Economics of Renewable Power, simplified.

[RegGuheert]

El Hierro update: <snip>

Thanks for finding this. I went looking for production data 6-8 months ago but didn't find anything except the same articles we had already discussed upthread.

You're welcome. I've been looking off-and-on, as well, with little success.

And thanks to Andy for finding this originally!

This is a very nice testbed for the technology. I hope they don't have any severe implementation snafus so that some real-world data comes out of this effort.

 

[AndyH]

El Hierro update: <snip>

Thanks for finding this. I went looking for production data 6-8 months ago but didn't find anything except the same articles we had already discussed upthread. I also re-read some of this thread to remind myself of what I wrote. In one post I said 65% provided by RE would be doing pretty good, with 80% about the max. to be expected, and it seems the company is in general agreement, predicting a peak of 77% then gradually declining as demand increases (and maintenance issues arise). Looks like they still have a ways to go to get a full year's worth of data with the system fully operational, but the 3%/97% RE/diesel split reported on a low wind day early on, and 25%/75% split less than a month later shows just how critical storage will be. Still, early days yet, and hopefully we'll see a paper at or before the conference next year reporting at least a full year of production/demand.

I may have missed it - I'll read the 'update' again - but a significant part of the overall project/process is to get to 100% by both growing wind/PV but also by replacing some traditional energy use with solar thermal and BEVs. So...80% is more than fine when more than 20% of the 'old' demand is also being removed. So far I've not found any updates on those, nor have I been able to find an actual commissioning date for the wind/water system.

 

[RegGuheert]

I may have missed it - I'll read the 'update' again - but a significant part of the overall project/process is to get to 100% by both growing wind/PV but also by replacing some traditional energy use with solar thermal and BEVs. So...80% is more than fine when more than 20% of the 'old' demand is also being removed. So far I've not found any updates on those, nor have I been able to find an actual commissioning date for the wind/water system.

According to the paper I linked, the system was commissioned in 2014 and is supposed to ramp up production over time.

I agree that there should be efficiencies coming online. Certainly PV should play a major role on that island. (I would think that at half-a-Euro per kWh it already would be!) But the paper discusses the fact that the population of the island is growing and (perhaps incorrectly) uses that as the basis for the ongoing load increase. But the much bigger issue that I see is that the El Hierro government has discussed its intent to move much of the vehicle fleet to EVs. If they do that, then the load will grow by a significant amount. Unfortunately, that aspect was not covered in the paper, so I don't know how to quantify it.

For reference, our LEAF uses about 2 MWh/year of electricity. If that is close to the average for a home on El Hierro, I wonder how much additional electrical load that would equate to.

Edit: The RMI article (which had been linked previously) says there are 4500 cars on El Hierro to replace with BEVs:

El Hierro’s next goal is to replace all 4,500 of El Hierro’s cars with electric vehicles. According to Javier Morales, El Hierro’s councilman for sustainability, if they sell electricity at the same price as gas, they can recoup the necessary $90 million in infrastructure costs in 10 years. The EV batteries will be charged with excess energy from the hydro-wind plant.

If we use my average of 2 MWh/year (~8000 miles/year) for each of the BEVs on the island, then that equates to 9 GWh/year. Converting that to power:

9 GWh/year * 1 year/365 days * 1 day/24 hours = ~1 MW

That's an increase of about 20% to the electricity load on El Hierro which appears to average about 5 MW throughout the year. It could be more if there are larger vehicles which use more electricity or ones which use it less efficiently or ones that use both such as a FCV for trucking.

 

[RegGuheert]

BTW, on the link providing information on El Hierro electricity production I see wind and hydraulic generators each producing about 25% of the load (total of about 50%) from about 2 PM until about 6:30 PM. The data looks a lot like a test, but it is good to see it producing real power sometimes!

