Thursday, January 26, 2012

Electricity Priced by the Hour Boosts Distributed Solar Value by a Third or More | ThinkProgress

Electricity Priced by the Hour Boosts Distributed Solar Value by a Third or More | ThinkProgress

Last week I wrote about the time-of-use pricing scheme that PG&E offers in San Francisco, and how solar power is worth 14% more compared to a standard flat-rate electricity plan. In reality, it’s 36% or more.
In the interest of simplicity, I only looked at the rates PG&E charges for using up to ~250 kilowatt-hours (kWh) per month (their “baseline” rate). But baseline rates only apply to the first 3,000 kWh consumed per year, one-third the U.S. average. Very few customers use so little electricity.
Rather, most customers will consume electricity in Tier 2, which applies to consumption from 3,000 to 6,900 kWh per year, or even Tier 3, which applies to consumption up to 14,500 kWh. And the electricity rates in these tiers are substantially higher.
For each peak hour kWh used in Tier 1 (the baseline), a customer pays 28 cents per kWh. But once they’ve used up their baseline amount, each peak kWh will cost 29.6 cents in Tier 2. If the customer hits Tier 3 rates in a given month, their peak electricity will cost 44.6 cents per kWh!
A solar array provides two benefits under this scenario. First, it produces electricity during peak periods, and second, it also reduces overall consumption. Thus, the electricity offset by a rooftop solar array is the most expensive, and it also can push the customer into a lower usage tier, reducing the rate paid on grid electricity.
A few examples:
A customer uses 3,000 kWh per year (the Baseline) and has a 2 kW solar array. The solar array provides 97% of the annual household consumption, and the value of the electricity produced by the solar array (based on the cost of grid power at the time it produces) is 22% higher than under a flat rate plan.
A customer uses 6,900 kWh per year (Baseline and Tier 2 power) and has a 2.5 kW solar array. The solar array provides 53% of the annual household consumption (but nearly all of the Tier 2 electricity), and the value of the electricity produced by the solar array (based on the cost of grid power at the time it produces) is 36% higher than under a flat rate plan.
A customer uses 10,000 kWh per year (Baseline, Tier 2 and Tier 3) – the U.S. average – and has a 2 kW solar array. The solar array provides just 20% of the annual household consumption (but nearly all of the Tier 3 electricity), and the value of the electricity produced by the solar array (based on the cost of grid power at the time it produces) is 253% higher than under a flat rate plan.
The chart at the top illustrates the good matchup between solar and time-of-use rates (the rates shown are for summer weekdays). The bars show the pricing by hour, as well as the higher prices in higher tiers of consumption (for Residential Schedule E-6). The green line shows the percent of daily solar output that falls during a particular time-of-use pricing period.
Overall, solar power is a pretty good fit with time-of-use pricing, a policy that should be used in more locales to improve the economics for local solar power.
Thanks to Mark, whose timely comment last week notified me of a change in PG&E’s residential time-of-use pricing plan.
– John Farrell is a senior researcher at the Institute for Local Self Reliance. This piece was originally published at Energy Self Reliant States.

Sunday, January 22, 2012

The passive house revolution (documentary) | Energy Bulletin

The passive house revolution (documentary) | Energy Bulletin:

'via Blog this'

In the U.S., green building can mean a lot of things — recycled greywater, roof gardens, solar panels and the U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED) certification all come to mind. But in Europe, many green builders focus laser-like on the amount of energy a building consumes, half of which typically comes from heating and cooling. Twenty years ago, German physicists erected a home that demonstrated how little energy a building would need if built with, among other things, thick insulation and airtight walls. The so-called “Passive House” (or “Passivhaus” in German) was soon replicated throughout the continent.

I learned about the concept when I met building scientist Henry Gifford — a persistent critic of LEED certification and noted leader of the New York City “Boiler Tour” — while researching a story on green building in Manhattan’s East Village. In the same way that I feel the ‘organic’ label doesn’t necessarily mean a food was produced in the most sustainable manner, it seemed the term “green” was often misleading when applied to buildings. But Gifford’s Passive House projects seemed like the real deal – no bells and whistles, just slashing energy use with some simple principles.

I embarked on a documentary project to show how far Europeans have taken the concept and to show the pioneering American builders who are bringing the movement across the Atlantic. The result was “Passive Passion,” a documentary selected for the 2011 Architecture and Design Film Festival.

See clips from Charles Hoxie’s documentary, “Passive Passion.”

