The issue here is the mandate that when you create electricity with solar that the electric company must buy that electricity from you as you feed it back into the grid, regardless if they currently need it or not based on demand. These power companies dont want to become energy storage companies, its too expensive. They prefer to simply make as much electricity at the moment as is needed.
I agree with the electric companies on this point. If they dont need the electricity, why should they be forced to buy it? That will increase costs for non-solar customers as they end up footing the bill for the battery storage needed by solar customers. I think the proper way to do these installs is to have customers always have on site batteries which store the energy for their own homes use. Yes, its nice to sell back electricity to the grid, but that feels like a very hackish way to use 'solar'. It makes sense also. If you want to save money on your electricity, you need to make your own, so you draw less from the grid- Not make it for someone else when nobody wants it.
Does anyone know if the power company is required to buy all forms of electricity currently? Could you just setup thousands of solar panels in a field you own and demand money from the grid? Seems like a easy return on investment, depending on the cost of panels/equipment.
Most net metering programs take solar from a home when the grid is facing its highest demand and energy is most expensive for the power company. They then provide a credit to your bill in watts. With a solar installation, you're drawing energy at night, when the grid basically wants to give away power to keep things balanced.
So you contribute a dollar worth of power, and you take out the same power at a later point in time, and the power company basically gives you a 5 cent credit.
The power companies make fistfulls of cash on the arbitrage.
They still hate it though, because distributed power generation threatens the model of power monopolies that get to fix prices while steadily reducing service.
Hawaii in particular has faced historically terrible load balancing, so some of the distributed generation is a response to the poor existing services and constant outages. HECO basically created all the incentives for the public to hate and want to work around them.
You couldn't just give them an out on whether they wanted to buy the power or not, since they despise distributed solar generation. They'd just build a messy and expensive quick spin up generator, buy expensive power from that during midday, and claim they don't "need" the solar, to deter investment in the technology, even though it'd be better for everyone if they bought the solar.
You can't ask a kid how much he needs foul tasting medicine. Sometimes you just have to deliver it.
>I agree with the electric companies on this point. If they dont need the electricity, why should they be forced to buy it?
A) Because they are operating a utility monopoly. We are forced to be their customers. They should be forced to be ours.
B) They could use it, but they would rather sell you the output from their oil fired power stations because the profit is higher for them. That is why they don't want your solar panels hooked up - not because your neighbors couldn't use the electricity they generate - because it challenges their monopoly position and eats into their profit margins.
If this were truly about electric companies not needing the electricity (as opposed to them viewing any challenge to their monopoly as a 'free market evil'), then they would be arguing for market pricing for your solar generated electricity. They are not. They want your solar panels to be completely disconnected. Ideally you shouldn't even have them at all.
>Yes, its nice to sell back electricity to the grid, but that feels like a very hackish way to use 'solar'.
Your argument for how energy policy should be set are informed by what you think "feels hackish"?
Having just gotten our PV panel installed on our roof this year, this is fresh in my mind. Of course everyone is doing it -- electricity in Hawaii is insanely expensive. Before we turned on the system, we paid $200/month for power! And this is in a house with no heat and no AC.
Do they have to buy the power? Yes, but not without limits. The system is built on "net metering". Every kWh we deliver to the grid can only go to offset one that we already have or will use. If your system is so large so as to make you a net producer of energy when averaged over a whole year, you will be giving that away to the utility for free.
The rules also limit installation of PV systems to a level that will not exceed the minimum daytime load on the local circuit, exactly because there is nowhere to store the power. So every kWh they get from us is one they would otherwise have to generate to supply to one of my neighbors.
It's clear that the utility companies aren't happy with this. But studies have shown that these "extra costs" the utilities talk about being saddled with are offset by savings to them as well.
Solar power typically produces power during times of high power demand, so the net effect of solar is actually to even out the daily load variance. This is good for the utility because they need to make sure they have capacity to handle peak load, even if it's only for a small fraction of the time. These "peak power" plants are expensive, because you almost never get to operate them. When PV reduces peak load, they don't need these plants and this is a net win for them.
Could you just setup thousands of solar panels in a field you own and demand money from the grid? Seems like a easy return on investment, depending on the cost of panels/equipment
This depends on your jurisdiction; in the UK you can put up to 4kW on an inhabited building and get a subsidy. Larger installations require pre-approval.
You are conflating the electricity producers with the grid. The grid itself actually saves money by installing storage, when compared to upgrading links, and does so when it can.