Edit: Looking at this further, it appears that the wind power today *might* have been used for generating the power to pump water up into the upper pool. I say *might* because there is a "(-)" after the word "Hidraulica", which makes me wonder if the sign of the graph is reversed from the rest of the graphs. I don't know...

Second Edit: I see how it works now. The "(-)" sometimes changes to "(+)". That applies only to the pie chart, NOT to the data in the graph below the legend. Also, when "Hidraulica" is drawing power, its wedge in the pie moves out just a bit from the center. So today the wind power generated was used to pump electricity up into the upper reservoir.

 

[GRA]

Issues at Ivanpah and solar-thermal in general, via the WSJ. Nothing we didn't already know, but this provides more details:

High-Tech Solar Projects Fail to Deliver
$2.2 billion California project generates 40% of expected electricity

http://www.wsj.com/articles/high-tech-solar-projects-fail-to-deliver-1434138485" onclick="window.open(this.href);return false;

Part:

. . . The $2.2 billion Ivanpah solar power project in California’s Mojave Desert is supposed to be generating more than a million megawatt-hours of electricity each year. But 15 months after starting up, the plant is producing just 40% of that, according to data from the U.S. Energy Department. . . .

Turns out, there is a lot more to go wrong with the new technology. Replacing broken equipment and learning better ways to operate the complex assortment of machinery has stalled Ivanpah’s ability to reach full potential, said Randy Hickok, a senior vice president at NRG. New solar-thermal technology isn’t as simple as traditional solar panel installations. Since older solar photovoltaic panels have been around for decades, they improve in efficiency and price every year, he said.

“There’s a lot more on-the-job learning with Ivanpah,” Mr. Hickok said, adding that engineers have had to fix leaky tubes connected to water boilers and contend with a vibrating steam turbine that threatened nearby equipment.

One big miscalculation was that the power plant requires far more steam to run smoothly and efficiently than originally thought, according to a document filed with the California Energy Commission. Instead of ramping up the plant each day before sunrise by burning one hour’s worth of natural gas to generate steam, Ivanpah needs more than four times that much help from fossil fuels to get the plant humming every morning. Another unexpected problem: not enough sun. Weather predictions for the area underestimated the amount of cloud cover that has blanketed Ivanpah since it went into service in 2013.

Ivanpah isn’t the only new solar-thermal project struggling to energize the grid. A large mirror-powered plant built in Arizona almost two years ago by Abengoa SA of Spain has also had its share of hiccups. Designed to deliver a million megawatt hours of power annually, the plant is putting out roughly half that, federal data show.

NRG and Abengoa say their plants will reach power targets once the kinks are worked out.

In contrast, incremental improvements to traditional solar panels have allowed SunPower Corp. to get more electricity than it originally thought it could from its 1,500-acre solar farm. California Valley Solar Ranch was designed to produce 600,000 megawatt-hours a year in 2013 when it started operating, but today it can generate up to 4% more. . . .

Solar-thermal developers including Abengoa and BrightSource continue to build new plants in South Africa, Chile and China. But Lucas Davis, an economics professor at the University of California, Berkeley, says it is unlikely more U.S. projects will gain traction as utilities opt for cheaper solar farms that use panels.

“I don’t expect a lot of solar thermal to get built. It’s just too expensive,” he said. . . .

Electricity prices from new solar farms average around 5 cents a kilowatt-hour, according to GTM Research, which tracks renewable energy markets. That compares with between 12 and 25 cents a kilowatt-hour for electricity generated by the Ivanpah power plant, state and federal data show.

It is unclear how much power would cost from a brand new solar-thermal plant, but it would be more than 5 cents a kilowatt-hour, said Parthiv Kurup, an analyst at the National Renewable Energy Lab in Golden, Colo. . . .

Even if solar-thermal developers could offer the same power prices as their solar-panel rivals do, solar-thermal plants face environmental hurdles in the U.S.