Today, there are tens of thousands of Passive Houses in Europe, mostly in Germany and Austria. To attain the label, buildings must hit benchmarks for energy use and air tightness, and Europeans apply the standard to just about every construction imaginable – homes, apartment complexes, schools, gymnasiums and others. These buildings share one trait: they use about 90 percent less energy for heating and cooling than a traditional structure.

But virtue isn’t the main selling point, according to Wolfgang Feist, the physicist who founded the Passivhaus Institut in Darmstadt, Germany.

“You really get a very comfortable home,” says Feist. “With no noise, with no drafts… and with a very high indoor air quality. This is I think the most important thing. And you get all of this with a very low consumption.”

A Passive House is quiet because thick walls and windows cancel out the din of the city and the late-night guitar noodling of neighbors. But perhaps even more noticeable is the difference in air quality. Although they are designed to be airtight, Passive Houses typically have advanced ventilation systems that constantly pump in fresh filtered air. And unlike traditional homes, which are like Swiss cheese by comparison with the airtight Passive Homes, all of the air coming in gets filtered. The stale air transfers its heat or cool to the fresh air, further increasing the home’s efficiency by avoiding thermal losses.

All of this results in an indoor air quality akin to stepping out of your car after driving from the city into the country. “It’s like being outside, but inside,” says Katrin Klingenberg, the founder of the Passive House Institute of the United States.

Fresher air also could mean healthier lungs. The filters remove particulates and pollen, as well as other potentially hazardous pollutants, like off-gassing from carpets or furniture.

In the U.S., Passive House building is still the domain of enthusiastic “true green” builders, but increased demand could lead to cheaper components, pushing the price tag down and amplifying interest even further. And that might improve the planet’s health as well as our own.

Top image: The Hudson Passive House designed by Dennis Wedlick Architect. Courtesy Flickr user BASF

Charlie Hoxie is a documentary filmmaker based in Brooklyn, NY. For more information on the documentary ‘Passive Passion’ visit

Original article available here

Friday, January 20, 2012

Cheap beads offer alternative solar-heating storage

Cheap beads offer alternative solar-heating storage:

'via Blog this'

colleagues explain how certain materials, known as phase change materials (PCM) can store a large amount of heat in the form of latent heat in a small volume. PCMs have a high heat of fusion and melt/freeze at a certain temperature. Heat is absorbed when the material melts and released when it freezes. Heated in the sun, the mixture of paraffin wax (which melts at about 37 Celsius) and stearic acid (a fat commonly used to make soap) becomes entirely liquid. However, as it solidifies it slowly releases the stored heat. The process is akin to the phase changing heating that occurs in hand-warmers that contain a PCM but in this case the material does not need to be boiled in a pan or heated in a microwave oven to absorb latent heat.
The team has now tested spherical capsules just 38 millimetres in diameter containing a blend of paraffin and stearic acid, which can be floated on the top of water in a tank. Stearic acid is a lot cheaper on the Indian market than paraffin and more readily available. The team found that costs could be held down without reducing the overall heating efficiency of the capsules by lowering the proportion of paraffin wax.

Friday, January 13, 2012

A Low Impact Woodland Home

A Low Impact Woodland Home:

