The Cheap and Reliable Form of Solar Energy Storage for Homes That is Already on the Market

(www.theenergycollective.com)

How should we store solar electricity? How about as heat? A Swedish research team is storing solar energy in liquid form, but it is still a way off being commercially available. A competing technology using molten salt is already on the market and shortlisted for a major renewable energy prize. But there is already a much cheaper and already well-proven solution now being used in a brand new context.

The problem

Solar photovoltaic power it is increasingly being installed on buildings but a major challenge is that it is difficult to store so that it can be delivered when needed.

Storing solar electricity as heat is useful because the world uses more than twice as much energy in the form of heat as electricity. So for solar power to become ubiquitous, it needs to be delivered as heat more than as electricity – and round the clock.

Liquid solar energy
The solution of researchers at Chalmers University of Technology in Sweden is a chemical liquid that can tranport solar energy and then release it as heat whenever it is needed. The research, described in March’s edition of Energy & Environmental Science, describes how the team came up with a way of copying the means by which plants store solar energy – in molecules.

Transforming it into bonds between atoms in a liquid chemical makes it possible to transport it as well as store it.

“The technique means that that we can store the solar energy in chemical bonds and release the energy as heat whenever we need it,” says Professor Kasper Moth-Poulsen, who is leading the research team.

“Combining the chemical energy storage with water heating solar panels enables a conversion of more than 80 per cent of the incoming sunlight.”

The research project has come a long way since it began six years ago when the solar energy conversion efficiency was 0.01 per cent and the expensive element ruthenium played a major role in the compound.

Four years later, the system stores 1.1 per cent of the incoming sunlight as latent chemical energy – an improvement of a factor of 100, and ruthenium has been replaced by much cheaper carbon-based elements.

“We saw an opportunity to develop molecules that make the process much more efficient,” Moth-Poulsen says.

“At the same time, we are demonstrating a robust system that can sustain more than 140 energy storage and release cycles with negligible degradation.”

The process is based on the organic compound norbornadiene, which upon exposure to light converts into quadricyclane.

Hybrid panels

The rooftops of buildings can take advantage of the benefits of installing both solar water heating and photovoltaic modules.

Typical efficiencies for photovoltaic modules are now at least 20 per cent. Solar water heating systems have an efficiency of between 20-80 per cent, depending on the application, location and the required temperature.

Solar water heating systems make use of the full solar spectrum, whereas photovoltaics can only harvest a much more limited proportion.

Some companies have used this difference to design hybrid panels which contain both solar water heating and photovoltaic cells, particularly since the water can be used to stop the photovoltaic panels overheating, making them more efficient. The downside is the expense.

The Swedish researchers think that one of the potential applications for their technology, when it has become more efficient, will be a new generation of hybrid panels that utilise the heat, which can be released from the liquid storage medium.

They say that combining solar water heating with their system allows for efficient usage of low energy photons for solar water heating combined with storage of the high-energy photons in the form of chemical energy.

Their simulations have persuaded them that these hybrid panels could be up to 80 per cent efficient. In terms of energy density they are comparable to a lithium ion battery.

The team will continue work on the technology to evaluate the potential cost and bringing it down by finding a way to mass produce the constituent chemicals, and to find a non-toxic solvent.

More than a pinch of salt

A totally different technology is from Sunamp, a British company that has developed its technology by collaborating with the University of Edinburgh School of Chemistry. It guarantees low-cost materials, exceptional long life, recyclability, safety and high energy density.

The technology has been shortlisted for the 2017 Ashden UK Awards alongside the work of the Passivhaus Trust and the Carbon Co-op, a community benefit society that helps its members to retrofit their homes.

Sunamp’s form of storage uses a salt as a phase change material. This absorbs and releases thermal energy during the process of melting and solidifying respectively.

Similar technology is used on a large scale with concentrating solar thermal power stations, typically located in hot, arid deserts.

In this case it is used for storing energy from photovoltaic panels, waste process heat, or heat from heat pumps and micro CHP (combined heat and power) systems, in order to increase efficiency.

How does it work? In the case of storing solar electrical energy, an electrical element connected to the solar panels heats up the salt, thereby melting it.

