vs-conventional-fuels.html?_r=0

Were we to overbuild wind 50% the price needed for wind farms to stay profitable would rise to roughly that of coal and CCNG.

Using EOS Energy Solutions zinc-air battery at $160/kWh it would cost about 8 cents to store a kWh of electricity for two days.  There are going to be some 'two day low wind/solar' days when it will make more sense to have extra capacity than to use storage.

What many people don't realize is that we now overbuild.  Our US natural gas plants run less than 30% of the time.  Our coal plants run less 60%.  70% and 40% of our plants come on line when demand is up and other sources can't meet demand.  When they aren't needed they get "curtailed".  We have NG plants that run only a few hours a year.

[domen_]

Overbuilding high capex energy source is different than overbuilding low opex. LCOE rises much faster because of financing costs.

Coal and gas are relatively low capex, wind and solar (and nuclear) are high capex.

I doubt that 6x overbuilding wind and solar is the way to go. Maybe 2x overbuilding would be doable (barely), but 3x or more is unrealistic. I think that biomass and biofuels (second generation) are much better to fill in the gaps.

[Bob Wallace]

Your capex costs are not correct.  Wind and solar overnight capital costs are about $2/watt in the US.  CCNG is about $1.  Coal is about $3.

http://en.openei.org/apps/TCDB/

(Their PV solar price is out of date.  As of July 2014 US utility solar price was $1.81/W.)

Financing does drive up the installed cost.

Wind Onshore 
 $1.63 Installed Cost/Watt
 DOE 2013 Wind Technologies Market Report

PV Solar
$1.81 Installed Cost/Watt
Greentech Media 2nd Qtr 2014 Executive Summary

CCNG
$1.09 Installed Cost/Watt
Open EI DOE Database Median Overnight Cost

Nuclear
$6.94 Installed Cost/Watt
Vogtle current cost estimate $15.5 billion for 2,234 MW

I really doubt anyone has ever seriously suggested 6x overbuilding.  2x, perhaps.  It would depend on the cost of storage and dispatchable generation.  Biomass and biogas may be good "deep backup" fill-ins.  They probably won't be competitive for 'couple of days' type supply.

[domen_]

These costs aren't adjusted to capacity factor. Nonetheless, the point is that nearly all of the costs with wind, solar and nuclear come upfront. Coal and gas are different, because significant fraction of costs are operational costs. That's why overbuilding coal and gas is something different than overbuilding wind and solar or nuclear. It's much harder to do the latter, because it hurts their finance much more.

[Bob Wallace]

You are correct.  Installed prices do not take CF into account.  What you want to look at if you want to see installed prices, CF, fuel costs and everything else (but owner profits) rolled up in one package is the LCOE.

I'll give  you the LCOEs from Lazard's latest study.  This is a crop of the full graph - easier to see the numbers.



http://www.lazard.com/PDF/Levelized%20Cost%20of%20Energy%20-%20Version%208.0.pdf

Actually overbuilding gas is not expensive, CCNG is just over $1/watt.  It's running gas plants that is expensive. 

CCNG starts out $1.09 vs. $1.63 for offshore wind.  But due the cost of fuel the electricity produced ends up being 6c/kWh vs. 4c/kWh.

[Sigmetnow]

Austin, Texas plans to use solar power, energy storage, and efficiency gains to get 55 percent of its power from clean energy by 2025. 

Texas boasts some of the lowest prices for small-scale solar installation in the country, and Austin’s recent contract with Recurrent Energy for a 150-megawatt solar plant was hammered out for an astonishingly low five cents per kilowatt-hour. Similar deals for solar plants in other states, which lock buyers and providers into long-running agreements, are an indication that players in the market are increasingly confident solar’s low prices are here to stay, and likely to keep dropping.

http://thinkprogress.org/climate/2014/12/16/3603991/austin-texas-renewable-energy-plan/

[Sigmetnow]

"Warren Buffett wants to tell you the best time to wash your clothes."
Smart grids can run your appliances when power is most available and cheapest.

