Wind, sun, storage, and efficiency

Efficiency is the key

Posted by Gar Lipow (Guest Contributor) at 12:30 PM on 27 Nov 2006

Wind I previously noted that efficiency is essential to eliminating fossil fuel use, because non-fossil sources have an overall market price cost higher than coal, natural gas, and even oil. This is not as obvious as it seems. Up to a point, renewable energy is competitive with fossil fuels; the problem is, that point is never a majority of consumption.

Take electricity.

You can produce unsubsidized wind power at 4 cents per kWh -- cheaper than natural gas, cheaper even than "clean" coal. Unfortunately wind (like most renewables) provides variable power. It can be predicted to some extent, but comes on nature's schedule, not when wanted. That doesn't matter much as long as it supplies around 20% or less of total demand. Up to that point, the utility can treat it as negative load; added power when the wind slows or stops comes from existing operating and spinning reserves.

Beyond that point, wind energy without storage requires additional capital, additional reserve-generating capacity. That brings the price up steeply. There are regions that have more wind capacity than this, sometimes a great deal more. But they manage it by exporting electricity to other utilities. If you look at the grid as a whole, and not just local sub-grids, you will find no place where wind supplies much more than 20% of consumption in practice -- without storage.

There are non-fossil fuel sources that don't suffer from this problem, but they are limited. Geothermal electricity is reasonably priced and fully dispatchable, but cost-effective world resources are limited with current technology. (Yes, there are nations like Iceland where that is not a problem, but it is true for most of the world.) The same applies to hydroelectricity. Biomass energy is inexpensive when produced from waste, but still more costly than oil when purposely cultivated on energy farms -- with serious water consumption, land use, and net energy issues.

In short, you have to add storage, and storage is expensive.

Further, if we are serious about renewable energy -- if we want to see a majority of our energy supplied from renewable sources -- we will need a lot of storage: days, not hours.

Aren't there inexpensive means of electricity storage? Yes, but again, they are limited. Pumped storage, wherein water is pumped uphill, can store energy at as low a cost as a tenth of a cent per kWh. And 70% to 80% of the energy put in can be gotten back out. But inexpensive pumped storage requires downhill water sources near large uphill reservoirs -- a fairly rare natural occurrence. Completely artificial pumped storage (water towers on steroids) would be expensive and impractical. Large-scale compressed air also requires uncommon natural features.

OK, so let's look at the most-often-contemplated means of storage: hydrogen. Forget hydrogen pipelines; electricity is a lot less expensive to transport than hydrogen, and suffers lower transmission losses. Let's look at hydrogen strictly as a storage method -- produced from variable electricity, and used to produce dispatchable electricity from dedicated sites.

At current prices, forget fuel cells as well -- combined cycle turbines can burn fuel at 60% efficiency for $500 per KW, a point on the price/efficiency curve no commercial fuel cell can match today. Add to this to the 4 cent per kWh electricity cost plus round trip electricity losses, along with $750 per KW electrolyzers, hydrogen storage, and transmission losses. Fully dispatchable wind electricity will end up costing 19 to 20 cents per kWh to make and transmit -- compared to 7 cents, if you average comparable costs for the U.S. as a whole.

What about our most extensive electricity source -- the sun? At current prices, photovoltaic cells on rooftops won't work. PV electricity costs about 15 - 20 cents per kWh before storage. A great deal of the storage cost of wind is due to electricity losses. Use 15 cents per kWh PV instead of 4 cents per kWh wind, and your cost rises to 40 or 50 cents per kWh.

But there is a form of solar electricity that provides a much less expensive dispatchable energy than PV or wind: solar thermal electricity.

For example, Stirling Energy uses parabolic dish mirrors to drive Stirling engines, providing energy for around 11 cents per kWh. They key is that heat is less expensive to store than electricity. A solar thermal farm could add additional mirrors and store the extra heat in molten salts, which the generators could tap at night or during periods of low sun. Such storage is estimate to run around $35 per thermal equivalent of a kWh. After you count storage losses and the cost of additional parabolic mirrors, the cost should run around $0.15 per kWh.