The salt is kept liquid in a vacuum-insulated container. When heat is required, cold water is passed through the liquid in a heat exchanger, absorbing the heat and causing the salt to re-solidify. The heated water passes to the tap and the salt is ready to be charged again.

Sunamp’s batteries come in various sizes and can be used in series, meaning they can be used in anything from small homes to large hotels, for example. They take up much less space than a hot water tank, can store heat for longer and are more efficient.

The battery can store heat at half the weight of hot water in a tank storing the same amount of energy. Whether they are cost-effective depends upon the location and pattern of usage.

The easy solution

Tenants moving into a new passive solar mini-housing estate in Wales – Pentre Solar, Glanrhyd, near Cardigan – have roofs covered with grid-connected solar panels and zero energy bills.
Dr Glen Peters, CEO of Western Solar, which is behind the development, has an ambition for his company to supply 1,000 homes and to work with housing associations and local authorities to provide sustainable, solar-powered social housing.

The occupants of the estate have been given a Nissan Leaf electric car to use collectively, charged by the solar panels on the roofs. So that’s one form of storage.

But the homes’ heating is provided in a surprising manner, using the best of old technology with new: solar electricity and storage heaters.
Storage heaters contain thermally massive blocks which are heated up by an element. They then release that heat gradually over many subsequent hours.

This form of energy storage was introduced to British homes in the 1960s and ’70s on a special tariff called Economy 7. Since nuclear power stations could not be switched off unlike other forms of electricity generation, these tariffs allowed people to use nuclear electricity at night – at a lower rate when national demand was low – to charge the storage heaters.

The problem was that by the time the heat was needed, the following evening, they were often too cool and many people subsequently removed them and installed central heating instead.

Here, the idea is to let the storage heaters be heated up during the day by the solar panels on the roof, meaning that they are able to provide adequate heating through the evening and night provided that there has been average sunshine (50% of a June summer day) during the day.

This may not be the case in the depths of winter and so the homes are also grid-connected. They export surplus energy when there is some – after the electric car and storage heaters have been topped up – and purchase it when not enough has been generated.

“Storage heaters are incredibly cheap,” says Glen, “and a well proven technology. Whereas the storage we had to start with in our prototype house – lithium ion batteries – were designated a fire risk and we had them taken out. They are also much more expensive – a couple of hundred rather than thousands of pounds.”

This sounds like a solar energy storage solution that deserves far wider application. Good luck to the other technologies, but if I was looking for energy storage for a house, I know which I would choose.

India cancels plans for huge coal power stations as solar energy prices hit record low

(www.independent.co.uk)

India has cancelled plans to build nearly 14 gigawatts of coal-fired power stations – about the same as the total amount in the UK – with the price for solar electricity “free falling” to levels once considered impossible.

Analyst Tim Buckley said the shift away from the dirtiest fossil fuel and towards solar in India would have “profound” implications on global energy markets.

According to his article on the Institute for Energy Economics and Financial Analysis’s website, 13.7GW of planned coal power projects have been cancelled so far this month – in a stark indication of the pace of change.

In January last year, Finnish company Fortum agreed to generate electricity in Rajasthan with a record low tariff, or guaranteed price, of 4.34 rupees per kilowatt-hour (about 5p).

Mr Buckley, director of energy finance studies at the IEEFA, said that at the time analysts said this price was so low would never be repeated.

But, 16 months later, an auction for a 500-megawatt solar facility resulted in a tariff of just 2.44 rupees – compared to the wholesale price charged by a major coal-power utility of 3.2 rupees (about 31 per cent higher).

“For the first time solar is cheaper than coal in India and the implications this has for transforming global energy markets is profound,” Mr Buckley said.

“Measures taken by the Indian Government to improve energy efficiency coupled with ambitious renewable energy targets and the plummeting cost of solar has had an impact on existing as well as proposed coal fired power plants, rendering an increasing number as financially unviable.

“India’s solar tariffs have literally been free falling in recent months.”

He said about it has been accepted that some £6.9bn-worth of existing coal power plants at Mundra in Gujarat were “no longer viable because of the prohibitively high cost of imported coal relative to the long-term electricity supply contracts”.

This, Mr Buckley added, was a further indication of the “rise of stranded assets across the Indian power generation sector”.

Investors from all over the world were showing an interest in India’s burgeoning solar sector.