The Ivanpah plant was delayed several months and had millions of dollars in cost overruns because of wildlife protections for the endangered Desert Tortoise. Once built, U.S. government biologists found the plant’s superheated mirrors were killing birds. In April, biologists working for the state estimated that 3,500 birds died at Ivanpah in the span of a year, many of them burned alive while flying through a part of the solar installment where air temperatures can reach 1,000 degrees Fahrenheit.

Bird carnage combined with opposition by Native American tribes to industrial projects on undeveloped land has made California regulators wary of approving more. Last September, Abengoa and BrightSource abandoned their quest to build a solar-thermal project near Joshua Tree National Park when the state regulator told them the plant’s footprint would have to be cut in half.

In March the Board of Supervisors of Inyo County, a sparsely populated part of California that is home to Death Valley National Park, voted to ban solar-thermal power plants altogether. “Ivanpah had a significant effect on the decision making,” said Joshua Hart, the county’s planning director.

That $0.05/kWh for utility-scale intertied PV is very encouraging. What's wind now, about $0.03/kWh (it was averaging about $0.04/kWh in 2011-2012)?

 

[RegGuheert]

BTW, on the link providing information on El Hierro electricity production...
<snip>

I've been looking at this link and it appears that in June they started dropping the power level of the diesel generators in steps:

- Until June 24, average diesel generation was at about 5MW.
- On June 24, average diesel generation dropped to about 4MW.
- Around Jun 27, average diesel generation dropped to about 3 MW.
- On June 30, average diesel generation dropped to about 2MW.
- On July 2, average diesel generation rose back to about 3 MW.
- On July 5, average diesel generation dropped back down to 2 MW.

Currently diesel production remains at 2 MW. It will be interesting to see how it tracks going forward.

 

[RegGuheert]

El Hierro diesel generators were operating around 1.5 MW for most of today. At that level, they have managed to shave about 70% off of their consumption and burning of diesel fuel (after their $90M expenditure). We'll see how much lower they can go.

The wind generators seem to be fairly well-sited (at least for this time of year), since they are producing a fairly-steady 6 MW.

 

[RegGuheert]

El Hierro diesel generators were operating around 1.5 MW for most of today. At that level, they have managed to shave about 70% off of their consumption and burning of diesel fuel (after their $90M expenditure). We'll see how much lower they can go.

Today El Hierro apparently hit a major milestone: it appears the diesel generators were off for over 1.5 hours! That's an important step since they can see how the voltage and frequency regulation works without those generators operating.

Most days these generators have been putting out 1.6 MW.

 

[RegGuheert]

Today El Hierro apparently hit a major milestone: it appears the diesel generators were off for over 1.5 hours! That's an important step since they can see how the voltage and frequency regulation works without those generators operating.

Most days these generators have been putting out 1.6 MW.

Since that time, the average power of the diesel generators has been around 3 MW.

So far, this system has been in place for over a year and I have only seen the diesel generators off for a bit over 1.5 hours. Hopefully this is simply because they are still testing, but a year is a LONG time for testing.

It sure would be interesting to be able see the water level in the reservoir along with the production information.

 

[RegGuheert]

This post by Euan Mearns brings home the points made in the OP of this thread as clearly as anything else I have ever read. Here is the main graphic from that post:

 

[RegGuheert]

Here is a post by Roger Andrews on the El Hierro island energy system. Somehow he was able to gather all the production data since the system was commissioned late last June and plot it in a single graph:

As you can see, since the system went into full-time production in June, it has produced about 50% of the island's electricity, a far cry from the 100% touted by many commenters. This equates to a capacity factor of about 28% for the wind generators during the windiest portion of the year. They may be able to increase the amount of electricity produced to near the 80% value that GRA has suggested earlier in this thread if they add double the capacity of the wind turbines.

No, producing electricity from 100% renewable sources is neither cheap, nor easy, even given nearly-ideal conditions.

Still, as I have previously noted, this is the kind of renewable project which makes sense: It is limited in scope since it is on an island with already-expensive electricity which means the extra cost of the renewables is not as much of a burden (especially when subsidized by the UN).