Such thermal electricity has another limitation: you can't concentrate indirect light. It works only on sunny days. That's why solar thermal electricity is generated almost entirely in deserts. Fortunately, the limits of electricity are about 5,000 kilometers, and most people on the planet live within that distance of a desert. There is no physical reason lines could not be constructed to allow, say, London to buy solar thermal electricity from Libya -- though that's probably not the most desirable source from a political standpoint.

Note that a breakthrough that produces inexpensive photovoltaic cells won't solve this problem. All that would do is let you produce solar hydrogen storage for the same 19 or 20 cents per kWh wind hydrogen would cost.

This makes it clear why efficiency is so important. We have the technical capability to generate as much reliable, convenient, fully dispatchable solar- and wind-based electricity as we need. But the costs of generation are expensive -- between 2 and 3 times comparable costs for fossil fuels. Total costs don't need to be that high, because we can factor in some inexpensive variable renewables, along with small amounts of geothermal and possibly hydro. But absent storage breakthroughs, we are going to have pay at least double our current per kWh cost if electricity is to come from renewables.

If the cost of producing electricity is to double or more, we need to triple the efficiency with which we use it. (Triple rather than double, because improving efficiency also costs money.) As I keep stealing from Amory Lovins, what we want from energy is warm toes and cold beer. If we can get more use out of each unit of energy, we can buyer fewer units of that more expensive power -- and still do the same things. So the per kWh cost of electricity would double, but our use of electricity would (unnoticeably) drop. Our electric bills would stay the same.

One last point. If efficiency is so much less expensive than new sources, why add new sources at all until efficiency opportunities are completely exhausted? The problem is one of opportunity cost. Some efficiency improvements, such as insulation upgrades, can be added at any time. But most efficiency improvements are only cheaper if implemented as existing infrastructure wears out. It is expensive to throw away a perfectly good pumping system in a factory with ten years of life remaining. It is very cheap, if you are doing a re-pipe anyway, to put in fatter pipes and smaller pumps; this reduces friction, the energy costs of pumping, but only pays for itself because you save money on the cost of the new pumps. It is expensive to replace a new inexpensive window with an expensive one. It is very inexpensive when replacing a worn-out window to put in an efficient rather than inefficient one.

It is thus essential not to avoidably amortize infrastructure prematurely; doing so would multiply the cost of efficiency increases. Similarly, it is essential not to miss any cost-effective chances for efficiency upgrades during infrastructure replacement or upgrade. Each opportunity missed either delays such improvement by at least a decade or multiplies the cost of increasing efficiency by many times.

If we are not going to upgrade our efficiency structure all at once, or even over a short period of time, it is essential not to miss opportunities to upgrade energy sources as well as energy sinks. At the beginning, we should make sure to put in place renewable sources that are cheaper than fossil fuels -- variable wind, solar thermal for low temperature use (such as water and space heating), up to a 65% of consumption (more if solar district heating proves out) use of waste biomass, and so forth. As efficiency improvements are put in place, we need to phase in other renewable sources that are competitive with what fossil fuels would have cost if the efficiency was not put in place.

In other words, as we phase in efficiency, we need to make the decision as a society to use that savings to phase in low-carbon sources, rather than continuing to buy comparatively cheap fossil fuels.

Efficiency is the key. Efficiency is what can pay for comparatively expensive dispatchable wind and solar electricity. If solar district heating (or other breakthroughs such as storage in natural zeolites) do not prove cheaper than fossil fuels, efficiency is what will enable us to use low temperature solar thermal to provide more than 65% of climate control and hot water needs.

For story: Wind, sun, storage, and efficiency
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Word

It is thus essential not to avoidably amortize infrastructure prematurely; doing so would multiply the cost of efficiency increases.

Somebody make a bumper sticker!

grist.org

by David Roberts at 1:01 PM on 27 Nov 2006

Efficiency sooner or later?

I agree on the economics of efficiency. The economics of efficiency delay are not always advisable.

We tossed out a perfectly good dryer for a clothesline.

