9 June 2015
Prospects Now Bright for Solar Solutions say Ecobuild Exhibitors
Billed as the world's largest forum for sustainable design and the built environment, this year's Ecobuild saw solar solutions take centre stage, although the sector still faces a range of political, technical and consumer challenges.
According to its organisers, Ecobuild 2015 was the world's largest forum for sustainable design, construction and the built environment. Alongside the admittedly impressive exhibition, a conference programme, spread across two arenas and seven seminar streams, offered formal continuing professional development opportunities. Additional workshops and seminars were also held within the exhibitors' spaces, focussing on a variety of products and case studies.
Perhaps unsurprisingly, there was a strong political presence at the event. Political involvement is, of course, important to the sector. Although many eco-friendly practices give immediate financial benefit, others may increase costs and damage competitiveness. Unless supported by public subsidy or enforced by legal requirement, many will simply not be put into practice.
Progress, however, is apparently being made on the basis of the 'carrot-and-stick' approach. This sees the construction industry and building owners cast as the reluctant mule, while being tempted forward with a carrot composed of grants, cash back deals and other incentives. At the same time, many are being whipped by a stick composed of building regulations and legal directives. As in real life, carrots have strings attached and can be difficult to obtain, while sticks may be effective, but are inevitably resented.
In a keynote speech, British Energy Secretary, Ed Davey emphasised the need for energy efficiency and the importance of tackling fuel poverty. In addition to tighter building controls for new housing, he said there was a pressing need to upgrade the existing housing stock by retrofitting. Announcing a further £70 million of funding under the Green Deal initiative, he suggested that his party would seek to upgrade around four million homes by 2020 and 10 million by 2025.
An interesting new idea on offer was 'Boilers on prescription'. Where a medical practitioner believes that a patient's health is being damaged by a poorly heated home, it would be possible to prescribe a heating upgrade on medical grounds. As a single emergency hospital admission costs about twice as much as a new boiler, this would potentially be a self-funding arrangement. This, though, relies on there being financial co-operation between different government departments.
The call for a much greater push on retrofitting was also taken up by industry leaders, including Mike Putnam, Chief Executive, of London-based Skanska UK, who is also the co-chair of the Green Construction Board. During one panel session, he called for a push on retrofitting and more help from outside of the industry when it comes to communicating the benefits of the practice to the public.
Inevitably, insulation and solar thermal technology seems likely to get a boost from any emphasis on retrofitting. Kingspan, headquartered in Ireland, has developed efficient, yet thin, insulation systems suitable for use on the solid walls and awkward roof spaces typical of the UK's large stock of older housing.
Solar thermal technology, though, has not enjoyed the success of solar photovoltaic panels (solar PV), but, according to Andrew Pearson, Director of UK-based Mint Renewables, it is the cheapest way to reduce carbon emissions. Requiring only four to six square metres of roof or wall space for the average house, he said solar thermal technology can provide 60% of the annual hot water requirement, (95% in the warmest eight months). The system can also be integrated with air-source and ground-source heat pumps for a total heating solution.
In a similar vein, SolarCool, based in Florida, had on show a patented system for integrating solar heat technology with climate control in order to provide energy savings for both heating and air conditioning. Chris Micallef, its UK Technical Director, said that the system runs refrigerant liquid through the panels, which becomes part of the air-conditioning circuit.
Overall, there was also considerable interest in biomass boilers, which use wood or other plant material fuel source in pellet form. Many examples were on show this year. These included examples from such companies as Innasol, based in Essex and Windhager UK, headquartered in Gloucestershire. The biomass fuel pellets required for these units can be sourced from a number of material feedstocks. The European Bioenergy Research Institute, based in Birmingham, also had on offer its own Pyroformer system, which is said to extend the biomass possibilities, using heat and chemical treatments to produce oil and gas fuel.