The Case for Urgent Preparation for Energy Descent

Human development has for the last two hundred years been powered by the use of fossil fuels. We have converted from locally self reliant agrarian focussed societies to a globalised society powered predominantly by fossil fuels. This global society is mediated by interdependent international financial markets. These markets and their various currencies have seen near continuous growth simultaneous with the growth in supplies of fossil fuels. This financial growth has also been raised by a number of powers due to the growth of speculation. Our financial transactions of trade are now dwarfed by the transactions of pure finances, the speculation on that trade and the speculation on that speculation. All of this financial activity is based on assumptions and predictions of continued growth. Of more trade tomorrow and the availability of more energy. On this our global society is dependent.
Climate change gives a clear imperative to curtail our fossil fuel use. In addition world supplies of fossil fuels are currently passing their peak of production. There is growing agreement that oil has passed its peak, gas will very shortly, and coal will peak in the next couple of decades. Uranium may not be a fossil fuel but that too will reach and pass its peak of production within the next few decades. Without these we either have to invent a new power source, make a transition to renewables, or reduce our power/fuel consumption.
Our society is operating under the assumption that economic liberalism and the free market will provide technological solutions for our future energy needs, the effects of climate change and any other problems that we might encounter. It is true that the free market and technological progress have extended our capabilities and even solved certain problems. However, all of this has been the product of increasing consumption of fossil fuels. The technological advance that would give us a replacement source of power to continue our growth is utterly unprecedented. Never before have we done what our society relies on us achieving now, by the essentially passive continuation of an unchanging method.
The belief that future technological fixes will enable continued growth is crucial for the functioning of our speculative economies. Without this belief our markets would collapse, and unlike the slow dwindling of fuel supplies, this can happen as investor confidence fails. At the moment we are staving off this occurrence with increasingly creative accounting and economic manipulation including inflated housing prices, and increased public borrowing. Already we are seeing how precarious this approach has been with the collapse of over extended banking giants and the beginning of the 'global economic downturn'.
There is a significant chance that replacement energy sources will not be realised before we loose the economic buoyancy that makes such technological progress possible. If this happens we will have no options but to make a radical transition to a non-growth paradigm and much lower energy ways of living. This will require major adaptions. The sooner we can begin to make these adaptions, the slower the transition will be and the more chance we have of positively managing the subsequent energy decent as an equitable and comfortable process. If wisely managed we still have a wealth of resources and powerful technology in our hands. With discerning use these assets could help us address our most fundamental needs for a long time to come.

Reducing our Energy Dependency

To reduce our energy dependency we will not only have to reduce our consumption but we will have to dramatically increase the productivity of our land and ecosystem. The most crucial parts of our society are our food production and distribution systems. Particularly in the developed world, our agricultural and food supply systems are heavily fossil fuel dependent. Most of our food is either imported, or has travelled many miles within the country. Also most of it is produced by industrial farming techniques which require both heavy machinery and fossil fuel derived fertilisers and pesticides. Calorifically, all of these inputs are many times greater than the outputs, meaning that we are constantly feeding energy into agriculture. Clearly without fossil fuels, agriculture needs to be a nett donor of energy to human society. Before the use of fossil fuels in agriculture, the vast majority of the population were involved in agriculture. If we are to move beyond fossil fuels this may well have to be the case again.
In addition to food producing agriculture, there is also a need for other important land based produce. Most notable is forestry and its derived products. As well as timber for building, tools and the making of other objects, wood is our primary renewable fuel source.
In contrast to the pre fossil fuel situation, we now have a much larger population to feed and provide for. We also have the benefits of a much more detailed understanding of the world as well as current access to modern technology and resources. We need to use these assets along with traditional practices to help us develop the infrastructure and skills required for energy decent. These developments must be started as soon as possible as they cannot be implemented overnight regardless of the resources available.

Sustainable and Resilient Communities

In order to be sustainable, a system or community must be self reliant in all the resources it requires. The greater the number of independent subsystems that can provide for the functions and required resources, the greater the resilience of the system. Whilst our global society still contains many different subsystems, they are not independent, being linked by shared fossil fuel dependency, trans-national ownership and the globalised economy. Where we can replace this with independent self sufficiency at the smallest scales, we will have sustainable and resilient local communities. This will give the most resilience and sustainability to our macroscopic society without precluding inter community interactions and co-operation.
Small scale land stewardship is also important to reduce energy inputs and allow greater intimacy between stewards and their ecosystems. It is though this intimacy that they will be able to go beyond being a simple steward to the required roles of nurse and then teacher.
Firstly we need to heal the infertility that is the legacy of ecological degradation and intensive farming. This starts with repairing the soil and crucial mycorrhizal fungi populations. Above ground we can replace monocultural deserts with interplanted systems using the principles and patterns of the natural world. In this way we can build a healthy and productive ecosystems where different species of plants and animals enjoy complex complimentary relationships. With this kind of intimate knowledge and management we will be able to actively manage our ecosystems to survive the unpredictable climatic changes that are to come.
Naturally the restoration of soil fertility will take time, as will the establishment of gardens, orchards and complex agroforestry systems. The same is even more true for forestry, Whilst highly productive firewood coppices can be established in a few years, the restoration of traditional coppice woodlands takes decades as does the establishment of productive new woodlands and regeneration of conifer plantations.
All of these forms of land based production require supporting infrastructure and processing facilities. These also need to be localised and provided in ways suitable for a post carbon future. Simple, low-impact homes can be built where they are needed, with natural materials and accessible methods. These buildings can easily provide high levels of comfort and efficiency at a tiny fraction of the cost of their conventional equivalents. Effective and reliable systems for water, sewage, heating, refrigeration and even modest electricity can be simply made in low-tech ways with reused and natural materials.
There will always be benefits and pleasures of community co-operation and facilities. There are a number of essential supporting facilities which also need relocalisation such as mills, forges, tanneries, lime-kilns and carpenters workshops. These communities should also have their own independent councils, markets, and local events. Local trading systems or currencies add to community resilience by strengthening the local economy and protecting against global financial instability.
Alongside the required infrastructure comes the need for many sets of skills. A lot of these are traditional skills to be revived, some will be derivative of the contemporary world, others will be a synthesis of the two. All take time to learn, develop and share.


