8 ms·
Capital costs vs. marginal costs. You're going to build a $100M desalination plant and run it for three hours a day? That's a ton of money sitting idle most o
by floatrock 8y ago
Capital costs vs. marginal costs.
You're going to build a $100M desalination plant and run it for three hours a day? That's a ton of money sitting idle most of the day, far more than what is recovered with zero operating costs.
(This is called the utilization factor -- how long a piece of equipment is used vs. staying idle)
Ideally you want useful processes with low capital costs and expensive marginal/energy costs. Desalination is not one of those.
- DoctorOetker 8y agoYes, depending on the timescale considered, the utilization factor of the plant should be weighed against the utilization factor of flood energy. In the long run it should pay itself back.
- woodpanel 8y ago> In the long run it should pay itself back. So in financial terms wouldn't this mean a rather weak profit margin? Plus the relatively high-risk that flood energy might not always result in free or negative energy prices gives it a bleak risk-to-profit ratio. In other words, there would always be something more utilizable to be done with excess energy (e.g. mining bitcoins etc. and buy water with it when you need it). PS: But I like the main point you make, to take in more aspects when calculating efficient renewable energy systems. Not a crypto-investor (or even believer).
- DoctorOetker 8y agoRight, I explicitly mentioned not really believing desalination to be a good example, I was using it more as a fake illustrative example. In hindsight I should have ended with posing the following question: how do we make a simple guide for factory/etc operators/consultants to recognize such steps in their production line? Desalination is a bad example, because you need a complete new plant, while it is conceivable that other products have one or more energy dense steps. What should such instructions look like? Follow the product through your production line, and at each step measure the energy consumed per part at the step, and the volume per part when efficiently stacked. Also note if the step is automated or needs a human, if it is human, check if it can be automated. If it is automatable, and the energy density for the step is high enough, calculate the cost for changing the production line, allocating sufficient storage, and possibly automating a certain task, and parallellizing the step such that it can be run during energy flood. Then calculate through the price difference how fast it pays itself back. Mention the importance of actually measuring the energy consumption, instead of just reading off a machine specification of wattage, and cycle time. Etc. Edit: The banks that wish to invest in cheapening such a step could train consultants and send them to factories interested in good deals. I.e. any potential profit is shared between company and bank, and the bank takes the risk (hence has the motivation to do the calculation properly, and will have best knowledge through experience of suitable step energy densities)
- theptip 8y agoI think the core of your idea would work well in theory; a much simpler example would be heating water, which both residential and commercial buildings do quite a lot. Once you have hot water, you can keep hold of it for quite a long time in a properly insulated tank. Or at a higher level of abstraction, instead of us trying to figure out which "energy dense step" is the right one to target, instead the grid can provide a real-time price signal that flexible loads can use to get a cheaper overall rate by selectively turning on when the demand is lower. This stuff is pretty well discussed under the umbrella of "smart grid" technologies: https://en.wikipedia.org/wiki/Smart_grid#Market-enabling https://en.wikipedia.org/wiki/Smart_grid#Market-enabling
- amluto 8y agoI wonder if a less efficient desalination plant would be cheaper. The modern efficient plants use RO with pressure exchangers, I think. Maybe a flash distillation plant or an RO plant without pressure exchangers would be economical to operate intermittently. But desalination may be a poor example in general. It’s not actually very energy intensive, at least compared to the value of potable water in an urban location.
- CompelTechnic 8y agoYeah, if I was gonna build a desalination plant built to use <$0 cost electricity, I would essentially build a giant (distillation) still. I'm not a process expert in flash desalination, but it looks similar to (maybe identical to) a still. Just a big resistor in a big tank (or pond), a big fume hood and coil to another tank. Capital cost can probably be minimized a whole lot.
- bufferoverflow 8y agoYou can use sun light directly for that. Just paint your boiler black, maybe concentrate some sunlight with cheap mirrors.
- hogwild 8y agoYea but not at night.
- imtringued 8y agoThe entire point of this discussion is to figure out how to use electricity only during the day.
- nine_k 8y agoThis works well when you have a lot of sun. Instead you might have a lot of wind. Also, you only want to run the desalination plant when the electricity price is too low ("below zero" with the transmission included), so you want generators for most of the time, when you actually sell the power.
- citrablue 8y agoA desal plant is a useful thing and can be run around the clock off traditional energy sources. The "free energy" hours would help lower the costs. I can even imagine a SETI-like application where people who over-generate power are able to donate it to causes of their preference...
