solar power

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Every window… Every screen, a power source?

The background

In 2010 a team of engineers in Massachusetts Institute of Technology’s (MIT) Organic and Nanostructured Electronics laboratory began work on a ground breaking technology that allowed any sheet of glass to become a transparent solar cell.  Richard Lunt, then an MIT post doctorate, suggested that it was possible to create a solar cell that would absorb all the energy from the sun except that part which allows us to see.

How can you create a solar cell that you can see through?

The theory went that as follows; all light is made up of electromagnetic radiation which spans a spectrum of wavelengths.  Each of these contain energy that can be collected by the solar cell, but as good as the human eye is, it can only detect a fraction of the spectrum – visible light.  By developing the cell to only allow that visible light through, the ultraviolet and infrared would be captured and we’d never notice!

Visible light

But it didn’t really work did it?

Well, yes it did.  But unfortunately a major stumbling block was the energy conversion rate, which was very low – around 2% – but at the time the team’s cells transmitted more than 70% of visible light, which is very similar to the tinted windows currently used in many tall buildings.

Is it scalable and can the efficiency rise?

Fast forward to 2015 and the latest transparent glass sheet cells are growing in size.  A detailed theoretical study back in 2013 showed that efficiency should rise to 12% once the glass is in production, a rating similar to current commercial solar panels and during a demonstration two years ago the solar cells powered the LCD display on a small alarm clock.

Already the transmitted light has improved to over 90%, and better production methods have started to increase the efficiencies.

One of the biggest barriers however is longevity.  In a commercial application such as windows, the cells would need to perform for many decades.  The team at Ubiquitous Energy – the company created by the researchers at MIT – believe that in time, with many companies striving to meet the same goals, this issue will be solved and the solar cells will become commercially viable.

Where can I find out more?

Ubiquitous Energy have recently won the 2015 Display Week innovation award for their work into Transparent Photovoltaic Energy products and debuted the Clearview Power™ technology at Display Week 2015, the Society for Information Display International exhibition in San Jose.  Their website can be found here http://ubiquitous.energy/.

If you’re interested in the mechanics behind the technology, MIT’s website has a newsreel dated in 2013 which gives some very technical information. http://mitei.mit.edu/news/transparent-solar-cells

So what does this mean for me?

In time to come, the windows in your home may be able to create enough electricity to run your television, or your fridge.  Offices might be able to harness the power of the sun, enhancing building efficiency in our cities without unsightly solar panels and reducing our reliance on traditional methods of energy production.  Even your smartphone may benefit from solar cells – running out of battery in the middle of that important phone call or web browsing session may just become a thing of the past.

Earthship Brighton

On Thursday 2 July I drove to Stanmer Park just outside Brighton to visit the Brighton Earthship, arranged by the Sustainable Business Network on behalf of the University of Brighton’s Green Growth Platform.

Along with 10 other guests we met our lovely guide Jane Glenzinsko at 9.30 and trekked somewhat breathlessly up a track for 10 minutes to the site of the Earthship.

After a tour of the inside and outside of the construction Jane provided a detailed history and explanation of the project.

Earthships have evolved over the last thirty years from the pioneering work of Michael Reynolds, Earthship Biotecture and the residents of the 3 Earthship communities in Taos, New Mexico.

Earthships are ‘green’ buildings, constructed using waste car tyres and other recycled materials. They use the planets natural systems to provide all utilities – using the sun’s energy and rain to provide heat, power and water. They are buildings that heat and cool themselves, harvest their own water and use plants to treat their sewage.

The basic building block of the earthship walls are used car tyres. The UK throws away over 48 million of these annually and they are now banned from landfill. The preparation method is quite simple. Line the tyre with cardboard, fill it with earth and ram the earth down with a sledge hammer until the tyre is fully inflated.

All tyres are worked on in-situ, being pounded a course at a time and together with a 1m of rammed earth behind them they create thick walls of thermal mass. Finally the tyres are rendered over with mud, adobe or cement.

Another waste material used in the earthship are glass bottles, which are cut up and taped together to form glass bricks. The glass bricks are then laid in courses in cement to form a wall, which are finally rendered over and look like stained glass. The hall floor is made from reclaimed granite and marble off-cuts from a local monumental mason in Brighton.

The sun provides heating by using a dynamic combination of solar gain, thermal mass and super insulation. The walls act as a storage heater. Behind the tyres and earth is the thermal wrap or insulation blanket that separates the mass from the earth that is sheltering the building.

The structure is orientated towards the south, which maximizes the opportunity for solar gain. The front glass windows are angled to allow for maximum sunlight during the winter months when it is most needed, but reflects it during the summer months when the sun is higher in the sky. The heat from the sun is stored in the thick walls and is slowly released during the night and colder days and seasons – the same as the heat you can feel emanating from a stone wall in summer after a sunny day. The size of the thermal store enables heat to be stored inter-seasonally over a long time.

The earthship also generates 20kw from 4 renewable technologies – photo-voltaic panels and a wind turbine for electricity; and solar thermal panels and a wood pellet stove for water heating. The earthship is zero carbon and there are no utility bills.

