Once a decision has been made to implement solar technologies in a building development and a “solar friendly” layout adopted or a building development with a suitable layout identified work can begin on implementation. A number of elements will be then be required to realise the solar installations:
• A champion
of renewables/PV to take a lead on including sustainability, renewables and PV into the plans.
• Technical knowledge
: This will be needed by the project leaders and overall planners, the PV engineers responsible for the design of the PV system and the rest of the project team. The project team will not need a detailed understanding but they will need some understanding of the implications of the solar system for their area of responsibility.
• Inclusion in the work plan
for the entire project team: Installation of a PV system will affect other members of the team, not just the PV installer, and they need to allow for it.
: The implementation of renewable energy projects has to fit within the construction timetable or there will be delays and extra costs. If the PV is added to the design late in the day it can result in compromises having to be made.
• Transmission links
: A connection to the local electricity network will be needed. This should be included in the planning from the earliest possible stage.
: Can it come out of the existing budget? If not, can money be raised from external funding sources or innovative financing?
: Last but not least there has to be some enthusiasm for renewable energy or the project will not result in the hoped-for emissions reductions.
Good communication between the different members of the project team is also important. Architects and engineers can appear to talk different languages at the best of times. The problem can be even worse when dealing with a technology which is new to some members of the project team. Clear communication between the team members on what they hope the PV can offer and the information they need should be discussed at an early stage in the project.
A renewables/PV champion
At the earliest stages someone needs to take a lead on including sustainability, renewables and PV into the plans. In some cases they are themselves sufficiently expert in PV to provide the technical knowledge needed at this stage. In other cases they have commissioned experienced PV consultants and designers to provide advice.
The renewables lead can come from many different places. In some projects the early lead has come from the municipality. For example in Kirklees
in the UK, the municipal environment unit brought together developers and PV specialists to enable the creation of PV projects. The municipality had the knowledge, confidence in the technology and contacts to provide the initial set of information required. This was crucial in getting the developers started with their first PV projects.
The lead can also come from the building owner such as in the Cologne-Wahn
case study where the landowner organized an architectural competition at the beginning to gather options for achieving a solar estate.
In other cases the lead has come from the architect, for example the Solarsiedlung am Schlierberg project in Freiburg
, Germany was led by architect Rolf Disch, who wanted to provide evidence that his idea of an Energy-Surplus-House® can work well for terraced houses and commercial buildings.
The role of championing the renewable/PV aspects of a new development is a crucial one. If there is no champion these aspects may be shunted aside by others who see them as a risky unknown. Note that the champion has to be directly involved in the development, be aware of progress in all areas and be sufficiently influential that he/she can keep the PV system on the agenda. If the champion is not in the whole loop they may not be aware of issues that will affect the PV, such as design modifications, until it is too late.
The design engineers responsible for the detailed design of the solar system are likely to be experienced in the technology. However they may not be in a position to champion the PV project or to provide expert advice to the rest of the design team. The design engineers may not be appointed until quite late in the development process, especially if they are sub-contractors to the main mechanical and electrical sub-contractors. They may also have very limited influence or even contact with other members of the development team.
The design engineers responsible for the detailed design of the solar system are likely to be experienced in the technology. They can be expected to understand the available systems and how to design and install them.
However the rest of the project team will also need some understanding of the implications of the solar system for their area of responsibility. The solar system will impact on building layout and positioning and hence road and path layouts, roof shapes and structures and positioning of chimneys and vent pipes as well as the electrical distribution system. Someone will need to be responsible for making arrangements for the export of electricity and whoever is responsible for sales of buildings will need to be able to explain the system to potential occupants.
Unfortunately most engineering offices and developers today have very little experience with PV technology. Lack of knowledge by the rest of the project team can lead to a perception of risk, fear of delays and extra costs being imposed to allow for the uncertainty. Having an explicit plan for providing training, advice and visits to completed installations in order to transfer knowledge to the rest of the project team is the best way of ensuring issues are foreseen before they become problems. Many different approaches can be used to transfer knowledge and experience, but the approach used has to fit in with the development process in the country concerned.
case study gives an example of the successful transfer of knowledge. The guidelines for the selection of developers required the team to include an engineering office specialising in energy efficiency and renewable energy systems. However it still appeared that none of them had any serious experience in PV. To remedy this lack a team of local specialists was set up to assist engineering offices and developers at all stages of the project, from the preliminary design to the commissioning of PV systems. This local team also organised site visits and training sessions and is helping developers in dealing with a complex financial scheme with multiple sources of funding.
project learnt from previous smaller projects in the Lyon area, such as the Les Hauts de Feuilly
housing development where PV was brought in fairly late after developers had been appointed and the site layout fixed. PV was able to be installed on a group of houses at Les Hauts de Feuilly
, most of which had a good orientation. However the orientation varies and is not optimal for all houses. Grid connection was also considered late and additional connection points had to be retrofitted at the utilities’ cost.