“The caliber of the global financial institutions who are bidding into India’s solar power infrastructure tenders is a strong endorsement of India’s leadership in this energy transformation and will have significant ripple effects into other transforming markets, as is already seen in the UAE, South Africa, Australia, Chile and Mexico,” Mr Buckley said.

These game-changing solar panels are cheap and can be printed

(www.mashable.com)

Despite places like Australia being bathed in sun, the cost of traditional silicon-based solar cells hasn’t inspired people to buy, buy, buy.

But what if you could make the technology cheaper and produce it at a higher scale? Some believe that printed solar is the way forward.

Leading the charge is Paul Dastoor from the University of Newcastle in Australia and his team of researchers, who are in the final stage of testing his printed solar solution.

The University of Newcastle is one of only three sites in the world testing printed solar, which uses electronic inks to conduct electricity. These can be printed at “massive scale” by machines, meaning they could be used for speedy rollout across large areas. Handy, especially in times of disaster.

“It’s completely different from a traditional solar cell. They tend to be large, heavy, encased in glass — tens of millimetres thick,” Dastoor explained. “We’re printing them on plastic film that’s less than 0.1 of a millimetre thick.”

Dastoor said the printed solar panels outperform solar photovoltaics panels in low light, and could prove to be more cost-efficient than fossil fuels.

“One of the advantages of these materials is they generate more electricity at low light levels than conventional PVs [photovoltaics], so that means I don’t really care where the roof is pointing, I just put it on there,” he said.

“And what we’ve shown through a series of economic models is that we can get these devices printing such that they’re readily comparable with PV devices. In fact, we expect in a short period of time the energy we generate will be cheaper than that generated via coal-based fire stations.”

Dastoor hopes the tiles will eventually be printed at less than A$10 (US$7.42) per square metre, considerably less than Tesla’s PV Solar Roof at A$315 (US$235). But before you rush out with your money in hand, the tiles’ performance and durability is still being tested.

“We’ve put in the first 100 square metres of printed solar cells up on roofs, and now we’re testing that durability in real weather conditions,” he said.

These printed solar panels are primarily made out of “extraordinarily robust” PET, the same material used for Coke bottles. Importantly, they’re recyclable. “All you do is melt it up and reform it,” he said.

The printed solar panels will be demonstrated in Melbourne next week at a printing convention called Pacprint, the first public display of the technology, then Dastoor will work with a number of industrial partners to make it reality.

Soon enough, you’ll have a cheaper choice when it comes to putting solar panels on your roof.

These “Printed” Solar Panels Were Made for Energy-Starved Regions

(www.inverse.com)

On Monday, a team of researchers in Australia unrolled a field of the first solar panels printed using a standard printer, solar ink, and thin, laminated plastic. And we mean literally unrolled, these solar panels are flexible enough to be rolled into a tube.

The panels are developed by Paul Dastoor and his team at the University of Newcastle, who have also created the solar ink and printing method over the last five years. The demonstration of the rollable solar panels covers an area of about 1,000 square feet, which Dastoor says is one of the largest solar tech demonstrations in the world in the announcement. Although the panels are not yet commercially available, this is one of the final tests before the rollable panels are released. And the $1 per square foot cost makes up for the fact they they’re not as pretty as a Tesla solar roof, particularly for the military.

To make the panels, Dastoor’s team puts a water-based electric ink into a printer cartridge and prints out the panels onto thin sheets of plastic. The solar ink is very sensitive and uses semiconducting molecules within the ink to catch energy from the sun and transfer it through the cell to a battery. Dastoor says he expects a commercial printer to be able to make kilometers worth of printed panels in a single day.

The exact rate of capture of solar power of the printed cells hasn’t been announced, but solar paint by Dastoor’s team converts about three percent of solar energy into power. Conventional solar panels can convert about 20 percent.

“This installation brings us closer than we have ever been to making this technology a reality. It will help to determine the lifespan of the material and provide half-hourly feedback on the performance of the system,” Dastoor says in the press announcement.

Despite the fact that it’s likely to produce less electricity than a more expensive Tesla solar tile, the panels have significant applications in military bases and disaster relief. The panels can be air-dropped into locations without fear of damage and are so light they have to be stuck down with velcro so they don’t blow away. With the ease of transport and low cost, they can easily bring electricity into areas that are cut off from infrastructure.

