Wind turbines in Denmark reached record level in 2014(energinet.dk) |
Wind turbines in Denmark reached record level in 2014(energinet.dk) |
This puts wind and hydro at around 42%.
https://www.scottishrenewables.com/sectors/renewables-in-num...
http://www.ise.fraunhofer.de/en/downloads-englisch/pdf-files...
There is an extensive planning process with weather forecasts and peak consumption predictions (break in the football world cup finals for example) to prevent sudden surprising changes. Different kind of power plants have different timelines that it takes to power them up and down. Small peaks in demand can be covered with gas plants since they are very fast to power up and down, but they are expensive. Coal plants take a day, nuclear - forget it-, and solar and wind can be predicted fairly well with the weather (there are plots about the success of predictions in the pdf), water is fairly stable and biomass behaves like gas. You really only want to produce what is consumed, and then there's export and import. There are charts for that as well.
https://carboncounter.files.wordpress.com/2014/11/germany.jp...
Pretty crazy, it really calls for storage solutions doesn't it. Hell even if you had the same smooth wind every day, there'd be a huge demand/production discrepancy during sundown if enough wind is installed.
http://spectrum.ieee.org/energy/the-smarter-grid/lets-build-...
I at least don't know yet how it's going to shape up.
I can imagine worse problems.
Certainly, it's economically suboptimal. We do need storage or some other kind of energy consuming business that can absorb energy that's nearly zero-valued on the spot market.
But having so much excess renewable energy that it has to be pushed on other countries - and possibly forces coal plants to throttled back there - is not all bad.
Right now the various grid operators pay huge money to get renewable producers to shut off production. This is not ideal.
If not, what percentage of total electricity use are we talking about?
If or if not, what percentage of total power use are we talking about?
The author mentions a 400 MW wind farm, and then says that correlates to 400,000 homes. Unless homes in Denmark use only 3% of what homes in the US use on average[1], that number should be somewhere closer to 15,000 homes.
So 400 megawatts might only power 300,000 US homes, but the scale is about right.
If 39% of Danes' electricity completely displaced the same amount of fossil fuels, my jaw would hit the floor.
https://en.wikipedia.org/wiki/File:Electricity-prices-europe...
Part of it, not shown in that breakdown below, is the "Public Service Obligation (PSO)" tariff DKK 0.214/kwh (USD 0.031/kwh), primarily used to subsidize renewable energy (http://energinet.dk/EN/El/Engrosmarked/Tariffer-og-priser/Si...). Given the wikipedia cited total price of ~USD 0.40/kwh, and the breakdown linked below showing that the actual cost of the electricity is only 18% of that, 7.2 cents per kwh, a 3.1 cent per kwh renewable energy subsidy is pretty significant...
Note that this subsidy has been going up with the increase in wind power. Q1 2014 price was DKK 0.19 - http://www.energinet.dk/EN/OM-OS/Nyheder/Sider/Energinet-dk-...)
"""For example, some wind turbines are guaranteed a fixed price for the electricity they generate.
The PSO tariff rises, as the electricity price is low at the moment and the difference between the amount the electricity consumers must pay for electricity and the amount some energy producers are guaranteed thus is more significant. Furthermore, Denmark will have more renewable energy. The objective is that 50% of all electricity must come from wind turbines by 2020. Finally, a new increased funding to electricity generated by biogas will enter into force - and must be paid out"""
See also, http://www.energinet.dk/EN/OM-OS/Nyheder/Sider/Energinet-dk-...
https://www.energifyn.dk/privat/elhandel/bag-om-elprisen
Orange is tax, grey is VAT, yellow also has some tax-like elements.
The slight problem with that model is that in principle, it should be cheaper when the energy is green, and more expensive when it is not. But the state has come to rely on the tax, so now it is a bit murky what it is really for.
Denmark's electricity price is the highest in the EU "when you count in taxes and VAT, which go to produce other useful outcomes. However, Ireland together with the UK has the highest energy prices excluding taxes, closely followed by Cyprus and Spain. Interestingly enough, three of these are islands.
It would be interesting to see these prices without subsidies, as the energy market is pretty global and these big differences must come from something else, I think."
http://ec.europa.eu/eurostat/statistics-explained/index.php/...
