Seven ways to get solar power
(Final part)
As mentioned in my last article, the new Spanish Building Regulations - known as the EH1 and the EH0 - relate to energy saving in buildings.
The EH1 limits the total amount of energy that our new and future buildings must use.
It divides Spain into different zones, allowing those in colder regions such as the central north regions to use more energy for heating or cooling the buildings.
It goes from 15Kw/m2 per year in warm regions like Valencia and Murcia etc, to 40 Kw/m2 in colder zones.
On the other hand, the H0 limits the energy consumption of our buildings in a similar fashion. All buildings built from the year 2020 must consume nearly no energy. Yes you have read it correctly, 0Kw.
Most if not all of the energy consumed in all buildings designed from 2020 onwards must come from renewable sources only.
As a recap of different sources analysed we looked at the following two: 1. Photovoltaic panels. We mentioned that photovoltaic panels are the best known system to collect energy from the sun, but are not the only way to harness energy.
2. Thermal: take advantage of the heat.
Thermodynamic solar technology, fruit of the union of the heat and the heat pump, takes advantage of the heat of the wind, the rain and the sun, and also works during the night.
Today we will enlarge on the other renewable sources available to us. 3. Focusing the sun's rays The Concentration of Solar Power (CSP) consists of a large number of mirrors that track the sun and concentrate its heat on one point. This generates steam that drives a turbine to produce electricity.
These facilities work even at night, since part of the heat is stored in oil or melted salt. Spain is a pioneer in this technology, with plants built on the outskirts of Seville.
This system can also be used on a small scale: the micro-CSP. Its design is much simpler and smaller and can be installed on the roof of tall buildings, factories or malls.
Photovoltaic concentration (CPV) technology is based on solar cells more efficient than conventional silicon materials. Being more expensive, cells are very small and mirrors, lenses, prisms, etc concentrate sunlight on the cells to increase their power. The USA, Germany and Spain are the most advanced countries in the world in this field. 4. Solar ink Several companies and research groups are working on the development of solar ink. They use new materials, based on nanotechnology, which can be painted or printed on surfaces and convert sunlight into electricity. Consumers could paint their roofs, walls or windows and generate their own power. 5. Solar roof tiles Solar roof tiles resemble conventional ones in shape or colour, but also produce electricity or heat. They function as the classical photovoltaic panels, but with new systems and materials, such as silicon mono-crystalline or an amorphous solid, to be flexible and able to take any form.
Several US and European companies are trading in this material, it can be found also in Spain. Several models are already used in cities such as Venice. Their prices are higher and their efficiency is lower than that of conventional panels so they are only recommended when aesthetics are a priority. 6. Hybrid systems Companies around the world tested several hybrid models that unite the best of photovoltaic and thermal technology to be more efficient. This was used in the Olympic village in Beijing (China). Another hybrid option is the union of photovoltaics with other renewable systems such as wind energy.
7. Futuristic: what else will be possible someday?
Drawing solar power from space? The idea would be to place solar panels in orbit and transmit microwave or laser energy collected to a station on earth for distribution to the network.
The high costs make it unworkable, but increasingly scarce and expensive fossil fuels and the advancement of technology could make it interesting in the future.
Another futuristic idea is to better imitate those life forms that produce energy from the sun: the leaves of the trees. Some researchers are already working on prototypes of artificial leaves and reproducing the process of photosynthesis in a laboratory.
It is not an easy task, since their apparent simplicity hides a complex system and the technological and economic challenges are great. This is something to be looked at in the long term.