building integrated photovoltaics

Gavin D. J. Harper

Advances in Building Integrated Photovoltaic Technology:

With Implications for Wales

Regional Science Association International – British & Irish Section

43rd Annual Conference & Doctoral Colloquium,Aberystwyth, Wales

19th – 21st August 2014

[email protected]@gavindjharper

www.gavindjharper.comhttp://orcid.org/0000-0002-4691-6642

http://www.gavindjharper.com/

What is BIPV?

What is BIPV?

• The principle of BIPV is that PV modules are incorporated into the building envelope, substituting standard glass and other cladding materials.

• This has the potential to result in environmental savings through reduction of duplication of materials and shared functionality.

• It may also lead to cost savings over separate PV and building materials.

How is it integrated?

• Additional / superimposed• Added to the structure of the building with the primary

function of generating energy. Sometimes referred to as ‘building-applied PV (BAPV)

• Integrated• Components are replaced with PV generating materials that

serve both purposes

• Standalone• Solar PV array is discreet and separate eg parking shading

Where is it integrated?

•Façade• as part of the fabric or as an additional wall

•Rooftops• sloping or flat

•Glazing• integrated into the window requirement

Why BIPV?For Wales and the wider UK

BIPV – the global market• Navigant Research estimate the BIPV market to be worth $2.4 Billion

by 2017

• They expect the BIPV total capacity to quintuple in the same time

• Other sources (Accenture Plc) see the solar glass market alone being worth $4.2 Billion

• New markets continue to emerge and existing markets expanding. Middle East is placing more onus upon energy and Far East is following close behind

• As energy prices continue to rise and LEED and BREEAM become more mainstream (as well as Zero Carbon buildings), the appeal of BIPV will continue to grow. More mainstream BIPV will become more the norm and newer versions will help create signature buildings with their novel properties

Solar Roadmap Part II (page 17)

• While it is impossible to quantify the potential, building integrated PV (BIPV) would push the maximum capacity which can be deployed on roofs higher than that achievable with conventional PV panels alone.

• UK companies strongly represented in BIPV supply chain.

• Encouraging deployment on buildings in the UK should help to boost this emerging sector, which has enormous potential globally.”


• The UK has a vibrant Building Integrated PV (BIPV) sector, where the building fabric is made from solar PV materials.

• Technology is starting to provide us with the opportunity to install PV directly into the fabric of building glass and cladding material.

• These products will allow architects designing new buildings to maximise the energy generation of the fabric of the building.

• Costs of BIPV products have fallen at a similar rate to conventional modules, as they share the same solar cells.

• BIPV looks set to be an exciting area of growth.


• The market for BIPV products will provide opportunities for UK companies to develop and manufacture these products, which look to provide welcome export opportunities.

• BIPV also provides opportunities for next generation solar PV materials to develop (e.g. Polysolar, Oxford PV) and be brought to the market through the substantial building industry supply chain.

Wales: Competing with China?


• So far, the PV sector has been dominated by one technology (c-Si) and one product (the flat photovoltaic module).

• This has triggered significant cost reductions in manufacturing but not a major change in the way in which the PV technology can be deployed and used.

• That step change could be harnessed through innovation of new technologies and improving integration to UK grid and the development of associated technologies.

• That said, crystalline silicon (c-Si) is expected to remain the top PV technology in the coming years.


• The UK, together with more established countries’ PV markets such as Germany, Italy or the US, could see a differentiated opportunity to that of China and Asia-Pacific countries to develop innovative products (e.g. BIPV; thin film, and printable organic PV)

• The UK has well-established research and development activity on a range of photovoltaic technologies and applications, which are predominately focussed on next generation technologies.

• This may provide a comparative advantage.


• With BIPV coming through, as a specialist product more likely to be made in the UK, the jobs component could be substantial. Conventional PV systems have supply chains that are heavily dependent on imported product from outside the UK.

• The major contribution to the UK supply chain is through development, installation and maintenance.

• However, BIPV is currently more likely to be manufactured in UK through companies such as Romag, Kingspan and others.

• The high technology BIPV exemplified by the glass and façade products under development by Oxford PV and Polysolar is yet to be industrialised in the mainstream, and there is therefore a significant opportunity to encourage the growth of a strong UK industrial base.

