Part of the BRE Trust

Steve Pester BRE NSC Conference 2014

What to test?

Technology - Where is NSC focussed?

– Materials & Cells

– Modules

– Systems

PV technologies (simplified summary)

Crystalline silicon trends

– Market currently dominated (~90%) by crystalline silicon (c-Si)

– More efficient materialse.g. Fraunhofer just announced n-type solar record 24% (cell eff.)

– Thinner cells

– Better ways to connect the cells (e.g. rear contacts, conductive films)

– Coatings (e.g. better anti-reflection, coloured cells)

Thin Film PV technologies

– What is the future for Thin Film?

– Leaders (by volume production & supply chain):o First Solar Cd Te (new record 20.4%)o Solar Frontier CIGSo 3Sun (Sharp, EGM, ST consortium) micro-cSi & aSi (triple junction)

– Others (e.g. Hanergy) in middle ground

– Innovators – e.g. in this seminar:o New materialso TF is starting to merge with the world of BIPVo Future is roll-to-roll, printable TF onto many types of substrate

What’s the most efficient technology?

Modules

– Drive for efficiency (at least 3 companies with 20% +)

– Warrantees – current standards & testing are lagging

– Cost reductions (now stabilising)

– Combining PV with other technologies

– Reducing degradation: o micro-crackso PIDo Tougher materials: backing sheets, encapsulants

PV-T

– Combines PV & Solar Thermal

– Not new tech, but a collection of new products is emerging

– Factors to take into account:– PV-ST time lags– Low grade heat– Potential for higher PV

efficiency in hot weather

Photo: Natural Technology Developments

Photo: Romag Ltd

Photo: Naked Energy

BIPV

Architectural requirements

– Durability

– Colours & textures

– Embodied energy

– Solar shading (increasingly)

Solar Decathlon 2010Photo: Ertex / Sunways

Photo: Ertex

Systems (Balance of)

– Key developments: inverters

– Increasingly sophisticated communications built-in

– Transformerless types becoming standard

– Efficiencies for string inverters ~ 98%

– Micro-inverters gaining market share

Micro-inverters and DC Optimisers– Advantages: Energy yield (esp. shading), safety, diagnostics

– Mounted outside, so subject harsher environmental conditions than string inverters

– High number of inverters per PV system(1 per module or per pair)

– Often in places with no easy access

– Therefore need (proven) very high reliability

– Many major manufacturers have recently launched products

Storage - batteries

– Products emerging now

– Not ‘off’grid’ storage, but smoothing demand peaks

– Typically 2 x PV rating (e.g. 7kWh for 3.5kWp)

Courtesy of SMA Solar Technology AG Courtesy of Solar ENLES Ltd

Li-on batteries• 70% DoD• 95% Eff.• 20 year life

Where to start?Long-term performance testing of modules & systems

Ground mounted PV installation testing

1) Side by side modules2) Whole system performance3) Orientation and inclination

The Site:

– Demonstration of best practice

– Biodiversity and land management

Performance testing

What will we achieve:

– Independent performance testing to give industry & users confidence

– Data to support due diligence

– Centre for manufacturers to showcase and verify their products

Who will benefit:

– Installers / designers – the best equipment to use

– Module Manufacturers

– Inverter Manufacturers

– End users

National Solar CentreTest Site

Test site initial layout sketch

System testing

Module testing

Site office / lab

I – V Testers

Raw Data

Also…

– Module Temperature

– Met data

– Very high quality Irradiance data

Example Outputs – to be published…

– kWh / kWp in real conditions, independent of inverters & BOS

– Effects on different module types & technologies:– Degradation– Temperature– Low levels of irradiance– Wind (cooling)– Wind (micro-cracking)

– Development of new fault diagnosis methods

We need…

– Manufacturers to submit their products

– Assisted by requests from installers & distributors

For more information contact:

Steve Pester

NSC

pesters@bre.co.uk

Mob: 07528 976224

Office: 01923 664 729