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India is now producing the world’s cheapest solar power (weforum.org)
176 points by ljf 16 days ago | hide | past | web | favorite | 118 comments

The current largest solar park in India and possibly the world, on google maps here https://www.google.com/maps/place/Thirumani,+Karnataka+57213...

Wow. I kept zooming out and there was more and more. That is incredible.

Do you know how much power it produces?

Looks to be this one: https://en.wikipedia.org/wiki/Pavagada_Solar_Park

So 600MW scaling to 2000MW

Just eyeballing it there seems to be 1 square kilometer of panels total. At regular solar panel efficiency, output would be 1000-2000MW total. So the same order of magnitude as one nuclear reactor.

Google map has a area measuring tool enclosed if you right click.

Closing a region gives you approximate area.

edit: There seems to be at least 35 sqkm.

More like 10 sq km so far. You'll see it if you zoom out more. There are plenty of panel "farms" in other parts of the town. More details here: https://en.wikipedia.org/wiki/Pavagada_Solar_Park

I think you’re off by a factor of ten. Sunlight is about 1 kW/m^2, so 1 km^2 (=1e6 m^2) would only be 1000 MW at 100% efficiency, 100-200 MW at 10-20%. That said, the plant looks bigger than 1 km^2 to me.

The wikipedia link shared above by aunty_helen ( https://en.wikipedia.org/wiki/Pavagada_Solar_Park ), which matches the name in the google maps link, says 53 km^2.

It also says that it could produce 600MW by the end of January 2018, can produce 1400MW now, with 650MW more under construction. It also says 2000MW capacity being planned for by the end of 2019.

I'm not sure how much of the 53 km has active solar panels, but they'd only need 3.8% efficiency to hit 2000MW with that much area.

Thanks, I didn’t see the link earlier. I’m glad to see it’s the array which is bigger than estimated. :)

almost 2000mw now (2GW)

Well that's the coolest thing I've seen all day, then

Is it normal for the panels to tilt north-south? Wouldn't it be better if they tilted east-west?

I assume they are at a fixed angle and don't change tilt throughout the day. Usually in the northern hemisphere south-facing is the best (the sun spends most of the day in the southern part of the sky but equal parts in east and west). Similarly you think of a south-facing side of the building as getting "the most sun" and design accordingly.

Wow, they don't track the sun? It seems a single motor can tilt the whole row of the panels with some relatively simple tilting mechanism. Heck, with gears a single motor can probably tilt multiple rows, since they need to move so slowly.

Because a solar panel's efficiency is proportional to the cosine of the angle to the sun, you actually don't gain that much performance from east-west tracking -- it's maybe 20-30% better.

These days, the panels themselves are cheap enough that it makes sense to just buy more of them, instead of adding enough motors and mechanical components to move panels that weigh millions of pounds in aggregate.

Yeah, the industry has been back and forth on this one - having a mechanical system incurs extra cost and maintenance for surprisingly marginal gains. Now that panels are cheap it's easier to just have more of them.

From the graph in the article it is pretty evident that the margins are very low compared to other countries. This is a case of the government doing something that makes sense for the growth of the country rather than letting privately run companies make large profits.

We are also benefiting here in Africa. I have begun to see Indian solar panels being sold here and they tend to be the cheapest at my preferred online retailer.

Which indian company is that?

The solar panels are called Renewsys[0].


Have you seen Atersa panels over there? It's a Spanish brand, someone told me that they were selling a lot of them in África, but didn't mention exactly where.

No I have not seen any Atersa panels in my neck of the woods. I do know there is Spanish involvement in a few solar farms being implemented in SA. I build the initial web site for this particular one[0].

There many solar panel retailers my goto one is this one[1]

[0]https://www.solarcapital.co.za/our-projects/de-aar-project-1... [1]https://www.sustainable.co.za/solar-power/solar-panels.html

Hmm, you're right, the indian ones seem to be the cheapest, even more than Jinko. IDK about Enersol, it looks like a spanish-made name but I can't find any info about it.

I asked you this because the spanish solar industry suffered a lot because of the Chinese competition. AFAIK Atersa was the only brand that remained producing in Spain, everyone else moved production to china.

You can't deduce that from the data in the article, so if you have another source do share. Most of India's capacity was built in the last 2 years [0] and almost all in the last 3. They might simply still be in some sort of build-and-spend phase and yet to sit back and start realising profits.

