We need to get out of the mindset that all power generators need to produce a steady amount of power 24/7. A flexible grid made of many power sources that can be ramped up and down can just as easily meet demand and may even be best since it is resilient when any one power source goes down for an extended period of time.
You can't just say that solar should be more expensive because it only works half the day. You could just as easily turn that argument around and say that nuclear and coal plants should be more expensive since they are only economical if run at a constant load and require long shutdowns every year for maintenance. There needs to be extra capacity on the grid to meet demand during nuclear/coal shutdowns, but no one states that nuclear and coal should be more expensive as a result.
The point is not that the "true" price in the sense of what it ought to be. It is the "true" price in the sense of what the market is actually paying for the service.
When people put out the number $23, they compare it with the cost of power and wonder why, if it is so much lower, it doesn't already swamp the current solution.
So the purpose of the comment is to explain that it is not a complete solution, and not reflective of the total ("true") bill.
Why should I worry about a complete solution?
We have a moderate sized portable generator, but running off that for weeks becomes a very unpleasant experience. Certainly far better than not having power, but unpleasant.
Driving 2 hours away to the nearest place we knew had unlimited fuel, turning my car into a rolling bomb on the trip back with dozens of gallons of fuel in gas cans, etc. And the endless droning of the thing running.
If those sorts of disasters are not a major concern for you, I don't think a battery makes much sense.
You can also store quite a lot of propane in a small footprint without some of the issues that come with gas or diesel.
That's a crass state, what causes these outages? Is it a investment backlog of the power grid?
You can also size your panels such that you never produce excess energy but you will be leaving a lot of roof space that could be making energy to waste. A sunny winter day still makes a ton of energy.
The grid will switch to solar + battery if it becomes cheaper than alternatives (gas, coal, nuclear, etc.)
It's such a damned shame that so many decades of potential progress in nuclear power were stymied by misguided FUD.
That's why.
If I move to a house with solar panels, I budget on power costs = cost of grid connection + X * grid power price + (1-X) * solar price (which is the capital cost of the panels smoothed out over their useful life).
The issue here is that I can't maneuver into a situation where my power price = solar price without sacrificing my ability to do anything after sundown without candles. Clearly, the true cost of power in a solar-enabled house is going to be higher than the cost of the solar panels.
Which was the point you misunderstood: dedicated storage installation are not needed at current production levels, and can be avoided even when solar's share of the energy mix grows.
Among the possibilities are "smart" appliances scheduling their demand to production peaks (dishwashers can often wait a few hours, cars might not need to charge right away). The same is true for industrial usage, where smelters, for example, have the natural capacity to store energy as heat.
A growing fleet of electric cars could also serve as distributed storage: if your car is parked for the night, it could feed energy back into the grid (partially, if you are paranoid).
More than batteries they utilize gas peaker plants, inefficient, dirty and expensive plants that can ramp up and down quickly to match demand.
You seem to be referring exclusively to solar photovoltaic.
Solar thermal generation has quite a different, evening-friendly, distribution curve.
I haven't followed closely recently but my impression was solar thermal has not delivered as promised. Things like Ivanpah was relying on natural gas more than expected. Is this an accurate impression?
Yet confusingly the article chose images of solar thermal. It's a bit of a worry when the journalists aren't conscious of the most basic aspects of the industry they are covering.
Perhaps, but we're better than conflating solar pvc with solar thermal - especially when we talk about large scale deployments, and even more especially when we talk about systems that incorporate Big Storage (batteries or otherwise).
Parent (to your comment) wasn't specifically PVC, parent (to them) wasn't either (more about true cost), and parent to them was bemoaning the common misunderstanding around how pricing works, rather than ethics / feasibility / ambiguity around underlying technology.
> I haven't followed closely recently but my impression was solar thermal has not delivered as promised. Things like Ivanpah was relying on natural gas more than expected. Is this an accurate impression?
My impression is that solar thermal is going to provide a much more scalable solution, especially in terms of avoiding the duck curve (or at least mitigating the impact of same). I see PVC + batteries being one of those tech combinations that works reasonably well in front of, as well as behind, the meter ... but solar thermal's definitely grid-level.
By coal standards?
It is swamping the current solution - it just takes a while for new plants to be built and old plants to go offline.
Which is to say, for example, that a grid supplied by solar and wind will need proportionally less storage per megawatt as the geographical size of the grid increases. A larger grid "averages out" the intermittent sources better as it gets bigger.
