4.5 CURRENT DEVELOPMENTS

For stand-alone power systems for industry and consumers, the main remaining Research and Technological Development (RTD) issues lie in further integration of PV and BOS components in the construction of a system. By contrast, stand-alone systems in rural contexts are usually operated far from the normal repair and maintenance infrastructure, so reliability and low maintenance are of prime importance. But since the end-users are often poor, the balance between reliability and cost is vital. Specific research areas that the European industry must focus on to respond to the needs of this potentially huge market are:

· Optimisation of low cost techniques for thin-film production.

· Improved storage technologies - notably an affordable alternative to the poorly suited and environmentally damaging lead-acid car batteries that are used throughout the developing world.

· Development of small, low-cost, reliable solar product packages that have the potential to extend clean energy service delivery to a larger section of the population.

· For grid-connected distributed generation systems (200Wp to several hundred kWp) the market can be divided into systems on houses and those on commercial or public buildings. For house based systems, where the aim is functional design at reasonable cost, RTD should focus on the use of pre-fabricated roof elements, PV kits and integration into the building process. Commercial grid-connected systems are often part of the building envelope, integrated into the façade or roof to displace other materials such as expensive marble façades, or to provide shading or ventilation.

· For grid-connected central power stations with generating capacity, the primary objective is to produce clean reliable PV power. RTD issues relate to support for these large systems e.g. grid-connection issues and inverters. Some PV power stations of the 50-1,000kWp range have been integrated into rooftops, however, and others have a secondary function as sound barriers or weather protection.

4.6 THE BENEFITS OF PV POWER

4.6.1 Advantages of solar electricity:

· The fuel is free

· Solar electricity technologies generate power even on cloudy days

· No moving parts to wear out or break down

· Minimal maintenance required to keep the system running

· Modular systems can be quickly installed anywhere and easily expanded as requirements or financial resources increase

· Produces no noise, harmful emissions or polluting gases

· Is equally well suited for installation in high density areas of the industrialised world, as well as in remote areas of developing countries

Photovoltaic power systems offer many unique benefits above and beyond simple energy delivery. This is why comparisons with conventional electricity generation - and more particularly comparison with the unit energy costs of conventional energy generation - are not always valid. If the amenity value of the energy service that PV provides, or other non-energy benefits, could be appropriately costed, it is clear that the overall economics of PV generation would be dramatically improved in numerous applications, even in some grid-connection situations.