As to, if they do not need the power, why should they buy it? Well, there are two reasons, one is that everyone else on the grid already gets to, so it would be anti-competitive to not allow it for the little guys, and the other is that someone will always want power, so it makes economic sense to buy the power and build storage to offset it and make money through arbitrage.
Hawaii is a particular shit show when it comes to electricity utilities. From their own page on renewable energy, no less:
Electricity can be made from a variety of energy sources. Some are fossil fuels such as oil, coal and natural gas. Over 90 percent of all the energy used in Hawaii for electricity, surface and air transportation comes from imported fossil fuels, mostly oil but some coal. (The synthetic natural gas used in Hawaii is refined here from crude oil.)
I think nobody here has the patience to wait for this particular dynosaur-consuming monster to catch up.
It seems inevitable that continued advances in PV will either destroy the power utilities or force them to reinvent their business as electricity brokers (focusing on distribution and/or storage).
Regulatory capture can slow this trend. But as the article indicates, it's only temporary. Advances in energy storage and moderated consumption allows customers to disengage from the grid entirely.
I feel like this is one good example of big changes coming to the world and traditionally established big business in the next 5-10-25 years. Hilariously, many of the following big business have "guaranteed profits" from the Government, which is also going to have to change.
If you're in the business of making electricity by burning stuff, or you sell oil, or cable TV, or internet, or 50 other good examples, you had better start reinventing your business now.
Those business make very rich people richer, so they're going to fight it tooth and nail, which is a shame when they could be putting that effort into reinvention.
I agree. If I were a utility, I would be working hard to figure out how to be a storage broker, because if homeowners figure out storage without the utility, the utility will eventually be left with nothing other than large industrial consumers (which might be a decent business, but probably less than half the size of the utility's current market).
Isn't Hawaii a special case because of its isolation?
If so many people install solar in Southern California or Arizona that the local utility has more power coming in during the day than it can use or store, it can sell the excess via the national grid to someplace that can use it.
As far as I've been able to determine from the internet, there is no connection between Hawaii power grids and the mainland. In fact, it looks like the grids of each island might be isolated from the others.
Exactly. None of the islands grids are connected. I worked for a power plant on the big island a few years ago and even then there was a big issue with too much power during the day and not enough at night. Coupling that with the intermittent wind power and you have a very hard grid to maintain.
I think that a home battery product from Tesla might help with some of these worries. If the rumors are true, Tesla want to take their existing car battery technology and turn it into a wall mountable product. This would allow homeowners to generate their own electricity during the day and use it at night. I'm not saying that people will completely drop off of the grid (though I'm sure some will) but it might be a way for the utility companies to manage peak demand. There is possibly even a good small business idea in building software to handle this type of thing.
The cost is still too high, so the electric companies have little to worry about in the short run as long as they can find ways to improve their own margins. Of course lobbying for regulatory fees and reduced buy-back rates is one way to do that, but the utilities best be careful there. That could cause a blow back reaction.
In the long run though it is all downhill. Battery tech is getting better at around 8% per year. Solar efficiency isn't far behind. What cost $20,000 now to add solar or $40,000 to get off-grid completely, will cost half that in about 10 to 15 years. If the trend lines continue then in 20 to 30 years years its a done deal. No house will ever be built again without it's own power generation system.
You can't get off the grid completely unless you are a) willing to suffer some downtime occasionally, b) way overbuild storage as compared to typical needs, or c) have your own backup fossil fuel generator.
Any way you cut it high availability costs money. If you expect the grid to handle backup for you then you should expect to pay them to do so. TANSTAAFL
I once worked at a utility studying this very issue.
The typical worries about solar are:
+Power intermittency (rapid, uncontrolled changes in power can push the voltage and frequency outside acceptable levels. This reduces reliability and can destroy electronics.)
+Voltage regulation (also, on a local level, PV can mess with voltage compensators, pushing voltage outside of acceptable levels at the end of voltage regulation zones)
+Morning power surplus (lots of solar power will drop the baseline demand from ~4AM to noon, reducing the amount of cheap baseline power you can run)
+Harmonics (crummy inverters can inject unwanted sine wave harmonics into the grid, again bad for electronics)
+Fault current danger (if a tree takes down a power line, both sides can be remain live if power is being pushed onto the grid by PV on both sides)
+Inverter tripping (the main way to fix the fault current problem is to mandate that inverters passively follow the grid's voltage/frequency and then disconnect if they detect problems. However, with high PV penetration this has its own problem: a transient fluctuation can cause a domino chain reaction where all the inverters turn off, taking the grid down with them.)