Amory's "Natural Capitalism" described consumer choices limited by consumer knowledge. Example: A front loader washer uses less water, less energy, and cleans the clothes much better than top-loader washers. I did not know this and did not experience the depth of benefits until after we replaced a broken top-loader. Now I know we should not have waited. Old working refrigerators should be replaced new efficient refrigerators. Economics alone would pay for the upgrade. We replaced a working electric space heater with a wood stove. We replaced working incandescent lights with swirl lights. And so on.

Waiting to replace old infrastructure is not always a good idea.

by sunflower at 1:11 PM on 27 Nov 2006

Burn U, not us

That's my best bumper-sticker effort.

--- G. R. L. Cowan, former hydrogen-energy fan
how motoring gains nuclear cachet

by GRLCowan at 1:11 PM on 27 Nov 2006

Solar thermal update

I had "load images" turned off, did not see those Stirling dishes made by Solar Systems. Stirling engines have maintenance problems and will not amortize even if the heat (or dish) is free. Those engines have been replaced with high-intensity photovoltaic cells to supply power with no moving parts. The 36% efficient pv cells are expected to cost less than $100 per kilowatt(e).

by sunflower at 1:42 PM on 27 Nov 2006

Stirling engines

Are you sure? In every one of the Stirling Energy mega projects, every report I can find says they are using heat engines, not PV.

by Gar Lipow at 2:18 PM on 27 Nov 2006

Economics of delay

>The economics of efficiency delay are not always advisable.

Nor are the economics of throwing out perfectly good equipment aways right. It depends. Incidentally, lot of people live in garage-less apartment buildings in rainy climate. If they have personal gas dryers, or the apartment provides shared ones, these will probably use less energy than having people drive to a laundromat.

by Gar Lipow at 2:23 PM on 27 Nov 2006

Efficiency

Gar - you've been using efficiency rather ambiguously. Contextually it seems pretty clear you're talking specifically about "end-use efficiency" am I right?

by nicknich3 at 2:55 PM on 27 Nov 2006

already competitive

As Shinnar and Citro point out, solar thermal is already a competitive source for a large portion of the electricity supply:

... But at present, [Concentrated Solar Power] for base load in more expensive than conventional coal power plants and nuclear power plants. However, when we consider the other 60% of the load, intermediate and peak electricity, the comparison changes completely and, as shown below, CSP becomes attractive even at present prices.
... Despite the fact that initially the capital investment for CSP plants is double that of coal and nuclear plants, their cost-effective design for intermediate and peak loads plus their lower maintenance costs and "zero" fuel costs make them competitive even today.

Ped Shed Blog

by Laurence Aurbach at 3:47 PM on 27 Nov 2006

http://solarsystems.com.au/

Stirling Energy Systems, Inc. is a Stirling developer.

I miss wrote, your picture is a Sterling Energy Systems dish in the US.

Some 3 billion was spent on US government r&d on solar heat engines. I attended a dozen research conferences. Small heat engines just do not have long lifetimes.

They were once compared to a VW engine, which runs cooler, is lubricated, and low cost due to mass production. There are 8760 hours per year, in sunny areas you might get 2190 hours equivalent peak sun, full torque on the engine. In a VW Bug going 45 mph that's 100,000 miles per year. With much care and maintenance you might be able to get 300,000 per VW engine, 3 years of sunlight. That is very expensive amortization. Big turbines have the same lifetimes on their moving metal contact parts, but those are just two seals on the shaft.

United States concentrator photovoltaic science is an economic breakthrough and needs engineering support like that found in Australia.

