Who's afraid of Solar PV?(theconversation.edu.au) |
Who's afraid of Solar PV?(theconversation.edu.au) |
This is a pretty good article, but misses a little context that maybe helpful to non-Australian readers.
1) Power bills in Australia have been rising rapidly over the last couple of years. The reactionary response has been to blame the new Carbon Tax, but the real causes are much more complex[1].
2) In South Australia at least it gets really, really hot. For example in February 2009 we had 6 Consecutive days over 40 °C (104 °F) and a maximum of 45.7 °C (114.3 °F)[2], and then in November 2009 we had 6 Consecutive days over 38 °C (~100 °F)[3]
These peak temperatures occur earlier in the day than the typical power spike (12pm-4pm instead of 5pm-7pm), and caused huge power spikes (from air conditioner usage), and this often causes power companies to have to shut off power (they have a policy of doing rolling blackouts when they don't have enough capacity).
This peak demand is much, much higher than the average peak demand shown on the linked article, and these are the peaks the power companies invest to meet. If these peaks are reduced by solar panel usage (which they should be, since the come during the best time for solar production) then it should reduce the requirements for larger power stations.
[1] http://www.heraldsun.com.au/opinion/power-play-between-feder...
[2] http://en.wikipedia.org/wiki/Early_2009_southeastern_Austral...
[3] http://en.wikipedia.org/wiki/Late_2009_southeastern_Australi...
*Edit: I can see a flatter usage profile should probably mean cheaper power, but still I think there is some justifiable paranoia in worrying about power prices increasing in South Australia again.
I think we need smart meters and a more market driven approach to retail pricing. Peak electricity costs can go through the roof and people will respond by shifting their usage to alternatives or different times when there is less demand and prices are lower. Unfortunately there is no market transparency and we are paying for retail electricity without any real understanding of the underlying costs. We are paying ridiculously increasing amounts for electricity so we can build infrastructure to handle peaks that many would avoid if there were market pressures on consumers. Changes like rooftop PV and wind farms are only a part of the picture.
The difficulty is that, unless storage gets dramatically better, we'll still need a huge conventional electricity base. And it will still burn a huge amount of fuel: most generators are not "instant-on" -- it can take weeks to spin up a nuclear plant, days to spin up a coal plant, and hours [1] to spin up a natural gas plant. Of course, there are some savings, but there is huge waste if you have to keep the whole conventional energy infrastructure spinning during the day just to fuel that 6 pm peak load.
Advice to entrepreneurs: finding a cost-effective way to store solar energy for 4 hours will be worth more than another 2% increase in efficiency. And inventing instant-on conventional-fuel plants will also make a huge difference in GHG emissions.
[1] - Page 8 of http://www.euec.com/getattachment/euecjournal/Paper_3.pdf.as... gives times between 1.2 hours for a warm start to 6 hours for a cold start.
Here in California we had a similar challenge but with Watar. We periodically go through drought cycles and during the last big incentives were put in place to get people to use less water, rebates for toilets, reduced cost if you were 20% below your non-drought average, no watering during the day, drip irrigation, etc etc. Then the utility needs a rate increase because they aren't getting as much water usage. It is a hard sell though to tell people "You have to use 20% less but we're going to charge you the same amount"
So electricity, like water, is a blended cost where the scarcity unit is priced to cover the physical plant costs of delivering the unit. We wholesale adoption of Solar PV it will require power utilities to come up with a different formula to recover their costs. The end result is that it will shift the cost from business (who pay the biggest power bills during the day) to non-businesses.
[1] http://sanfrancisco.cbslocal.com/2011/04/19/east-bay-custome...
If solar adoption continues along the path described (which is inevitable at this point, considering steadily dropping solar PV equipment prices) then the midday spot price will continue to drop as well.
We'll find out some answers to the question, what do you do when the spot price of electricity approaches 0? Water desalination. Pump water uphill. Charge electric car batteries. Electrolysis to convert water to hydrogen, for later use in fuel cells or combustion engines.
We will certainly see some innovation in short term energy storage, since the price of electricity just before the late afternoon peak will be much lower.
http://reneweconomy.com.au/2012/why-generators-are-terrified...
http://grist.org/article/2011-11-23-the-problem-with-the-ren...
http://www.recycled-energy.com/newsroom/publication/the-batt...
http://www.ilsr.org/solar-grid-parity-101/
http://www.greentechmedia.com/articles/read/how-will-the-cal...