A state sized utility solar installation is non-trivial and that's why you don't yet see utilities providing solar themselves to the grid, and even if they did the price would be different.
So you don't see everyone using it because it's expensive to get started and because utility providers have yet to build solar plants capable of supplying a state. I don't think anyone has.
In time though, a combination of rooftop solar and utility scale battery/renewable systems to cover baseline load will probably be how we power the nation. Perhaps some gas or other generators will stick around to provide the baseline.
Solar is great for businesses and schools, well basically anything that operates mainly or totally during the day.
This chart is a few years old, but it shows that the peak demand was in the early evening:
https://www.eia.gov/todayinenergy/detail.php?id=830
The peak demand will also vary at different locations and times of year. As the wikipedia article states:
>...It depends on the demography, the economy, the weather, the climate, the season, the day of the week and other factors. For example, in industrialised regions of China or Germany, the peak demands mostly occur in day time, while solar photovoltaic system can help reduce it. However, in more service based economy such as Australia, the daily peak demands often occur in the late afternoon to early evening time (e.g. 4pm to 8pm).
My chart, if you look closely, has a granularity of one half hour. If you want something even more granular, ISO New England data more clearly shows the peak to be between 2pm-3pm for a typical summer month: https://i.imgur.com/rX1JqoJ.png
I think you might have posted the wrong image to imgur. You linked to: https://imgur.com/wTIt5tg
I am not sure how you are getting half hour indications on that weekly chart.
>...ISO New England data more clearly shows the peak to be between 2pm-3pm for a typical summer month:
Yes, that was why wikipedia says:
>...It depends on the demography, the economy, the weather, the climate, the season, the day of the week and other factors. For example, in industrialised regions of China or Germany, the peak demands mostly occur in day time, while solar photovoltaic system can help reduce it. However, in more service based economy such as Australia, the daily peak demands often occur in the late afternoon to early evening time (e.g. 4pm to 8pm).
https://en.wikipedia.org/wiki/Peak_demand
The EIA web site was talking about October, not the summer months when air conditioning would be used.
As another data point, With PG&E pricing, the most expensive hours are noon to six:
https://www.pge.com/en_US/business/rate-plans/rate-plans/tim...
I think my point is that statements like "hat matters is peak grid usage (ie. residential+industrial) and it is actually mid-day—perfect for solar." can over simplify the problem. The amount of demand will vary in different areas at different times of the year and even when it is raining, there will still be demand.
See https://i.myimg.io/wi9J.png
«The EIA web site was talking about October»
This is why I also showed an October chart, with a peak at 3-4pm.
But, yes, peak can vary with weather, time of year, etc. All I'm saying is that in general—not always—peak PV generation coincide reasonably with peak electricity demand.
OK, for many reasons we are just going to have to agree to disagree on that chart. (I just measured https://imgur.com/wTIt5tg and on my machine it definitely is more than 41 pixels between each day but that doesn't mean each pixel is representing exactly x minutes of time, there is no indication on the chart each pixel actually represents 35 minutes or if it is interpolated data, etc. To me it gives a rough showing of energy demand over a week.)
>...This is why I also showed an October chart, with a peak at 3-4pm.
It isn't clear to me why there would be peak demand at 3-4 in the afternoon in an October day. As the EIA site says:
>...During this period, usually in the early evening, operators need more generating capacity–including more costly "peaking" units. Both day-ahead and long-term forecasts account for these peaks to ensure the assignment of adequate capacity.
>...But, yes, peak can vary with weather, time of year, etc. All I'm saying is that in general—not always—peak PV generation coincide reasonably with peak electricity demand.
I think we basically agree on that. Peak PV generation is probably closer to noon, but in general more energy is needed during daylight hours than at night. (And obviously a hot sunny day will spike energy usage for cooling and solar PV is a perfect fit at that time.) The problem to me is when people over simplify this issue. The amount of demand will vary in different areas at different times of the year and even when it is raining, there will still be demand. I've always been a supporter of solar power but there is a lot of handwaving going on when people say we can get 100% of our power from solar and wind without there being some huge advances in energy storage.
If you think of it as two power grids, then "the big power grid"—the industrial grid—can be fully powered by solar, and the residential grid, i.e. "the small power grid", is kind of trivial to solve in comparison.
