Scotland does pretty well with regards to renewables with ~49.8% of energy consumption sourced from renewable sources (17.1k GWh wind/hydro out of 19k GWh total renewables).
Scotland (and other countries besides) has a lot of 'pumped storage', lakes at a relatively high point that are fed from lakes at a lower point by running pumps that push the water from the lower lake to the higher one when energy is cheap and then back into the grid when it is more expensive (when there is a scarcity).
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.
Pumped storage is typically reported separately from Hydro. So much so that Hydro is officially referred to as "Non-pumped storage Hydro". Pumped isn't included as a renewable because the energy mix will depend on when it's recharging as a consumer of the grid. Typically this is overnight so usually nuclear power and wind is used as coal and gas spin down then.
No, pumped storage is not "white-washing" : energy storage is the key piece to making unpredictable energy sources viable, by storing during low demand and having a buffer instantly available to respond to peaks. It displaces having extremely expensive gas turbines on standby or lighting up fuel burners during peak loads, so it has a direct impact on reducing fossil fuel consumption.
Of course it is. The arbitrage is what makes it happen because that's what makes it profitable. If the energy so generated were labeled with the point of origin then it would count as fossil fuel and then it would yield less on the energy market. The load variations are not such that the generating capacity could not be reduced in time, but there is less money in that.
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.
Pumped storage has the same "greenness" profile as the whole grid had when the pumping was happening, minus the efficiency loss from the round-trip conversion.
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.
Gas turbines are not that expensive in capital. Instead they cost a lot to run, since they use gas that's much more expensive than coal. (Nevermind Uranium or wind or the sun.)
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.
Scotland only has one pumped storage scheme (Cruachan). It's annual generation was only 705 Gwh (as at 2009), which is only 13% of total hydro generation. Sure there might be "green electron" washing going on, but it's probably not significant.
I visited the station a few years ago and it is the reason for my original comment, at the time this was explained in some detail by one of the people on the tour. Very impressive by the way and highly recommended if you're in the region.
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.
> 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.
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.
I thought the whole point of pumped storage was to use solar / wind to do the pumping and release the water back (thus running the turbines) when it was dark or not windy. Why are they using nuclear or fossil fuels?
Yes, that's another use. But when it is favorable economically speaking then fossil fuels and nuclear will be used as well. The pumps don't care what color the electrons are. It's mostly a matter of bookkeeping and less one of technology. And as long as demand for electricity during peak times does not coincide with the point in the day when the peak amount of electricity is generated this is a nice way to make some money for the operators.
The owners of coal and nuclear plants are the ones that paid for the pumped storage, they had the idea of making their plant operations more efficient, not of storing renewable energy.
This is one of the early large ones, built by the local utilities:
I am not sure about coal, but you can't easily shutdown a nuclear reactor, so there are times during the day when you are overproducing. So pumping some water is a way to not totally lose the energy produced during that time.
Sure, but during a suitably windy night who's to say that a good number of those electrons used to refill pumped storage schemes aren't sourced from wind farms?
Does that report mention consumption anywhere?
This article is about consumption, not production, so it doesn't really make sense to compare this report to the article.
If you put it into the net, it has to be consumed somewhere. If there is too much production you have to take plants off the grid, and I think those are not included in the plots.
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.
The big problem with this is oversupply of the grid. While Denmark has the ability to export to Norway, Sweden and Germany (amongst others) it's likely wind production will be at high levels in neighbouring countries. Germany often has a huge oversupply of energy, with electricity prices turning negative.
This is just a temporary problem. One alway could just switch wind/solar plants off, if there were really no other way to deal with the electricity. The problem is not so much with oversupply but, that there is not enough oversupply for other uses of electricity to become economical interesting, i.e. large scale storage, building long-range networks, power to gas, etc.
That surprised me a little, Germany oversupplying because of wind. Wind is about 10% of electricity there, but then I looked up variability and it explains why:
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.
