Yes, although it's not technically an efficiency. Because the work is mechanical, the conversion efficiency of that mechanical motion into electricity can be extremely high.

However, there is a maximum amount of power you can remove from the air and still have air flow given by Betz' Law, and is given by about 59%.

Alan -

Sure, pumped storage is a very effective practical means of load stabilization. The only hitch is that not too many locales have a topography conducive to building pumped storage.

As the pumped storage reservoir has to i) be quite large even for a modest size power generating facility, and ii) be at a significantly higher elevation than the turbine it will be running, pumped storage systems are generally located in mountainous areas (e.g., Switzerland has a nice big one operating at a head of several thousand feet, Pennsylvania has at least one).

Any place that has a flat terrain, such as all of the Plains states, the Great Lakes area, and most of the South, is not a good candidate for pumped storage. It is simply not practical to build an artificial mountain with a large lake on top of it.

Conceivably, you could go in the opposite direction by having a lake at ground level and putting the water turbine down some deep mine shaft, but then you have the problem of where to store the water on the downstream side, as the receiving reservoir has to be the same size as the upper one.

Try this little exercise: assuming a 200-ft elevation difference and 100% efficiency, calculate the volume of a reservoir capable of providing 8-hours worth of energy storage from a wind farm generating 200MW of power.

Best Hopes for Pumped Storage,

They didn't say too much about matching the demand, but implied it would mostly be for wintertime space heating needs. No mention of whether that is resistance heating, or more efficient mechanisms such as air-source heat pumps, or ground source heat pumps. The amount of power needed would dramtaically be reduced with the heat pump technologies, as would better insulation. Presumably these are mainly (pun inteneded) existing structures which already have FF and/or wood based heating systems installed. These could be relegated to backup heat sources (for when it is both cold, and windless), rather than for baseload heating. That way the legacy heating could substitute for storage of wind energy. I am firmly of the belief that significant demand management will play a significant part in our energy future. I think the cost of storing power will be much greater than the cost of adapting to variable supply.

The real issue, is at what cost these resources can be developed. DavaMart assumes pretty high cost for the UKs planned off-shore wind. To be economically viable these would have to be considerably cheaper.

Oil? Wind turbines don't need oil!

Resources are MUCH better used for one 1 MW (or 2 or 5 MW) wind turbine than thousands of small residential WTs for a number of technical reasons (not enough time ATM to list).

All steps to make WTs can be done using renewable energy, but there is not enough of it/it costs too much (Iceland has a steel smelter using renewable electricity, used to make specialty silicon steel for electrical applications).

Aluminum (>50% from hydroelectricity) can used for many applications.

Best Hopes,

Alan

for maintainence and replacement you'll need specialized vessels.

An offshore field of turbines could be like a flip ship. A glorified spar bouy with blades. Towed to position and set up. Put them out, bring them in, service and return. The mooring system would include the power docking. It's not clear to me if one would go straight to electricity - and what type - or maybe to some other intermediary fluid that would drive a turbine cluster. Not my job, man. I do vegetables.

cfm in Gray, ME

The most economical current designs for offshore wind involve turbines on anchored barges. This allows for placement further offshore than with a rigid pole to the seabed, and takes advantage of our expertise with oil derricks to locate the wind power where there is much higher wind speed. Power in wind goes as the cube of the velocity, so increasing wind speed makes the power output vastly better.

More importantly, by using barges, you can take a normal ship and simply tow the entire wind turbine in to shore for onshore maintenance. This is much, much cheaper than hiring a crew and doing offshore maintenance.

There is never any surplus hydropower in the USA NW to produce hydrogen from (decades ago there was a couple of weeks of surplus after heavy rains, they turned down the nuke (Trojan ?) to save fuel).

All existing and future small hydro projects in the lower 48 can find good use in the grid (the highest and best use of electrical energy *IF* we improve efficiency). It would be good to expand transmission capacity to find a home for future/potential BC hydro (mainly in CA, AZ, NV, but also in AB).

Yes, a scam IMO.

Wind, OTOH, has the potential to be built faster than we can build transmission. And it cannot be scheduled like most hydro can. Winter peak, summer minimum generally (good also in spring & fall), so an economic use for surplus/stranded wind electricity (too much wind generated electricity for local consumption and transmission) would be a good thing, perhaps a very good thing.

Ammonia used in Iowa today (example) now comes from Trinidad, etc. where it is produced from otherwise stranded NG. Local seasonal production of ammonia from surplus wind in Iowa is worthy of additional R&D IMHO. (No CO2 generated in ammonia production from stranded wind, unlike NG sourced ammonia).

HV DC and pumped storage can shift wind power for time of day and even weekend > weekday, but not seasonally (spring > summer). For, say, a 50% wind grid (HV DC over North America, 50% of GWh from wind), some economic use in the spring, fall and perhaps winter for surplus wind would be needed for, perhaps, 3%-5% of total wind generation.

Best Hopes for Turkey with friends,

Alan