Detached houses at Les Hauts de Feuilly showing PV systems with different orientations.
Another example of technical information being passed on effectively is the Stad van der Zon
, in the Netherlands. Here a new town area is being developed with PV on houses constructed by different architects, developers and builders. As soon as the detailed urban design and architectural aspects were in sight, a PV workshop was organized for architects and PV system manufacturers, resulting in draft designs and a book. The workshop was repeated in 2002. From a technical point of view, there were no problems in the design and realization of this ambitious project. There have, however, been major problems with the funding, as well as incompatibilities between the development timetable and the timescales required under the final funding arrangements.
Inclusion in the work plan
The urban development process tends to be complex, with a lot of issues needing to be taken into account. Everyone involved in the development is likely to be very busy and to have a defined scope of work which may not mention PV. Within the overall development of an area, PV has a very small role and cannot be expected to be high on the priority list of everyone concerned. However each of the following points needs to be explicitly included in someone’s work plan. This should be backed up by access to expert advice whenever queries arise.
• Site layout for solar access.
• Building design with suitable surfaces for PV systems considering solar orientation and shading. Also minimizing cable routes and providing an accessible location for the inverters.
• Negotiating any planning amendments for the PV system.
• Roof structure and any extra weight or wind load from PV.
• Design and installation of PV system, likely to be a specialist sub-contractor.
• Lightning protection.
• Scaffolding, secure storage and insurance against theft before installation.
• Electric network layout for the site including co-ordination with the DNO. May need to be done before installer appointed.
• Electrical design in the building; needs co-ordination between PV installer and electrical contractor.
• Electricity export may need negotiating and tariff agreeing; this should not be left to individual building owners to deal with once buildings are sold.
• Solar training and awareness.
• Consideration of arrangements for servicing and maintenance once buildings are handed over.
Considering the possibility of solar technology being included in the development site as early as possible will maximize opportunities for designing in good solar access and exploring synergies between PV and other aspects such as shade provision, day lighting and environmental image.
Difficulties in fitting a PV project into a development timetable can cause many problems. If PV is added late in the timetable it will often lead to less-than-optimal designs. If external funding is required, another level of complexity is added with difficulties matching dates of funding rounds, and restrictions on the dates that money must be claimed by. It may even be necessary to have two versions of the design, with implementation of the PV version being dependent on award of funding. Major developments have many constraints and hurdles to overcome, and PV is only a minor part of the overall picture. Waiting for PV funding cannot drive the timetable, a fact some funding organizations appear to be unaware of.
Photovoltaic systems in buildings are part of the building electricity distribution system and hence are normally connected to the local distribution grid. Technically, connection to the grid is straightforward so long as the local grid can absorb the extra power without exceeding voltage limits. However, agreement to connect to the grid must be obtained from the local Distribution Network Operator (DNO). In addition, a contract for the sale of electricity, at an agreed tariff, is normally required unless extra electricity is spilt to the grid with no payment obtained. Significant delays and additional costs can arise if discussions with the DNO are left too late.
Large PV systems, or large groups of systems, should be taken into account during the design phase of the distribution grid in order to correctly size the new distribution grid and avoid any additional infrastructure work once buildings are completed. Attention should be paid to the location of medium voltage/low voltage (MV/LV) transformers and the size of transformer feeders to make sure that each PV system can be connected to a suitably robust LV grid. Single systems or small groups of systems can normally be connected to the existing grid without any modifications.
Dedicated connection points may be required for contractual reasons. For instance in France, in order to benefit from the feed-in tariff for all of the energy produced by a PV system, the utility has to create an additional, dedicated connection point. So for a new development of houses with PV the DNO may need two connection points for each house, rather than the normal one. Unfortunately, the current administrative system officially requires detailed information about power plants before the DNO can take them into account. As the detailed information required is unlikely to be available during the infrastructure design phase, there is a potential problem.
At Les Hauts de Feuilly
, France, a group of 19 houses with PV roofs needed dedicated connections to the grid. However, the DNO was not officially informed of this until the houses were complete. The problem delayed the commissioning of all PV systems while dedicated connection points were installed. In this case the extra costs involved were borne by the DNO, rather than the inhabitants, as the power of each PV system was below a certain level.
