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Students in India Develop Photovoltaic Driven Refrigerator

A team of students in the Innovation And Entrepreneurship Development Centre (IEDC) of RMK Engineering College in India has developed a prototype photovoltaic driven refrigerator and warmer system that could potentially replace appliances that use refrigerants and other liquids for operation. According to an article in the Deccan Chronicle, students Surith Nivas M, Sai Prasad S and Ram Kumar P.H. designed a system powered from solar panels using a battery bank for electrical storage. In an adaptation of thermoelectric refrigeration, the system does not require a compressor, expansion valves, absorbers, condensers or solution pumps. It also does not require working fluids or any moving parts, making it friendly to the environment and resulting in increased reliability. The device uses electrons rather than refrigerants as a heat carrier.

Thermoelectric systems are defined as solid-state devices that either convert heat directly into electricity, or transform electric power into thermal power for heating or cooling.

The system’s primary application will be to bring refrigeration to rural communities, especially in India, where sunlight is plentiful and refrigeration products rare. However, the potential for replacing Freon and similar liquid-based devices could revolutionize the industry.

The team’s findings are reported in a paper posted on the International Journal of Advancements in Research & Technology web site.



Bring in Da Noise, Bring in Da Funk: Loud Music Makes Zinc-Oxide Solar Cells Work Better

You may not be able to get mad at your neighbor for blasting loud music anymore. At least not if that music is aimed at making the solar cells on his roof work more efficiently. According to an article reported by science writer Ceri Perkins on, researchers in the UK have discovered that blasting music at zinc-oxide solar cells makes them perform up to 50% better. The researchers said pop and rock music works better than classical music, but they suggested that any noise with a broad range of frequencies would produce similar effects. The discovery might be exploited by placing the devices on top of buses, air-conditioning units and in other noisy spots.

Zinc oxide is a piezoelectronic substance (piezo comes from the Greek "to squeeze"), meaning that when it is subject to mechanical strain, the symmetry of its component crystals is distorted and a polarization charge appears. Nanomaterials expert Steve Dunn of Queen Mary University of London and Imperial College photochemist James Durrant hypothesized that by using acoustic vibrations, they could induce tiny piezoelectric currents in zinc-oxide nanorods, and boost the cells’ electricity output. To test their idea, the researchers used computer speakers to play the music from their mobile phones and individual frequencies from a signal generator at volumes of about 75 dB—equivalent to a lively office.

They found that the device was 40–50% more efficient when particular types of music were played. “It quite liked Adele and AC/DC,” said Dunn, “but then Safa [Shoaee] played some Persian funk at it and it was really loving that!”

The researchers suggested that a similarly broad range of frequencies arise from many types of everyday noise, making their devices eventually feasible for use on laptops, public transport and near airports. But even with the 50% increase in efficiency, zinc-oxide cells only achieve 1.8% power-conversion efficiency and lag way behind crystalline silicon’s 10–20% standard.

The team’s research is published in Advanced Materials.



Energy Saving Strategies for Older Homes

If you live in an older home, you know it’s a challenge to keep energy costs manageable, especially during cold weather. According to articles posted on and, there are a variety of steps you can take to keep your home warm and efficient, and keep your energy bills lower:

  1. Consider insulating attic spaces. This can have a tremendous impact on a home’s energy efficiency, and significantly reduce heating and cooling costs. The best types of insulation available now are blow-in spray foam options.
  2. Add insulation to the roof and exterior walls, as well as to the basement foundation walls and floor slab.
  3. Seal cracks, leaks and holes. These retrofits will help reduce heat losses in winter and heat gains in summer. Common spots where air leakage occurs include electrical boxes, plumbing, wiring and ducts that run through exterior walls or into the attic, around chimneys and exhaust fans in attic spaces, and where the first floor joists rest on the foundation wall. Windows and doors with worn or missing gaskets and weather-stripping or those not well-sealed to the surrounding walls are also locations of air leaks.
  4. If it’s feasible from a budgetary standpoint, replace old windows and doors and choose new, energy efficient options. Since this is expensive, adding storm shutters and clear plastic coating to windows can help an old home be more efficient. For homeowners who can’t replace doors and windows, adding window stripping and caulk is also a good idea.
  5. Insulate the hot water heater and associated pipes, and keep the thermostat set at 120 degrees Fahrenheit. If possible, consider a tankless water-heating unit. These are an upfront investment, but they save money in the long-term, because they only heat water when it’s needed.
  6. Enact home heating zones. This means strategizing to heat a home based on usage. For example, heat the downstairs of an old home during the day, and the upstairs at night.
  7. If an old home also has old appliances, it may be worthwhile to invest in newer energy saving models. While there are some things owners of older homes can’t control without big remodeling investments, this is a less expensive alternative.
  8. Just because a home is old doesn’t mean it can’t take advantage of new technology, like home automation systems. A home automation system can allow owners of older homes to control the systems located within, even remotely, including the thermostat.
  9. Above-grade walls in older homes are typically wood frame, and there may be fiberglass batt insulation in the stud cavity. To increase insulation values in the exterior walls, the existing interior drywall and polyethylene can be removed and a new second row of wood framing installed. Insulation and a new polyethylene vapor retarder and air barrier can then be added to the new stud wall complete with new gypsum board finish.
  10. Replace existing single- or double-glazed windows with double- or triple-glazed windows that meet or exceed the Energy Star rating for your location. Energy-efficient windows often have low-e coatings, argon-gas fill and low-conductivity insulating glass edge spacers.
  11. Below-grade walls are often concrete or concrete block, and they may either be uninsulated or have wood-frame walls with fiberglass batt insulation that were added some time after the house was built. One way you can increase the thermal resistance of the foundation walls is to install foam board insulation directly against the inside surface of the foundation wall. Be sure to insulate and air seal the area between the floor joists where they rest on the foundation wall. For the basement floor slab, if you have adequate ceiling to floor height, you may be able to install extruded polystyrene board insulation over the existing slab and then add new finished flooring.



Germany to support battery storage as next move in renewables

Germany has been a leader in Europe’s push toward more renewable energy generation, helping to make solar more affordable to consumers and keeping red tape to a minimum. With its record of making renewables more affordable, Germany is also taking the next step and investing heavily into battery storage technologies for their renewables.

Over the past five years, Germany has been largely responsible for priming an 80 per cent fall in the price of solar modules. Now it is looking at bringing down the cost of the next piece in the puzzle of its energy transition – battery storage.

At its disposal is the giant state-owned but independently run development bank KfW. It performs in the clean energy space a similar function to Australia’s recently created and imminently doomed Clean Energy Finance Corp, but at such a scale that is not contemplated in most countries, possibly with the exception of China.

It has assets of more than €500 billion, and lent €73 billion last year – with one-third of that targeted at renewables and climate investments. Over the past three years it provided €24 billion in loans for energy efficiency investment in homes, leveraging a total investment of €58 billion, helping insulate and seal more than 2 million homes, employing 200,000 people a year and saving more than 150 million tonnes of carbon.

Even though Germany is helping to mitigate the costs of implementing, they are taking a more conservative approach this time around.

Unlike the subsidised uptake of solar PV enabled by the deployment of generous feed-in tariffs, the support mechanism for energy storage is more cautious. Indeed, KfW is looking for investors who are willing to take a loss on their investment.

“The market for energy storage systems is very young  … batteries are still very expensive  … and the economics don’t yet work,” program manager Dr Holger Papenfuss, told RenewEconomy in an interview in KfW’s sprawling headquarters in Germany’s financial centre of Frankfurt this week.

In fact, even with the assistance of the loans and grants, it is still not economically viable. Which is why KfW has stepped in to ensure that the commercial banks provide the funds for development.

The program is relying on “early adopters” and “renewable pioneers” – the same profile that were the first to get into electric vehicles, or solar panels a decade ago – who have the money and are willing to accept a negative return on their investment. Right now, Papenfuss says, people would be better off selling power to the grid.