>> In this nightmare, a utility commits to build new equipment.
>> However, when electric rates are raised to pay for the new plant, the rate shock moves customers to cut their kWh use.
We have a "death spiral" in water prices in my local (southern California) water district.
There was a drought. People were asked to conserve. People conserved too much. Drought ended. Water use did not return. Water companies then need to raise prices to meet their distribution costs. Which lowers demand further.
It can only end ugly.
I pay about $120 in fees. Then the water is the rest of it.
In winter, when we use less water, my bill goes down to about $130. $10 worth of water per month.
Of the water present on the planet, 97% is salt water which is unusable for drinking or agriculture. Of the 3% freshwater, 68.7% is locked in glaciers. So, 1% of the water on the planet is liquid and most of that is underground. We don't really have a lot and things like fertilizers damage what we have.
It turns out that the amount of fresh water is relatively constant. If we want more in places that have less then we have to manufacture it from seawater, steal it from our neighbors by cloud-seeding, or rely on the weather cycle convert seawater into fresh water and then distribute it.
If you live in Dubai, you aren't waiting for it to rain. You're building desalination plants and processing seawater.
EDIT: http://www-das.uwyo.edu/~geerts/cwx/notes/chap10/continents.... (Sorry for the horrible background, the data is there)
The peak load for South Australia was 1.8 gigawatts. There are 1,275,041 motor vehicles registered in SA.
If you could get all of them turned into electric cars plugged into the grid, it would be a 1.4 kW power drain per vehicle, which is less than the power drain of an ordinary kettle here (240V, 10A, ~2.4 kW).
The cheapest Tesla Model S has a 40kW hour battery meaning it could sustain that power drain for over 28 hours (a total of 51 GWh). It's got a 10kW charger standard, which is more than enough.
So if everyone had the cheapest Model S, kept it plugged in with the ability to send power back into the grid, and didn't mind that their car was sometimes down to 20% charge, you could power the entire grid on solar alone.
That's obviously a set of unrealistic assumptions, but it does indicate that it is feasible to solve the problem like this.
A more realistic set of assumptions:
* 1/10 cars are turned into a Model S base model equivalent
* Through financial incentives, the owners are willing to keep them plugged in
during the day and using up to 20% of the battery to push back into the grid.
* Cars need to shave 0.2 gigawatts off of peak load for four hours to bring
it in line with the rest of the day
We have 127,504 vehicles, can can use up to 8kWh and 20kW each, giving:
1 GWh of capacity and 2.5 GW maximum power draw.
So it's just enough. Alternatively, 5% allowing 40% usage works, etc. The power draw is insignificant.
Owners can be heavily compensated for pushing energy back into the grid. I won't run the numbers here for length and time reasons, but knocking out peak power usage is incredibly profitable. You're literally decomissioning a large percentage of power plants. It would be feasible to make all the energy your car uses free; likely the lithium ion battery packs, too.
The question is; would 5% of the driving population buy a $50k car if they no longer had to pay for fuel or battery packs? Financially that would probably put it closer to a BMW. I think it's feasible. What about in 10 years when the cars are $20-30k? Undeniably. In 20 years when you only need 2% of the population to be in the scheme due to battery increases and the cars cost $20k? No brainer.
The system would require a smarter grid (so you can plug your car in at work and have it all taken care of), 10 years of Moore's Law for batteries, etc.
But I think the numbers check out, and it means we could go crazy with solar (the explosion in solar must continue to charge these vehicles during the day). What's needed is the will to make it happen.
The OP said cost effective, not pie-in-the-sky.
Even if you took out the battery packs and sold them separately, the cost would exceed 10 years worth of electricity supply.
>Owners can be heavily compensated for pushing energy back into the grid.
You're asking people who cannot afford the expensive technology to subsidise those who can. This is the exact reverse logic of most progressive taxation regimes.
>The question is; would 5% of the driving population buy a $50k car if they no longer had to pay for fuel or battery packs? Financially that would probably put it closer to a BMW.
So you want to subsidise the purchase of expensive cars to the point where it is financially a good deal. This magic money no doubt comes from other taxpayers.
And for what end? Just so you can have some type of boutique distributed power generation system?
>What's needed is the will to make it happen.
No, what's needed it pots of other peoples money.
I've spent the best part of 5 years trying to hose down the jetsons fantasies of people pushing ridiculous schemes like this as not only unworkable, but inequitable for forcing up a basic cost input of life - energy - for effectively vanity purposes of a small subset of the population. I usually cop a pile of flamebait and downvotes each time, but I do so because there seems to be a mass delusion going on, and this has become one of those things you can't say.