PV in WalesRegional StrengthsCommercialisation& Manufacture

Centre for Solar Energy Research (CSER) @

OpTIC GlyndwrExpertise in thin-film,

Cadmium Telluride cells. Expertise in novel

MOCVD process & advanced optics.

G24i Manufacturer of dye sensitised solar cells.

GB Sol, PV Module manufacture.

Mounting Systems Manufacture.

Bangor UniversityDye sensitised cell research Sharp Silicon Module

Manufacture.

Pure Wafer (Reclaimed Silicon Wafers)

Ser Solar, Swansea UniversityPV Research

SPECIFIC, Swansea University

BIPVCoDyesol

IQE Multijuction PV (Concentrators)

PV Technology PathwaysDoes Wales Regional Strength Lie in Technological Diversity?

Photovoltaic Technology Options

Photovoltaics

1st Generation (Silicon)

MonocrystallineMono c-Si

PolycrystallinePoly c-Si

2nd Generation (Thin Film

Cadmium Telluride(CdTe)

Copper indium gallium

(di)selenide(CIGS)

Gallium Arsenide

3rd Generation (Organic & Excitonic)

Dye Sensitised Solar Cells (Grätzel Cells)

Comparing Photovoltaic Technologies• Thin film technologies compete on the basis of slightly less efficiency, but at a lower cost / kW

• Slightly less efficient per unit area. But better at capturing diffuse light – so potentially well suited to Welsh climate.

• Seen as a “substitute product” rarely the default choice.

• Crystalline silicon raw materials cost around 20%. For thin film, figure is 10%

• Crystalline silicon manufacturing technology is “commodified” whereas thin film manufacturing technology is proprietary.

• Efficiency of cell technologies directly impacts the cost of installed technologies, improvements in thin-film performance improve competitive position.

Thin Film / Excitonic Cells:Continuous Production?Crystalline Silicon Cells

“Batch” Production

Thin Film / Excitonic / DSC Cells

“Reel to Reel” Production

Image: G24i Power, DSC Cell ProductionImage: Sharp, Llay Wrexham, Silicon Cell Production

BIPV Design Considerations

Environmental Factors

• Insolation available• Climate & weather conditions

• High ambient temperature will reduce PV output• Local atmospherics such as cloud can impact• Pollution of any form can require cleaning

• Shading • Latitude (affecting optimal angle of PV panels)

Prof. Michael Wallis,Loughborough University

• “What we are saying that if you have the solar panels facing east-west then you can even out the power during the day. You may lose about 10 per cent of power if you go east-west but this addresses a problem that exists in Germany where because everything is facing south, you get this peak power at midday which is very difficult for the grid to cope with.

• “So in Germany they are advising people to go east-west so they are smoothing out the supply of power from all these solar panels. We get similar spikes of power too, although it wouldn’t make sense for people to change their solar panels if they have already been installed.

• “In total we have 2.8 Gigawatts of solar in the UK but Germany has approaching 20 Gigawatts. In Cornwall they can’t install any more solar panels because the grid can't handle it.”

BIPV Building Technologies

Bifacial PV Cells

• Cells encapsulated within glass, allowing light to be captured from both sides of the cell.

• This improves the efficiency of the cell.• Bifacial cells are prized for their aesthetic properties,

and are often used on canopies of shades.• They are useful architecturally as they allow some light

through to the area below, but also provide shading.• Bifacial cells offer a 25-80% energy power advantage1

over monofacial cells.

1.http://www.nrel.gov/technologytransfer/pdfs/igf20_gamma.pdf

Glass PV roof

• Using the glass PV panel itself to form the surface of the roof

Glass PV roofStriking when used in large areas

PV Skylights

Onyxsolar.com

Range of interesting ‘transparent’ thin film and organic technology trajectories.

PV Skylights cont.

• These can be installed as the skylight glass itself• An alternative is as an additional layer over the skylight

itself. This has the added bonus of ease of maintenance/repair and added insulation and cooling

• PV’s can either be:• Opaque, with clear glazing between adjacent cells allowing

light through.• Semi-transparent – DSC technologies and suchlike, which

allow some light through.• Newer technologies promise “see through” photovoltaics,

which attenuate the light, but allow for clear vision.