While Germany and KfW are being more conservative with their investments this time around, they are still working to bring down the price of storage for renewable energy.

Read more at RenewEconomy.



Liquid-metal batteries almost ready, beginning production

Ambri, a spin-off of MIT, is getting ready to begin production of its liquid-metal based batteries. Ambri currently has two customers ready to begin, a military base on Cape Cod and a wind-energy project in Hawaii.

The company will be making prototypes and demonstration units in Marlboro for installation next year and intends to have a full-scale manufacturing facility in 2015.

To keep battery prices low, Ambri uses inexpensive materials and a simple design. Each battery cell is a square metal box about 10 centimeters per side. Each cell contains two metals and a salt electrolyte that are all in liquid form when the battery is running.

According to the company, each unit - sixteen packs of 54 cells - can provide up to 500 kilowatts for up to four hours when several are connected together. And, because of the technology, there is very little storage capacity loss expected over time. This aspect, in particular, is an important feature for utilities and their budgets.

Ambri’s goal is to bring simpler, more affordable battery storage for clean energy generation and that is what they are beginning to do. To see it in action, we will just have to wait for their working prototypes. Until then, they have our attention.

To read more, visit IEEE Spectrum.



State of New York promoting green energy with new law

New York Governor Andrew Cuomo recently signed a law that will provide low cost loans for installing green energy sources in both residential and commercial applications.

Program applicants receive free or reduced-price energy audits to determine the most cost-effective green energy technologies for their home or business. They can then take out small low-cost loans from the state that they pay back through their utility bill.

Homeowners could receive up to $25,000 in loans that they then back over five to fifteen years at a 3.5 percent interest rate. The loans are administered by the New York State Energy Research and Development Authority.

The program, which aims to allow property owners to “spin the meter backwards,” is another aspect of the state’s efforts to increase the proliferation of green technologies. It goes further than earlier efforts by pushing for alternative and green energy generation rather than focusing on energy-saving efforts like improving insulation.

Where earlier efforts largely focused on more modest methods of bringing down energy costs like weather stripping and insulation, the new law is designed to expand the use of more significant technologies like solar photovoltaics, wind turbines, hydro-electric generators and fuel cells. All of those alternative energy sources have significant up-front costs that the new program aims to reduce.

“It will open up the door to a lot of homeowners,” said Conor Bambrick, air and energy director at Environmental Advocates, a statewide environmental advocacy organization. “They're scared off by the sticker shock of it.”

NYSERDA issued $24.3 million in bonds in August, which is where the funding for this initiative, and others, will come from as part of the Green Jobs - Green New York program.

To read more, head over to Capital.



Microgrids more popular as US looks to avoid weather-related blackouts

With the repeated blackouts stemming from storms hitting the East Coast, states, the military, and the federal government are all looking at ways to keep the lights on when large storms hit the country.

From the military to main street, the United States is trying to avoid Superstorm Sandy-like blackouts by developing more backup power in the form of microgrids

Many of these mini networks produce power onsite and store it for emergencies. They operate independently of the nation's electrical grid, which distributes power from coal, natural gas or nuclear plants, so they can keep the lights on when a storm brings down the grid.

Just one year after Sandy turned out the lights on 8.5 million Americans, there's been a proliferation of generators, fuel cells, solar panels paired with batteries, and combined heat and power technologies. These varying microgrids aim to make the main grid more "resilient" — energy's 2013 buzzword.

Reliability is the issue when it comes to electricity generation and transmission during storms. As the prices of solar panels has decreased and the quality of battery storage technology increases, microgrid systems are solving this problem.

Microgrids — once used mostly by colleges and hospitals — are now expanding to other facilities as the U.S. Department of Defense, businesses and local governments work to avoid the risks posed by extreme weather, expected to intensify with climate change-related power risks.

More than 50 U.S. military bases now operate, plan or are testing microgrids, according to fourth-quarter 2013 data by Navigant Consulting, a research group that's compiled a microgrid database.