"The comments talk about electric cars effectively being used as batteries to help supply the grid during peak times which is a concept I haven’t heard of. Electric cars being plugged in overnight to increase the night-time demand would certainly help as you would significantly increase the base-load demand, thereby improving the load factor of the network. This then distributes the fixed infrastructure costs over a higher number of kWh lowering the per/unit cost of energy."
We agree on some form of distributed storage and maybe generation, though, combined with a smarter grid. It's all current or 5 years out technology.
No, that's the average load at a particular time of day. (Averaged over all days over two years). The peak is about twice that:
South Australia experienced a mild summer with only a few days exceeding 40°C. A relatively short heat wave occurred in late January 2011.
The maximum demand for the year was 3,433 MW, and occurred 4:30 PM (Australian Eastern Standard Time) Monday 31 January 2011 (at a temperature of 42.9°C). A higher maximum might have been expected if the same conditions had occurred later in the week, after an extended hot weather period.
http://www.aemo.com.au/~/media/Files/Other/planning/0400-003...
This is a solved problem. It's called pump storage[1], and is in use world wide. The US has some existing pump storage power plants (eg [2]), but typically they are used to smooth out demand on non-renewable generators (Coal, Nuclear etc).
[1] http://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity
[2] http://en.wikipedia.org/wiki/Bath_County_Pumped_Storage_Stat...
Solar can top up the grid, and correlates well with air-conditioning driven demand on hot days. But it doesn't coincide with peak load - especially in winter - and will always be a diffuse power source.
You would not only need a cost effective storage solution (and none is in the foreseeable solution) you also need a lot of available space. Even if the panels were virtually free - there still remains large problems with solar power as a baseload energy source. If you solved the storage problem - cheaply - you'd still need 4 - 5 times the collecting capacity to get close to being able to reliably produce power over even a 48 hour period.
It's a great boutique energy solution, particularly for remote usage. But large scale electricity generation will remain the dominant energy source well into the foreseeable future.
http://www.ted.com/talks/donald_sadoway_the_missing_link_to_...
For heavy duty appliances (eg. air conditioning, water heating) the consumer pre-programs it with a desired average cost and a maximum price per kWh.
Then as demand and supply rises and falls on the grid, the spot price changes, and the devices receive signals and turn themselves on and off as needed. (There would be a certain minimum of fixed-price energy per month to make sure financially strained families never have to go without any)
The sun will be high in the sky at 5-7pm, generating power when we need it most.
This is a good idea, except electricity transmission costs are significant over long distances like that.
Refrigeration! Put all the air conditioners and refrigerators on timers. Run them hard during peak solar hours. Then turn them off during the evening peak. If that would make the buildings too cool, make ice and melt it later to chill the air. (Some event venues already do this to handle air conditioning ten thousand people during midday.)
That said, it actually makes my case significantly stronger. With 10% EVs and 20kW chargers, you can put 2.5 GW into the grid at peak, which is over 2/3 of the instantaneous maximum demand for the year.
I'd love to see figures on how much you could save providing a grid with 1.8 GW of base load vs having to engineer it to be able to handle nearly twice that, once a year.
You'd have to go to 15-20% EVs to support that, but if you're shutting down half your traditional power stations and investing heavily in solar, it may actually make sense with today's prices. Then again, lithium prices would skyrocket going to those kinds of extremes...
If they're like the UK water companies then they'll be moaning they're suffering but still be making vast profits.
It's like "we can't fix the pipe network without increasing water bills and we already put them up 10% this year; oh and we made 20% more profit this year so we must be serving our customers well ....".
PS I've never been to Australia, but I'd like to come someday :)
Power prices vary dramatically during a day, and are often gamed by generators. Exposing retail customers to those swings directly is dangerous IMHO.
Having said that, there are many intermediate steps that help. For example, many power companies do partition prices by time of day, which makes a lot of sense[1].
In South Australia, ETSA is trialing "Direct load management", where they can shut off air conditioners for 30 minutes using smart meters when there is high demand, in return for much lower tariffs[2].
[1] http://www.savepower.nsw.gov.au/Portals/0/docs/news/Media071...
[2] http://www.etsautilities.com.au/centric/our_network/demand_m...
Using 0-100% of your "allocation" is one price. It's about 2x the cost to use 101-149%. 150-199% is an even higher rate. Etc.