http://solarsystems.com.au/

by sunflower at 4:19 PM on 27 Nov 2006

Subsidies and Efficiency

You would think that none of the traditional electric provders had received any incentives based on this article when such is far from the truth. The people of the US paid for virtually all the hydroelectric dams that are currently producing power at $.04 per watt. The cost of the new XCEL coal gasification plants is being subsidized by the public as a separate item on every utility bill. Cost of natural gas is continually subsidized in the same way. It is a delusion to believe that these providers are not also receiving incentives for production.
As for the efficiency of solar, the base reality is that that once the system is in place, THE ENERGY IS ABUNDANTLY FREE. You can not say that about any of the competing systems, not from XCEL or any of the other electricity providers. The shear abundance of the sun's free energy available over periods of time that dwarf our civilization make this arguement totally about installation, not efficiency. While it takes less space to put on a more efficient system, once the collectors are on the roof, they are producing free energy, no matter how inefficient they may be. Look around your belongings and find one other item you have recently invested in that you can claim the same and at the same tiem without any carbon footprint.
The harder we drive this industry with incentives, the more rapidly the enormous investments will flow in and the potential to install those cheep 40-50% efficient modules that will produce electricity at lower than market cost.

Fred Pittenger Simplicity Solar Grand Junction, Colorado Fred@simplicitysolar.com

by Fred Pittenger at 6:59 AM on 28 Nov 2006

one alternative not discussed

I know it's taboo and I'll probably get a lot of boos but what about Nucler Reactors more specifically "Breeder Reactors". If you want abundant effeicient non-oil source of energy within 20years Nuclear Reactors is a viable alternative. Breeder Reactors recycle the waste produced to make more energy. It is not 100% but France does have working Breeder Reactors now. Just a thought anyway.

by kllarue at 2:18 PM on 28 Nov 2006

subsidies and competiveness

>once the system is in place, THE ENERGY IS ABUNDANTLY FREE.

Hmmm - I wonder if I can get an eight million dollar mansion on that basis. Of course I can afford it. Cause one I have paid for it the rent is abundantly free. In life cycle costs, renewable energy, once you use it in large enough quantities to require storage is more expensive than conventional sources - at least until you consider social costs.

>solar thermal is already a competitive source for a large portion of the electricity supply:

Not strictly what they are saying. Their key argument is that with large scale mass production costs could be reduced by 2/3rds per kWh. They are probably right. The comparatively small production increase Stirling achieved via its rec ent larger orders already lowered costs by a third.

In general I think we are going to see big breathroughs over the next few years in storage. For example, there is proposal to make pumped storage system with large scale underground storage. So you have a closed cycle, with your "high" reservoir at ground level. That may well provide comparative inexpensive electricity storage

>Small heat engines just do not have long lifetimes

Hmmm - some of the plants in California have been running for twenty years. So it seems that these commercially manufactured engines do have a decent lifespan.

by Gar Lipow at 3:12 PM on 28 Nov 2006

Breeder reactors' fuel is inexhaustible ...

but so is that of the more usual once-through thermal reactors, as Jim Hopf argues here. Also see How Much Uranium is in the Earth. Most of the U that is discussed there is as near the surface, proportionally, as the skin of an apple.

kilarue says nuclear is an option that has not been discussed in this thread, but in fact my bumper sticker idea, "Burn U, not us", amounts to a discussion of it.

--- G. R. L. Cowan, former hydrogen-energy fan
Oxygen expands around B fire, car goes

by GRLCowan at 4:05 PM on 28 Nov 2006
[ Parent ]

Show me 50,000 hours on a small heat engine

(under full torque) and I will buy that engine. I will follow up on your source if you have it.

by sunflower at 4:18 PM on 28 Nov 2006

Show me 50,000 hours on a small heat engine

Here is the link for Stirling Energy Inc.

http://www.stirlingenergy.com/

Here is the email f...

So they have to replace the engine every ten years. Given that most of the cost of solar thermal is in the mirrors this is not bad.

by Gar Lipow at 4:48 PM on 28 Nov 2006

there is a reason for preview.

OK - another try at posting the email:

ses(AT)stirlingenergy(DOT)com

again in non-harvestable form that human common sense can translate

by Gar Lipow at 4:51 PM on 28 Nov 2006

Renwable Storage

Pumped hydro and hydrogen are not the only options.

Try Vanadium batteries from VRB systems at about $150/kWh
http://www.vrbpower.com/
Another good Aussie inve...
help solve 2 problems with one solution - climate change and peak oil.