[0] https://en.wikipedia.org/wiki/Solar_power_in_India

They are. Most of the large solar plants are being used for selling power as a service (via open-access) to other businesses. Source: I was working in analytics for a solar power firm in the past

Article says "low-priced panel imports from China". There is ~30% Govt. subsidy in costs for residential installations. Also, https://solarrooftop.gov.in/rooftop_calculator

Does anybody here know the percentage of panels actually produced in India and major solar cell(mono/poly) manufacturing(not assembly) plants in India?

Edit: (old data) https://en.wikipedia.org/wiki/List_of_photovoltaics_companie...

What's more suprising is Italy 2nd place, which is a great thing. IMHO we need to transition our energy generation even more into solar, but also changing our habits to reflect that (do laundry during the day vs the night, cool down things during the day, etc.)

I think that will happen when the power companies develop and deploy "smart meters", i.e. make pricing transient, and inform users of predicted and live prices.

Strangely enough, Italy has one of the highest electricity prices in the EU. 20-30 cents/kWh. Though a lot of it is taxes (besides VAT).


Why do you do laundry at night ?

Is it like in France where you can have different prices during day and during night ? The night price being the lower ?

Largely because people are at work during the day.

> Renewable energy now generates a third of global power capacity.

I find this remarkable and uplifting, because if I ask myself whether I could live using only 1/3 of my current electricity consumption, my answer is that I would have to make sacrifices, but relatively painless ones.

And this is the baseline - renewable capacity is only going to grow.

And this is with old industries dragging their feet for so long. Imagine how far we could've been if lobbying wasn't so bad and the US had lead the way with renewable energy a decade a ago. We'd be way past 50%, probably closer to 2/3 by now.

Don't get so excited comrade. Renewable does not mean clean. It is mostly biomass, solar is still tiny % overall.

We are making progress towards clean energy but it is much slower then propaganda numbers.

PS. Congrats to India...

> Renewable does not mean clean. It is mostly biomass...

Biomass can be as 'clean' as you want it. The term is applicable to anything from a heap of sticks used to cook a pot of cassave to a combined biogas/gasifier plant which emits nothing but CO₂ and H₂O. Don't get scared by CO₂, it is 'clean' as long as it is part of a cycle.

My friend works for Engie/GdF. They are importing coconut shells from Sumatra to France in order to fulfill biomass requirements in their power plants. This is nothing near to clean. It is just another absurd due to eco-regulations.

No, that is a nonsensical construction comparable to what is being done in Stockholm where they import biomass from south America to fuel CHP (combined heat and power i.e. co-generation) systems, this in a country where biomass from forestry is abundant.

The problem here does not lie with the use of biomass but with those who decide to implement it in such a way. Biomass works when there is a reliable fuel source in the form of forestry or agricultural waste, water treatment plant waste, sewage, etc. If you have to import biomass from the other side of the planet just to satisfy some 'green' requirement it is far better to use another power source - this being France I'd say nuclear power should be one of the first options.

And South America to Stockholm distance is covered by some dirty fuel.

Bunker fuel is pretty horrible but shipping by water can be extremely efficient. Seems like you have to do the math to see which effect is more important?

Not necessarily. There are so many cases (even in industrialized countries) of former bog areas turned into farmland by lowering the water level that a biogas plant from corn grown on such ground produces 8 times the CO_2 a lignite plant would have per MW. Just by steady degradation of peat in the ground of the fields.

Also, solar and wind for electricity is a disaster in terms of CO2. People ought to look at the real numbers before thinking that intermittent energies instead of nuclear are going to save us.

Source please.


Solar is listed at 4x more and wind seems to be on par with nuclear. Both solar and wind are far better than the hydrocarbon alternatives.

I used to be very pro nuclear but I think nuclear has a lot of hidden costs - very long ramp up time, long and expensive cleanups.

Doesn't account for the technology needed to make solar and wind reliable, you won't get the same numbers.

See some numbers in https://solar.lowtechmagazine.com/2015/05/sustainability-off...

> Both solar and wind are far better than the hydrocarbon alternatives.

Agreed, of course. I'm only mentioning nuclear because people tend to think that merely replacing fossil with pv/wind is good enough. Not only is it not enough, it's also more expensive and barely getting us to the right track. Nuclear isn't perfect of course, but all things considered it's still better.