At the subsequent Confluence
project in Lyon the designers were aware of this potential problem so organized a technical meeting with the DNO to find a way, during the design phase of the distribution grid, to take into account the fact that several buildings would be equipped with PV. The objective was to correctly size the new distribution grid to be built and avoid any additional infrastructure work once buildings are completed.
Having individual building owners regarded as generators, with all the associated regulatory requirements, is a very recent phenomenon. Appropriate administrative procedures are not yet in existence for dealing with groups of small identical generators. Standard procedures for export of electricity normally require complicated and time-consuming forms to be filled in. However, if the forms are to be completed by individual householders and this is left until the houses are occupied, problems and delays are likely to result.
Experience at [Les Hauts de Feuilly-doc68] housing development in France led to suggestions that a developer that chooses to install PV systems on its buildings should assist future home owners until the commissioning of the PV system. In particular, developers should make sure that future home owners have signed the contract for the connection of the PV system to the grid with the DNO and the contract for the purchase of the electricity produced at a specific feed-in tariff.
PV is undoubtedly expensive. Most urban-scale PV projects to date have obtained some level of capital funding subsidy, but subsidies are becoming harder to obtain. In some countries their role has been replaced by funding paid via premium rate feed-in tariffs for renewable energy. This guaranteed income can allow finance to be obtained through loans.
Sources of funding range from the European Commission (which tends to fund larger projects but not individual buildings), national or regional renewables programmes, which tend to be more accessible to smaller projects, and local municipal or utility funding. Those municipalities which have created renewables funds, such as Kirklees
– which decided to set up the Kirklees Council Renewable Energy Capital Fund in 2000 – have been able to get a range of projects going in their area and start up local supply and installation companies.
If no subsidies are available the full costs may be met by developers or builders, and then passed on to the purchasers of the building. If there is an obligation that all new buildings in an area install renewables, then anyone who wishes to own a building in that area has no option but to pay the cost. If there is no obligation then such buildings have to be marketed at a premium price justified by their sustainable design. The viability of that depends on the local market and preferences of purchasers.
In some locations, such as Croyden
, London (UK), there is evidence of higher property values for properties with PV systems. Here, some developers obliged to install renewables have found PV the most cost-effective solution because it does not take up any space in the house, and the cost of the space needed for a hot water tank for solar water heating outweighs the higher outlay for PV.
Some projects have raised money by selling shares. The financial feasibility of this is improved in countries where a premium feed-in tariff is paid for electricity from PV.
Austria, a 10.44 kWp communal PV power plant on the roof of the offices of utility company Feistritzwerke-Steweag was the first PV power plant in Austria realised through a shareholder programme. This project made it possible for environmentally engaged people to own a share of a PV power plant. Initially, sales of share certificates were slow. The project manager put a lot of effort into advertising the project and in the end, 68 people bought shares which financed 80% of the costs; the remaining 20% was financed by the utility.
In Freiburg, Germany, financial difficulties were encountered during the development of the Solarsiedlung am Schlierberg
eco-housing estate. These were solved by starting a fund, called ‘1. Solar Fond Freiburg,’ with an invitation for subscription to share certificates of €5000 each. The shareholders were primarily private citizens who wished to make a sustainable long-term investment. The total investment was €1.5 million. This new financing model was the key to success. The first one was followed by three other investment funds with a total investment of €3 million each. In total, 15 rental houses belong to these four solar funds. The roof integrated PV systems were marketed separately. Either the homeowners or other investors purchased them. A return on investment is granted by the 20-year payment of the feed-in-tariff under Germany’s National Renewable Energy Act.
Once upon a time renewable energy projects were few and far between. The ones that were implemented tended to come about as a result of enthusiastic and knowledgeable individual clients, architects or engineers. The knowledge and the enthusiasm were there, at least in part of the design team. The problem was to raise the money, fit it into the timetable (often complicated by having to wait for results from funding bodies) and get the rest of the team on board.
Today the inclusion of renewable energy in a development may be a requirement imposed by others. There may be little knowledge and less enthusiasm in the design team. However on the plus side if the requirement is there from the beginning the timetabling may be easier and implementation of the renewable energy aspects is less likely to be dependent on winning some form of competitive fund raising procedure. The challenge today is moving from locating funding to providing knowledge and enthusiasm.
Fortunately experience shows that enthusiasm tends to arrive naturally with knowledge. Once a commitment has been made to include PV in a development, results from many projects suggest that developers and architects are often surprised at how easy a technology PV is to design with and install. The key is spotting issues at the right time and providing access to the information needed.
As more and more PV projects are implemented, so PV will become part of the standard repertoire of architects and engineers. The need for training and information provision by PV specialists will reduce. There may also be a reduced level of uncertainty on the part of clients and other members of the project team, which should lead to further cost reductions.