Moving outdoors and the aesthetic appearance of all types of solar panels is an issue for consumers. Tony Henshaw, representing Viridian Solar, a manufacturer based in Cambridgeshire, said his company's range of both solar heat and solar PV units, with matching Dormer windows, were designed to blend into the roofline and become far less conspicuous.
The market for solar PV panels – most of which are made in China – is strongly affected by government policy. At a well-attended solar solutions workshop, Jonathan Selwyn, Managing Director of the UK's Lark Energy, described the country's commercial landscape as a "solarcoaster", full of ups and downs and unforeseen twists.
In the UK, solar electricity generation is funded by selling it to the National Grid under the Renewable Obligation (RO) or the Feed-in Tariff (FIT) scheme. Alternatively, the electricity can be sold to a user directly under a Power Purchase Agreement (PPA) or used by the owner directly. As well as changes to the qualifying rules for ROs and reducing levels for both ROs and FITs, larger schemes are not always allowed to link to the National Grid, usually due to technical problems. This situation is constantly changing, making planning difficult.
Selwyn saw the provision of smaller schemes, situated on commercial rooftops, as an underused, more stable and growing market sector. Owners of commercial buildings, he said, could install their own schemes, either alone or with partners, and then use or purchase the electricity themselves.
Commercial premises' roofs could even be rented out to energy providers, who would make the necessary investment and enter into PPA, or sell directly to the National Grid. The necessary pre-accreditation, planning permission, operation and maintenance would be carried out by the energy company, thereby removing a significant barrier to adoption by the building operator.
The variable output from solar PV has led to the market being tied to the National Grid and subject to reducing returns from FITs and ROs. The desire to use the power generated on-site has led to an increasing interest in the use of storage batteries. As a result, several companies were offering storage systems for solar PV, based on lithium or lead batteries.
Tim Jones, Senior Account Manager for the UK's Battery Megastore, said that, although lead AGM batteries had been used for many years and were still a relatively cheap solution, their weight and temperature sensitivity had led to lithium batteries being the favoured option, despite their higher cost. The development of thin plate pure lead (TPPL) batteries – with up to three times the cycle life of AGM batteries and a very high charge/discharge rate – represents a low-cost alternative with similar performance.
All solar PV systems require inverters and power management systems, converting DC to AC, in order to integrate with mains electricity. With this in mind, Israel's Solar Edge showcased a system that overcomes key problem with any PV array – the tendency to be limited in efficiency by its weakest panel. This may be due to manufacturing tolerances, soiling, shading, snow or other causes. It also makes it difficult to combine panels with different orientations.
Using the Solar Edge intelligent, management system, more of the roof space can be used efficiently. In addition, unlike a conventional system, which remains live whenever the sun is shining, the system is able to shut down the array and therefore protect installers, maintenance personnel, and even firefighters, should this be necessary.
An interesting alternative approach to the use of solar PV was offered by Patrick Winterbotham, owner of Solar Ready, based in Berkshire. He pointed out one particular problem – solar PV generates DC electricity and that energy is lost in converting to the AC power necessary to synchronise with the National Grid.
By installing a local DC micro-grid serving DC lighting and equipment, these losses can be avoided and battery storage requirements massively reduced. Particularly suited to such projects are auxiliary classrooms and site offices, for example. In line with this, his company is currently engaged in a project to build an off-grid compound at Heathrow airport.
Solar PV efficiencies remain at around 16% with the polychrystalline versions having about 0.5% superior performance. According to Daniella Moreale, Marketing Manager for Germany's Znshine Solar, the main improvements have been in guaranteed power outputs. All solar PV panels decline in output with time, but Znshine now guarantees 10 years at 90% output, plus a further 20 years at 80%. Impressive, if it can be borne out over the long-term.
Ecobuild 2015 was held at the Excel Centre in London's Docklands from 8-10 March and attracted more than 1,300 exhibitors and 40,000 visitors.
Glenville Holmes, Special Correspondent, London