Eco-building III: Renewable Energy – Solar

Climate change and the looming peak oil crisis is forcing us to create a new model of energy use, one that won’t cause financial or social imbalance, and this is where renewable energy comes in. energy is at the heart of a healthy home and in the next two issues Sara Shaikh looks at the ecological alternatives, starting with solar and its two main applications: photovoltaic and thermal
Despite being the country with the most hours of sun in Europe, development of solar technology is still in its early stages in Spain. Andalucía is the region with the most potential to make the most of the sun’s resources: current climatic and geographic conditions along with industrial and economic development mean Andalucía could spearhead the country’s efforts to become an international leader in the use of solar energy. Both the way your home is built and its orientation can maximise use of the sun passively, and in addition, solar energy can either be transformed into electricity via photovoltaic technology (PV) or it can heat water, known as solar thermal.

Photovoltaic solar energy is generated by panels directed at the sun. The IDAE (Institute for Energy Saving and Diversification) explain that a PV plant is made up of “a photovoltaic generator (panels) as well as a storage system (batteries) when the installation is isolated”. In remote locations PV energy is stored in batteries and then passed into the domestic system either as 12V or through an inverter to create regular 240v mains power. However when the system is connected to the grid, all the energy produced by the panels is sold directly to the electricity company. “The electric company has to buy the energy at quite a high rate, up to 0,41 euros/Kwh, while the electricity we buy costs less, about 0,09 euros for each Kwh consumed. So if I put panels connected to the grid on my roof or land and sell energy, I’m selling everything I produce because I get a great rate for it, and I just buy what I need at a lower price”, explains Jason Lindfield from Energía Spain.
Thermal solar energy produces hot water which can be used to provide your domestic hot water, heat your swimming pool, or run central heating systems. To achieve this kind of energy you need a flat-plate collector. Energía Spain explained the details: “there are many flat-plate collector designs but generally all consist of a flat-plate absorber, which intercepts and absorbs the solar energy, a transparent cover that allows solar energy to pass through but reduces heat loss from the absorber, a heat-transport fluid (air or water) flowing through tubes to remove heat from the absorber, and a heat insulating backing”.

When investing in your solar system keep an eye on these decisive factors:
– over their 20-25 year life span, panels will slowly become less efficient, so you’re best off with a high-end panel to begin with.
– Panels eligible for grants are approved by the IDAE, and better panels get more financial support.
– Look for flat-plates with a minimum manufacturers guarantee of between 5 and 10 years.
– There are different types of solar thermal plates: make sure your provider advises you whether the selective, black or vacuum tube variety is best for your needs. Many industry professionals warn against the use of the latter in Andalucía.
– Each project is unique; make sure you find an installer who will look at your case in detail and can explain why the system they sell you suits your needs.
– Grants: according to BOJA Nº81 from April 25th 2007, you can apply for Solar Thermal grants until 31st December 2008, covering up to 50% of the flat-plate’s cost depending on the features of your system. It’s faster and more practical to have your solar panel provider apply for the grant on your behalf. There are two application procedures, the “ordinary” one and the “simplified” version, which usually comes through in 30 days. For full info on available grants call 902 11 30 00.
Consejería de Innovación, Ciencia y Empresa
Subvenciones/ Grants: 902 11 30 00

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