The article also links to another discussion of an island which has achieved nearly 100% renewable generation since about 2008, albeit the demand (and therefore the system) is significantly smaller). Pretty cool!

 

[GRA]

Thanks for finding this, and the Eigg article as well (which dates from 2008). I hope you cross-post the El Hierro data into that thread. I found this 2015

Analysis of off-grid electricity system at Isle of Eigg (Scotland): Lessons for developing countries

http://www.sciencedirect.com/science/article/pii/S0960148115002438

but haven't had time to read it yet. It appears to include trade-off configuration analyses, which is good because barring exceptional conditions, AFAIA there's little economic justification for PV anywhere in the British Isles if you've got good wind resources, unless battery LCC is excessive. Edit: I've had time to skim through the configuration analysis section, and while the insolation is poor (avg. 2.79kWh/m^2/day), it's also nicely timed to complement wind, and the % from each source matches up well with NRL's HOMER analysis program. However, when full costs are used (i.e. without all the grant or 'free' money), the system changes as I'd expect, and has less PV and more wind. The 'hard' demand cap also plays a major role in the costs of this system.

 

[GRA]

From the lessons section of the analysis linked in the preceding post [my emphasis]:

6. Discussion and lessons for developing countries

The Isle of Eigg off-grid electrification system clearly shows that an off-grid system can support the electrical energy needs of a modern life style. The residents of the island are enjoying a reliable supply of electricity that meets their requirements effectively but more importantly, their carbon footprint has fallen considerably as about 90% of their electricity comes from renewable sources of energy. It is reported that the CO2 emission per household in the island is 20% lower than the rest of the UK [5]. The first lesson from this experience is that a suitably designed off-grid system can be an effective electrification option for any developing country. This experience confirms that reliable and modern life-style enabling supply can be ensured through an off-grid system and that such a system is not inferior to the supply obtained from the main grid. The islanders receive 24 h supply and have no complains about the supply. This demonstrates that an off-grid supply need not be a temporary or a pre-electrification option. This is an important message given that policy-makers and users are not always aware of successful examples and inaccurate or wrong impressions influence their decision-making.

While the island system provides a reliable electricity supply, it also placed a demand cap on the consumers. The appropriate level of service and benefits desired by the consumers that they can afford plays an important role in the system design. It is likely that domestic consumers of rural areas in developing countries will demand much less electricity and their needs can be met with a much lower level of cap. At the same time, commercial, agricultural and small-scale industrial activities could be envisaged to achieve a better capacity utilisation of the system and to generate income for the supplier and the local community. The second lesson from the study is that a tailored solution that adapts to the local needs works better.

Yet, the cost of supply remains a major challenge. Based on our simulations of the Isle of Eigg system we find that the residents are paying a tariff that is equal to the operating cost of ensuring the supply without taking capital investment costs. Even this level of tariff is much higher than the tariff for a comparable supply from the central grid elsewhere. This is still the case despite the high share of hydropower in the electricity supply mix in this island. Although the residents have reduced their expenses on diesel fuel and alternative energy supply options (such as batteries), there is no denial of the fact that even the operating cost recovery makes the tariff high and unless the users are able to pay such high tariffs, an off-grid system cannot become operationally viable. In this example, islanders have accepted the cost as the alternative they relied on earlier was costlier. They also have the ability to pay but this remains an issue in many developing countries, particularly in rural areas where income may be limited and villagers may not afford to pay high charges. Thus the third lesson is to design an effective tariff system to ensure the financial viability of an off-grid system, without which a sustainable supply cannot be ensured. Unless the supplier is able to recover costs and provide for future replacement of components, such projects are cannot be sustained in the long-run. The feed-in tariff, where available, can help reduce the burden to some extent and promote private investment in this area. However, implementing a feed-in tariff system for off-grid areas in developing countries with a limited number of electricity consumers and poor institutional arrangement remains a challenge.

