Nice Photovoltaik Peak in Germany

[chalsall]

Originally Posted by cheesehead

However, if a solar plant's output is greater than demand, lowering their output does not allow then to store future potential energy by not "burning" their "fuel". If there's no storage (such as batteries), then unconverted sunshine will simply go unused and won't be available for easy future use.

There's still the consideration of whether it's cheaper to store energy when the sun shines in order to release it later when there's not enough sunshine, taking into account the conversion and storage inefficiencies. But unlike unconverted coal or unconverted gas the unconverted sunshine can't be stored for future input to the generator.

Completely agree. However, you might be missing another dimension to this equation...

In warm regions (or even seasonal regions during the summer), the peak electrical power loads often correlates /very/ strongly with the amount of sunlight being experienced (mostly for Air Conditioning and refrigeration).

And, yet, the electrical power supply companies seem to be fighting "tooth-and-nail" against "grid-tying" (read: allowing those who have PV panels or wind-turbines to "feed back into the grid" during peak periods during the day, and "draw from the grid" during the evening).

Perhaps I'm just being stupid, but it would seem to me to make sense for any region which consumes electricity for cooling during the day to accept power into the grid from alternative suppliers. This would eliminate (or, at least, lessen) the need for power storage.

(And, just as an aside, the Barbados Light and Power Company successfully delayed a positive move forward on this matter for "further analysis and consideration". Meanwhile, one of my clients experiences a sustained 20V to 30V drop on their three phase 210V Alternating Current supply most days right around noon....)

[CRGreathouse]

Originally Posted by chalsall

And, yet, the electrical power supply companies seem to be fighting "tooth-and-nail" against "grid-tying" (read: allowing those who have PV panels or wind-turbines to "feed back into the grid" during peak periods during the day, and "draw from the grid" during the evening).

Of course -- they're competitors. What else would you expect?

[chalsall]

Originally Posted by CRGreathouse

Of course -- they're competitors. What else would you expect?

Nothing less, from them. They're doing their job (well).

The Regulators, on the other hand....

[CRGreathouse]

Indeed. Regulatory capture seems to be the order of the day.

[chappy]

There are a couple places where I think you guys are completely wrong (at least with respect to the US and Canada--I can't speak for other power systems such as the fun that Chris writes about) or, at best, uninformed about the electric generation and transmission industry.

These places have mostly to do with how independent power producers (which includes most "green energy" producers) don't pay for or contribute to grid stability. (such as maintaining reactive power and voltage regulation on the grid.)

Typically they also don't help pay for the grid infrastructure--with some exceptions recently legislated no home solar panels sell back power that reflects grid costs. (which is similar to how electric cars don't pay the road tax in gasoline that helps maintain the roads yet they benefit from the roads)

Further, utilities in the US have been required to maintain peak voltage plus extra generation capacity despite the inherent cost inefficiency in preparing for the worst case scenario. New "green energy" initiatives are largely immune to such requirements and are therefore able to provide generation at only the most economic levels (and still, even after heavy subsidization, are not as cheap as traditional electrical producers)

this makes traditional utilities inefficient, certainly, but most people like to have power in the heat of the summer and the cold of the winter when excess production is expensive.

to that end a social contract has emerged between large utilities and the public that new companies by and large are not required to follow.

I have only the Midwest North America numbers to guide me, but wind power is more than three times as expensive as the most expensive coal plants in the midwest on the open market and about 40% more expensive than natural gas. (around $69 a megawatt) And that's with a 30% capacity factor if they are lucky.

Solar hits the 30% capacity factor but is also heavily subsidized and still not lucrative on the open market ( I don't have the price in data because there just isn't that much solar on the open market. but costs are generally 6-7 cents per kw in the same range as wind, but aren't reflected on the open market in the midwest because they are typically on residences or owned by large utilities. (my company is currently building such a plant)

There's a very small chance that I'll have the opportunity to work at that new plant. Which I will jump on if I get the chance.