"The United States is by far the world's leader on microgrids," says Navigant's Peter Asmus, principal research analyst. He says the nation now accounts for nearly two-thirds, or 62%, of global microgrid capacity that's either planned or operational. He says the number of microgrids worldwide has increased from about 400 early last year to about 600 now, nearly half of which are in the U.S.

Asmus says Sandy, along with other recent extreme weather events, exposed the growing unreliability of the nation's aging and "Balkanized' power grid, which is subject to varying state-by-state regulations.

As with any developing technology, microgrids are still working out all of the kinks and are being deployed differently from state to state. However, because they are becoming more popular solutions to grid reliability problems, they are slowly reaching a standard for regulation and installation.

Read more at USA Today.



USB could change the future of energy distribution

We use USB cables and devices daily to transfer information, charge our electronic devices, and, in some cases, connect devices to our cars. However, according to the Economist (and reported by Think Progress), we could see USB in the form of USB Power Deliver (USB PD).

Currently USB cables support only 10 watts of direct current (DC), just enough to charge the current iteration of iPads, but USB PD will permit up to 100 watts.

The Economist argues that this could “presage a much bigger shift, reviving the cause of direct current (DC) as the preferred way to power the growing number of low-voltage devices in homes and offices.”

USB co-inventor, Ajay Bhatt, who has become somewhat of a tech rock star at Intel since inventing the device to develop a universal port, said in an interview with IEEE Spectrum that USB PD, with power flowing in either direction, will allow “a power source and a computing device to negotiate power delivery mechanisms, or the voltages and the current.”

The move toward DC power is being backed up by the creation of DC-powered datacenters by companies like Facebook, JPMorgan, Sprint, and more. These datacenters report a 20 percent efficiency increase over AC-powered datacenters and used significantly less floorspace because of reduced equipment needs.

With the proliferation of solar power generation, having buildings and microgrids completely DC powered makes more sense than ever. USB PD will simply make the transition easier.

To read more, visit



Maryland home to commercial solar microgrid

Maryland’s first commercial solar microgrid has recently been completed for Konterra Reality in Laurel, MD. of the first for the nation: a 402kW system combining grid-interactive energy storage and a 1,368 panel solar PV canopy array… The solar microgrid system is expected to generate of 20 per cent of the annual building power for the Konterra headquarters, as well as power for two electric vehicle charging stations and LED parking lot lighting. The energy it will generate is equivalent to the electrical usage of about 57 American homes for one year or removing 90 passenger vehicles from the roads per year.

The PV array would also stay online in the event of a conventional power grid outage, with the batteries of the advanced energy storage system  able to maintain a critical load of 50kW for just over four hours overnight and recharge the next day.

With the completion of this project, the combination of solar generation and battery storage can be tested on a large scale and in real-world conditions and help keep the price of solar power dropping.

To read more about this project, visit



The battle of AC and DC supremacy heats up as tech improves

While AC, or alternating current, won the ‘War of the Currents’ in the 1800s, most of our electronics run on DC, or direct current, electricity which requires an AC converter. Recently, though, with the increase in solar and wind power generating, and microgrids tending to run on, DC power, it is beginning to look like switching from AC to DC might make sense.

While once it was ease of transmission that made AC the standard for electricity distribution, new technology has eliminated this advantage, according to DC advocates.

Also, Bidanda said, it is now easier to use renewable energy systems, such those that use solar power, with direct, rather than alternating, current. "This is an important crossroads we're at. We're looking at an entire new paradigm in the energy cycle," he told The Prague Post. "The technical obstacles have been overcome. Now it's a question of the scale of obstacles, resistance to change, ignorance."

Developing countries could be particularly suitable for the introduction of DC as they may not be linked to national grids and can instead make use of local, even village, level alternative energy generation and distribution systems that involve direct current.

According to Bidanda, the use of direct current could become widespread in some developing countries within five years, but it could take two decades for this to happen in developed countries.