+Power factor/vars (one important function for the grid is to keep current and voltage in phase, but today's PV inverters are dumb and blindly produce power with a power factor of 1, which can mess with automatic capacitor banks meant to help counteract the inductive load of the grid)
Now, some of these problems are more real than others, and many don't become an issue until PV penetration reaches like 30%.
The good news is that these are all solvable problems. Energy storage or additional natural gas peakers can fix the intermittency problem, and for the other problems the grid can be redesigned to allow better two-way power flow and inverters can be designed to produce higher quality power.
However, the bad news is that all of these fixes are expensive and all of them take years. Furthermore, many utilities do not have the expertise or confidence to make big changes to their grid and still guarantee reliable high quality power. Utilities are known for being slow and risk-averse, but they are risk-averse for a reason - blackouts are very costly to society.
Another issue for the utility is how to charge for power. Historically, utilities have tried to keep things simple for residential customers by charging only for power consumed. However, if residential PV becomes popular, utilities will have no choice but to change their pricing model so that they can be compensated for the non-kWh value they provide (e.g., reliability, stability, option value, power quality regulation).
The bottom line is that the problems from high PV penetration are real. Utilities are cautious, not evil, and they have good reasons to be. (Also, I think it's ridiculous when people claim that PV will kill utilities - barring a radical shift in technology/economics, wires and pooled power regulation and economies of scale make a grid hugely valuable, even if power generation becomes more distributed.)
That said, these are all solvable problems and I am hopeful and optimistic about the long-term future of solar power.
> However, the bad news is that all of these fixes are expensive and all of them take years
As a power electronics control engineer I strenuously disagree. The historical problems with massive renewable penetration aren't just solvable, they are well-solved already!
For example, grid-tied inverters and PFC rectifiers have been meeting IEEE-519 harmonics guidelines for many years already.
We even have virtual impedance methods which provide harmonic and reactive support for the grid available right now. The problem is that the utilities have actively blocked their implementation!
The grid accepted an almost total transformation from nonlinear RCD computer loads to PFC-corrected loads without difficulty at all, and there are far more switching power supplies on the line than there are active inverters. So I view the "problem" with unity power factor inverters as a red herring.
Anti-islanding has been in effect for many years already, which completely eliminates the "felled tree leaves live wires" problem. Again, another non-problem.
Consider very carefully what you get from the entrenched utilities, because they are coming to the table with a tremendous amount of preexisting bias.
Unless they're already started up (i.e., part of expensive spinning reserve) gas peaker plants can't respond fast enough to solar PV ramp rates, which can be hundreds of MW/minute when clouds blow over a utility scale plant like Topaz (550MW). They take 10-15 minutes to come online from a cold start and sync with the grid. Gas peaker cold starts are expensive - the plants I've looked at (GE, mainly) allow some number of cold starts before the plant has to be taken down for service. But keeping them hot (spinning reserve) is expensive, too.
The fix for rapid PV ramp rate is enough storage at the PV site to give ~ 15 minutes of continued nominal output when insolation drops out. This is enough time for classical grid management tools to be engaged.
One driver for the equipment upgrades needed to deal with reactive power compensation, etc., is the price premium paid for "ancillary services", or power supplied at short notice for grid stability/management needs. The multiple over normal, average power pricing can be 100x depending on the circumstances.
When residential inverters are smart and can respond to utility signals, then residents can participate in the ancillary services market. That will (or should, at least) pay much more than simple net metering schedules. The economics should accelerate deploying equipment that can do this, and that will mitigate the problems brought on by high grid penetration of PV generation.
Wouldn't the solution to charging be the same as any other consumable utility? Charge x dollars per month for the base keeping the wires hooked up fee, and then x cents per kilowatt hour?
I have a solar startup that specifically focuses on automating interaction with utilities, and the excitement and ambition in the solar industry right now is off the charts. There is an unbelievable amount of momentum in favor of solar, and most solar companies see these problems as totally solvable. Hawaii is seen as a microcosm for the way the rest of the U.S. will be in 10 years or less.
Here's some of the things that solar has going for it:
1. The Governor of California recently set a mandate to reach 50% renewables by 2030[1]. We want to hit this target in ten years or less.
2. The Department of Energy's Sunshot initiative is funding solar technology and software development to drive the installed cost below $1 per watt by 2017[2]. So far, we are on track to hit these targets.
3. Batteries are getting super cheap, which will turn solar into a non-intermittent source and allow solar+storage to be just as cheap as grid prices[3]. In fact, there is actually quite a bit of worry about grid defection (we are starting to see this Hawaii)[4].