I think it's a mischaracterization to say that the coal industry is ____x___ as the coal industry is a not a thing that can be for or against something. there are plenty of utilities that are for green energy initiatives, but they generally wonder why one group of electric producers is required to provide power to all people at a set rate, while another group of electric producers is not required to provide the less profitable power.

[Mark Rose]

Originally Posted by chalsall

Completely agree. However, you might be missing another dimension to this equation...

In warm regions (or even seasonal regions during the summer), the peak electrical power loads often correlates /very/ strongly with the amount of sunlight being experienced (mostly for Air Conditioning and refrigeration).

And, yet, the electrical power supply companies seem to be fighting "tooth-and-nail" against "grid-tying" (read: allowing those who have PV panels or wind-turbines to "feed back into the grid" during peak periods during the day, and "draw from the grid" during the evening).

Perhaps I'm just being stupid, but it would seem to me to make sense for any region which consumes electricity for cooling during the day to accept power into the grid from alternative suppliers. This would eliminate (or, at least, lessen) the need for power storage.

(And, just as an aside, the Barbados Light and Power Company successfully delayed a positive move forward on this matter for "further analysis and consideration". Meanwhile, one of my clients experiences a sustained 20V to 30V drop on their three phase 210V Alternating Current supply most days right around noon....)

A problem they've been having in Hawaii lately is too much power being generated in residential neighbourhoods during the day. The power generation is largely unregulated (engineering, not law), causing problems like voltage spikes when the current generated exceeds neighbourhood demand. The voltage drop due to transmission losses into a neighbourhood also works in reverse, meaning local voltage will spike as current is pushed back into the regional grid.

If solar power were consistent, and didn't fluctuate moment to moment, or demand matched solar output exactly, this could be accounted for (it would function like a base load plant). But it doesn't. When a cloud passes overhead, air conditioning units are still running. The only way to keep things stable is to have a net inflow of current into a neighbourhood at all times.

In the regional grid, voltage is kept stable by load-following in power plants. In hydroelectric, they control water flow, in hydrocarbon, they control fuel flow. Just about all power plants have to do this because they used fixed alternators that produce a specific voltage at a specific frequency (50 or 60 Hz). If the voltage changes due to load, the alternators turn either too slowly or too quickly, and the generated frequency will drift out of sync with the grid frequency. Moment to moment changes are handled by large flywheels attached to the alternators.

Nuclear can also load follow by adjusting the moderator, but nuclear plants are not typically designed or operated in this way (other plants make the large changes in output instead). Because nuclear operating costs are very cheap and the capital costs very expensive, it makes the most economic sense to always produce electricity at full capacity if possible, even if selling at a "loss" and recouping at least some cost. For example, much of the Great Lakes region is powered at different times of day (depending on the season) by excess nuclear capacity in Ontario, and the spot electricity rates get very cheap (down to 1-3¢/kWh).

Any solution requires additional expense. Less resistant (higher voltage) circuits are expensive and occupy space. Batteries are expensive. Fly-wheels are about half that but still not cheap. Pumping water uphill is reasonably efficient (70-80%) and cheap -- if you have a place to pump the water to.

So it's not as simple as power companies being greedy.

Also, I am not a power engineer, so please excuse me if I have any details wrong. But I do have a passing interest in power generation and a nice view of a 550 MW combined-cycle natural gas facility from my balcony. :)

[Nick]

It sounds as if we should invite nuclear power generators to get involved in GIMPS!

[chalsall]

Originally Posted by chappy

There are a couple places where I think you guys are completely wrong (at least with respect to the US and Canada--I can't speak for other power systems such as the fun that Chris writes about) or, at best, uninformed about the electric generation and transmission industry.

I appreciate that you are, without question, much more informed than I am about Generation, Transmission and Distribution. And, I would be very happy to learn more from you on these matters.