Of the four you mention, three aren't connected to that grid, and I would guess the link with Spain doesn't have sufficient capacity to even out peaks and troughs in Spanish demand (http://ses.jrc.ec.europa.eu/power-system-modelling does show a fairly thin line between France and Spain, both large countries in population)
The above is 100% educated GUESS. Corrections welcome.
The cheapest fixed price I could find is $0.34 per kWh, on Elpristavlen[0] (lists of power prices)
DONG Energy[1] states a price of $0.27 per kWh.
Note that the price might not include power sources from renewable energy, and it excludes the subscription you pay to the power company.
[0] https://www.elpristavlen.dk/
[1] http://www.dongenergy-distribution.dk/erhverv/eldistribution...
There is also this statement:
" Wind power achieved a new record of 29.7 GW in peak power production at Friday, 12th of December 2014. The daily wind energy production was 562 GWh. Both figures represent new records. The last records of 5th of December 2013 with a maximum power of 26.3 GW and a daily energy of 485 GWh have been exceeded by 13% resp. 16%. Photovoltaic power reached a maximum of 4.9 GW at the same day. The maximum total power from solar and wind was about 34 GW, which is well below the maximum of 14.4.2014 when a total production of 38.8 GW was reached.
In order to provide sufficient space for the wind power in the grid, nuclear power plants have reduced their base load generation by about 10%, lignite plants by about 30%."
[1] http://www.ise.fraunhofer.de/en/downloads-englisch/pdf-files...
There's also a plan that involve simply pay large power consumers to halt production do compensate for missing electricity in the grid.
The Danish power grid is also closely linked to the those of Norway, Sweden and Germany, allowing export of cheap wind power, when there's a surplus and import of nuclear, hydro, coal and gas when there's no wind.
You're right in as so fare that wind power isn't magical, there needs to be a backup when the wind isn't blowing.
But wouldn't it be true to say that store is the cheaper alternative to installing excess capacity, the alternative with less local resistance (a political issue with both on and offshore wind), and the alternative with fewer maintenance issues versus e.g. offshore wind? Let me know if you have any numbers on that.
I've checked some numbers myself. For example, even domestic storage (which includes things like an inverter already) like the Tesla powerwall costs $3500, and has 5.000 full depth cycles of lifetime, and a capacity of 7 kwh. Meaning purely for storing and using 1 kwh, it's about $10c. That's more than the cost of onshore wind (about 7c or so, differs per country).
But we know that utility scale batteries can be much cheaper (I mean these Tesla powerwalls are quite similar to batteries that go into cars, their energy density is very high due to space constraints. If space and weight is not a concern you can build cheaper batteries), plus batteries as an industry are currently on a much steeper decline in cost annually than renewable generation technologies so going in to the future storage should become much more attractive, even as extra generation becomes more attractive, too.
One example is Alevo, found an interesting post about it I'll quote here: > Alevo is claiming $100/kWh and 40,000 cycles. That works out to $0.003/cycle. Financed for 20 years at 5% would mean a $0.022 price per cycle over the first 20 years and then the cost of storage dropping to roughly zero for 89 more years.
That's 2-3 cents per cycle. It'd be really hard to make the case for excess wind capacity over storage. Particularly because on some days wind generation is still near zero. The image I showed shows the top day generating 200x as much as the bottom day. To generate enough on the bottom day, you need a ridiculous amount of excess capacity generation to compensate, capacity that may be more expensive per kwh than storage, that overproduces the rest of the year (while still costing money, unlike storage which costs money per cycle, i.e. when used), and exacerbates the non-financial issues of wind (e.g. landscape changes that local people resist).
It's looking like storage is going to be playing a huge role.
Of course storage is going to play a huge role, that would be hard to deny. I just find the fact interesting that you can live with less storage if you have more capacity for energy production.
You only assume battery storage, right? AFAIK Norway has offered extensive storage by pumping water into high reservoirs (don't know the english name), which would be another option, and just one of many. Of course, that would require a lot of investments into infrastructure, and we're already fighting about that locally. (Nobody wants the power lines in their backyards.)
It's just pumped storage! :) Easy to remember.
But yeah there's a lot of things. Pumped storage is a big one, The International Renewable Energy Agency in their roadmap for 2030 for example call for just 150 GW of battery storage, but a whooping 325 GW of pumped storage.
There's other ones, too. One of them is storing thermal, heat energy in caverns, or in rocks. You can then extract when you need to, so you could take wind energy at night when there is barely any demand and use it to electrically heat up rocks, and store the energy for the next day.