Solar Energy Brings A Ray Of Hope To Salt Farmers In Gujarat

(www.huffingtonpost.com)

A vast majority of India’s salt comes from Gujarat’s Little Rann of Kutch desert. Here, about 43,000 salt farmers, mostly women, work in brutal heat to produce salt from briny tidal water. It is hard work for little pay. Most of these salt farmers barely earn enough to support their families. But a new effort to bring solar energy to the salt flats is helping lift these rural women and their families out of poverty and into India’s clean energy future.

Salt farming is the only source of income for the local Agaria community, where children start typically working on the salt farm at age 10 and have little education. During the dry season, salt farmers pump briny groundwater out over the salt flats, and coax out the salt using rakes and rollers over the next few months as the water evaporates. The pumps are typically diesel-powered, meaning most salt farmers have to set aside 40. The yearly fuel expenses keep these women and their families in poverty.

The Agarias use the power of the sun to help dry the salt— but today, they can also use it to operate their pumps, avoiding the expense and pollution of diesel. Over the past three years, the Natural Resources Defense Council (NRDC), working closely with India’s Self Employed Women’s Association (SEWA) and other partners, has helped design a program to bring more than 500 solar-powered water pumps to salt farming families in the Rann of Kutch. The pumps have proven to be more efficient and reliable than diesel pumps, and save time and money for the hard-working farmers.

I met one of these families recently when I visited India, a multi-generational crew who all worked together in the salt marsh. Thanks to a system set up by NRDC and SEWA experts, they were able to obtain a solar pump through a low-cost loan a few years ago. The pump has been so successful they’ve already paid back their loan and want to buy one more. I asked the matriarch what she was doing with all the money they were saving and she laughed, gesturing to her grandchildren. “It’s all for them,” she told me, “what else?”

NRDC-SEWA research showed that salt farmers who switched from diesel to solar-powered pumps saw their savings increase more than 150. Today, as prices for pumps have fallen substantially and the price of diesel has increased, farmers who make the switch could save even more. The new pumps allow families like the one I met to have more economic independence, to do things like send children to school.

The solar pumps also run cleaner than diesel pumps. Diesel exhaust contains fine particles which can enter the lungs and bloodstream, creating respiratory problems, heart disease, and even premature death. Other chemical components in diesel exhaust are known carcinogens. Even in India’s rural areas, fine particle pollution can be four to five times higher than national air quality standards.

Climate pollution from diesel is a serious concern as well. Millions of Indians are vulnerable to the more frequent and intense heat waves, flooding and drought caused by climate change. An analysis by NRDC and SEWA estimates that replacing diesel water pumps in the Rann of Kutch with solar and hybrid solar/diesel water pumps can potentially avoid as much as 115,000 tonnes of carbon dioxide (CO2) emissions per year. That is the equivalent of taking more than 24,000 cars off the road.

NRDC and SEWA’s work has allowed salt farmers to demonstrate a solid track record of paying back their loans, which should open the door for commercial banks to make more solar loans available to thousands of salt farmers who still use diesel pumps. But the story doesn’t end in the deserts of Gujarat. The financing models and other lessons learned from this project can be applied to communities across India. By developing new methods of clean energy financing, India can greatly expand clean energy access and build a clean energy economy that will benefit millions of people.

India’s ‘Fruit of the Gods’ Could Make Solar Cells Cheaper and More Efficient

(www.ecowatch.com)

Scientists at the Institute of Technology (IIT)-Roorkee in India are investigating if commonly available fruits and fruit juices could help make solar cells cheaper and more efficient.

The researchers were able to fabricate Dye Sensitized Solar Cells (DSSC) by extracting the anthocyanins—or the plant pigments—from plums, black currants, berries and a black plum called jamun as inexpensive sensitizers.

“We extracted the pigment using ethanol and found that anthocyanin was a great absorber of sunlight,” lead researcher Soumitra Satapathi, assistant professor at IIT-Roorkee, told Quartz India.

Dye Sensitized Solar Cells, also known as Graztel Cells, are thin film solar cells comprised of a porous layer of titanium dioxide coated photoanode, a layer of dye molecules that absorbs sunlight, an electrolyte for regenerating the dye and a cathode, PTI reports.