The Northern Powergrid system was able to reduce energy consumption 10 percent at peak times by encouraging customers to use electricity when it was cheaper, while cutting overall use by 3 percent.
...
“Customers can work with us to use their energy in a different fashion, by a range of techniques,” said Ian Lloyd, head of network technology research at Buffett’s Northern Powergrid Holdings Co. The program encourages people to use power in a way that “complements the running of the distribution network.”

http://www.bloomberg.com/news/2014-12-17/buffett-s-smart-grid-idea-takes-over-your-washing-machine.html

[Sigmetnow]

Solar With Batteries to Hit $1 Billion in U.S. by 2018
http://www.bloomberg.com/news/2014-12-18/solar-paired-with-batteries-to-reach-1-billion-in-u-s-by-2018.html

[Bob Wallace]

Solar With Batteries to Hit $1 Billion in U.S. by 2018
http://www.bloomberg.com/news/2014-12-18/solar-paired-with-batteries-to-reach-1-billion-in-u-s-by-2018.html

I'm doubtful.  I think there's a good chance that grids will implement fairly high connection charges and lower the cost of electricity.  Utilities will be able to sell wind electricity for less than end-users can store their own.

Few people are going to go totally off the grid, it's just too big a hassle. 

[Sigmetnow]

Apparently they think most of the solar-with-battery systems will still be connected to the grid -- just increasingly "sustainable", if you will.  Smarter grids will take advantage of the flexibility to give and take energy from such systems. 

Today, many places like New York City don't allow independent interconnections, so those few with working solar couldn't use them when Superstorm Sandy took out the power.  I don't see why an automatic utility switch-over like I have with my emergency generator couldn't be used with solar.  Energy sharing ON when utility power is present; cut over to isolate the residential solar when the utility goes out.

From the above article:

Combining solar panels with batteries means users can store power during the day and use it at night, reducing electricity bills. Those savings can be more significant for customers who pay higher rates for electricity during peak periods, Shayle Kann, senior vice president of GTM, said in an interview. So-called time-of-use pricing is typically more common now among commercial users.

The report measured systems that are connected “behind the meter” to the power grid, allowing households to sell energy back to utilities when their panels are producing a surplus. Such setups will become more common with commercial customers as well, Kann said.

[Sigmetnow]

Worlds largest tidal energy project to begin, using undersea turbines off Scotland.

Construction of the largest planned tidal energy project in the world is expected to begin off the Scottish coast next month, developers have announced.
...
The project has the potential to power nearly 175,000 homes through a network of 269 turbines on the seabed at Ness of Quoys in Caithness, north-east Scotland.

http://www.theguardian.com/environment/2014/dec/19/green-light-for-worlds-largest-planned-tidal-energy-project-in-scotland

[Bob Wallace]

I don't see why an automatic utility switch-over like I have with my emergency generator couldn't be used with solar.

No reason why not.  If people start installing storage then we'll see the regulations adjusted.

[ghoti]

Unfortunately the regulations in North America for grid tied inverters require them to only work when connected to an active electrical supply. An automated power transfer switch as they currently exist therefore wouldn't result in power flowing from the PV system. We'll need either all new inverters or a power transfer switch that somehow supplies what appears to be grid power so the inverters are enabled. I'm sure this can be done I just don't think it exists now.

[sidd]

Manually operated transfer switch is legal in PA,NY,OH,NJ and a bunch of other places. This isolated load from utility while simultaneously transferring supply to (typically) a generator, but no reason the supply couldnt be solar charged batteries. I have installed these before, the utility dont care. In these cases, you do not need a grid tied inverter. Note that this will also work, with some thought, with a grid tied inverter, and still meet regulation. Careful with the grounding, ground loops are not necessarily innocuous, can kill.

sidd

[Bob Wallace]

sidd, isn't it the case that grid-tied inverters won't feed power into the grid unless the grid is energized?

Seems like all that is needed is a "grid safe" inverter that is capable of shifting from grid to battery supply and back based on the grid being powered or not.

People already have home battery storage that jumps in when the grid goes down - UPS systems for their computers.