Molten salts is similar but different.
Ice, same thing for air conditioning purposes. At night you use excess electricity and essentially run a big fridge on your roof to create ice, and then use that to cool the air during the day.
Those are all thermal storage. Then there's say pressure based storage, like compressing air and releasing it when you want to.
Flywheels are also a thing, you have a wheel and rotate it really fast using energy, and then just slow it down and capture the energy when you want to. It sounds pretty ridiculous but it works and there's various ways to reduce friction.
There are other big problems too with this. Firstly, the discharge/recharge rate - are these batteries actually able to pull in all this spare capacity and discharge it quickly enough - and also there is some loss going from AC to DC to battery to DC to AC which changes the picture a bit. Less of an issue if you have them right next to the solar, as you can push DC straight in, but otherwise an issue.
That'd put the daily storage at 140 gwh for Germany, or 140m kwh. (so definitely billions on a global scale).
Tesla cars might be a decent comparison point, they sell about 50k cars a year (more even this year), at an average of a 80 kwh battery per car they produce 4 gwh of storage each year.
But the Tesla gigafactory is set to produce a projected 85 gwh (of battery packs and cells combined) in a few years. Tesla's current battery products are set to last 15 years, although this may not be a reliable figure to use as it's a consumer grade, not utility grade product. But assuming it is, then every replacement cycle it can produce 1275 gwh of storage. Germany (with my crappy and quick assumptions above) would need about 140 gwh, and Germany represents about 1/16th of the world economy by the way, so a global figure with Germany's model would require 2240 gwh, about twice the projected 15 year production of the gigafactory. (which, we ought to assume, wasn't built without checking if there was enough lithium to run it :p, and given there's already talk of the next one (it's been renamed gigafactory 1, this alone probably says that lithium running out probably isn't the biggest concern).
About reserves though... well there's lots of resources, like close to 40 million tons. reserves (resources that are, today, economically and technically feasible to extract) are lower, but still a substantial 14m tons.
So how much does storage need... well for one we can look at annual production which is 36k tons for 2014. So if we capped out at today's rate, the 14m tons of reserves (the resources that can be mined at a profit), would last close to 400 years. I think it's pretty likely we'll hit a rate of usage that's 3-4 times higher than it is today at some point, so that'd drop that figure down to just 50 years. But I also think more resources will become reserves (as mining technology cheapens), and more resources are found (as exploration techniques improve, see shale gas), and I also think recycling will pick up and increase net production without reducing reserves (afaik recycling is still small for lithium, but growing).
One thing to note here is that apparently lithium is only accountable for about 1% of a battery's cost (at least a few years ago, with lithium prices not dropping and battery prices dropping the past years, it may be a few percent by now). This is generally good news as it means that you can pay e.g. (hypothetically) 5x as much for lithium while barely increasing the price of a battery by a few percent. And if lithium prices go up by 5x, then more resources become reserves, and more resources will be found through exploration due to renewed economic feasibility, meaning lithium scarcity can be sharply reduced without increasing prices of batteries much at all.
Actually I found some numbers too, about 500g of lithium metal for every 1 kwh of storage. So how much storage can we built if we exhausted the 14m reserves entirely, well almost 30k gwh. For comparison, The International Renewable Energy Agency called for 150 GW installed capacity by 2030, which corresponds to roughly 200 gwh or so.
Plus the company I mentioned is going for ridiculous amount of cycles, like 40k of them. That's a very long lifetime compared to say the 5k cycles of the new 7kwh Tesla powerwall, or the 1.5k cycles of the 10kwh version. That means production can be cut in half because batteries last longer, to sustain the same storage levels. Plus grid-scale storage I think is much easier to recycle compared to consumer storage.
So I don't think we've got a resource problem, but again all of these are back of the envelope numbers I'm just throwing out there. I also didn't mention that batteries are only about a third of total lithium consumption, so there's that, too. The other issues you mentioned though are there and definitely need to be overcome.
The net effect of this is that electricity originally generated by nuclear plants and other fossil fuel plants gets 'converted' into (more expensive!) 'green' energy.
It's a kind of white-washing for electrons. The price difference can be substantial more than making up for the cost of the pumping and subsequent re-generation.