Even for domestic users, electric storage heaters, water heaters and electric car charging are all amenable to demand shifting. Over time, those will probably become the largest users of electricity if prices keep plunging.
I think there's a lot of money to be made out demand shifting tech, especially if people keep erroneously believing that variability is a problem best solved with expensive lithium ion batteries.
Oh, and my stomach says dinner is most definitely not irrelevant.
This completely ignores the fact that the people buying solar get subsidies and they aren't the ones paying for the burdened grid.
In some states, distribution companies are paying retail prices back to solar producers. That means these people get to freeride on the grid and force the power company to deal with their unstable power supply for free.
The point of the article is that in this case, even without subsidies solar would beat anything else. This is despite heavy import duties that were recently imposed.
Unless they are taxing solar, that's not a subsidy when comparing the two.
Where fossil fuels are subsidized is in the externalities they don't pay for (i.e. environmental impact).
A coal power plant does not get paid retail rates for the power it generates. The utility company charges more precisely to pay for transmission and the people to maintain it.
Let's punish the free riders and reward the people who are reducing the total societial cost of energy.
The fact that solar owners get access to the energy grid for free seems like a clever way to punish the free riders by increasing their costs in a roundabout way.
Don't want to pay the higher costs for your power grid? Then upgrade to cleaner energy! Sounds great.
The companies that operate grids are not the free riders. By having idiotic legislation that allows solar owners to free ride the grid, you only punished the utility company. Sometimes they own power plants, sometimes they don't.
In CA, though solar continues to be installed, we've reached a point--due to a lack of good/cheap storage ability--that at the end of the day (where Solar has been working fine all day), in order to meat evening demand, the only way to address steep demand is to fire up coal-fired plants. They work, but they're not only expensive, they're dirty.
Yes, yes we are.
The correct calculation uses the capacity factor, not the name-plate capacity.
Unless you're trying to power the grid with a single power plant (like on a small island), argument made above doesn't hold. The grid is a network of generators (and loads) with different operating characteristics.
I'm not even remotely an expert in this field, but the towers at the solar furnaces I've seen continue to glow well into the night, meaning they're hot enough to still generate steam, and thus electricity, long after it's dark.
I don't expect they generate electricity all night, but maybe not as much energy needs to be stored as people assume.
“Three years ago you almost never saw batteries as part of a new solar or wind project,” Naam said. “In 2018, we’ve seen battery storage frequently show up as part of these bids. Energy storage is becoming the new normal with solar bids.”
So they are already working on it with some of the projects at least, and there's no reason to think they won't scale up and start becoming competitive before too long.
All of these are far less developed than lithium ion cells, but have the potential to do a lot better on cost and longevity grounds.
Here's an entry on the storage facility: https://en.wikipedia.org/wiki/Bath_County_Pumped_Storage_Sta...
"The biggest battery in the world is a giant lake tucked away in the Appalachian Mountains on the border between Virginia and West Virginia"
One of the more promising things is actually water-based storage using back-to-back reservoirs. Water has a lot of mass per volume and is really low tech. And it's a proven strategy that has been operational for many decades.
maybe there is a possibility for retrofitting some existing dams that are used primarily as resevoirs and not power plants, since pumped-storage are net-neutral on resevoir storage.
example: https://en.wikipedia.org/wiki/Parker_Dam
...but i am NOT an expert by any means, and it's probably way more complicated than that.
Play that out a bit. Suppose you have a 500MW or 1000MW transmission line. It normally has a 1% loss. Today, you notice that it has 1.25% loss. Maybe someone's stealing power. What do you do? Shut off the transmission line entirely?
http://www.sciencemag.org/news/2016/01/better-power-lines-wo...
http://www.sciencemag.org/news/2016/01/better-power-lines-wo...
For all the talk about inventing new batteries, I wish improving the existing grid would be more prominent in the conversation. High-voltage longer-distance power markets are something that can be built right now.
Not all lithium batteries are created equal in terms of longevity. A traditional lithium manganese battery might have 500 cycles in it before hitting 80% capacity. A lithium titanate [1] battery might be closer to 5000 cycles. A battery could be designed for long term usage and thus lower the long term cost, if not the upfront cost.
[1] https://en.wikipedia.org/wiki/Lithium%E2%80%93titanate_batte...
See CAES storage (Texas) and Pumped Hydro energy storage (https://en.wikipedia.org/wiki/Bath_County_Pumped_Storage_Sta...)