Solar and wind are reliable, just not necessarily consistent. Aging coal plants are unreliable (they can and do fail without warning), compared to solar and wind, which run reliably when the sun is shining or wind is blowing, both of which can be predicted quite accurately for a few days.

That's not the same meaning of reliable. What is usually meant is "can I trust this source to give me this amount of power at this time", or can I rely on it being available: fossil can, intermittent (by definition) can't. You need to look at the overall electricity generating system, not just the individual sources hoping they will seamlessly integrate in the grid with little changes.

What is the basis for your claim? EROEI? I’m curious what those were, so I found these:

Solar EROEI: 9-35

Wind EROEI: 20-50

Nuclear EROEI: 59-70

Which certainly looks great for nuclear (I do actually like nuclear in general), but is it actually important to be the best when it’s high enough to be economic?

You have to compare comparable things: in this case the comparable metric that is actually useful is "be able produce N GW of electricity with a 10% variation over a 60 year timespan". If you count this you'll have to account for the fact that solar and wind are intermittent, which means you'll need batteries or a reliable electricity source, and that's _always_ fossil based (typically gas). You also have to account for the fact that the expected lifespan of batteries and panels is around 30 years, so you have to buy them twice.

In the other side, a nuclear plant does provide a reliable current, has a long lifespan, and turns out to be cheaper. Even the GIEC says so: we won't be able to efficiently reduce our greenhouse gases without nuclear.

Speaking of comparing things correctly, what's supplying the peak power in this nuclear alternative?

Are you accounting for the cost of sufficiently overbuilding nuclear and/or storage? Mostly people seem to fixate on nuclear supplying the legendary "baseload" and leave all the other power as someone else's problem.

And if you add in whatever supplies the power until the nuclear gets built (either solar and wind, which makes nuclear redundant or fossil, which makes it a non solution) then nuclear doesn't really pencil out.

Nuclear today is surprisingly flexible, so it's totally feasible to use it not just for the baseload but for more, like 75% to 90% of the needed power. Hint: there's a country that has shown this as a viable solution.

> And if you add in whatever supplies the power until the nuclear gets built

I don't understand. Are you suggesting building a throwaway source of power until nuclear reactors are built ? That's not how things work. When there really isn't enough countries buy from neighbors. But I agree with your underlying point that building a plant takes a long time; that's why we need to stop being freaked out already and start building them, so we can get rid of all those coal plants.

You're referring to France, the government of which is planning to phase out nuclear in favour of wind and solar and projecting that it will save them billions. So they don't seem particularly convinced by your argument.

They also are one of the largest power exporters in the world, which doesn't really scale up unless we start exporting power to mars.

But regardless of those two separate fatal flaws, I don't think wind/solar advocates would be let off by nuclear advocates if they just handwaved away 10-25% of power and just ignored costs because the extra money would come from hidden subsidies to a nationalised energy sector so I don't see why the reverse isn't fair.

The problem is ecology isn't run by facts anymore, it is run by feelings. The French government will have spent 120 billion dollars to fund intermittent energies. All that money will reduce the nuclear part of the mix to replace it with another source that won't provide more than 10% of the electricity yet will pollute more. Even the Cour des Comptes is complaining that this is absurd and that money should have been spent elsewhere to have actual results (https://www.lemonde.fr/blog/huet/2018/04/19/la-cour-des-comp... in french, didn't find other source).

The French Nuclear eventually needs replaced by something, either more nuclear or renewable, as it's bearing its end of life.

That makes them not too different from any other nation, and they've made the same decision as every other nation, which is that nuclear is too expensive and slow to be considered.

So I agree that other things should be done as well but unless someone has some secret method of building cheap nuclear that they're not sharing then France will spend 120 Billion to replace nuclear with renewables because the alternative would cost even more.

No, they've done the same as other countries, which is follow the so-called ecology-oriented organisations and kill nuclear because that's what the population is asking for, not because it's the best thing to do. Again, if priority number one is to reduce CO2 then renewable won't be enough. If the priority is to find something quick and cheap, then sure, a solar panel is cheap. Except if you need a sustained production for more than 30 years then it's actually more expensive than nuclear. Again, in France it's not replacing fossil, it's replacing nuclear, the second cleanest form of electricity.

If you just want to please the masses and don't care about the environment, then sure, that choice was the good one.