And of course it's the energy sold to the public that matters, not how it was originally generated so by double counting this energy it changes the balance considerably without there actually being more renewable energy to begin with.
Currently both pumped and hydro are making up about 1% of the UK grid each: http://www.gridwatch.templar.co.uk
It's only useful to think about it in the short term as long term it adds nothing. It just functions as a buffer.
You can go round one in Wales: http://www.electricmountain.co.uk
This is not renewable energy though it masquerades as such. Note that before green energy became a thing this was already happening so it is simply a re-labeling rather than that these lakes suddenly got re-purposed for renewable energy storage.
If the source of the electricity is not originally renewable energy then it is deceptive to sell it as such. People pay a pretty premium for renewable energy.
Pumping upward typically happens when the renewables are overproducing and the (controllably) variable power plants are idling. It makes no sense to run the pumps for storage when you could throttle back the gas turbines instead. But you can't adjust cloud cover, or tweak windspeed. So when the sun is shining, and the wind blowing, and the methane not burning, you store that excess for later.
That may also include relatively constant baseline power plants. But even then, the storage is often allowing those plants to run at their optimally efficient design capacity. If you idle the coal plant to 80% rated output, you may still be using 85% as much coal (made-up numbers for illustrative purposes). Trying to adjust the output of a nuclear plant is rather complicated, and may involve altering shutdown and maintenance schedules such that the output capacity several months in the future is affected by a decision made today.
So on the whole, re-generation from pumped storage is going to be greener than the baseline plants, and definitely greener than other types of adjustable peak load power plants, like natural gas turbines.
A big part of US climate strategy seems to be to install a lot of wind and solar power and fill the rest with natural gas, phasing out coal. Keep the nukes that are there. That's possible since in the USA, natural gas is cheaper than in many other places.
As for the bookkeeping:
A certain amount of electricity is produced using renewables which is always < the current baseload. It is then (much) more profitable to sell this energy to consumers directly and then to use the reduced base load requirements to top off the lakes before reducing base load generation capacity. At night the process reverses and now the 'newly minted green electrons' get added to the green energy already being sold. This makes more money than selling the nuclear/coal/NG generated electricity directly even though there is some loss from the whole pumping operation.
Note that the scheme already made money based on the demand pricing of electricity, the 'green' aspect simply made it more profitable.
In some situations, even pumped storage storing non-renewable power power is "greener" than you seem to imply. The problem is that nuclear generators can't stop producing electricity when it's not needed; let's say you are France and a large part of your electricity is generated with nuclear power. If you can't store your energy, during the night you're producing power that you need to waste away. And during peak hours, you need to turn on many gas turbines to get additional power.
If instead you can store your additional energy during the night, and use that one during peak hours, you burn less fuel and pollute less.
This is one of the early large ones, built by the local utilities:
Not necessarily!
It may be, it may not be. It depends on the time and place and whatnot. Pumped hydro today might be mostly "white washing" today in Scotland. It might not be "white washing" tomorrow in Germany. It depends on a lot of factors.
If the electrical rates do occasionally go negative in mainland Europe (from wind) and there are pumped hydro stations there then it's entirely possible that the wind electrons are the ones pushing the water uphill rather than the fossil fuel electrons, and then when that water eventually does generate electricity again, it's technically still renewable.
https://en.wikipedia.org/wiki/List_of_pumped-storage_hydroel...
It sounds like the plant that you visited in Scotland was white washing, at least when you visited. But that doesn't mean that all pumped hydro everywhere in the world definitely, for sure, guaranteed, is also doing the same.
Yes !
> Trying to adjust the output of a nuclear plant is rather complicated, and may involve altering shutdown and maintenance schedules such that the output capacity several months in the future is affected by a decision made today.
Older nuclear power plants may take many hours, if not days, to achieve a steady state power output but modern nuclear plants with light water reactors are designed to have strong manoeuvring capabilities. Nuclear power plants in France and in Germany operate in load-following mode.
http://www.world-nuclear.org/info/Country-Profiles/Countries... says:
"There are two ways of varying the power output from a PWR: control rods, and boron addition to the primary cooling water. Using normal control rods to reduce power means that there is a portion of the core where neutrons are being absorbed rather than creating fission, and if this is maintained it creates an imbalance in the fuel, with the lower part of the fuel assemblies being more reactive that the upper parts. Adding boron to the water diminishes the reactivity uniformly, but to reverse the effect the water has to be treated to remove the boron, which is slow and costly, and it creates a radioactive waste.