Stephen Gloor Perth Western Australia

by Ender at 11:10 PM on 28 Nov 2006

Concentrated solar power

I am awaiting a reply from Stirling Energy Systems, Inc., also from Solar Systems in Australia. I have met John Lasich, nice guy...

A $420 million large-scale solar power plant - the biggest and most efficient solar photovoltaic power station in the world - is to be built in north-west Victoria.

http://www.solarsystems.com.au/documents/SolarSystemsMedi...

by sunflower at 9:16 AM on 29 Nov 2006

VRB

>Try Vanadium batteries from VRB systems at about $150/kWh

Last I check out their FAQ, the cost was more like $325 per kWh. Having a capacity of one hour per KW for wind would let it overcome the 20% barrier, while other displaced "spinning" reserves would pay for most the capital cost. But you can't use $325 per hour storage for a fully renewable grid that requires about 75 hours of capacity. That is where things like pumped storage (where it can be done in an environmentally sound way) and thermal storage shine; they are simply cheaper than other means. Even hydrogen, which I tend to dismiss, is cheaper than VRB batteries when you are talking large capacities.

Note that the it's lates sale to large wind farm in Ireland provides about 12 megawatt hours of storage to a 39 megawatt wind farm. Nominally that is less than 20 minutes of storage, but if you consider actual average production wind turbines it is probably close to an hour of typical output.

by Gar Lipow at 10:30 AM on 29 Nov 2006

Oh and VRB may be an Australian invention

But VRB power is a Canadian company.

by Gar Lipow at 10:31 AM on 29 Nov 2006

Vanadium batteries

Gar - why the requirement for 75 hours of capacity. There is no way that a distributed renewable grid would have no energy input for that long. Forcing a requirement for this is like forcing the present grid to be 100% reliable. It is not, which makes a company like mine spend a couple of million dollars providing a UPS for each of it sites for when the grid does fail.

To make renewables more dispatchable then only something like 6 or 12 hours storage is needed. If V2G gets going in a big way then we will have a lot more storage available however just the local storage of vanadium batteries would be sufficient for a much greater expansion of renewable power. These batteries are vastly more efficient and evironmentally friendly that pumped storage or hydrogen however some hydrogen, or hydrogen converted to methane or methanol, will always be stored.

6 hours storage for a 90MW wind farm:
From the FAQ
:As the size of the system in kWh increases, the cost per unit decreases significantly. The incremental cost of storage for large systems is approximately $150 per kWh.:

In six hours a wind farm of 90MW would be expected to deliver .3 * 90 000 * 6 = 162 000 kWh. At $150 per kWh then the this would cost
162 000 X 150 = $24 300 000. Which would increase the cost of the wind farm from 50 million to 75 million however it would now be despatchable and have a repository to store excess wind power.

"The vanadium redox (and redox flow) battery was first patented by the University of New South Wales in Australia in 1986"
http://en.wikipedia.org/wiki/Vanadium_redox_battery

Stephen Gloor Perth Western Australia

by Ender at 8:22 PM on 29 Nov 2006

Gar Lipow

How do you run the grid on 100% renewables without some sort of storage? What if cloudy weather coincides with windless days for three days in a row? Can happen. Especially since a lot of good wind sites have times as long as a month when they produce nothing, which means you are going to be relying entirely on sun. If you are in area that is cloudy and has to import sun, that could easily give you three days without either sun or wind sources. An alternative to storage is backup - but when you need to backup 100% of capacity, that is expensive too.

I want to avoid confusing what is works when renewables provide a minority of grid power to what it will take to make them dominate. That is very small amounts of storage will greatly improve the value of variable sources in a fossil fuel dominated grid. It takes a lot more to replace fossil fuels completely or nearly so.

But I may well have overstated the case. The only studies I could find suggested a three day storage requirement for any grid where 80% or more of power was supplied by variable sources. Has anyone done a robust analysis study suggesting a smaller number? I'd be very interested - cause this is an area where I'd be thrilled to be proven wrong. The less storage you need the less expensive storage becomes, the more you can afford to pay for capacity.

by Gar Lipow at 8:53 PM on 29 Nov 2006

Distributed generation and storage

Wind power is 4 cents per kwh without subsidies, eyyh Gar? Cheaper than coal and natural gas with subsidies. How much is coal or natural gas without subsidies?