CAES in Texas was constructed inside of abandoned mine-shafts. Line the mine-shafts with steel to contain compressed air, and bam, cheap energy storage.
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The USA has lots of lakes and mineshafts. And electrical storage in one area can serve multiple states. Indeed, the Bath County Pumped Hydro plant contributes to the electrical stability of 16 or so states.
A $5 billion project here and there will serve more people and in a wider area. If the USA can take advantage of natural resources, in a sustainable way (it doesn't seem like Bath County's Reservoir is damaging the environment), then it should happen. We know how to make hydro-plants that are safe for Salmon and other wildlife (we need to ensure that future Hydro plants need salmon ladders for example), but as long as environmental concerns are identified and addressed, leveraging our natural resources is the most obvious way forward.
There's "baseload power" (coal, nuclear, wind, solar is really good for this), and there's "Peaker power" (natural gas and hydro are really good for this).
Hydro is super-simple. Just block the water if you don't need energy, and unblock it when you need energy. Ditto with Natural Gas, which can spin up / spin down arbitrarily.
Solar, Nuclear, and Wind generate power on their own schedule and can't really be bothered. But you use OTHER forms of energy when the sun stops shining.
Natural gas is expensive to run 100% of the time. But if you can run Natural gas only 20% of the time, then you're still saving money.
Once the heavily regulated energy market has time to adjust to market conditions you are going to see this energy surplus during the day being adjusted for. Where solar panels make economic sense today they may not tomorrow when energy prices for mid-day use plummet due to oversupply.
Just offer economic incentives to put ac on a timer.
Would still make a huge dent to energy needs and the existing infrastructure already in place.
This means that no matter how many additional solar panels you add to the system, you are not displacing a single fossil fuel plant. Sure it's good that those plants are running nominally fewer hours per day per additional solar panel, but the cost to own, operate, and maintain the panels is roughly constant.
This results in the effect of increased prices for fossil power in a way that can't be offset by solar.
Industrial energy usage can be time shifted.
Who cares about residential power, if it is a small percentage of total energy usage?
There's also the opposite problem, particularly in the case of wind turbines; if you have enough, then your base-load (ie coal, nuclear, hydro) plus renewable may sometimes exceed demand. This happens from time to time in Ireland, for instance, due to a large installed base of wind. At that point you have to turn off renewable, and that's not always trivial or instant. Storage would help there, too, by absorbing the excess.
This is only true if the load on the grid is growing. In North America, it is not. Otherwise, you already have enough dispatchable generation available when the sun isn't shining or the wind isn't blowing.
The article I saw the other day showed growth of 4.5% (comparing Q1 2017 with Q1 2018)
Surely that growth in production is matched by a growth in load?
https://renewablesnow.com/news/wind-solar-farms-produce-10-o...
It is not, although consumption growth may trend upwards again as transportation is electrified (and oil consumption moves to electrical consumption).
https://www.bloomberg.com/view/articles/2018-03-01/americans...
How much does "existing infrastructure" charge to handle the gaps? This calculation differs wildly from as low as $6 to as high as $15, but I think $12 is the right answer.
So add $12 to solar only as a rough rule of thumb. Note that this $12 still comes with transmission issues, and environmental impact.
1. You can buy power from them at normal power company retail rates. You get power from the grid that they buy at wholesale rates, profits go into building out solar.
2. You can become a member by buying any number of shares. Capital gets used to fund solar buildout, profits go back to each shareholder. Each shareholder has one vote regardless of the number of shares they own to prevent buyouts.
3. You can rent them your roof space. You get paid, other people put cells on. You get reduced-rate power from your own roof's cells, excess goes to grid.
4. You can buy solar panels and rent them to the cooperative. For every large installation they make, they'll ask people to buy panels. You get paid a part of what the panels produce for 20 years, at a guaranteed rate, and at market rate after that.
5. You can have them act as a solar installer and set up panels on your property for your own use. They'll buy excess production and sell you grid power when you have insufficient production. In this case you finance the install yourself.
They have excellent economies of scale from standardizing installs and they allow people with capital but no roof space to connect with people with no capital but usable roof space. Because retail rates for power are high and they've centralized installation costs they're making an okay profit. Maybe something like this can work where you are?
True, you still need an alternative source of energy in those cases. But realistically, cloudy days reduces the sun, which usually leads to lower temperatures.