A complete changeover to DC is not however necessary to realize most of the benefits linked to this form of electricity, he said.

DC power systems are more efficient, saving users energy and energy costs. Even using a combination of AC and DC power in the home can be beneficial when it comes to the amount of energy used and utility costs. As far as the battle between AC and DC is concerned, DC is coming back with new and improved technology to make a claim for power generation and transmission superiority.

Read more on this story at



Utilities, customers clash over solar battery storage

In California, there has been some argument over the use of battery storage with solar power systems between customers and several California utilities.

Edison International (EIX), PG&E Corp. and Sempra Energy (SRE) said they’re putting up hurdles to some battery backups wired to solar panels because they can’t be certain the power flowing back to the grid from the units is actually clean energy.

The dispute threatens the state’s $2 billion rooftop solar industry and indicates the depth of utilities’ concerns about consumers producing their own power. People with rooftop panels are already buying less electricity, and adding batteries takes them closer to the day they won’t need to buy from the local grid at all, said Ben Peters, a government affairs analyst at Mainstream Energy Corp. , which installs solar systems.

There has been a recent increase in the number of solar power systems with battery storage as the price of storage falls, though the systems are still expensive. After installation of these systems, however, the utility has the last say in whether it can be connected to the grid, and in turn, to the house.

Matthew Sperling, a Santa Barbara , California, resident, installed eight panels and eight batteries at his home in April.

“We wanted to have an alternative in case of a blackout to keep the refrigerator running,” he said in an interview. Southern California  Edison rejected his application to link the system to the grid even though city inspectors said “it was one of the nicest they’d ever seen,” he said.

“We’ve installed a $30,000 system and we can’t use it,” Sperling said.

Utilities say the storage systems open the possibility of fraud. The issue is whether all the electricity being sold through the net metering program is generated only by renewable sources, as required. Consumers in theory can fill the batteries with power from the grid and then send it back designated as renewable energy. With the solar-battery systems, there’s no way to determine the source of the energy. Solar suppliers say that’s not happening.

The issue in these cases is that utilities cannot verify where the battery-stored power is coming from when it returns to the grid, meaning that if they accept power that has been stored, it may be from non-renewable sources, and does not comply with the state’s mandate for more renewable energy to be used on-grid.

The solution to the problem is to add cost to the already expensive solar power systems, installing an extra meter to record whether the stored energy is from the solar system or the grid, since the utilities have been been able to keep up with the changes in the solar power and battery storage industry.

No matter how you look at it, though, this will continue to be a problem until the utilities catch up with the technology.

To read more, visit



Investors move toward energy storage

Recently, investors like Bill Gates and Warren Buffett have been investing in energy storage companies. This is moving in the direction that Citi Bank has suggested will be the “next big solar boom,” since solar and other renewables are already in the mix and there is a need for balancing power supply with demand.

Last week, Gates and well-known cleantech investor Vinod Khosla last week bought into Varentec, a US company that is developing “smart” technology that will link storage devices and renewables, and lead to what Khosla describes as “cost-effective, intelligent, decentralized power grid solutions.”

Energy storage, as described by investment bank Citi in its new “Energy Darwinism” report, is likely to be the next solar boom. Citi says the main driver of this investment will not be just to make renewables cost competitive, because they already are in many markets – but for the need to balance supply and demand.

This, in turn, will make solar and other renewables even more attractive. It may even mean the end to the domination of centralised utilities, as storage will allow the industry to split into centralised backup (based around the old rate-of-return regulated utilities model) and much smaller “localised” utilities that harness distributed generation such as solar and storage.

Even though energy storage technology can be seen as a way to undercut the utilities, utilities are also working on storage technology to work in concert with the grid in order to keep it from being overloaded by the influx of solar, wind, and other renewable energy sources. It’s no secret that energy production is changing and the current grid is not prepared to handle these changes en masse. With renewables and energy storage, the grid - and the industry - will be able to handle the changes that come.

Read about storage technology investment at RenewEconomy.