[sidd]

There are no approved grid tie inverters coupled with auto transfer switch approved by USA/CAN NEC as of a few months ago. I have done as follows. Manual (or auto) transfer switch switched load to utility or backup. Load side has solar panels with grid tie inverter attached. When transfer switch is in utility position, and utility power is up, all is well, grid tie inverter syncs to utility power. Now utility goes out. Grid tie inverter stops working, nothing to sync to. Now you switch the transfer switch to backup position. If you supply power from backup (say a generator), the grid tie inverter will sync to backup power, and supplement backup. This backup can come from a generator ... or another (non grid tie) inverter from auxiliary battery bank. If you are (very) careful and clever, the auxiliary battery bank can be the same as the one feeding the grid tie inverter. 

If the utility wants to be difficult they will want a lockout cutoff switch that linemen can get to, right by the meter, so they can be sure that your generation and load is islanded.

Get competent help if you do this.

sidd

[Sigmetnow]

Great info on grid-tied solar / cut-off.  Thanks!

[Sigmetnow]

An island school in Maine sends a class to Denmark to investigate their 100% renewable island.
http://dotearth.blogs.nytimes.com/2014/12/19/from-maine-to-denmark-islanders-including-students-seek-sustainable-energy-solutions/

[Bob Wallace]

Lower your power bill and add battery storage protection from power outages.
Until now, gridtie solar power systems operated only when utility power was available. When the grid went down, the electricity from your solar panels was not used. Now, specialized inverters from Outback Power enable your gridtied solar panels to charge a battery bank from which you can power your home.

How do these Grid-tie Systems with Battery Backup work?
When the grid is running properly, your home or business will use power generated from your solar panels or pull electricity from the grid. Any excess power generated over and above your needs go back to your utility company for credits on your power bill in areas where net-metering is available.

In the event of grid blackouts, these systems will switch to "off'-grid mode" drawing power stored in your battery bank to power your home AND using your solar panels to recharge your battery bank.

http://www.wholesalesolar.com/grid-tie-battery-backup.html

The Radian Series GS8048A and GS4048A Grid/Hybrid™ (full-flexibility grid-interactive/off-grid) Inverter/Charger is engineered toward one goal: making system design and installation easier and faster in grid-interactive and comprehensive off-grid applications. The new Radian Series inherit the hallmark features of the original design, including: dual AC inputs for grid/generator flexibility with no external switching required, unparalleled surge capability and operational stability, easy field upgradeability and stacking capability for large system scaling, simplified system commissioning through a powerful, easy-to-use configuration wizard, and multi-mode operational flexibility.

In addition, both models have a new Advanced Battery Charging (ABC) profile option to support leading-edge battery technologies such as Lithium-Ion and others, and enhanced diagnostics for improved performance.

http://www.outbackpower.com/outback-products/inverters-chargers/item/radian-series-gs8048a-gs4048a?category_id=444

[sidd]

I was told by two utilities serving PA,OH,NY and NJ a few months ago that the grid ties with islanding were not yet approved by NEC. I shall have to inquire again if the radian systems are approved.

sidd

P.S. I have a feeling that the issue is related to grounding, but don't quote me ...

[sidd]

Just got off the phone with a retired EE from electric utility. He thinks the reason grid-tie inverter + battery + transfer switch has not yet been approved is that utility line overvoltage induced failure modes  and reclosing time issues have not been satisfactorily addressed.

Briefly: 1) Lightning strike on utility line might cause the system to fail in such a manner that generation is not islanded to load,  but energizes utility line, and that 2) short on utility line causes breaker to trip deenergizing the line, but breaker recloses after a set period (depending on breaker temperature constraints) to see if the short has cleared (squirrel has been vaporized) and then opens again if short does not clear (squirrel has not been completely vaporized). This can happen several times (lights coming on an off) before breaker calls it a day and remains open. In such a situation utility wants to be sure that the system remains islanded. This latter situation is also accompanied by wild voltage swings depending on amount of reactive load reconnected each time on reclosure, as well as generator constraints and can cause large common mode currents which could flow through improperly configured grounding; recall that ground and common are (usually) bonded at main breaker.

In short, linemen are expensive, and they don't like third degree burns and death.

sidd

[Bob Wallace]

That's not making sense to me.  A grid-tied inverter is not going to reconnect unless it detects an up and working grid.

There's no reason why a grid-tie inverter would isolate a solar array from the grid but not a battery pack. 

I suspect what we have is regulations trailing innovation, which is normal and not without reason.