A related issue is the funding of the investment for developing the system. The initial investment for the off-grid system in the island was £1.66 million (that turns out to investment above £44,000 per resident). Clearly, mobilising such an investment is not a mean task. For this island, the funding came from various sources with residents contributing about 6% of the cost. Unless such capital subsidy arrangements can be developed, poorer countries will find implementation of off-grid electrification projects very challenging. Thus the fourth lesson that Isle of Eigg offers is that even in a developed country context, capital subsidy could not be avoided for off-grid electrification and that the poor in developing countries cannot be expected to pay for their off-grid electricity supply systems. Sufficient grant fund has to be mobilised to create the electricity infrastructure in developing countries.

This study also confirms that in order to ensure a reliable, round-the-clock supply from an off-grid system, demand assessment and demand management remains very crucial. There may be some periods of excess generation while there are other periods when the supply will be constrained. An equitable and fair energy budget for all users and a smart energy monitoring system are essential to ensure effective user engagement in managing the supply-demand balance. The islanders have ensured success of their system by learning to share the limited resource using the signals provided through their meters. The fifth lesson therefore stresses the need for active user participation. The success of the system crucially depends on the active co-operation of the users who manage their demand effectively using the energy monitoring system. In a small system with limited diversity of demand, balancing supply and demand is always a crucial task and just relying on the supply-side management cannot ensure a reliable supply.

Sixth, our simulations also highlight the importance of system design and component selection for a cost effective outcome. As indicated earlier, the island system was over-designed to ensure high system reliability. In fact, the diesel generator capacity itself is much higher than the demand, although such a non-renewable option would lead to an excessive cost of supply (£1/kWh). It has been pointed out earlier that similar levels of reliability could have been achieved with 80 kW of diesel generator capacity (instead of 160 kW installed at present) but this would require using smaller generator sets that can be maintained and operated as required. Similarly, a better result would emerge if more wind turbines were installed instead of solar PV in this site. We have also indicated that direct feeding of AC load from AC sources could reduce the inverter and battery capacity requirements and can enhance the reliability of supply (simply because the entire system does not depend on batteries in this case). The technical choice has significant cost implications, particularly for the capital investment and a careful system design with innovative smart features can offer better value for money.

 

[RegGuheert]

From the lessons section of the analysis linked in the preceding post [my emphasis]:

Thanks for finding this article. Several of the items in the article struck me:

This is the big one:

The initial investment for the off-grid system in the island was £1.66 million (that turns out to investment above £44,000 per resident). Clearly, mobilising such an investment is not a mean task. For this island, the funding came from various sources with residents contributing about 6% of the cost.

So the islanders managed to pay 94% of the system costs using other people's money, thus allowing them to lower their COE to around £0.20/kWh plus a monthly connection fee. It appears that they also enjoy a FIT on top of the initial investment, something which is no longer available under current laws.

This leads to a couple of likely conclusions:

1) It is VERY unlikely that this system would have ever been built had the beneficiaries been required to bear the entire cost of the system.

2) This system is now seven years old and things are going to begin to fail. I wonder if the residents will be able to maintain their supply of electricity in the case of a failure of one or two major subsystems. Some parts of the system will undoubtedly last for a very long time, such as the distribution system, the PV modules and the hydroelectric generators, but the batteries, wind generators and the inverters are likely already in the second half of their lives. When these items start to fail and need replacement, the residents will need to pay more in order to handle the expenses.

Regarding operational issues:

3) Hopefully the four banks of batteries are being operated in a manner which will cause them to fail at different times, perhaps spaced two years apart. That will allow them to operate without the failed bank of batteries and inverters for a period of time necessary to procure and install appropriate replacements.

4) I expect that 6kW wind generators will have an average life of about 10 years, if not less. Hopefully those failures will be spaced apart by at least a year to allow the residents to arrange for and pay for appropriate replacements.