- roenxi 8y agoBut if you are using traditional energy sources to run it all the time, it is no longer 'solving' the problem of burning off excess energy during peak renewable times. Someone is having to build a lot of highly wasteful, redundant infrastructure.
- westurner 8y agoRational cryptocurrency mining firms can use the excess (unstorable) energy by converting it back to money (while the sun shines and the wind blows). Money > Energy > Money > Someone is having to build a lot of highly wasteful, redundant infrastructure. We're nowhere near having the energy infrastructure necessary to support everyone having an electric vehicle yet. Energy storage is key to maximizing returns from renewables and minimizing irreversible environmental damage.
- chlvsl 8y agoIsn't a process like this is already utilized in local areas in the US through pumping water up into a water tower?
- sandworm101 8y agoIn the oil market, stabilization of price occurs only because a handful of countries (really just Saudi Arabia) maintain extra capacity. They don't run their capital assets at 100%. This is where capitalism fails. You need one absolute authority, some autocrat who doesn't care that their processing plant isn't running at 100%, who is able to react instantly without making new capital improvements. This is the place for a state-owned market participant, either on the supply or consumption side.
- prostoalex 8y agoStabilization? https://www.nasdaq.com/markets/crude-oil.aspx?timeframe=10y https://www.nasdaq.com/markets/crude-oil.aspx?timeframe=10y
- lovemenot 8y agoThis idea may be outdated. USA has been considerably undermining Saudi's traditional role of swing producer. Not through their centralised market control, but by having many intensely capitalistic shale operations, each with profitable capacity at a different price-point. Each one quickly toggles on/off when the market price crosses its own threshold.
- russdill 8y agoYes, but you are in one sense "competing" with other solutions (such as batteries) that face the same utilization factor problem.
- malloryerik 8y agoWhat about using the energy for various forms of carbon sequestration? Making biochar [1] for example? An area's biodegradable waste could be collected according to existing garbage schedules, and the grid's excess electricity used to create biochar from it at garbage/recycling sites. [1] https://en.wikipedia.org/wiki/Biochar#Production https://en.wikipedia.org/wiki/Biochar#Production
- eloff 8y agoDesalinization isn't a good example for the reasons you say, but theptip writes below that heating water in residential and commercial settings might be better. Since water once heated stays hot for a good while in the insulated storage tank. Also buildings can be heated with hot water instead of forced air, typically through pipes in the floor. Which is nicer because it keeps your feet toasty and doesn't dry out the room so badly. A freezer is possibly another such use case, if it keeps the temperature to within +/- X degrees of the set temperature, it can delay kicking in during periods of expensive electricity, and over-cool during periods of cheap electricity. I could load the washer or dryer and program it to run it when it's cheapest if I'm not in a hurry. Charging an electric car could work the same way. Air conditioners are a huge deal, my single biggest electricity consumer. In a world where things were smarter they would chill coolant/water/ice during times of cheap electricity, and that would be used to cool during the hot evenings. The problem is I have no way to take advantage of any of that. The electric grid isn't giving me feedback on the spot price of electricity (and in many places they don't even break it down on the bill, showing just one value for $/kwH for the entire month - that's what my bill looks like.) Even if that problem is resolved, my appliances are too dumb to take advantage of that information to optimize my costs. The grid needs to convey the realtime pricing information to customers, and then smarter appliances will be developed to take advantage of that information. The market may be able to do a surprisingly effective job of moderating demand itself if both the information and the means to apply it are available.
- teachrdan 8y agoA great example of this is ice bank refrigeration, which literally uses a giant block of ice to cool air in a building. https://en.wikipedia.org/wiki/Ice_storage_air_conditioning https://en.wikipedia.org/wiki/Ice_storage_air_conditioning
- frankydp 8y agoThere is a program to provide that feedback. I already own an enabled water heater for example. https://smartgrid.ieee.org/ https://smartgrid.ieee.org/ http://www.whatissmartgrid.org/smart-grid-101 http://www.whatissmartgrid.org/smart-grid-101
- 8y ago
- Arnt 8y agoNot hours per day. But if your climate has wet winters and dry summers you might choose to build a desalination plant that you only really need to run for three months per year. And then you have the plant sitting there for most of the year, able to help the power grid. So the example makes sense.
- PopeDotNinja 8y agoFor something like a desalination plant, I wonder if that would be a good candidate for pumping water up a hill/tower/something, and then using the stored energy the other 21 hours per day.
- test6554 8y agoI can't imagine that the capital required for "water boiling equipment" would be very high. Metal tanks, pumps, heating unit, etc.