Permaculture is a set of design principles for human scale, sustainable systems. It is based on the three ethics of 'people care, earth care and fair shares'. It provides an approach that is most frequently applied to small scale agriculture, but can equally be applied to buildings, domestic systems or community interactions to name a few. The permaculture vision is quite well described by the picture outlined above.
Permaculture has played a key role in Cuba's 'special period' after the collapse of the Soviet Union in 1990. Oil imports were cut in half, and food by eighty percent. The island "quickly transitioned from a highly mechanised, industrial agricultural system to one using organic methods of farming and local, urban gardens" . This kind of transition is what we can choose to meaningfully curtail our contributions to climate change and what we may well soon face without choice in the face of peaked oil and economic instability. The Cubans' response largely based on permaculture and community agriculture was highly successful. Vegetables were planted on rooftops and abandoned car parks. Havana now produces 60% of its food from urban land within the city itself.
Another inspirational example of permaculture is Austrian farmer Sepp Holzer. His farm is between 1000 and 1500 meters above sea level with average annual temperatures of 4.2°C. Outdoors here he grows kiwi, lemons, peaches, figs, wheat and more . His success is due to careful observation and intelligent design, following permaculture principles.

A Force for Change

There is significant and rapidly growing energy at the grass roots for permaculture type solutions and the intentional move towards relocalisation and energy decent. Organisations such as the Transition Towns Network and the Soil Association are part of the gathering momentum in this direction. Their message is clear, that the time has come to make the move now. The fact that such a move is essentially contrary to the growth paradigm means that the call to energy decent is never going to come from the corporate or political arenas. It is coming now from the grass roots, with rapidly increasing numbers of people unwilling to remain on the sinking ship of consumption and growth waiting blindly for the techno-fix lifeboat.
The enthusiasm for these kinds of changes come not only from intellectual concern about the issues involved but also from a much more powerful heartfelt attractive force. It is not without reason that this kind of life is often referred to as 'the good life' and 'a place in the country' is a perennial retirement goal. We have an evolutionary history and expectation of living close to nature.
The scale and power of this enthusiasm became clear to me after our family's experience of building a simple low-impact home in a Welsh woodland where we lived whilst helping with woodland management, small scale animal husbandry and setting up a forest garden. Part of our motivation was to show others that this kind of living was possible. I put a few photographs of our home on a simple web page to show half a dozen friends who had helped us with the construction. Within a few weeks, it had been passed on and started to appear on a few blogs. Since then this website has been receiving up to 50,000 unique visits a day and has been looked at by 2 million people. I have had thousands of emails from excited and inspired people. Some with tears, some with plans, some with their own stories and every single one with enthusiasm and encouragement. This has been a humbling but also eye opening experience. People are attracted to the house and the way of life. Very little explanation is needed and virtually all have an immediate and clear understanding of the philosophy and way of life. This experience amongst others has made it very clear to me that a significantly large number are keen to make the move to an energy decent and a simple land based life.
It is also clear to me from this experience that as people move in this direction they experience a positive feedback cycle of learning as illustrated below.
The combination of this feedback cycle with the enthusiasm and innate appeal of this route makes this a powerful movement, and one that is capable of making effective change at every small step. The major obstacles holding it back are availability of land and peoples time. These again are economic issues. The sort of work required to begin to make the transition to an energy decent is inherently uneconomic and shall remain so until the point at which there are no longer any other options. It is both crucial and appealing that before this time comes we do whatever we can to build local resilience. Whilst large numbers of people are pursuing this kind of work in their leisure time, it is impossible for most to follow it as a full time vocation at the same time as paying for housing and the land they are working.