4. Wall Street is funding solar projects at a massive rate[5]. The bottleneck right now in solar is finding customers, not financiers.
5. The federal subsidy for solar is expiring in 2017, but the industry is on track to absorb the cost and continue to thrive without any subsidy[6]. This will make us much harder to kill off politically.
6. The advent of community solar will solve the renting problem, where renters be able to buy pieces of a remote solar farm since they don't own their roofs[7]. This opens up the solar market to serve the entire electricity-using population, not just the building owners.
What will be hard:
Stranded assets. Solar is growing so quickly that it will soon be able to replace the capacity of existing fossil-based generators that still have lifespan[8]. Investors in those assets will see them stranded. This will start with coal and natural gas plants over the next 10 years, but as batteries get cheaper and electric cars get more prevalent solar will start stranding oil assets[9].
This is where things get hard. Utilities are traditionally pretty bad competing (since they usually don't have to), but oil companies are another story. They are very used to ruthless competition and have a lot of experience bribing their way into governments. We are expecting very heavy push back from oil after 2025 because electric vehicles risk leaving already purchased oil in the ground.
I, for one, can't wait until we fight that fight. It is the fight that our generation will be remembered for.
P.S. The entire solar industry is hiring (including my startup).
Is it really that hard to forecast the amount of power residential PV generates? I'm pretty sure you could build a model that is pretty good just based on weather data, but failing that why not just put a single small PV panel on each (plant, substation, power pole... choose your level of granularity) and have it report back the amount of solar energy in that location? That should get you a very good idea of the amount of power coming in.
If the utilities drag their feet, their could be reasonably good micro/neighborhood/apartment complex-level solutions - $100-250k of batteries on a loan & small buy-in per-unit, and the batteries & smart-system can optimize the buy/sell process around historical/current usage & prices & storage levels.
It is an interesting conundrum. I'm looking forward to whole house inverters with decent battery packs to take me completely off grid. At that point a simple fuel cell tied to the gas line to top off the battery pack when low on energy and you're good to go.
Can anyone comment on the claim that private solar power generation affects the stability of the grid? What kinds of infrastructure changes would be needed to properly support power generation in private homes?
There is a disconnect between market forces in energy production right now.
Right now, short-term grid frequency and voltage stability (periods of seconds to a few min) is regulated automatically by the governor response of the various generators on the grid. These governors bid in advance to set their proportional gain for frequency stability. Basically, they promise to autonomously raise or lower their throttle in the future based on the observed grid frequency and voltage, and get paid later when they make good on their promise. Long-term stability (periods of 15 min or so) are regulated with market action in the spot market for power. Very long term stability is regulated by markets that clear 24 hours in advance of their estimated delivery.
However, some energy producers effectively have flat rate contracts that don't participate directly in grid stability. Wind and nuclear will negotiate a fixed power-purchase agreement (typical prices are about 50 USD/MW-hr or so in the US) that will be fixed for years at a time. Likewise, residential solar customers sell back their power under the same, basically fixed rate schedule that they use to buy power.
So, as the penetration of fixed-rate power increases into the market, the pricing volatility continues to increase as well. There are technologies that can help. In fact, it is trivially easy to get a grid-tied inverter to be sensitive to grid changes with controls that model virtual inertia, impedance, throttle, and so on. This is part of what I do as a controls engineer. The difficulty isn't in implementing such controls, it is in adjusting the markets such that all of the existing players are comfortable with the result.
Witness this in Hawaii - the retail price of power is so high that it makes obvious good sense to install your own generation. But instead of adjusting the rates to reflect the new availability of supply, the incumbent utility seeks to raise barriers to competition instead.
The grid is built on the assumption of a few central points producing almost all electricity. This creates a grid focused on distributing away from those points. A more distributed and fluctuating producer situation will need more distribution between different branches of the network than the current infrastructure can handle. It will also require extra power generation that can be started on demand when the power production is lower (due to clouds, night, etc). This requires a lot of extra capacity that will get very low average utilization and therefore be very expensive due to being expensive to set up.
Well for one, whenever a power-line goes dead... the Solar panels need to shut off so that the workers can safely replace the powerline.
There's nothing quite like "Oh, some home in this neighborhood is still powering this powerline, despite the fact that we've shut off all the other power sources". That's quite the real "shocker" to the poor worker.
anybody else confused about why a guy who lives in Hawaii, one of the most temperate climates in the populated world, is spending $700 per month in electricity?
serious question for Hawaiians: do people run the a/c round the clock there? Or is it something else?