So to minimise these impacts for the last 25 years EdF has used in each PWR reactor some less absorptive "grey" control rods which weigh less from a neutronic point of view than ordinary control rods and they allow sustained variation in power output. This means that RTE can depend on flexible load following from the nuclear fleet to contribute to regulation in these three respects:
- Primary power regulation for system stability (when frequency varies, power must be automatically adjusted by the turbine).
- Secondary power regulation related to trading contracts.
- Adjusting power in response to demand (decrease from 100% during the day, down to 50% or less during the night, etc.)
PWR plants are very flexible at the beginning of their cycle, with fresh fuel and high reserve reactivity. But when the fuel cycle is around 65% through these reactors are less flexible, and they take a rapidly diminishing part in the third, load-following, aspect above. When they are 90% through the fuel cycle, they only take part in frequency regulation, and essentially no power variation is allowed (unless necessary for safety). So at the very end of the cycle, they are run at steady power output and do not regulate or load-follow until the next refueling outage. RTE has continuous oversight of all French plants and determines which plants adjust output in relation to the three considerations above, and by how much.
RTE's real-time picture of the whole French system operating in response to load and against predicted demand shows the total of all inputs. This includes the hydro contribution at peak times, but it is apparent that in a coordinated system the nuclear fleet is capable of a degree of load following, even though the capability of individual units to follow load may be limited.
Plants being built today, eg according to European Utilities' Requirements (EUR), have load-following capacity fully built in."
http://www.neimagazine.com/features/featureload-following-ca... says:
"Slow ramps of =1.5% Pr per minute are most often used in France and the typical low power level is about 50% Pr. However, sometimes nuclear power plants operate at power levels below 50%. Some plants operate in a special operating mode (18 hours at rated power and 6 hours at low power) with steep ramps of 2-5% Pr per minute. In this mode the reactor is always capable of returning to the rated power level in a very short period, with a fast ramp of 5% of Pr per minute."
More on load following in nuclear power plants: http://www.oecd-nea.org/ndd/reports/2011/load-following-npp....
Basically, it takes about 500 hours (3 weeks) before a chain-reacting fission core reaches equilibrium with neutron-absorbing reaction products. A core that is late in its fuel cycle might not be able to achieve a self-sustaining chain reaction from a shut down state until after the radioactive neutron absorbers have been left a while to decay.
The longer the fuel rod has been in the reactor, the less you are able to modulate its output.
You really do have to look at Europe (especially France) for operating nuclear plant best practices, because most plants in the US are not built to a common design, and they may not be able to adopt improvements pioneered at another site. The US solution is usually to put the upgrades into the next-generation reactor designs, which never quite get to replace the old existing designs because of radfear and NIMBYism.
Let's say you charge $0.15/kWh for "green" electricity and $0.10/kWh for "black" electricity. You can't change the color of the electrons once they are in the grid, just to make more money.
To say otherwise is to end up with stupid schemes like using a sulfur plasma lamp, powered by coal-burning, to shine artificial light on a solar cell. Or run air fans with your nuclear steam turbine to blow air across your wind turbines. Or endlessly pump the same water over a hydro turbine.
Power from pumped storage generates the same "color" of electricity as the electricity used to run the pumps. If the grid was 15% green when it went up, it will be 15% green when it comes down.
Awesome trip, we took a mini clubman (the real deal) to Scotland.
http://www.amazon.co.uk/dp/1841582255
Also this chap has a fairly good bunch of images and maps of various scheme throughout Scotland, apparently blagging his way into some facilities to take photographs:
http://www.corestore.org/hydro.htm
It's a bit "Web 1.0" but there's some interesting stuff to look at if you like that sort of thing (which I do :) )
This is one of the reasons that the blackout of 2003 lasted as long as it did, due the rapid decrease in load a couple of nuclear plants did a rapid shut-down.
Most base-load generating plants are difficult to adjust to a rapidly varying load.
This does create a minor issue if the grid fails, but that’s a rare event and doing an actual shutdown is considered safer.
http://www.oecd-nea.org/ndd/reports/2011/load-following-npp....
https://www.oecd-nea.org/nea-news/2011/29-2/nea-news-29-2-lo...
What's more, we have dammed almost everything we could dam ...
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