Doesn't solve peak usage or distribution issues, but it's a (relatively) easy concept to understand. The detailed statements pretty clearly explain how much each "allocated unit" of energy costs.
As you say, many other technologies are far more suited to this kind of use.
You may be right about the cycle count; EVs are designed to be daily drivers, but charging and discharging 40-50% of a battery daily is likely more punishing than 10-20%. Though even if that is the case, it would just push my analysis 10 years into the future, when cheaper batteries and PV will make up the difference.
The proposal isn't a subsidy. It's a straight market payment for an economic benefit - the difference in cost between off-peak and peak electricity is real, and this means that storing off-peak electricity and releasing it at peak is an activity that's worth money.
I'm not sure I agree that the economics work out exactly as described, though - if it would be worth paying for everyone's lithium car battery packs to do this, then it would be even more profitable to build a giant lithium storage battery in a central location.
This is in contrast to dedicated lithium ion batteries, which just don't work out economically. Otherwise you're right - the utilities would do it themselves at scale.
Attacking them because they're "pie in the sky" frankly sounds like you're deliberately misinterpreting me, or at least you didn't bother reading the post.
Secondly, the scheme I'm proposing does not require any government subsidies. The money comes from selling the power back to the grid.
With my proposed figures - 5% EV ownership (63,752 cars), 40% battery usage sold back to the grid, you could reduce peak power usage by 15%. South Australia spent ~$990 million on electric power last year (not exact figures; based on 619k households from the census with an average spend of $1600).
Assuming 15% reduction in peak power is a 10% reduction in cost (which is reasonable, because capital costs and fixed running costs dominate electric spending expenses), that yields $99 million a year in savings.
The cost of 63,752 Model S cars is $3.1 billion. However, you have to look at the marginal cost of purchasing a Model S, vs whatever car the high end of the market is buying anyway, AND subtract the spending on fuel.
We're saving $1571 per car per year. Tesla's prepaid replacement program is $12,000 (over ten years), which eats a big chunk of it, however we're also charging with cheap peak solar (the abundance of which is causing this issue to begin with), plus maintenance is cheaper.
BMW 5 series MSRPs are from $38k-68k. Taking the lower end of that, we're paying a $12k premium for a car with significantly lower maintenance costs and little to no fuel costs.
Could you get 5% of cars on the road taking that deal? I don't know. Today? Maybe, maybe not. But I do know that as the price of peak solar and battery technology falls, it will go from being a 'maybe' to a 'no brainer' over the next ten or fifteen years.
In any case, I may be wrong in my analysis. I'm merely presenting an argument for the way I see it. If you disagree on a specific point, I'd be happy to talk more about it, but nothing I wrote deserved your response.
Agreed. And when that is the case, then this behaviour will appear at large and be taken up enthusiastically.
At the moment this manifestly isn't the case (stored solar by batter cheaper than large-scale power), so any calls for it to happen is usually a disguised call to force it to happen by producing regulatory benefits to a small subset by driving up the cost for others.
I have zero problem with people electing to spend their own money on solar + battery storage. I find the tech interesting. I am simply determined to point out whenever I see this type of call that usually this means taxing poorer people to pay for richer peoples desires.
Elsewhere someone corrected me that the peak grid usage in a year is actually significantly higher - the figures I was looking at were average daily figures - which may make grid savings quite a bit higher than 10%.
I don't think it necessarily is a clear financial win now; I'm just saying, if you squint just right it kind of makes sense now, and with the march of battery technology and PV, not to mention the inevitable adoption of EVs whether or not this scheme exists, it's going to look better and better from here on in.
(Since we know that the latter isn't economical, then that also indicates a problem with your numbers - I suspect that for one thing, insurance couldn't be economically provided at $12k/pack if all of those packs were being used for daily peaking storage).
The key is probably that the $12k replacement program is an investment in Tesla; they're cash starved, and are willing to sell the batteries at a loss in return for the cash advance. Also, they're betting on the batteries being ~half price in 10 years.
From further reading, they'd be $30k - 2.5 times the price - to buy upfront today.
But that doesn't mean that the subsidy doesn't exist - if 1% of consumers would buy a Model S due to its other advantages, maybe 2-3% would if that purchase returned $1500 a year back to them.
So while you're right that it's not outright going to pay for itself in 2012, it probably halves the gap between a Model S and a BMW in the same class, and it's only going to get better as battery/PV technology improves.