There are growing numbers of community supported agriculture and similar projects which allow people access to land but cannot help them satisfy their housing costs. They also do not allow the proper permaculture approach which puts the home at the centre of a series of notional zones where the things requiring most attention are closest to your living to ensure maximum attention and efficiency.
The planning system does make allowances for farmers and seasonal forestry workers to live on their land, it is commonly subject to strict tests of their functional need to be there and proof that the enterprise is a viable business. This framework does not make allowance for production for self-sufficiency nor for the low cost lifestyles favoured by those living off the land in this way.
Small numbers of individuals and communities have been taking a direct action approach and simply moving on to agricultural land and getting on with their projects without advance planning permission. Many of these projects end up coming to the attention of the planners upon which they make retrospective applications, usually under the agricultural guidelines described above. Almost without exception, those who can afford the lost sleep and considerable paperwork of a planning appeal, get awarded permission although it is often short term temporary permission.

Understandably the majority of people are put off this route by the insecurity and the common impression that development without prior planning is illegal. If the planning system gives concessions to those wishing live on and work small pieces of agricultural land in this way the situation would be a very different one. Once the route is established it will be appealing to sufficient numbers of people to make significant preparations for the transition to energy decent.
Following unresolved retrospective planning cases and significant negotiation Pembrokeshire added such a planning policy to its JUDP in the summer of 2006 . There are a number of applications lodged with the county including the 'Lammas Project' this proposal for a low impact settlement of 9 smallholdings has taken approximately 5 man-years of paperwork and planning and was designed to fit the policy as tightly as possible. It was initially rejected on the ground of supplying insufficient information and has been resubmitted after more work. The Lammas team are still waiting to hear and hope to move on to their land within the next year. Other applicants under the same policy have similar stories.


Climate change and ecological crisis require an urgent and dramatic cut backs in fossil fuel use. If we do not move first, they may well be forced on us soon by dwindling supplies and an over-extended global economy. There is currently no other viable energy source to continue our escalating growth.
The transition to energy decent will be difficult. However, the sooner we can start preparing for it, the easier it will be. We need to make local communities self reliant and resilient. We also need to restore the fertility and productivity of the land. We need to develop and adapt supporting infrastructure as well as learning basic skills. permaculture is an effective approach which we can use to make these changes.
There is a strong grass-roots enthusiasm to make changes in this direction as well as accelerating positive feedbacks. If a workable route can be made within the planning system to grant access to land, and the right to live on it, to those wishing make these changes, we can allow a rising tide of people to make real progress towards a sustainable society. If a workable route is not found, we will be reliant upon the increasing numbers of people ready to take to the land without permission.

Monday, January 9, 2012

Japanese discovery of a "windlens"  could triple energy output!

Now what if a breakthrough came along that potentiallytripled the energy output of those turbines? You see where I'm going. We could in theory supply the TOTAL annual energy needs of the U.S. simply by exploiting 20 percent of our available wind resources.
Well, such a breakthrough has been made, and it's called the "wind lens." 
Imagine: no more dirty coal power, no more mining deaths, no more nuclear disasters, no more polluted aquifers as a result of fracking. Our entire society powered by the quiet "woosh" of a wind turbine. Kyushu University's wind lens turbine is one example of the many innovations happening right now that could in the near future make this utopian vision a reality.
Yes, it's a heck of a lot of wind turbines (about 2,640,000) but the U.S. with its endless miles of prairie and agricultural land is one of the few nations that could actually deploy such a network of wind turbines without disrupting the current productivity of the land (Russia and China also come to mind). It would also be a win-win for states in the highest wind area — the Midwest — which has been hard hit by the recession. And think of the millions upon millions of jobs that would be created building a 21st century energy distribution system free of the shackles of ever-diminishing fossil fuel supplies. 
It's also important to point out that growth in wind power capacity is perfectly symbiotic with projected growth in electric vehicles. EV battery packs can soak up wind power produced during the night, helping to equalize the curve of daytime energy demand. So the controversial investment currently being entertained by President Obama to pipe oil down from the Canadian Tar Sands would — in my utopian vision — be a moot point.
It is indeed a lofty vision, but the technology we need is now in our reach. And think of the benefits of having our power production fed by a resource that is both free and unlimited. One downside often cited by advocates of coal and gas power is that wind turbines require a lot more maintenence than a typical coal or gas power plant. But in a lagging economy this might just be wind power's biggest upside — it will create lots and lots of permanent jobs, sparking a new cycle of economic growth in America.
Editor's note: Want more info? Karl breaks down the math in his next post.