I live on the big island and pay over $.40/KWH so a $700 bill would be more like $200 on the mainland.
That is one reason why my new house is off grid solar - cheap (compared to $.40/KWH), clean electricity.
The other is that the grid here is unreliable. I had 87 outage events last year for a total of 37 hours and that is not including the nine days with out power post hurricane.
Many people, at least on O'ahu, live in urban areas with serious "heat island" going on. In those locations, if your windows catch the prevailing winds, you don't need a/c, or perhaps only rarely. If there are buildings or terrain blocking the breeze, however, you'll be more comfortable if you have a/c, or if you make some lifestyle changes that make it less necessary.
That said, when I lived there, my bills never approached that figure, even with a/c.
My bill got up above $500 one month (normally around $350) without A/C. My friend's cousin on Maui had a new neighbor move in next door from the mainland and installed central A/C like every decent apartment on the mainland has. Their first month's electricity bill was $3,000 (three thousand United States dollars) because of that A/C. It gets very expensive, very fast.
It may not be A/C. A pool with a single speed pump plus an in-ground hot tub could conceivably run between four and five hundred bucks a month for heating. Of course if that's the case he could save a couple hundred bucks a month by installing a solar heating system and a two speed pump.
[+] [-] DanBlake|11 years ago|reply
I agree with the electric companies on this point. If they dont need the electricity, why should they be forced to buy it? That will increase costs for non-solar customers as they end up footing the bill for the battery storage needed by solar customers. I think the proper way to do these installs is to have customers always have on site batteries which store the energy for their own homes use. Yes, its nice to sell back electricity to the grid, but that feels like a very hackish way to use 'solar'. It makes sense also. If you want to save money on your electricity, you need to make your own, so you draw less from the grid- Not make it for someone else when nobody wants it.
Does anyone know if the power company is required to buy all forms of electricity currently? Could you just setup thousands of solar panels in a field you own and demand money from the grid? Seems like a easy return on investment, depending on the cost of panels/equipment.
[+] [-] brownbat|11 years ago|reply
So you contribute a dollar worth of power, and you take out the same power at a later point in time, and the power company basically gives you a 5 cent credit.
The power companies make fistfulls of cash on the arbitrage.
They still hate it though, because distributed power generation threatens the model of power monopolies that get to fix prices while steadily reducing service.
Hawaii in particular has faced historically terrible load balancing, so some of the distributed generation is a response to the poor existing services and constant outages. HECO basically created all the incentives for the public to hate and want to work around them.
You couldn't just give them an out on whether they wanted to buy the power or not, since they despise distributed solar generation. They'd just build a messy and expensive quick spin up generator, buy expensive power from that during midday, and claim they don't "need" the solar, to deter investment in the technology, even though it'd be better for everyone if they bought the solar.
You can't ask a kid how much he needs foul tasting medicine. Sometimes you just have to deliver it.
[+] [-] crdoconnor|11 years ago|reply
A) Because they are operating a utility monopoly. We are forced to be their customers. They should be forced to be ours.
B) They could use it, but they would rather sell you the output from their oil fired power stations because the profit is higher for them. That is why they don't want your solar panels hooked up - not because your neighbors couldn't use the electricity they generate - because it challenges their monopoly position and eats into their profit margins.
If this were truly about electric companies not needing the electricity (as opposed to them viewing any challenge to their monopoly as a 'free market evil'), then they would be arguing for market pricing for your solar generated electricity. They are not. They want your solar panels to be completely disconnected. Ideally you shouldn't even have them at all.
>Yes, its nice to sell back electricity to the grid, but that feels like a very hackish way to use 'solar'.
Your argument for how energy policy should be set are informed by what you think "feels hackish"?
[+] [-] lutorm|11 years ago|reply
Do they have to buy the power? Yes, but not without limits. The system is built on "net metering". Every kWh we deliver to the grid can only go to offset one that we already have or will use. If your system is so large so as to make you a net producer of energy when averaged over a whole year, you will be giving that away to the utility for free.
The rules also limit installation of PV systems to a level that will not exceed the minimum daytime load on the local circuit, exactly because there is nowhere to store the power. So every kWh they get from us is one they would otherwise have to generate to supply to one of my neighbors.
It's clear that the utility companies aren't happy with this. But studies have shown that these "extra costs" the utilities talk about being saddled with are offset by savings to them as well.