If you run the calculations you can see that the more you have installed over capacity the less storage you need (since you can also fully provide if there is less wind). It's a trade-off, really.
Of course, you don't need to run any numbers to see make the logical conclusion :-/
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.
I have some numbers from a basic simulation, but not on the political side. It has costs, though. (It's a bacholor thesis in German.)
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.)
> pumping water into high reservoirs (don't know the english name)
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.
Is there actually going to be enough lithium to build the many millions (billions?) of kWh of batteries to do this?
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.
Good points, I don't really know. Germany's currently producing 10% of electricity with wind, assuming they'd triple that to 30%, and then assuming that say about 25% of the generated wind energy falls so far outside of peak demand hours that it's excess energy to-be-stored.
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.
Norway uses mainly wind and hydro, Sweden mostly hydro and nuclear. When there's surplus wind energy, Sweden and Norway scales back on hydro and import from Denmark and Germany (through Denmark) instead.
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.
Energy storage is quickly becoming a critical part of the distribution infrastructure, whose cost should be borne by the unpredictable intermittent producers.
As other say: it is converging to Hawaii-prices, but most of that is Taxation. In Denmark, the policy has been to put taxes on resource usage in the later years and not only on income. In this case the resource usage is on fossil fuels.
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."
Looking at https://en.m.wikipedia.org/wiki/Synchronous_grid_of_Continen... and combining that with your remark, I would guess the electricity market isn't "pretty global". Yes, you can ship coal and oil about everywhere, but there seem to be economies of scale in larger networks, especially if your grid spans time zones (people switch on their stuff at different times in GMT), and Europe's does that.
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 text doesn't mention it, and it often is implied in these kinds of reports that this only is about domestic electricity use, so: does that include industrial use?
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?
I'm no electrical engineer (could be doing the math wrong), but I think there is a pretty glaring error in this page:
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.
You have not accounted for the difference between power and energy. 909 kilowatt hours (energy) divided by a month (720 hours) is an average of about 1250 watts (power).
So 400 megawatts might only power 300,000 US homes, but the scale is about right.
No, this is a correct figure. I think you are confusing power with energy. Also, the consumption of the average US home is a lot higher than in Europe.
But how much of this was overlapping power production with baseline fossil fuel production? Wind power often doesn't displace fossil fuels, it coincides with it, since wind is less predictable and coal plants take hours to ramp up/down.
If 39% of Danes' electricity completely displaced the same amount of fossil fuels, my jaw would hit the floor.
The charts I linked below [1] have a comparison for 2013-2014 for Germany (eg page 8).
I assume the situation in Denmark might be similar.
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%."
A few years ago I worked on software that manages selling electrical power from small decentralized power plants. When the wind isn't blowing the missing power can be supplied by electricity generated by plants that are built for generating heat. These are typically 2MW plants that can ramp up in 20 minutes or so, and they are scattered through out Denmark. These are all a mix of biomass, gas, oil or goal, or even garbage incinerators. The smallest one I saw was a large commercial greenhouse, with a 0.7MW generator. You bundle all the small plants up into 10MW packages and sell their potential output via www.nordpoolspot.com.
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.
As long as the windpower installed reduces the need for baseline to be produced the efficiency can get pretty good indeed. No matter how high it goes this will not result in all baseline power generation being halted simply because it takes time to bring those plants online (shutting them down can go quite fast but ramping them back up takes time). Also, because of the inherent instability of renewables you always want to have a certain percentage of the current requirement available as non-renewable just in case.
Not sure if its the same for the Danes, but in the US coal is being displaced by natural gas, which can be throttled quickly for grid demand response (and is cleaner, and releases drastically less CO2 per unit of power generated, and can be moved across the country quicker via pipeline vs trains).
It's more complicated than a simple breakdown of "high price because of taxes".
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...
"""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"""
This puts wind and hydro at around 42%.
https://www.scottishrenewables.com/sectors/renewables-in-num...
http://www.gov.scot/Resource/0048/00480365.pdf