With distributed generation and stortage plenty of storage time would be available even if renewables all shut down at once. All that is needed is a few hours to fire up natural gas power plants until coal plants can then come online.

These plants are already in place and would supplement the power shortage from areas that still have wind, water, or solar power. The part of the grid that was without renewable power would be powerd by backups in that local area as well as surrounding areas.

Eventually as superconducting grid storage comes online and more renewable power is available from further away, the role of backups will shrink.

And they can be convereted from coal and gas fired steam turbines to solid oxide fuel cell/turbines with 3 times the efficiency. With biogas from waste digestors and dry cellulose from algae fueling most of the backup power. But pulverized coal and regular natural gas can be used until the renewable sources take over.

Just as you wrongly assumed wind was more expensive than coal and natural gas, you now imagine storage makes renewables much more expensive. It just isn't so.

I agree on efficiency though. But it is best acomplished with geothermal heat pump heating and cooling, electric plugin hybrids, and muti-fuel cell/turbines. Another big efficiency sterp is to do energy intensive manufacturing like smelting and refining only when excess renewable energy is available, when the energy excess subsides the factories are idled.

http://amazngdrx.blogharbor.com/blog

by amazingdrx at 11:42 PM on 29 Nov 2006

American superconductor aquires Windtec

http://thefraserdomain.typepad.com/energy/2006/11/america...

Check it Gar, SMES (superconducting magnetic energy storage) financial synergy with wind.

The question is; does storage really make wind cost more or does it actually make total cost per kwh less because more fossil and nuclear power is replaced?

In the case of battery storage for a home for instance, you can buy power at 5 cents per kwh in offpeak and use it or sell it back to the power company at peak demand times for 10 cents per kwh, making storage a great investment that pays itself back very quickly.

Maybe SMES would work in a similar fashion on the grid as a whole?

http://amazngdrx.blogharbor.com/blog

by amazingdrx at 6:29 AM on 30 Nov 2006

Distributed generation

>Just as you wrongly assumed wind was more expensive than coal and natural gas,

Where did I do that for variable power

>With distributed generation and stortage plenty of storage time would be available even if renewables all shut down at once. All that is needed is a few hours to fire up natural gas power plants until coal plants can then come online.

In the long run, we don't want natural gas and coal as backup. In the short run - I already said that small amounts of expensive storage can pay quite well. Where I'm talking about storage as the bottleneck - it is the bottleneck for getting a really high percent of power from renewables. Look we have enough variable wind to provide many muliples of our current needs in North America - even before efficency. the problem is, above 20% you need storage. If you only have a few hours storage, then natural gas and coal are still going be supplying huge amounts of your energy. I agree, and have said in the past that an hour or so of storage could be very valuable. It would certainly break the 20% barrier; but it would not break the 50% barrier.

There are two things.

We have breakthroughs coming through.
But it is very hard to get people to support starting a path - when you are depending on stuff we can't currently do inexpensively. So it is better to lay out a way to eliminate fossil fuels with stuff we have a price for now. And then you can end up doing much better than projected as the inevitable advances occcur.

Incidentally in terms of efficiency - making manufacturing follow the natural rhythms of wind and sun is not exactly cost free. Extremely costly in terms of capital and labor utilization.

by Gar Lipow at 10:02 AM on 30 Nov 2006

100% renewables

"How do you run the grid on 100% renewables without some sort of storage? What if cloudy weather coincides with windless days for three days in a row?"

No-one is suggesting that we do this. You cannot run the grid on 100% thermal coal or 100% nuclear either as both these technologies require 'backup' from peaking plants to provide the demand for short term changes that neither of the technologies can provide.

We need to get away from the concept that renewables need backup. Fossil fuels need backup as well and it is called spinning reserve. Right now there are massive generators spinning consuming energy, producing CO2 and generating nothing. They are doing this because at any time a large generator could drop out and they are the backup.