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Personally, I think that cold-energy storage (aka: run air-conditioners on overdrive to chill water. Then use chilled-water to cool your house) is the ideal.
It turns out that a vat of 480 Gallons of cold-water has a lot of cooling potential. Chill the water to 40F and you can cool down homes for hours using fans alone. With proper compressors and such, you are like 95%+ efficient.
Your failure mechanism is the probability that your vat of water begins to leak its cold air. Certainly a problem, but way simpler and less of a problem than explosive Li-Ion batteries.
If you see it from a total-cost-of-ownership, the chilled-water + air conditioning unit is overall cheaper than you'd expect. The air conditioner doesn't need to be rated for the peak-loads anymore, but can run more continuously at lower temperatures (ie: at night to store chilled energy into the water).
So you downsize your air conditioner, as you aim for average-loads... compared to everyone else who has to buy an air-conditioner sized for peak loads.
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You seem correct about utilization. Now I wonder if a dual-use heat-pump / cooling system would be best. Heat up your house in the winter, cool down your house in the summer to double-duty the water-tank thermal energy storage.
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The "Earthships" discussed elsewhere in this topic effectively use thermal energy storage in dirt itself to heat and/or cool the entire house. It seems to use a lot of land, but single-family home owners generally have a large-ish yard where the earth can serve as the energy storage mechanism.
------------ Using it for winter and summer does increase the utilization and would be best practice but places with winter/summer seasonality have a golden zone where you don't need active heating or cooling. If you're below 24c and above 18c you don't need much energy to maintain thermal comfort, provided you're not in a high humidity environment. During the winter it's better to use solar collectors with a thermal syphon for heat collection instead of stocking up heat since peak thermal demand occurs at night.
------------ They're known as earthpipes or earth hear exchangers and they come with their own problems, namely proximity to surface and thermal load imbalance over seasons. The earth is a really shitty thermal reservoir because it bleeds heat out the side and the top, the really big thing that it has going for it is that it's free. When you use the system in an environment thats either mostly hot or mostly cold you change the ground temperature in the long run, either increasing it or decreasing it over time. This in turn affects the ability of the system to condition air, there's also the problem that it can only bring the air temperature up to that of the ground during winter so you still need a heating system to supplement it; works great for cooling though. Basically the system gives you thermal energy at no operational cost(other than the fan) but you have to either accept whatever temperature it gives you or have a way to further condition it. Earthships generally use the sun in the winter to bring the temperature up during the day and have a thermal mass inside the house that maintains the temperature at night.
> The Nevada auction also included a number of projects that link up utility-scale solar with batteries. Mastering solar plus storage will be critical for renewables to truly overtake fossil fuels, since they only generate power when it’s sunny or when the wind blows.
> “Three years ago you almost never saw batteries as part of a new solar or wind project,” Naam said. “In 2018, we’ve seen battery storage frequently show up as part of these bids. Energy storage is becoming the new normal with solar bids.”
That's the job of the inverter, right? It uses free solar energy first and maintains reliability by supplementing it with costly grid power.
It is true that a wide electrical grid needs a base load.
It is also true that solar isn't great at continuous power because of, you know, the Sun sometimes being behind the Earth.
But that doesn't mean you need necessarily need batteries. There are at least two scenarios where you don't:
1. You have an alternative to batteries for storage. This could mean using excess solar power to create some fuel that may well also be portable. This isn't an economic way of creating gasoline (yet) but in remote places this might not matter. It also might not matter if this power is essentially "free" (eg you need to build a certain capacity anyway which leaves times where excess power is being generated).
2. Power usage on electrical grids is also not smooth. It also peaks during the day when, as it happens, the Sun is also out. So your solar capacity is actually reducing your peak grid power requirements, which is incredibly useful.
In particular, in Solar-heavy situations, the peak energy is now 5pm. When the sun begins to set but there's still a large demand of electricity.
Batteries in today's form cannot solve the duck curve. So the only reasonable situation is to use natural gas plants to supply the grid with power. Future batteries need to be built more efficiently and cheaper to deal with the many Gigawatts and Gigawatt-hours (both power AND energy capabilities need to grow) to deal with the future duck curve and/or nessie curves.
The solar + battery price is also going down, though not as fast as the solar only piece. But that's the metric we should be following. When that hits $30 per MWh, it'll be game over.