If you’d said that even a few years ago, you’d have been right. Now renewables-plus-batteries have about the same LCOE as nuclear even in France, with plenty of reason to expect both renewable production and storage to become even cheaper. (France already has pumped hydro plants, but I’m not even counting them in the LCOES because I don’t know their capacity or how long they will last, but they’re unlikely to build more because they apparently battery storage is now cheaper).

And I’m saying this as someone who is a fan of nuclear tech and who thinks most of the public fears are disproportionate.

There discussion today that addresses this.


"a reliable electricity source, and that's _always_ fossil based"

Hydro, bio fuels?

And don't forget that big nuclear reactor will need maintenance, so you'll need overprovisioning just like wind and solar.

Ps "be able produce N GW of electricity with a 10% variation over a 60 year timespan"

I know you're attempting to compare like with like, but there isn't any inherent reason why this should be the case. Just because the grid has been based on a certain model in the past, doesn't mean we can't use a different model in the future.

Ok so you're actually saying that we should not only approve of those, but also pay to change a working grid ? When there's a perfectly vlaid and working solution ? If it ain't broke, shouldn't we not fix it ?

It is broken, it relies on pumping tonnes of co2 into the atmosphere, so there does clearly need to be a fix. Should the fix be nuclear or something else? That's the question.

Nuclear is expensive, slow to build, but worst of all, it doesn't have the political support. Personally I'm not against nuclear, you get someone to build it then I'll support it, but I don't want to spend time talking other people round to the idea when we could and should be doing something now.

Yep, here's the central point of contention: do we build nuclear that emits little CO2 but needs public support, or intermittent sources that pollutes tens of times more for an equivalent service ? Is the priority feel-goodness about what we're doing, or actually solving the problem ?

Where's your figure for polluting ten times more?

If this is all from (currently) dirty electric grids, then aren't you arguing against cleaning up the grid, because the grid is dirty? That doesn't seem to make much sense.

My comparison is always solar and wind against nuclear. Here's a very good analysis on solar alone: https://solar.lowtechmagazine.com/2015/05/sustainability-off...

In short: in the very good case of an insolation of 1900 kWh/m2/year and panels built in Spain (who has a relatively clean electricity), a reliable system of panels+battery will have emitted 85gCO2eq/kWh over its life. If we correct for the more realistic case of 1000kWh/m2/year (the average in Germany) and panels being built in China with its dirty electricity, the system will have emitted 217gCO2eq/kWh. On the US the insolation is higher, at 1700 kWh/m2/year, so it is going to be around 100gCO2eq/kWh. Here's a map of insulations here: https://upload.wikimedia.org/wikipedia/commons/1/1e/Global_M...

In contrast, nuclear is at 12 gCO2eq/kWh (https://en.m.wikipedia.org/wiki/Life-cycle_greenhouse-gas_em...). The disaster that solar is should be clear for everyone.

Your own link which claims 12 gCO2e/kWh for nuclear also claims 48 gCO2e/kWh for utility scale solar.

The same reference also put coal at 820 gCO2e/kWh.

Given the two options are:

1) nuclear power in 5-10 years when the reactor is finished, saving nothing for the intervening period and (820-12) = 808 gCO2e/kWh for the next 50 years

Or 2) solar power now, saving (820-48) = 772 gCO2e/kWh for the next 30 years, while totally not preventing you from also building nuclear reactors and simultaneously lowering the carbon footprint of any new power plants whose construction involves a lot of electricity…

…I think you’re making the good the enemy of the perfect.

One is a 98.5% reduction, the other is a “mere” 94.14% reduction, where in both cases we need to also roughly halve non-electric CO2 emissions.

Your figures are measuring different things.

The lowtechmag link is for an off grid solar and battery combo. Off grid nuclear isn't a thing as far as I'm aware.

Whereas the wikipedia link includes comparisons on all generating methods, which I would guess means they're an apples to apples comparison, so that means onshore wind in better than nuclear, offshore wind is as good as, and solar is only 5 times worse.

And to restate the point in my last comment, the lowtechmag figures at least are based on a dirty grid, as the grid cleans up and the solar figures improve. Lets assume you get your way and we build out nuclear. Solar's figures will improve and eventually surpass those of nuclear. In that situation would you support moving over to solar?