Earthship Brighton harvests all the water it needs from the sky. All rain water is collected, used and treated on site, saving on infrastructure investment and not depleting the overstretched ground water in the drought stricken south-east of England. The area of the roof coupled with the average annual rainfall for Stanmer Park means that it can harvest around fifty thousand litres (50m3) of water per year.

The rainwater flows from the roof through two filters, including a vortex filter, into four underground water tanks. There is enough room to store twenty thousand litres of water, which is enough to supply the earthship for two to three months.

This was a thought provoking and entertaining tour and presentation – a visit is thoroughly recommended.

Fracking in Balcombe

Living in close proximity to the village of Balcombe, West Sussex, our senior account manager David Elliot-Rose is well aware of the fracking issues over the past couple of years – so with all the previous negative publicity it is pleasing to see some positive renewable energy news.

Some of the villagers in Balcombe in Sussex have scaled up their plans for a solar farm that has already begun generating electricity. If successful the community-owned farm could generate enough power for themselves but also the neighbouring village of West Hoathly.
Renewable energy cooperative REPOWERBalcombe was established by residents as a positive way to unite with renewable, locally-owned power, after the controversy over oil drilling by fracking firm Cuadrilla in the 2013 summer. After a successful share offer earlier this year, solar rigs are soon to be installed on the roofs of two local schools. This follows a pilot in late 2014, where 69 panels were installed on a cowshed at a nearby farm.

The investment for the solar installations at Grange Farm and the primary schools came entirely from local people.

Solar Impulse Round the World flight

Swiss pilots Betrand Piccard and Andre Borschberg are hoping to write themselves into the history books with the first solar powered, all electric flight around the world which took off from Abu Dhabi this week.

Over the next five months the zero emissions aircraft will fly through Oman, India and China, where it will then cross the Pacific ocean and call in at Hawaii and the USA before crossing the Atlantic into Europe or North Africa before finally landing back in Abu Dhabi.

Solar Impulse weighs just 2,300Kg and has a 72 metre wingspan, some 3.5 metres longer than the latest Boeing 747-8I.  It has a speed range of 20kts (22mph) to 77kts (47mph) and is made of very light carbon fibre.  Whilst it has the potential to fly non-stop it is limited by human endurance abilities, and can carry a single pilot and no passengers.  As an electrically powered aircraft, using only energy stored from its solar panels it has zero emissions – 0g of CO2 per Kilometre.

As a comparison, a 747-8I has a maximum take-off weight of 448,000Kg and has a cruising speed of Mach 0.855 (570mph at 35,000ft).  It has a range of 9,210 miles with 467 passengers and baggage.  The B747-8 is one of the greenest aircraft manufactured today and produces approximately 35Kg of CO2 per Kilometre*.

On this epic trip round the world, the pilots are only able to take naps lasting 20 minutes every two to four hours, and are using specially developed light emitting glasses to help them sleep.  The lights are programmed to flash in very precise patterns to send the pilot into a deep sleep very quickly, and bring them out very quickly too.  Another difficulty is the size of the aircraft.  In order to save weight the pilots are restricted to their chair, which acts as a seat, bed and toilet throughout the flights, which will last up to 5 or 6 days and nights in a row on the “long-haul” legs of the trip.  In order to save weight the cockpit is unpressurised and unheated, although the cockpit structure does employ high density thermal insulation.

At the time of writing the aircraft had recently landed in Ahmedabad having covered the 1,465Km from Oman in 16 hours.

It’s safe to say that Solar Impulse is uncomfortable, impractical and slow – but with huge potential for increasing global awareness of solar energy and showcasing the cutting edge technology involved in this 12 year-in-the-making adventure, the Solar-Impulse team will be hoping their pioneering flight is a success.

 

Keep up to date with the mission progress at www.solarimpulse.com

 

*Based on 100% load.  And if you think 75g per passenger kilometre is a lot, the greenest 1.4L TSI VWs produce upwards of 85g per kilometre.

Solar Insurance Offering Reduces Potential Risks of Underperformance in Solar Power

New insurance products are always being developed to react to potential risks faced by owners and developers.  For example, a reduction in yield can have a significant impact on a solar installation’s financial performance which may not be as a result of any damage suffered.   As a leading provider of insurance products for the renewable energy sector,  Nsure Renewables help companies to better manage the impact a reduction in yield can have on business.

Nsure’s Solar Protect insurance product provides cover for reduction in expected yield due to an installation’s under performance, without the need for proof of negligence or defectiveness to trigger coverage for revenue losses, providing cover for reductions in yield when production falls as a result of, for example, inclement weather, temporary sky obstructions, smoke, or volcanic ash clouds.

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Nsure Client’s solar park battery storage

In a first for the UK energy efficiency market, a solar park owner, energy supplier and energy efficiency solutions company have joined forces to commission one of the country’s first commercial scale battery storage units.

The collaborative project undertaken by Nsure client Farm Power Apollo, in conjunction with Opus Energy and Anesco, has seen a 250kWh battery storage unit connected to Farm Power Apollo’s Slepe Farm solar park in Dorset. The unit will be used to store energy generated by the 498.4 kWp ground-mounted solar installation and released when it is more needed by the National Grid.

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