While Dye Sensitized Solar Cells are not yet as efficient as conventional silicon-based solar cells, the emerging technology has been touted as a low-cost alternative since titanium dioxide is cheap and widely available. These cells could have a lot of potential in India, since the country is rapidly expanding its solar capacity and has pledged to have an energy mix of 40 percent renewable sources by 2030.

Satapathi explained to PTI that the the dark color of jamun and abundance of jamun trees on the IIT campus “clicked the idea that it might be useful as a dye in the typical Dye Sensitized Solar Cells.” (Fun fact, the sweet and juicy jamun fruit is indigenous to South Asia and is nicknamed in India as “the fruit of the Gods.”)

According to the study, published in the Journal of Photovoltaics, the anthocyanin extracts of blackcurrant and mixed berry juice had the highest power conversion efficiencies of 0.55 percent and 0.53 percent.

“Widespread availability of these fruits and juices, high concentration of anthocyanins in them, and ease of extraction of anthocyanin dyes from these commonly available fruits render them novel and inexpensive candidates for solar cell fabrication,” the study’s authors stated.

Furthermore, “anthocyanins are naturally occurring biodegradable and nontoxic molecules that are extracted using techniques that involve negligible low cost to the environment and therefore can provide ecofriendly alternatives to synthetic dyes for [Dye Sensitized Solar Cells] production.”

San Francisco’s Rapid Transit Likely Nation’s First to Run on 100% Renewables

(www.ecowatch.com)

Taking public transportation already makes a big difference in reducing your carbon footprint. Now, the San Francisco Bay Area’s rapid transit system is reducing its own carbon footprint by committing to 100 percent renewable energy.

The Bay Area Rapid Transit (or BART) is likely the first electrified public transit system to make this ambitious goal. The BART is used by about 434,000 commuters each workday.

Earlier this month, BART’s board of directors approved a new wholesale electric portfolio policy enabling the transportation agency to buy more power directly from renewable sources, including solar, wind and small hydroelectric facilities.

Transit agencies usually buy power from their local provider but under a 2015 California law, BART has the freedom to choose its own power sources. The aim is to increase its use of renewable energy to 50 percent by 2025, and 100 percent by 2045.

BART said its current portfolio is already 78 percent cleaner in terms of carbon content compared with a typical large customer of electricity utility PG&E, but its new “aggressive guidelines” makes it even greener.

BART is one of the largest power users in Northern California, consuming roughly 400,000 megawatt-hours annually. That’s slightly more than the city of Alameda, which has an estimated population of 80,000.

“Every day, BART takes cars off the road and helps drive down our greenhouse gas emissions,” said BART Director Nick Josefowitz in a statement.

“But especially now, BART and the Bay Area must shoulder even more responsibility to combat climate change. Even though BART is not required to comply with the state’s renewable energy standards, we have committed to purchasing 100 percent renewable electricity and taking a leadership role in decarbonizing our transportation sector.”

BART’s clean energy goals puts it on track to exceed California’s Renewable Portfolio Standard that mandates 50 percent renewables by 2030.

“Given that renewable energy supply costs have fallen significantly in recent years and have approached cost parity with other supply sources, BART has an opportunity to set clean energy goals that are both ambitious and realistic,” BART’s Sustainability Manager Holly Gordon said.

Floating solar panels possible wave of future

(www.fox5sandiego.com)

A plan to use floating solar panels at the Olivenhain Reservoir has been moving forward.

The first solar array of its kind has been billed as a triple technology threat by producing energy saving water and cutting costs all at the same time.

“I think the technology has matured. There are more companies in the US. doing this,” said Kelly Rodgers, San Diego County Water Authority energy program manager. “It was a great opportunity for the Water Authority to reduce our costs.”

The plan is to cover 10 percent of the Olivenhain Reservoir with solar panels that would generate roughly 6 megawatts of power annually, which translates to powering 1,500 houses a year.

According to officials, no tax dollars are needed, so rate payers would not be burdened by the floating solar panels. SCWA officials say they believe the plan is a “win-win.”

“It could have benefits by reducing evaporation, water our precious resource as well as potentially reducing water quality issues such as algae bloom,” said Rodgers.