Really? You already know you're wasting two thirds of your electricity? If I had to cut consumption by two thirds I'd be sitting in the dark a lot. Do you have an example of what you'd cut?

In most Western homes, lighting is a tiny part of electricity consumption, and even more so now that LED lights are becoming prevalent.

Heating, air conditioning, refrigerators, washing machines, tumble dryers, dishwashers, hobs or ovens are typically responsible for more electricity consumption.

Personally, since I don't have air conditioning, only use heating ~3 months a year (I live in a very mild climate) and almost don't use the tumble dryer, I would have a very hard time cutting my consumption by two thirds. Maybe not using the dishwasher, washing clothes less (or by hand) and cooking less, but probably it wouldn't be enough.

I would ditch the TVs, re-wear lightly soiled clothes instead of using the washing machine / tumble dryer so often, more line drying in the summer, be vigilant about switching off unused lights, unplug unused appliances overnight, cook with the electric hob and microwave less, eat more fresh and uncooked food, buy a more efficient fridge and freezer, use the computers less, get rid of the electric shower, spend more time out with others rather than indoors.

That’s just in the home.

All would involve sacrifices, but doable ones without having to live in Mad Max.

Seriously, ditch the dryer. You'll be amazed at how much power you don't use. You can even line dry inside although you have to be careful of the humidity in your house. If you live in a cold climate and heat your house, then probably you'll be doing yourself a favour by drying indoors. We have a combination dryer washer (the dryer uses a heat pump), but use the dryer maybe 2-3 times a year (only during the rainy season when it rains for weeks on end).

If you want to simply save energy, avoid the car. It's really apparent if you have an electric car because you have units that you can compare with other things, but for example, we burn probably 6 kWh per day in the car and this absolutely dwarfs our daily consumption in our apartment. If it's close enough to walk, then walk it.

Just dryer and car may get you close to your goal.

"cook with the electric hob and microwave less", "get rid of the electric shower", "spend more time out".

Arent these just displacing your electricity usage? I assume you aren't going to have less showers for example. And I can't see a trip to the coffee shop or cinema being 'greener' than the stay at home equivalent.

Basically live like your grandparents did.

Buy a solar water heater. I live in a climate that varies between -20 and 35 degrees, and this solar water heater has worked consistently for 10 years over these temperature ranges. It is, essentially, some glass pipes attached to a tank at the top with a 260 litre capacity, capacities vary, all neighbours have them, and a meter to press a button to auto- fill up when needed. This will be a huge cut in your electricity bill. For cost and context, including installation, mine cost about $200.

And, well, for tips, a washing line. There is no need to tumble-dry anything, a piece of rope, some pegs, and wind and relative humidity do a pretty good job themselves.

Get a smaller home, reduces costs of lighting, heating and cooling proportionally. Move to a city with good public transit and stop using a car. Take a train for vacation instead of flying, or just don't travel for vacation.

Do all of those and cutting your emissions by 2/3 is very easy with most of your quality of life intact. Big homes, cars and flights don't make people happy, so moving to such a lifestyle wont be a catastrophe. I am not sure why so many in the western world dreads it.

More likely you would be sitting in the hot. Cooling is the main electrical energy consumer in the not so hot uk [1].

[1] https://www.ovoenergy.com/guides/energy-guides/how-much-elec...

Yes, cooling the milk, meat, frozen pizza and ice cream according to that chart.

I'm very surprised by and suspicious of lighting being 600 kWh/year, so I question their sources or analysis. They note themselves LED lights are around 6 kWh/year.

Edit: Their source appears to be a 10 year old survey from before LEDs being generally available in shops, and before tungsten was banned from general sale. No wonder the numbers are off.

This is very misleading because the capacity factor of solar is from 10% to 30% and wind from 20 to 30, but every other power source is in the 80%.

Please tell us, I'm struggling to identify what this 2/3 of optional power usage is?

A super computer in your spare room? Tesla coil security??

Probably air conditioning, mostly. Maybe using an electric kettle? Leaving the TV on while you do housework? There's a lot of low hanging fruit that most people could save with relatively little sacrifice.

In Central Europe 80% of energy consumption for average household is heating in winter (September to May). Unplugging phone charger won't help. And the solar ain't available October to April.

Solar isn't available? All my friends here in the UK with panels would beg to differ. Sure less than the summer, but a rooftop aray and still put out a decent amount of power much of winter. Maybe not in the high North, but esp since you qualified that with 'central Europe' I'd wager there is plenty of solar generation going on then across Europe.