What the true picture is that each generating source has its capacity factor - storage increases this for renewables. Yes a single wind farm, even in a good wind area, may not have any wind for a month however a coal plant may be out for the same period for maintenance or faults and nobody bats an eyelid. Some nuclear plants are out of action for a year or more from serious faults.

Due to the fully automatic operation of vanadium batteries and the fact they are as efficient small as they are big they do not have to big and central. The storage can be distributed in thousands of small power nodes in communities providing local storage not only for wind farms but local PV plants on people's homes.

Stephen Gloor Perth Western Australia

by Ender at 5:45 PM on 30 Nov 2006

So what percent of the grid

So what percent of the the grid do you want to be powered by fossil fuels? Do you want 30% of your energy from coal and natural gas? 40%? 60%?

by Gar Lipow at 6:37 PM on 30 Nov 2006

PHEV and EV for storing electricity

When plug-in HEV with 60 miles of electric range and electric vehicles become widespread, at least a significant portion of the capacities of their batteries can be used for storing electricity produced from solar (and wind) energy, and/or used as the means for load leveling of the electrical grid. You are talking about up to 20 kWh of storage by cars alone for each car when all the vehicles have 60 miles of EV range. If there will be 100 million PHEV/EV in this country, the storage capacity can be as high as 20 x 100 = 2 billion kWh/day.

For wind energy storage, the battery may be able to charge and discharge a few times a day as a means of load leveling.

I guess 2 billion kWh/day is likely enough to make up the shortage in nights in this country - remember we will always be able to generate a significant portion of the electricity during nights from wind, hydropower, nuclear, and other types of power plants.

The key is to develop rechargeable batteries with very long cycle life and a reasonable cost, I believe.

by Jianguo Xu at 1:42 PM on 01 Dec 2006

100%..eventually

It will not be a fixed percentage, but rather the percentage from renewables will increase with time.

The question is how fast do we want to get to as close to 100% renewable as we can? I think 10 years to 75% and 20 years to 100% is feasible.

On that time scale global climate change could be reversed in time to head off much of the worst damage. Before the ocean current conveyor stops and plunges the US and Europe into an instant ice age. And before ocean levels rise to cover most major oceanfront cities.

Using coal and natural gas plants to backup renewables will be how this is done, then coal and gas plants will eventually all be converted to fuel cell/turbine running on biogas and powdered algae that the veggie oil has been removed from for biodiesel.

By expanding conservation reserve cropland and going to organic agriculture, global climate change creating GHGs can actually be sequestered back out of the atmosphere until the natural balance is restored.

http://amazngdrx.blogharbor.com/blog

by amazingdrx at 7:28 AM on 02 Dec 2006

ACORE goal, 25% by 2025

Too mild, we need radical action.

100% renewable in 20 years!! 75% in next 10 years, that remaining 25% will take more clever storage solutions. But the first 75% is a cake walk in 10 years, compared to WW2 war production.

Just ramping up production of the new 35kwh altair quick charge electric car battery until the cost drops to 3000 dollars per unit would solve the oil part of the energy equation. A few billion dollar orders ought to do that. Step up Gates and Branson!

http://amazngdrx.blogharbor.com/blog/_archives/2006/12/2/...

http://amazngdrx.blogharbor.com/blog

by amazingdrx at 8:54 AM on 02 Dec 2006

great article

I'm a little late arriving to the party, however this article represents the most pragmatic recommendations I've read in this area for a long time. It is foolish to prematurely write-off existing infrastructure and replace it with renewable sources. The economics simply don't add up (even after attributing value to CO2 social costs).

Now this is true for developed nations (the West). However how do these economics stack up in India and China? Regions which do not have massive sunk cost investments in existing fossil fuel consumption. These two giants are also about to rapidly expand their energy infrastructure and thus may represent excellent targets for implementation of new technologies.

A challenge to the folks who submitted with religious zeal about new renewable technologies: If these new renewables are so great right now, let's see you step up in India and China.

by Siwash Rock at 11:06 AM on 14 Dec 2006

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