PV Canopy

gepower.com

PV Canopy

• One of the simplest installations Gaining popularity in warmer climes where shading of parking is often normal

• Visibly promotes charging of cars (if a charging point is fitted) and gives visitors an early indicator of company ethics

onyxsolar.com

Silicon Based Bifacial Cell

Dye Sensitised / Semi Transparent

PV Building Façade • Designed as a façade that generates energy

as well as performing as a façade• In this example, the manufacturer

(ruukki.com) provides a complete mounting system with studs, flashings, fasteners and electrical components. There are no visible cables and no wall penetration for the electrical install (easier to install and maintain)

PV Building Façade cont.

M9 ARCHITEKTEN Senfter + Lanzinger

Schott Solar

EWE Arena Oldenburg, colt 2009

PV Building Façade cont.

• As on the previous page, the façade can be used to provide shading to the occupants

• Shading can be constant, intermittent, fixed or movable, such as these examples of brise soleil

ertex-solar.at

• Retrofit can be used to improve the quality of the built environment.

• Many buildings with system built concrete / exposed finishes. Structurally sound, but exterior facades suffer from spalling.

• PV offers an attractive solution.

Price of façade materials (2011)

• Figures based on Odersun products and are Euro per m2

Brise Soleil• This is not a picture of a solar

installation.• These are plain old boring Brise

Soleil!

• BUT, illustrates an interesting point.

• City centre school in Nimes (France)

• Unintended consequences• Kids use as a climbing frame!

Spandrels and Parapets

• Spandrels are part of the exterior wall of a building (between the floor and the bottom edge of the window).

• Parapets are waist-high barriers at the edge of balconies, bridges, etc. Semitransparent PV modules integrated into spandrels/parapets can obscure the view of the inside, while allowing a free view of the outside.

• Structurally, they have the properties of laminated glass and can be used to create attractive accents on the façade (solarfassade.info)

Spandrels

syracuseglass.com archpaper.com

bisem-usa.com

Parapets / Balconys

kolumbus.fi

solarbuildingtech.com

Solar PV Rooftops

• The standard rooftop mounting available:• Parallel to roof

• Angled mount

imetco.com

asera.net

• C21 Solar slates.• Integrate with cost-effective concrete tile system• Low visual impact, aesthetically pleasing.

Solar Roof Slates

Images courtesy: Solar Century

Solar shingle

• Dow are marketing solar integrated shingles in the US under the name Powerhouse

Thin film roof PV• Flexible thin film modules

laminated to a roof membrane

• Lower efficiency than rigid, but more flexible in location

altenergymag.com

Direct mount PV

• By tweaking the design of regular PV panels, a direct mount that negates many mounting problems / wind load etc

lumetasolar.com

Direct mount PV

• If this mode of PV deployment were to be included in the design phase, savings could be made• Roof load would be lower reducing requirement

• Elimination of fixtures, removing cost and speeding build

• Less wind load issues as PV is flush to the roof

Direct mount PV• Including the PV as part of the sawtooth / northlight design. Alignment complements both aspects.

solarfassade.info

Who do you need to involve for a successful design?• BIPV manufacturer• Architect• Project manager• Structural engineer• Electrical engineer• Building shell designer• Façade / roof contractor

Opportunity for firms offering an approach that holistically integrates professions and trades.

What other functions could BIPV perform?

• Privacy screening• Solar protection• Architectural design element• Heating• Thermal insulation• Weather protection• Residual structural support• Burglary protection (toughened glass)• Sound protection and insulation

Conclusion

• There is a global future for BIPV• It is growing• It will remain focused upon the primary areas of façade, roof,

spandrels, parapets and balconies• Increasing energy efficiency and carbon reduction measures

will drive demand, as will improved PV efficiency AND innovation in the field

• Success will come from the integration of the BIPV into the construction process and the building itself, so a partnership with façade / roof manufacturers and/or those providing the mounting systems would seem optimal

Gavin [email protected]

http://www.cser.org.uk/

https://www.westproject.org.uk/

@gavindjharper

@CSER_PV

@LCRI_WEST

If you found any of this interesting…Please stay in touch

mailto:[email protected]

http://www.cser.org.uk/