Look at fig 6.

> Due to low availability of solar energy in December, the required area is as much as 341.0 m2.

No one will put 340 sq meters of solars panels on small house's roof or on it's lawns. And no one is Suwalki would like to freeze in December.

There are other technologies like heat pumps etc. But solar is not of use in winter. Not for heating.


That is for heating a single family home. Not many homes in Europe or heated with electricity, especially not with solar electricity. Especially not in somewhere as cold as Poland.

Turning the TV off whilst doing the house work is basically a rounding error.

You'd have to drink a lot of tea (or rather stop drinking) before kettle usage starts accounting for anywhere near 2/3rds of your electrical usage.

Air conditioning/electrical heating is possible. But if its 2/3rds of your energy usage, it doesn't sound that optional.

The biggest users of electricity are ones you can't easily cut out. Electric car, hot water, heating/cooling, cooking, washing machine, dryer, fridge. They're the major energy users in the home, and you can't easily reduce them by the 2/3rds required. Unless you took your shack to passivehaus standards, and that's only for heating cooling.

Air conditioning and heating can easily be 2/3rds or more of your usage and is trivial to reduce. Instead of running aircon in the summer you can probably use a fan most days and save 5-10kWh per day. In winter, dress warmly and rug up in a blanket instead of keeping your room at 22°C. This on its own would make up the bulk of the savings.

Electric hot water is another huge power drain, switch to solar hot water and 3/4 of the year your hot water could be free (depending on climate, of course). Otherwise keep showers short, set the water heater thermostat to 50°C instead of 70°C and you could save a lot.

Depends on your TV, my old one pulled 400W or so. Not huge compared with heating/cooling but still significant if you leave it on all the time.

Tumble dryers use tons of power. Hang your laundry up instead and you could save yourself 20-30kWh/week.

If you're driving an electric car you're loaded enough that the cost of charging it will not be an issue anyway (especially given that every dollar you spend in electricity is saving you several dollars' worth of petrol).

So basically all of these things can be reduced a lot for very little extra effort or inconvenience. I don't think 2/3rds would be out of the question without making major sacrifices.

"Air conditioning and heating can easily be 2/3rds or more of your usage and is trivial to reduce" its not trivial to reduce it to zero which is what we are talking about, absent other changes.

"Tumble dryers use tons of power. Hang your laundry up instead and you could save yourself 20-30kWh/week"

How much washing do you do each week?! You're right though, in the best best case this could be reduced to zero, assuming no rain, or winter.

"solar hot water" this is kind of cheating. If solar hot water were the cheapest or generally accepted option v solar electric I'd accept, but that isnt the case as far as I aware. I wouldn't accept gas heating or hot water either.

I don't deny that you could construct a scenario where you can trivially save 2/3rds of your electricity usage, but we have an OP who has done the work to identify that they can save this without too much trouble, so they have some awareness of the issue, but then we have to assume they are starting from a high base and haven't done anything to lower their usage, which doesn't make much sense, and then also assume they live in an incredibly temperate climate where they don't need heating/cooling, but simultaneously assume they they like it really warm in winter and really cool in summer. That's too many leaps for me.

I havent done these sums, so I'm less dedicated than the op?, but I already have an lcd tv, led lights, hang my washing out when its sunny, put a jumper on in winter, and don't possess aircon. I don't have 2/3rd fat to trim, and that's energy usage. If anything I'd expect my long term electricity usage to increase, my heating, hot water and hob are gas, and my cars petrol. I expect those to become electric in the medium term.

So your point is that if you've already taken the low hanging fruit, there aren't low hanging fruit? OK then.

No my point is you have to assume the tree is amazingly well laden in perfectly ripe fruit, the OP has taken stock, and rather than taking a fruit to eat, has gone off to do something else.

So buy more efficient devices then.

We are talking about reducing 2/3rd of your electricity consumption.

The only 2 classes of devices that could save that much is incandescent -> led light and resistive heating -> heat pump.

And those efficiencies aren't enough to offset all the other devices where efficiency improvements are in the single digit percent.

So you're still having to combine that with something else, which seems to be moving away from the relatively painless the great(?) grandparent described it as.

Last time I tested it, boiling a kettle takes less than 2 minutes, it draws 2 kW, so 8 cups per day is 22 watts average.