Solar power typically produces power during times of high power demand, so the net effect of solar is actually to even out the daily load variance. This is good for the utility because they need to make sure they have capacity to handle peak load, even if it's only for a small fraction of the time. These "peak power" plants are expensive, because you almost never get to operate them. When PV reduces peak load, they don't need these plants and this is a net win for them.
[+] [-] pjc50|11 years ago|reply
This depends on your jurisdiction; in the UK you can put up to 4kW on an inhabited building and get a subsidy. Larger installations require pre-approval.
[+] [-] maxerickson|11 years ago|reply
[+] [-] lotsofmangos|11 years ago|reply
As to, if they do not need the power, why should they buy it? Well, there are two reasons, one is that everyone else on the grid already gets to, so it would be anti-competitive to not allow it for the little guys, and the other is that someone will always want power, so it makes economic sense to buy the power and build storage to offset it and make money through arbitrage.
[+] [-] revelation|11 years ago|reply
Electricity can be made from a variety of energy sources. Some are fossil fuels such as oil, coal and natural gas. Over 90 percent of all the energy used in Hawaii for electricity, surface and air transportation comes from imported fossil fuels, mostly oil but some coal. (The synthetic natural gas used in Hawaii is refined here from crude oil.)
I think nobody here has the patience to wait for this particular dynosaur-consuming monster to catch up.
Heres their current fuel mix:
http://www.hawaiianelectric.com/heco/Clean-Energy/Latest-Cle...
Scroll down to see to see Oil listed at >60%.
[+] [-] jellicle|11 years ago|reply
[+] [-] wyldfire|11 years ago|reply
Regulatory capture can slow this trend. But as the article indicates, it's only temporary. Advances in energy storage and moderated consumption allows customers to disengage from the grid entirely.
[+] [-] grecy|11 years ago|reply
If you're in the business of making electricity by burning stuff, or you sell oil, or cable TV, or internet, or 50 other good examples, you had better start reinventing your business now.
Those business make very rich people richer, so they're going to fight it tooth and nail, which is a shame when they could be putting that effort into reinvention.
[+] [-] pingswept|11 years ago|reply
[+] [-] tzs|11 years ago|reply
If so many people install solar in Southern California or Arizona that the local utility has more power coming in during the day than it can use or store, it can sell the excess via the national grid to someplace that can use it.
As far as I've been able to determine from the internet, there is no connection between Hawaii power grids and the mainland. In fact, it looks like the grids of each island might be isolated from the others.
[+] [-] david2777|11 years ago|reply
[+] [-] Corrado|11 years ago|reply
[+] [-] transfire|11 years ago|reply
In the long run though it is all downhill. Battery tech is getting better at around 8% per year. Solar efficiency isn't far behind. What cost $20,000 now to add solar or $40,000 to get off-grid completely, will cost half that in about 10 to 15 years. If the trend lines continue then in 20 to 30 years years its a done deal. No house will ever be built again without it's own power generation system.
[+] [-] bradleyjg|11 years ago|reply
Any way you cut it high availability costs money. If you expect the grid to handle backup for you then you should expect to pay them to do so. TANSTAAFL
[+] [-] tedsanders|11 years ago|reply
The typical worries about solar are:
+Power intermittency (rapid, uncontrolled changes in power can push the voltage and frequency outside acceptable levels. This reduces reliability and can destroy electronics.)
+Voltage regulation (also, on a local level, PV can mess with voltage compensators, pushing voltage outside of acceptable levels at the end of voltage regulation zones)
+Morning power surplus (lots of solar power will drop the baseline demand from ~4AM to noon, reducing the amount of cheap baseline power you can run)
+Harmonics (crummy inverters can inject unwanted sine wave harmonics into the grid, again bad for electronics)
+Fault current danger (if a tree takes down a power line, both sides can be remain live if power is being pushed onto the grid by PV on both sides)
+Inverter tripping (the main way to fix the fault current problem is to mandate that inverters passively follow the grid's voltage/frequency and then disconnect if they detect problems. However, with high PV penetration this has its own problem: a transient fluctuation can cause a domino chain reaction where all the inverters turn off, taking the grid down with them.)
+Power factor/vars (one important function for the grid is to keep current and voltage in phase, but today's PV inverters are dumb and blindly produce power with a power factor of 1, which can mess with automatic capacitor banks meant to help counteract the inductive load of the grid)
Now, some of these problems are more real than others, and many don't become an issue until PV penetration reaches like 30%.
The good news is that these are all solvable problems. Energy storage or additional natural gas peakers can fix the intermittency problem, and for the other problems the grid can be redesigned to allow better two-way power flow and inverters can be designed to produce higher quality power.
