There are places in the grid that cannot accept independent power input (distributed power) from sources such as wind or solar, but most of the grid is capable of accepting alternative energy sources. The larger issue is tariffs. Alternative energy sources typically can sell power to the utility for very low rates because their energy is not "Dispatchable," meaning available on demand. Until alternative energy is "Dispatchable" it will be a poor and secondary source of power.

There are ways to make it more dispatchable, but little attention has been devoted to that concept, so far.

The issues regarding blackouts are very complex. On one hand, everyone would like their locale to have power in the event of problems. On the other hand, utilities could disconnect from the grid in the event of problems, thereby isolating the problem to a small area. So, should the utilities protect themselves with isolation, or honor their power sharing contracts with neighboring grids? As stated before, it is a complex situation. What do you think we should do?

One way to even out delivery of alternative energy, and make it dispatchable, is to convert the power to hydrogen, then convert it back into electricity and dispatch it as needed. It can also be converted to compressed air, molten salt, water pumped to a high level pond etc. I can't see why this is an issue, aside from the added cost involved. The grid must be modernized sooner or later. Low prices of natural gas and petroleum will make difficult for awhile. Nations without cheap and abundant natural gas and petroleum will become the first major adopters of alternative energy.

Converting power back and forth to hydrogen is a waste of energy. The hydrogen highway will never work. You cannot store it properly. It is another "ethanol" type of disaster being promoted by mis-informed people.

Making methane while recycling the CO2 would be much better as it can be liquefied easily but any leak produces 50X worst green house gas than the CO2. Nothing is perfect...

We may eventually find another gas/process that would allow recycling the CO2 and store energy by adding Hydrogen to it without wasting too much energy doing it.

Wikipedia says that hydrogen can be easily stored underground in caverns or depleted oil fields etc. Do you have any statistics on the energy loss involved in converting electricity to hydrogen and back into electricity when needed? Would appreciate yours or others answers to this question. I had been thinking of fuel cells, but special generators have been mentioned.

I did some research recently and found the IDEAL electrolysis process can be no more than ~83% efficient. The reverse process through a fuel cell is basically the same. So the IDEAL round trip is ~68%. It looks like ~50% has been achieved in practice.

one possible ref

http://hyperphysics.phy-astr.gsu.edu/Hbase/thermo/electrol.html

When you subtract the energy needed to compress, refrigerate, or transport the H2 gas, the process efficiency drops even more. I'm not saying it doesn't work. However, if the overall efficiency of the process is worse than competing methods, hydrogen may not be the panacea many would have us believe.

Thanks for the info. I had no idea it would lose that much value. I will have to look at some of the other options.

I don't know about the underground cavern approach for hydrogen storage, but I do know that any above-ground storage of hydrogen gas is problematic. In a summer job more years ago than I like to admit, we handled high-pressure gas cylinders filled with hydrogen. We limited the number on hand because they would actually leak through the steel walls of the cylinder. The H2 molecule (remember that free hydrogen exists as H2 so that two hydrogen atoms share electrons) is small enough to penetrate the interstices in the steel of the tank or a pipe. As a result, any storage of hydrogen results in fairly high loses due to leakage.

It would seem that underground storage would offer similar problems.

Your point is well taken, I know underground storage of helium in USA is well controlled but they have to limit the pressure of the reservoirs to avoid leakage. Hydrogen would be twice as bad being half the molecular weight ,but it is being stored in a salt cavern on the gulf coast so it seems to be a practical method.

I was under the impression that at sometime in the past it had been contemplated to use underground atomic bombs to form caverns but don't know if this was ever followed up possibly long term radiation could be a problem for storage.

"It would seem that underground storage would offer similar problems."

Underground storage of Hydrogen, Carbon Dioxide and any other gas will face another obstacle: environmental impact on the underground ecosystem. Don't laugh. Recent discoveries of complex underground communities will be utilized by the anti-industrial left to roadblock carbon sequestration and other underground storage schemes by bringing environmentally-based lawsuits.

I'm really glad to finally hear someone talk about the energy loss in converting hydrogen.

I think everyone should make an informed descision about alternative fuels and not just what manufacturers tell them. Too often we hear these "Green" movements suggesting an alternative energy source but completely ignoring what it takes to get from raw materials to something we use.

I heard a speech last year by the guy in charge of the grid in Texas. His comment was that his number one threat to grid reliability was the wind farms out west. They are having a hard time managing the load, especially the way it rolls for big wind days, to calmer evenings...

I did a RCM project for the one of the big wind farms the company I work for holds. The top reliability hits to the operation were all electrical; transformers, switch gear, etc. The rest of the reliability impacts, including turbine gear boxes were insignificant in comparison.

it doesn't matter much most people that go for alternative energy system want to be off-grid........

No, they would like to sell excess to the grid, for a fair price, and rely on the grid if needed.

It is not that the grid operation is a mystery, it is predicting where and when that huge monster that feeds off the grid (we the consumer) will attack next. The occasional hardware failure, natural disaster, and HUMAN ERROR, are always in the mix as well.