An electric shower is about 20 kW, so at 30 minutes per day that’s an average of 417 W. I’m not sure about electric ovens, but I think it’s a similar range.

Heating/cooling and transport are the biggest users. The low-hanging fruit is mostly a mixture of “eaten” and “not tasty” if you’ll excuse extending the metaphor.

Kettle has to be the cheapest way of boiling water, so economising it away seems short sighted. Or do you mean by switching to only cold drinks?

Having spent a while camping and using solar there are a lot of things that can go. Heating costs can go to zero by using insulation. Macbook Air type computers and LED lamps are low enough power to run on solar etc. We still tended to use gas for cooking.

At $793/KW, a 10KW system means no electric bill after 3 years. If the lifetime of the system is 20 years, that's at least 15 years of free electricity.

Only when someone else is subsiding the grid, which under net metering acts as a battery for free.

That's not sustainable, especially as the price of solar drops making it a no brainier.

The true cost of solar includes enough batteries to cut the grid connection, or buying and selling energy at market rates, which will involve generating many more kWhs than you consume.

That said, we desperately need a carbon tax which would help swing the pendulum back even without net metering.

Most full accountings of solar's value to the grid show that homeowners with solar are subsidizing the grid (not the other way round) and other customers by providing power at peak usage times and being paid at rates that are averages and therefore below peak, and not accounting for wider costs/benefits:


Yeah, I've read a handful of studies that claim to show something like that, but every time you dig down in to the numbers there are glaring errors.

Given that the Maryland study accounts for the benefit to the local economy (??), I'm not going to bother spending an hour on that. They've left their thumb on the scale.

Typically solar does not provide much power at all during peak use, which is why the duck curve was coined.

You can clearly see that homeowners with solar aren't subsidizing the grid, because laws needed to be passed in order to force utilities to accept the power. If someone hands you free money, you don't turn it down.

Net metering was a handy subsidy to get solar started, but it's an obscene transfer of wealth from the poor to the rich in the long run.


Many utilities are run on a cost plus basis which means they would be entirely economically rational to literally turn down free money, because it would reduce the amount of profit they could make.

Also, the duck curve doesn't show peak use. The duck curve shows the peaks that are left after solar has been subtracted.

Go find a duck curve, note that it will almost certainly be in springtime when overall demand is low. Then look up the yearly demand peak for that region. It will almost certainly be in the afternoon in the summer and will dwarf the duck curve peaks. So solar will be directly reducing the requirement to build out capacity (and further reducing utility profit potential/ saving everyone lots of money).

Worst case scenario for the duck is to throw away a bit of solar power sometimes because other parts of the system need time to ramp. People clutch their pearls at this, just like they do at negative prices, but it's just nonsense with no logical basis.

It's like complaining that buying a dozen eggs is wasteful if you only need 11. Yeah, but it's cheaper than buying 11 individual eggs so maybe just think of something to do with your "free" egg instead of complaining about a non-issue.

To the extent that solar is economically beneficial, net metering isn't necessary. Just sell it at market rates, which are astronomical on peak days. How's that for logical basis?

Yeah, sounds great to me. Add in a carbon tax, removal of fossil subsidies and allowances (to capture externalities) and a whole bunch of nonsense gets solved by the power of the market incentives.

I'm not in favour of net metering as an end in itself. As I said I think it still cheats solar providers. But it's a neat hack that quickly and easily moves us closer to the real solution than we were before, while using the existing deployed hardware (the basic idea is the existing meter runs forward and backward and you pay the net).

I'd love a carbon tax.

However, I still think you're mistaken that residential solar is in any way subsidizing the grid.

Utility scale solar is under half the price, and the gap is only going to widen as PV prices fall and the panels become a smaller part of total cost. Why would you pay a homeowner $2.5/W to install panels on their roof instead of paying $1/W to build a power plant that has the same profile?

The only benefit you get is the distribution of the power generation, but if that's the goal and we're willing to pay a lot of money to subsidize it, BEVs capable of demand dispatch powering a home or even battery to grid are a significantly better target. The new Leaf can do this, but there's limited enthusiasm as the economic benefit can't be easily captured.

We need to switch to BEVs anyway, and it's crazy not to take advantage of the dual use potential. Solar might shave a bit off the peak days - whether residential or utility by the way - but BEVs would go much further, and enable much higher wind and solar mixes in the grid.