Finally, I will note that the expenditure of £44,000/person on this Island has allowed the reduction of their overall fossil-fuel consumption by 20%. I'll take an educated guess where the rest of the fossil fuels are consumed:

10% Water Heating
20% Transportation
40% Space Heating

It is likely that all of these needs could be met by renewable energy (boating fuel may be an exception), but I suspect that would require a system 2.5X to 3X the capacity of the current system. BEV charging would need to be spread over the available power curve of the renewable genrators and many of those online batteries could provide for the needs of the community during times of low renewable generation, particularly if BEVs with oversized batteries are purchased. Water heating coud be done using heat pumps, at least during the warmer portions of the year. Likewise, space heating could be done using heat pumps.

Such a change would require total per-person capital investment (assuming existing system did not exist) of approximately:

- £120,000 for electricity system
- £20,000 for BEVs (one for each pair of residents, on average)
- £5,000 for home heat pumps (one for each pair of residents)
- £500 for heat-pump water heaters (one for each pair of residents)

The bottom line then (very roughly) comes to a cost of approximately £150,000/resident to move an island such as this to nearly 100% renewable energy. Assuming the capital is available via a low-onterest loan, does that represent an increase in the total cost of energy for the residents? I would gues yes, given that they would be making all of the capital expenditures all at once rather than in the past. By how much? It's hard to say. I'll guess 3X, but perhaps it's only 2X (above their already-high energy costs).

What will be interesting to see is whether, going forward, the residents of this island will continue to cut their fossil-fuel consumption, hold their own, or increase it. I think the answer will largely depend on whether or not they are able to afford to keep the existing system operational.

 

[GRA]

<snip>
This is the big one:

The initial investment for the off-grid system in the island was £1.66 million (that turns out to investment above £44,000 per resident). Clearly, mobilising such an investment is not a mean task. For this island, the funding came from various sources with residents contributing about 6% of the cost.

So the islanders managed to pay 94% of the system costs using other people's money, thus allowing them to lower their COE to around £0.20/kWh plus a monthly connection fee. It appears that they also enjoy a FIT on top of the initial investment, something which is no longer available under current laws.

This leads to a couple of likely conclusions:

1) It is VERY unlikely that this system would have ever been built had the beneficiaries been required to bear the entire cost of the system.

2) This system is now seven years old and things are going to begin to fail. I wonder if the residents will be able to maintain their supply of electricity in the case of a failure of one or two major subsystems. Some parts of the system will undoubtedly last for a very long time, such as the distribution system, the PV modules and the hydroelectric generators, but the batteries, wind generators and the inverters are likely already in the second half of their lives. When these items start to fail and need replacement, the residents will need to pay more in order to handle the expenses. <snip>

What struck me was the relatively large distance covered by the grid for such a small number of households and businesses, and the restricted loads. I haven't bothered to try and cost it out, but with the numbers given in the analysis and your estimates, ISTM entirely likely that it would have been cheaper to just give each house (or each cluster of houses) their own stand-alone system, given that they were already practicing a 'hard' demand management. I always told my off-grid customers that the more they understood the system, the less it would cost them because they could practice demand management and load shifting, and although this is top-down rather than bottom up DSM, the end result is the same. Lots of stand-alone would be a lot easier if they had better solar and less wind and hydro, because scale is less important with PV.

 

[RegGuheert]

Here is another article about El Hierro. This is from the same site as the last one, but from a different author. In the first comment, one of the primary site authors disputes some of the assumptions made in this article.

Here's the summary:

SUMMARY

An analysis of the El Hierro island electric data found on the Red Eléctrica de España site for the period from June 26 to August 31, 2015 shows that the renewable contributions have covered 49.5 % of the electric demand of the island. It also shows that with the present wind plus storage system this renewable fraction can’t exceed 80.1 %(2). Neither the capacity of the smaller reservoir of the pumping system, the power of the pumps, nor their efficiencies appears to be the limiting factor. Increasing the active wind power appears as the most effective option to reach a higher renewable fraction.