However, the bad news is that all of these fixes are expensive and all of them take years. Furthermore, many utilities do not have the expertise or confidence to make big changes to their grid and still guarantee reliable high quality power. Utilities are known for being slow and risk-averse, but they are risk-averse for a reason - blackouts are very costly to society.
Another issue for the utility is how to charge for power. Historically, utilities have tried to keep things simple for residential customers by charging only for power consumed. However, if residential PV becomes popular, utilities will have no choice but to change their pricing model so that they can be compensated for the non-kWh value they provide (e.g., reliability, stability, option value, power quality regulation).
The bottom line is that the problems from high PV penetration are real. Utilities are cautious, not evil, and they have good reasons to be. (Also, I think it's ridiculous when people claim that PV will kill utilities - barring a radical shift in technology/economics, wires and pooled power regulation and economies of scale make a grid hugely valuable, even if power generation becomes more distributed.)
That said, these are all solvable problems and I am hopeful and optimistic about the long-term future of solar power.
[+] [-] brandmeyer|11 years ago|reply
As a power electronics control engineer I strenuously disagree. The historical problems with massive renewable penetration aren't just solvable, they are well-solved already!
For example, grid-tied inverters and PFC rectifiers have been meeting IEEE-519 harmonics guidelines for many years already.
We even have virtual impedance methods which provide harmonic and reactive support for the grid available right now. The problem is that the utilities have actively blocked their implementation!
The grid accepted an almost total transformation from nonlinear RCD computer loads to PFC-corrected loads without difficulty at all, and there are far more switching power supplies on the line than there are active inverters. So I view the "problem" with unity power factor inverters as a red herring.
Anti-islanding has been in effect for many years already, which completely eliminates the "felled tree leaves live wires" problem. Again, another non-problem.
Consider very carefully what you get from the entrenched utilities, because they are coming to the table with a tremendous amount of preexisting bias.
[+] [-] ridgeguy|11 years ago|reply
Unless they're already started up (i.e., part of expensive spinning reserve) gas peaker plants can't respond fast enough to solar PV ramp rates, which can be hundreds of MW/minute when clouds blow over a utility scale plant like Topaz (550MW). They take 10-15 minutes to come online from a cold start and sync with the grid. Gas peaker cold starts are expensive - the plants I've looked at (GE, mainly) allow some number of cold starts before the plant has to be taken down for service. But keeping them hot (spinning reserve) is expensive, too.
The fix for rapid PV ramp rate is enough storage at the PV site to give ~ 15 minutes of continued nominal output when insolation drops out. This is enough time for classical grid management tools to be engaged.
One driver for the equipment upgrades needed to deal with reactive power compensation, etc., is the price premium paid for "ancillary services", or power supplied at short notice for grid stability/management needs. The multiple over normal, average power pricing can be 100x depending on the circumstances.
When residential inverters are smart and can respond to utility signals, then residents can participate in the ancillary services market. That will (or should, at least) pay much more than simple net metering schedules. The economics should accelerate deploying equipment that can do this, and that will mitigate the problems brought on by high grid penetration of PV generation.
[+] [-] Sanddancer|11 years ago|reply
[+] [-] diafygi|11 years ago|reply
Here's some of the things that solar has going for it:
1. The Governor of California recently set a mandate to reach 50% renewables by 2030[1]. We want to hit this target in ten years or less.
2. The Department of Energy's Sunshot initiative is funding solar technology and software development to drive the installed cost below $1 per watt by 2017[2]. So far, we are on track to hit these targets.
3. Batteries are getting super cheap, which will turn solar into a non-intermittent source and allow solar+storage to be just as cheap as grid prices[3]. In fact, there is actually quite a bit of worry about grid defection (we are starting to see this Hawaii)[4].
4. Wall Street is funding solar projects at a massive rate[5]. The bottleneck right now in solar is finding customers, not financiers.
5. The federal subsidy for solar is expiring in 2017, but the industry is on track to absorb the cost and continue to thrive without any subsidy[6]. This will make us much harder to kill off politically.
6. The advent of community solar will solve the renting problem, where renters be able to buy pieces of a remote solar farm since they don't own their roofs[7]. This opens up the solar market to serve the entire electricity-using population, not just the building owners.
What will be hard:
Stranded assets. Solar is growing so quickly that it will soon be able to replace the capacity of existing fossil-based generators that still have lifespan[8]. Investors in those assets will see them stranded. This will start with coal and natural gas plants over the next 10 years, but as batteries get cheaper and electric cars get more prevalent solar will start stranding oil assets[9].