Solar is cheap enough already. Net metering did its bit as a kick starting subsidy, but for new installations today it serves only as a wealth transfer to the upper middle class, who get to break even on something uneconomic, greenwash their lives, and displace spending on utility scale solar.

Let's solve the issues of tomorrow instead of doubling down on what worked yesterday.

In Varanasi in India, many businesses have their own batteries as power cuts happen often enough that it's a necessity. I am using just a single city as an example, but potentially India already has much more battery installations than you expect (and than other countries with more reliable power sources).

And many homes have battery backup systems as well. However, they all use lead-acid batteries. There is a real opportunity for better battery technologies to be deployed in India.

My understanding (as limited as it is!) is that if space and weight are not an issue, then lead batteries provide a great deal of benefits today, especially when you can add to your system with 'dead' car batteries and the like. It is only where space and weight are an issue that you need to move to newer tech.

I am fully prepared to be incorrect here though!

This. Net metering is cool and all, but with the wrong grid fee structure it ends up as a subsidy to the already well off.

at 10kwh system means it basically falls in line with the average usage per household in the US (source https://www.eia.gov/tools/faqs/faq.php?id=97&t=3)

Therefore, this ought to be self-sufficient, if there's storage. Batteries cost extra, no doubt, so it's not "free" after 3 years, but would be pretty cheap if batteries can be amortized over their expected 25yr lifespan (assuming same batteries as telsa's).

You'd need to size the generation for your worst days, not the average over the year; if you're using any kind of electric heating (e.g. reverse cycle air con), and your generation is lower in the winter months, you'll drain your battery each day, and the overabundance in the summer months doesn't help you.

Add in more solar panels for this, as well as the cost of a battery that can store a few days worth of power, and you're talking a substantially larger expense to cut the grid tie. However, the days of 100 year paybacks are clearly behind us if we're seriously doing back of the napkin math here. The progress in the field is impressive.

> your generation is lower in the winter months, you'll drain your battery each day, and the overabundance in the summer months doesn't help you.

Certainly in the UK, you sell your over-generation back to the grid. This will offset the cost of buying from the grid on the days when your generation is lower than consumption. Certainly in the UK you may never get 100% net zero cost (not enough winter sunshine hours I suspect), but will help since most homes in the UK are heated via gas (as in gas, not petroleum)

It might be cheaper to add a generator for exceptional days. Build the rest of the system for efficiency.

It depends where the 10kw figure comes from.

If its been sized to sell enough power back to the grid to cover the grid tie then there's no subsidy.

10kw does sound high for the average Indian family.

I assumed parent was talking about the States, given both the size of the system and the electricity bill amount used for the payback calculation.

If it's an overprovisioned system for India, then what I wrote should be disregarded.

Maybe they should buy some cheap electrical scooters as well ...

This is great news! India is extremely energy deficient and imports a large quantity of oil. Reducing petroleum dependency can help reduce poverty in India as more production can be consumed domestically and not sent abroad.

That’s one way to look at it. Unfortunately, Indian banks have been granting billions of dollars of loans to the coal sector[1] and if solar power cost drops and we can’t export excess power, we’re in for trouble . Talk of second order effects ..

[1] https://mercomindia.com/public-sector-banks-loans-coal/

Looking at all the new coal power plants being built / planned in India is really disheartening though: https://en.wikipedia.org/wiki/Ultra_Mega_Power_Projects

Australia has also huge potential in solar power and big problems with electricily, I wonder why they didn't invested serious money yet.

It's a growing industry though. https://en.wikipedia.org/wiki/Solar_power_in_Australia

As for increased investing, there's probably politics at play.

Our coal industry in Australia has the government in their pocket. Despite coal power globally in the decline, the government has agreed to open and subsidise new coal plants.

It's all socializing the costs and privitizing the profits.

Ah yeah, coal lobby.. Thanks Heaven, they aren't too strong in USA/EU.

I am East Asian in India, where are cheap solar panels being sold in India?

I tried looking for them and everyone told me you need to import Chinese panels on which government has imposed massive duty.

So which company is offering cheap panels in India?

I'm not 100% sure, but my Dad had brought a solar panel from some exhibition a couple of years ago and I believe it was from BHEL.

I'm guessing due to lower labor costs and permitting costs.

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