Really, the article makes the case that the current system *could* achieve about an 80% renewable fraction IF it were operated differently (which is what is disputed in the comments).

Another interesting point:

The upper reservoir is larger: 380 000m3(8) . It has other functions than electric production. For instance it provides irrigation services. This explains why the sea can’t be used as lower reservoir.

In other words, this system is a fresh-water system. I hadn't realized this The lower reservoir can be emptied into the sea, but it cannot be filled directly from the sea.

Another surprising bit of information from this article is the amount of electricity used for the provision of fresh water (desalination and pumping) for agriculture and residential use:

6. According to local authorities 50% of the island’s electricity consumption is allocated to the production and distribution of water. According to my scenario 48% of the electricity generated on El Hierro between June 26 and August 30 went to produce and distribute water (5,500 MWh, about evenly split between desalination and pumping, out of 11,400MWh total generation).

Finally, from the first comment by Roger Andrews, we see this image:

What is obvious is that after the first part of September, diesel has again become the dominant source of electricity on El Hierro island.

It's clear that El Hierro is still a long way from providing 100% of its electricity from renewable sources, in spite of the many news reports that this would be the case.

 

[RegGuheert]

Here is yet another article on El Hierro. The main point of this article is that most of the water pumped into the upper reservoir this summer was NOT used to produce electricity, but rather for irrigation and other uses:

The other significant point is that this project is very far from providing 100% of the island's electricity consumption. Instead, it has merely provided that fraction of the electricity which represents growth since the project was conceived a few years ago. Unfortunately, the addition of renewable energy to El Hierro island has not significantly reduced the consumption of fossil fuels. Rather it has primarily allowed the consumption of more electricity.

Simply put, what has been hailed as a hallmark of what renewable energy can accomplish is instead proving to be an extremely clear demonstration of Jevon's Paradox.

 

[AndyH]

http://energytransition.de/2015/11/renewable-energy-and-storage-lessons-from-germany/

According to conventional wisdom, renewable energy need storage options. While it is true that a completely renewable energy system would need mechanisms to balance supply and demand, there is surprisingly little need for energy storage until renewables reach a really high share in the power mix. Martin Tampier reviews the scientific literature and looks at the implications for North America.

“To achieve the mind-term goals of the Energiewende, does not depend directly on the addition of power storage options… In the longer term, if the share of flexible energy generation options (such as solar thermal or biogas) increases and if demand can be managed flexibly, then even high renewable energy penetrations (about 90% in Germany and over 80% in the rest of Europe) can be balanced by the power system without the addition of new storage options” (p. 45 of the German summary).

In the same vein, the second study, led by the renowned Fraunhofer Institute, concludes that “Up to a renewable electricity share of 60%, the addition of power storage devices is not a condition for the addition of solar PV and wind power plants… Even at high degrees of penetration (90% in Germany), the required balancing can largely be achieved without additional power storage” (p.13).

 

[WetEV]

http://energytransition.de/2015/11/renewable-energy-and-storage-lessons-from-germany/

I love the last comment.

I really wonder how one can come to the conlusion that no additional storage capacity is need. Just look at wind and pv production in UK, Denmark and Germany from October 17 to 21. Tiny production for four days in a row.
The conventional capacity to provide almost 100% of demand will not be around forever.

I wonder as well.

 

[AndyH]

http://energytransition.de/2015/11/renewable-energy-and-storage-lessons-from-germany/

I love the last comment.

I really wonder how one can come to the conlusion that no additional storage capacity is need. Just look at wind and pv production in UK, Denmark and Germany from October 17 to 21. Tiny production for four days in a row.
The conventional capacity to provide almost 100% of demand will not be around forever.

I wonder as well.

That's actually covered in sufficient depth in the article. TLDR: Germany and the rest of the EU already has more than sufficient storage in place because the fossil fuel grid requires back-up as well.