Bath conference part 2: Photovoltaics in the UK, European SSL projects and LED improvement targets

May 27, 2011
In part 2 of this Bath conference meeting report, Matthew Peach reports on UK support for photovoltaics, DC-powered buildings, LED improvement targets, SSL projects and market drivers.
Read Part 1: LED lighting design and solar-powered signboard trends.

Lee Richards, senior business support manager at Regen South West gave the conference an update on the Feed in Tariff (FiT), one year after its launch. The FiT offers a payment for every unit of renewable electricity generated (a generation tariff), as well as an additional payment for every unit of electricity that is exported to the grid (an export tariff). Regen SW, based in Exeter, UK, is a centre of sustainable-energy expertise established in 2003. Its mission is to speed up the region’s (and the nation’s) transition to a lower carbon economy. The UK’s targets are designed to reduce CO2 emissions by at least 34% on 1990 levels by 2020 and 80% by 2050. All new buildings must be “zero carbon” within a decade – dwellings from 2016, public sector from 2018 and commercial from 2019.

Richards acknowledged that the UK still has a long way to go in the area of generating renewable energy, where the PV sector could be influential. Currently, with about 2% of its energy derived from renewable sources, the UK is ranked 24th out of 26 European countries, only above Malta and Luxembourg. Considering the Feed in Tariff, which the Bath meeting seemed to regard with a degree of skepticism, Richards pointed out that its potential benefits were based on a planned 25-year lifetime and that it was too early to dismiss it.

On a more positive note, he said that the South West of England is “generally blessed by sunny weather” and is embracing PV-based electricity generation. During 2010 the South West installed almost 3000 power generation systems under the FiT scheme, second only to the 3300 of the South East. Another positive sign for PV is that it is now the dominant renewable technology: the number of PV installations in the past two years exceeds the combined total of all alternatives such as onshore wind, landfill or sewage gas plants and hydroelectric generation. On top of that PV installation would become a substantial employer with perhaps 40,000 new jobs in the region by 2020, Richards ventured.

Francesco Anselmo of Arup described the company’s Irradiation Mapping Tool, which is designed for solar irradiation mapping, with applications such as optimizing the placement of PV systems on building roofs or in optimal locations world-wide.

Based on validated lighting simulation this scalable software-based solution can simulate solar irradiation ranging from a single building to entire large cities. It offers automatic conversion from GIS/3D to simulation and depending on the model size, results can sometimes be derived in hours rather than weeks. Explaining why Solar Potential Mapping was an important growth area, Anselmo cited the UK Government’s Renewable Energy Strategy: “for which, at least 15% of overall energy consumption will have to come from renewable energy by 2020.”

Simon Daniel, CEO of Moixa technology, gave a presentation entitled “Smart Low Energy Future” which focused on buildings running on a lower voltage DC circuit, with more scope for locally generated electricity from renewables. With a track record in inventing and innovation – Daniel was behind the palm-top foldable keyboard some years ago – he was evangelical about reducing “grid peak” and energy waste.

Moixa (that’s axiom backwards, by the way) advocates DC power supplies, potentially supplied by PV generation, because of the energy advantages of removing AC-DC conversion losses, which could typically boost power delivery efficiency from 40% to at least 90%. Moixa’s SMILE approach is a combined Smart Meter Integrated with Low Energy – a low voltage solution that could be applied to domestic dwellings, SME offices and accommodation (although not factories, supermarkets or other buildings requiring heavy duty voltages).

European SSL programs

Gareth Jones from the Electronics Sensors Photonics KTN described several new SSL pilot projects that are to be funded under the EU Competitiveness and Innovation Framework Programme (CIP). The first theme entitled ICT for a low carbon economy and smart mobility will consist of two strands: Innovative lighting systems based on Solid State Lighting (SSL) with funding up to EUR 10 million; and ICT for Energy Efficiency in Public Buildings, worth EUR 7 million. More information is available at

Jones explained, “Consortia must comprise a minimum of four independent, legal entities from four different EU Member States although larger consortia are allowed. This is not a technology research call but an implementation and demonstration of state-of-the-art lighting solutions. The EU is seeking “Flagship Projects” that can be used to light the way for best practice in reducing the Union’s energy usage.”