Considering the possible failure modes and how fickle the masses are, the grid system in the US is remarkably reliable (for most of us). This is because most of the sources are fairly large and stable ( coal, nuclear, hydro, etc.). When a large number of highly variable sources ( wind, solar, homes, etc.) eventually becomes part of the system, there is concern that the grid will not be able to handle them. It is feared that severe disruptions and outages may become common.

There should be concern about this possibility. However, we should not stop renewable energy development because of it. Since we are AWARE that it could be a problem, it should be added to the list of hurdles we need to overcome as we develop and connect new power systems.

Ah yes, human error, about 9 years ago a trainee at a local municipal utility switched on a recently purchased, very expensive ($400,000.00?) transformer. This transformer was acquired apparently to alleviate the frequent black-outs the city was known for. All the surrounding area is served by FPL, they're not perfect but cheaper rates and more reliable. So he turns on the transformer, but the old hands at the plant neglected to tell him to turn the OTHER switch first which controls the cooling fan. Result: big pile of useless scrap. Hey, I'm no rocket surgeon but wouldn't ya' think there would be an interlock to prevent this or a checklist to consult. I guess the Post-it note fell off the control panel. The employee was punished by being made a building inspector.

Thank you for that explanation.

Distribution seems to be the key in alternative energy sources for electricity.

T. Boone Pickens' wind farm is a prime example: http://green.autoblog.com/2009/07/08/t-boone-pickens-wind-farm-plan-dies-out/

When you listen to this video spot, you will hear him mention the distribution challenge only in passing. Then he is on to his other agenda. No one wants to make the inability to plug in these other sources a big deal.

Our current power grids need to be upgraded. They pose a security weakness.

I feel, if we as a nation are vulnerable to terrorist's attacks, it will be power grids not train stations.

Thanks,

Bill, grantsforhome@yahoo.com

I think T-Bone's agenda is to secure right of way for the water resources that he has control of, that and natural gas.If I remember correctly he is trying to get water from the middle of nowhere( Northwest Texas?) to civilization. His big push with the ads during the election were to achieve these ends. If there were wind turbine farms, coincidently, in Northwest Texas they would need powerlines to run the power to where it could be used. Then he could run his waterlines to sell the water, that is going to be the moneymaker in the future, one can derive energy from alternative sources but you can't drink switchgrass. T-Bone is not displaying farsighted altruism, he is just out to get richer by hornswaggling the public.

In India wind power is converted to a synchronized three phase form that can be fed to the existing grid. It is difficult to conceive something more outdated than what we have. The technology is to covert the collected energy to a compatible form at the wind farm. Tax incentives on initial investment allow companies to buy a wind generator at the farm and get power elsewhere in the state for its use or get paid by the grid operator.

As stated by others in this thread, the issue "appears" to be reliable power. The truth of the matter is that all of the alternative energy sources in this country combined are such a small percent that their effect on the grid is negligible. That does not mean utilities ignore them. Actually, they seem to penalize alternative energy sources with the rate structure. Since alternative energy sources can rarely provide constant power, the utility buys their energy at a deep discount. If the alternative energy source could guarantee power delivery, then utilities would have to buy it at a standard rate. So, the tax incentives encourage investment in alternative energy while the rate structure discourages it.

Alternative energy can be stored in many ways other than batteries. It can be stored as hydrogen, molten salt, water in elevated reservoirs, compressed air underground, etc. It would then be dispatchable. I would appreciate reference to sites that discuss the engineering of alternative energy storage ideas.

You are partly right, but read the above threads regarding to storage losses. Once you add the storage cost to a technology that is only viable through subsidies, it then become a money pit that only politicians and religious greens will support.

We as engineers, must find viable solutions to these problems and tell the politicians what will work and what won't. It is our money after all that is wasted in these experiments. Let's make sure that they get it right!

I intend to provide links to these discussions to the ministry of resources and energy (Canada) and hope that somebody will read them. That may be the beginning of their education in common sense approach to problem solving.

While not everybody in our discussion agree with every details, I find that most engineers have a good handle on what works and what doesn't. After all, we are the ones who have to make it work...

I can't recall where I saw it, but someone is storing energy on some kind of massive flywheels. Has anyone heard of this?

I believe the energy revolution must become locally independent; NOT be grid connectable. Yes, the power grid is relatively reliable. It is also estimated to be about 30% efficient. Energy generation must evolve to close proximity to the consumer; either be supply on demand or locally stored. Energy storage technology such as batteries is making advances. Other avenues, such as pumped storage, must continue to be explored.

Hey how about the super-deep hole the Russians bored into the earth that yielded higher temperature than expected water/steam plus hydrogen gas. Seems to me if you were to utilize this at the site, gas turbine+ waste heat and/or steam to make electricity, it could be transmitted via HVDC to avoid synchronization and excessive transmission loss.

It's unfortunate that neither wind or solar can supply a base load, or operate in bad weather conditions. Recently the south-eastern sates of Australia experienced extremely bad dust storms with very high winds. The solar panels were covered in a thick red dust afterwards and the wind farms shut down in high winds. No alternative energy except the 80 hydro electric generators of the Snowy Mountains installation.

I wonder how they clean the solar arrays, maybe this is one of the new green careers.

Apparently the wind generators issue forth with a low whooshing sound that makes life hell for the occupiers of neighbouring properties. Has this been experienced elsewhere?