This is where things get hard. Utilities are traditionally pretty bad competing (since they usually don't have to), but oil companies are another story. They are very used to ruthless competition and have a lot of experience bribing their way into governments. We are expecting very heavy push back from oil after 2025 because electric vehicles risk leaving already purchased oil in the ground.
I, for one, can't wait until we fight that fight. It is the fight that our generation will be remembered for.
P.S. The entire solar industry is hiring (including my startup).
[1]: http://www.latimes.com/local/california/la-me-renewable-goal...
[2]: https://www1.eere.energy.gov/solar/sunshot/pdfs/dpw_white_pa...
[3]: http://rameznaam.com/2015/04/14/energy-storage-about-to-get-...
[4]: http://www.rmi.org/electricity_grid_defection
[5]: http://www.fool.com/investing/general/2014/12/23/why-wall-st...
[6]: https://www.greentechmedia.com/articles/read/What-Happens-Wh...
[7]: https://www.greentechmedia.com/articles/read/Solar-Summit-Sl...
[8]: http://www.utilitydive.com/news/jon-wellinghoff-utilities-ar... Disclosure: Jon is one of our advisors.
[9]: http://theenergycollective.com/energydeborah/2216626/podcast...
[+] [-] spenrose|11 years ago|reply
[+] [-] rurabe|11 years ago|reply
[+] [-] w8rbt|11 years ago|reply
Edit: Bob Bruninga has written a bit about solar power in cars. Great content. http://www.aprs.org/APRS-SPHEV.html
[+] [-] themgt|11 years ago|reply
[+] [-] fapjacks|11 years ago|reply
[+] [-] ChuckMcM|11 years ago|reply
[+] [-] unknown|11 years ago|reply
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[+] [-] kpozin|11 years ago|reply
[+] [-] brandmeyer|11 years ago|reply
Right now, short-term grid frequency and voltage stability (periods of seconds to a few min) is regulated automatically by the governor response of the various generators on the grid. These governors bid in advance to set their proportional gain for frequency stability. Basically, they promise to autonomously raise or lower their throttle in the future based on the observed grid frequency and voltage, and get paid later when they make good on their promise. Long-term stability (periods of 15 min or so) are regulated with market action in the spot market for power. Very long term stability is regulated by markets that clear 24 hours in advance of their estimated delivery.
However, some energy producers effectively have flat rate contracts that don't participate directly in grid stability. Wind and nuclear will negotiate a fixed power-purchase agreement (typical prices are about 50 USD/MW-hr or so in the US) that will be fixed for years at a time. Likewise, residential solar customers sell back their power under the same, basically fixed rate schedule that they use to buy power.
So, as the penetration of fixed-rate power increases into the market, the pricing volatility continues to increase as well. There are technologies that can help. In fact, it is trivially easy to get a grid-tied inverter to be sensitive to grid changes with controls that model virtual inertia, impedance, throttle, and so on. This is part of what I do as a controls engineer. The difficulty isn't in implementing such controls, it is in adjusting the markets such that all of the existing players are comfortable with the result.
Witness this in Hawaii - the retail price of power is so high that it makes obvious good sense to install your own generation. But instead of adjusting the rates to reflect the new availability of supply, the incumbent utility seeks to raise barriers to competition instead.
[+] [-] yxhuvud|11 years ago|reply
[+] [-] HarryHirsch|11 years ago|reply
[+] [-] dragontamer|11 years ago|reply
There's nothing quite like "Oh, some home in this neighborhood is still powering this powerline, despite the fact that we've shut off all the other power sources". That's quite the real "shocker" to the poor worker.
[+] [-] vishaldpatel|11 years ago|reply
[+] [-] tsotha|11 years ago|reply
[+] [-] mark212|11 years ago|reply
serious question for Hawaiians: do people run the a/c round the clock there? Or is it something else?
[+] [-] damoe|11 years ago|reply
That is one reason why my new house is off grid solar - cheap (compared to $.40/KWH), clean electricity.
The other is that the grid here is unreliable. I had 87 outage events last year for a total of 37 hours and that is not including the nine days with out power post hurricane.
Now don't get me started on internet quality!!!
[+] [-] jessaustin|11 years ago|reply
That said, when I lived there, my bills never approached that figure, even with a/c.
[+] [-] fapjacks|11 years ago|reply
[+] [-] tsotha|11 years ago|reply
[+] [-] tlb|11 years ago|reply
[+] [-] jahnu|11 years ago|reply
[+] [-] maxerickson|11 years ago|reply