Some of these projects’ key aims, which could interest LED and PV technology developers, include: addressing a range of interior and exterior lighting and illumination applications; supporting the refurbishment of existing buildings and ensuring compatibility with building management and existing installations. Primary focus should be on the commercial and/or non-residential sector, including large public, semipublic or private infrastructures.

LED improvement targets

Considering the market potential of LEDs, Duncan Allsopp, from Bath University’s Department of Electronic and Electrical Engineering, focused on the market pull for solid-state lighting. Sales will grow from $9 billion in 2011 to $14.9 billion by 2013, a CAGR of 24%. US market analyst Strategies Unlimited has recently predicted growth of 31%. Either way, this dramatic growth will come partly from demand for displays, backlighting for laptops or mobile phones, automotive and flat screen TVs. The other major driver of LED sales will be general lighting, which Allsopp said will grow from $600 million in 2009 to $4.5 billion by 2014 (compared with an estimated $15 billion market for light bulbs).

However, Allsopp noted that to meet this demand and the global market’s technical expectations, there will need to be significant improvements in LED performance and value for money. Quoting from the International Workshop on Nitrides (IWN, Tampa, Florida, 2010) Session on the LED-Internal Quantum Efficiency Roadmap, Allsopp said, “We need to have only one chip in a light bulb if its cost is to remain under $5… which means the IQE must be greater than 90%. Currently it is only about 75%.”

Allsopp added that there are several technology developments still needed to achieve this performance in the “ideal” $5 LED light bulb. These include: moving up to producing 4-inch and 6-inch diameter sapphire and Si wafers; achieving LED epitaxy growth on silicon substrates; designing thinner vertical chip designs for improved heat extraction; also improving both light extraction and material quality to boost IQE.”

He noted that Bath University’s was the first UK group to report a blue LED grown on a silicon substrate, although since then Cambridge’s “inter-layer” technology offers potential advantages over Bath approach. A simpler strategy for reducing dislocation density to improve IQE and LED growth on 4-inch Si wafers has been demonstrated, which is now an underpinning technology in EPSRC Programme Grant “Lighting the Future” – a collaboration between Cambridge, Bath, Manchester and Strathclyde.

Such research and development is likely to benefit both LED and PV performance, Allsopp concluded. Considering the prospects for higher efficiency SSL he noted the following: white LED efficacy is already > 200 lm/W; this performance level for LEDs grown on silicon low-cost substrate is “round the corner;” photonic crystals are enhancing EQE and provide beam shaping; and UK is building capability to be a key player in LED development.

Considering the prospects for higher efficiency InGaN PV, he said research will build on today’s InGaN-on-Si capability for low cost; there are opportunities to exploit the UK’s nanostructure and photonic crystal know-how for advanced solar concentrator PV; and that overall the InGaN-on-Si opportunity space is much greater than AlGaAs based PV.

Market drivers

Concluding the presentations, John Lincoln, director of SEPNET and organizer of the conference gave a detailed round-up of market drivers and likely performance of both LED and PV technologies. “The LED lighting take over is market driven, dictated by market economics,” he said. “Ultimately demand is limited, but it will be at least 2020 before there is market saturation. Aesthetic values mean that commoditization is possible at the LED chip but not at the system level.” One of the power benefits of the LED revolution would be that by 2020 widespread deployment of SSL could remove need for at least 500 full-sized power plants, Lincoln suggested.

Switching to photovoltaics, Lincoln argued that growth of PV is [currently] policy driven, dictated by political economics. “Demand could be unlimited but penetration is still very slow,” he said. By 2020 PV should provide 4-6% Europe’s electricity but only about ~1% of the global energy demand. He concluded, “There is a lot of volume growth to come but commoditization in the PV sector may limit growth in its market value.”