Discovery of a 'dark state' could increase maximum theoretical efficiency of solar cells from 31 to 44 percent

Discovery of a 'dark state' could increase maximum theoretical efficiency of solar cells from 31 to 44 percent:

Zhu and his team have discovered that it's possible to double the number of electrons harvested from one photon of sunlight using an organic plastic.
"Plastic semiconductor solar cell production has great advantages, one of which is low cost," said Zhu, a professor of chemistry. "Combined with the vast capabilities for molecular design and synthesis, our discovery opens the door to an exciting new approach for , leading to much higher efficiencies."
Zhu and his team published their groundbreaking discovery Dec. 16 inScience.
The maximum theoretical  of the silicon solar cell in use today is approximately 31 percent, because much of the sun's energy hitting the cell is too high to be turned into usable electricity. That energy, in the form of "hot electrons," is instead lost as heat. Capturing hot electrons could potentially increase the efficiency of solar-to-electric  to as high as 66 percent.
Zhu and his team previously demonstrated that those hot electrons could be captured using . They published that research in Science in 2010, but Zhu says the actual implementation of a viable technology based on that research is very challenging.
"For one thing," said Zhu, "that 66 percent efficiency can only be achieved when highly focused sunlight is used, not just the raw  that typically hits a solar panel. This creates problems when considering engineering a new material or device."
To circumvent that problem, Zhu and his team have found an alternative. They discovered that a photon produces a dark quantum "shadow state" from which two electrons can then be efficiently captured to generate more energy in the semiconductor pentacene.
Zhu said that exploiting that mechanism could increase solar cell efficiency to 44 percent without the need for focusing a solar beam, which would encourage more widespread use of solar technology.
The research team was spearheaded by Wai-lun Chan, a postdoctoral fellow in Zhu's group, with the help of postdoctoral fellows Manuel Ligges, Askat Jailaubekov, Loren Kaake and Luis Miaja-Avila. The research was supported by the National Science Foundation and the Department of Energy.
Science Behind the Discovery
• Absorption of a photon in a pentacene semiconductor creates an excited electron-hole pair called an exciton.
• The exciton is coupled quantum mechanically to a dark "shadow state" called a multiexciton.
• This dark shadow state can be the most efficient source of two electrons via transfer to an electron acceptor material, such as fullerene, which was used in the study.
• Exploiting the dark shadow state to produce double the electrons could increase solar cell efficiency to 44 percent.
Provided by University of Texas at Austin (news : web)

Wednesday, January 4, 2012

Solar power: Building a better suntrap | The Economist

Solar power: Building a better suntrap | The Economist:

A new way to collect solar PV, using a metal abosrber with microscopic pits that concentrate heat, radiate onto gallium arenide, that is placed behind it.

The result, according to Dr Bermel’s calculations, would be a system that converts 37% of sunlight into electricity. This compares with a maximum of 28% by standard silicon-based solar cells that have not had the incident light concentrated by parabolic mirrors, and 31% by those that have—a significant enhancement. The next step, of course, is to try it for real, but Dr Bermel is pretty confident his sums are correct.
Tungsten, as a material, was much used in the filaments of incandescent electric light bulbs. These are going out of fashion because they convert too much of the electricity passing through them into heat, rather than light. A nice irony, then, that running the process backwards may not only give tungsten a new lease of life, but might also help solve the world’s shortage of renewable energy.


Zinc-Air Battery With 30-Year Life Could Revolutionize Grid Energy Storage, Boost Wind & Solar Adoption

The technical highlights, according to EOS, are that its zinc-air battery could last for around 30 years (they claim to have reached 2,700 cycles without degradation) at about half of what additional natural gas would cost. The company wants to sell megawatt-scale batteries with 6 hours of storage at a capital cost of $160 per kilowatt-hour. They could be used to store energy at times of low demand to then release it during peak time, acting as a kind of damping buffer. They could not only be used to absorb the daily demand cycles, but also to store renewable energy from intermittent sources; for example, it could store energy from a wind farm over a windy night and then release it to the grid the next day during peak demand time. This is something that grid-connected electric cars can also help with, especially if we have a smart grid that can communicate with them.
EOS Energy Storage is currently raising funding from investors and will start taking pre-orders in the Spring of 2012, but it's not clear when they'll start shipping batteries. If their claims are accurate, I hope that they'll be able to ramp up production quickly and get to large scale deployment soon, because we really need more energy storage on the grid.