The idea still has hurdles to jump through, like an environmental report and getting the neighbors to climb on board. So far most locals seem to be supporting the idea.

“It’s progressing for sure, and it’s the coolest thing. They’ve been talking about having it in the desert, but panels on the water is just like an abstract thing,” said James Hagger, a local resident.

If the floating solar plan clears all obstacles it might come on line as soon as 2018.

Massive Hail Storm Takes On Over 3,000 Solar Panels And Loses

(www.denver.cbslocal.com)

Monday’s severe hail storm destroyed a countless number of roofs, cars and windows as it cut a large swath across the Denver metro area.

One place hit hard was the National Renewable Energy Lab in Golden which is home to over 3,000 solar panels.

“Many employees had damage to their vehicles. There was concern about how all of the solar on our campus fared,” said NREL’s David Glickson.

Hailstones up to 2.75 inches in diameter were reported in the area.

Amazingly, out of 3,168 solar panels on NREL’s Research Support Facility, only one sustained damage. It’s a true testament to the resilience of renewable energy.

“As the storm hit performance dropped to night-like levels but quickly recovered once the storm passed,” said Glickson.

Power plants could cut a third of their emissions by using solar energy

(www.phys.org)

Led by VTT Technical Research Centre of Finland, the COMBO-CFB project has developed a new innovative concept to increase solar energy production in the energy system. According to this research, the concept can reduce fuel consumption and emissions stressing the climate by more than 33 per cent. The concept is based on the combination of concentrated solar power (CSP) technology and a traditional power plant process into a hybrid plant which produces electricity on the basis of consumption.

If part of the fuel used by a power plant is replaced with solar energy, power plant emissions will be reduced. This is also required in order to meet the emission reduction targets. The COMBO-CFB project − Combination of concentrated solar power (CSP) with circulating fluidized bed (CFB) power plants − examined how various types of hybrid plant solutions can produce power flexibly according to demand, without the need for energy storage. The project analysed and compared different hybrid plant concepts.

The concept in which steam generated by a solar field was fed directly into the power plant’s high-pressure turbine brought a reduction in emissions and fuel consumption which, at best, exceeded 33 per cent. Furthermore, a reasonable dimensioning of the hybrid plant and process optimisation can bring efficiency benefits as compared to the use of separate power production methods. In the aforementioned case, the plant’s net efficiency improved by 0.8 per cent. In addition to positive climate effects, good hybrid plant planning can also bring financial benefits since part of the power plant components are shared by two power production methods.

The COMBO-CFB project applied the Finnish project partners’ high-level expertise in boiler technology. In a hybrid power plant, solar energy production which varies with weather is balanced by using a steam boiler. The production concepts developed through this project will expand the application possibilities of the CSP technology.

The dynamic nature of a hybrid process poses challenges to production system design and operation, particularly when the share of solar energy in power production is high. The COMBO-CFB project examined these challenges by using the Apros software designed for dynamic modelling, as well as through combustion tests conducted by using VTT’s pilot equipment in Jyväskylä, Finland. This dynamic assessment at the plant design stage proved extremely important since it enables designers to take account of factors such as those affecting the lifetime of components.

The concept in which part of the feedwater preheating is substituted with solar steam can be implemented in the present power plants, but compared to the aforementioned high-pressure turbine concept, the benefits are considerably smaller due to the smaller share of solar energy. The functioning of a hybrid process can be generally improved by attaching to it an advanced predictive control system and a short-term solar irradiance forecast. In the COMBO-CFB project, Vaisala developed a cloud camera which identifies cloud movements in the sky in order to increase the accuracy of the solar irradiance forecast for the area.

The implementation of the CSP technology in power production is reasonable in areas with an abundance of sunlight. In Europe, this means, for example, the countries bordering the Mediterranean. However, this technology can also be implemented in areas with less sunlight by using hybrid power plants in which solar power is supported by another form of energy. For the time being, Finland is not applying this technology, whereas Denmark is already using a CSP-bio hybrid plant to produce district heating.

Finland has unique, internationally competitive expertise that it can provide to the hybrid power plant export markets. The COMBO-CFB project’s partner network can support the commercialisation of such hybrid plants. The Finnish project partners’ areas of expertise include boiler and control technology, process modelling and weather measurement and forecasting.