However, to put on the table, I'm not entirely ignorant on such matters, either. For example, I have worked very closely with Barbados Light & Power (BL&P) in the past, and appreciate how very difficult electrical power is. I was also an "Intervenor" at the BL&P "Rate Hearing" conducted by the Barbados Fair Trading Commission (the regulator here).

Originally Posted by chappy

Typically they also don't help pay for the grid infrastructure--with some exceptions recently legislated no home solar panels sell back power that reflects grid costs. (which is similar to how electric cars don't pay the road tax in gasoline that helps maintain the roads yet they benefit from the roads)

But I would argue that while Transmission is a "Natural Monopoly", Generation (and possibly even Distribution, in certain cases) isn't. And yet, for historical reasons, all three are very (very!) often grouped together under the control of one company.

In my opinion what is happening (at least, in a few cases) is the regulators are trying to decouple this legacy reality, as new technologies could make the situation more efficient (to the benefit of the consumer). There may be a period where the legacy monopolies are "disadvantaged"; as in, they have to take on the costs of "T&D" integrity which the new (often small; often "green") Generation suppliers don't.

At the same time, let's be honest -- the historical "G&T&D" monopolies are making a reasonable (and actually effectively guaranteed) Rate of Return. 10.5% in the case of BL&P here in Barbados. They should be able to absorb a small bit of extra cost for a short period of time to encourage distributed, "Green" Generation.

But, at the end of the day, I agree with you, and I think that everyone who "Generates" should share in the cost of the T&D network (in proportion to their usage), just like the Consumers do.

(Another point worth discussing at another time: It can be easily be argued that the T&D "plant" (read: the Poles, Transformers, Capacitors and Cables which are the T&D network) are really "A Public Good". They were paid for by the Consumers of the Network.)

Originally Posted by chappy

I think it's a mischaracterization to say that the coal industry is ____x___ as the coal industry is a not a thing that can be for or against something. there are plenty of utilities that are for green energy initiatives, but they generally wonder why one group of electric producers is required to provide power to all people at a set rate, while another group of electric producers is not required to provide the less profitable power.

I'm not as hysterical as some about coal, and I would argue that it's not only the coal generators which have such an obligation. It is whoever is the regulated monopoly provider of Electrical Power who control the T&D.

Further discussion (and counter-arguments of any of my points) very welcome!

[chalsall]

Originally Posted by Mark Rose

So it's not as simple as power companies being greedy.

Also, I am not a power engineer, so please excuse me if I have any details wrong. But I do have a passing interest in power generation and a nice view of a 550 MW combined-cycle natural gas facility from my balcony. :)

We cross-posted.

To be clear, I've *very* appreciative that it's not as simple as power companies being greedy. There's also the ***very*** important matter of line-man's safety, for example. If a sub-section of the grid has been shut-off for maintenance, but some independent generation supplier is still feeding into the sub-section (or suddenly comes back on-line), people could die.

Also, I an not a power engineer either. But am also very interested in the subject, so would welcome feedback from those who actually know what they're talking about.

[Mark Rose]

Originally Posted by chalsall

We cross-posted.

To be clear, I've *very* appreciative that it's not as simple as power companies being greedy. There's also the ***very*** important matter of line-man's safety, for example. If a sub-section of the grid has been shut-off for maintenance, but some independent generation supplier is still feeding into the sub-section (or suddenly comes back on-line), people could die.

Indeed. It's happened before.

[chalsall]

Originally Posted by Mark Rose

Indeed. It's happened before.

But, to be clear...

While the considerations may be similar, no amount of "grid-tied" regulations could have stopped this particular death.

While regulated "grid-tied" Generation providers are required to have special interconnections and meters, any idiot can wire a generator into their panel, but forget to switch the "main's breaker" to disconnected during an outage.

The best results are that the idiot's generator explodes when the mains come back on-line (and that the idiot is refueling the generator at the time, and also dies).

The worst results are that people who are trying to repair the "grid" die, but the idiot with the generator boasts to his friends about how he still had power during the outage because he had a generator....