What are Kiva loans?

I read about the Kiva loans some years ago in Business Week. Today I stumbled upon their websites and I got reminded of this remarkable initiative.

Kiva loans are directed to entrepreneurs around the world, with very good potential and in a real need of finance. The curious thing about these loans is that they can be as small as 25 USD. It turns out, when given to the right person they can really make a difference :)

Check out Kiva online, and get inspired to help :)

Some more solar power insights

I really like one specific sales technique - when you explain to the customer what your product is worth, by describing it in units and words that have an obvious meaning for everybody, regardless of their knowledge.
See here 10 important reasons, which the company Solel Solar Systems gives, explaining why power from the sun makes sense to invest in.

Here is one product you would need if you want to build a solar power plant - highly reflective foil:


Solar Energy has always been there. Hence, using it for heat production is not completely new idea. It has been there for a while and has been put into implementation.
Here are some examples of CSP plants:

Kramer Junction, California, USA:





Solar One, Nevada, USA
This power plants uses parabolic troughs as thermal solar concentrators.





Solar Two, Barstow, California, USA:
This power plant uses mirrors, which move tracking the sun light, similarly to plants :)



Seville, Spain:
All the heat from the sun's radiation is concentrated in the top of the tower (Receiver), where the working fluid is heated to become steam. The following process is the same as in most electricity power plants - the so called Rankine cycle.





And the world's largest solar plant, Mojave Desert, Israel:



And here is how they remove desert dust from the huge mirrors:)



The main question in an engineer's mind about production of electricity is on first place: 'How to generate heat?'. One obvious answer is there, staring at us :) The sun's radiation is our perfect completely renewable source of heat, if we only want to use it. And, one more green point, completely CO₂ free :)

Sun, wind, water, geo - which has biggest potential?

Recently, I have been growing an interest for renewable technologies for energy production. Therefore, I visited a lecture of Prof. Aldo Steinfeld at Zürich University, entitled: 'Global Potential of Renewable Energy Technologies'. Having a restricted beginner knowledge in this field, I benefited a lot from this presentation. Here I would like just to mention what struck me the most.

Prof. Steinfeld took a scenario (made by the oil company Shell), which predicted a global increase in demand of CO₂ free electricity of ~30 TW. (1TW =10¹²W). Two reasons for that:

* Almost doubled population
* Higher amount of energy per capita

Which technology of renewable energy production has the chance to close the energy gap?

After looking at the practical and theoretical potentials of all possible technologies - wind, hydro, biomass, geothermal and solar - the answer was given: SOLAR!

Solar energy can be the real solution to the expected 30TW gap. Currently the overall energy consumption on Earth is 1.2 x 1014 W. To satisfy that using only solar power, we will need a square area of 500 x 500 km. The theoretical potential of solar power is 120 000 TW, practically 600TW can be achieved. So it is worth discussing.

Prof. Steinfeld presented two main technologies for solar power:

PV - Photovoltaic (Solar Cell) Systems. Through this technology the light (photons) is directly converted into electricity (voltage). Here is a short explanation from http://www.renewableenergyworld.com/: 'Solar cells are made of semiconducting materials similar to those used in computer chips. When sunlight is absorbed by these materials, the solar energy knocks electrons loose from their atoms, allowing the electrons to flow through the material to produce electricity.' Typically, a solar cell has a 15% efficiency, so only 1/6th of the energy that strikes it is converted to electricity. The first solar cell was used in 1950-s and had only 4% efficiency. Today there are also some cells which can reach up to 40% effiiciency. The world growth of PV technology is 34%; European growth - 87%, half of which is in Germany.

CSP - Concentrated Solar Power. Here is a short Wiki Explanation: 'CSP use lenses or mirrors and tracking systems to focus a large area of sunlight into a small beam. The concentrated light is then used as a heat source for a conventional power plant (Rankine plant - a thermodynamic cycle, which converts heat into work. The heat is supplied externally to a closed loop, which usually uses water as the working fluid.). A wide range of concentrating technologies exists. These methods vary in the way they track the Sun and focus light. In all these systems a working fluid is heated by the concentrated sunlight, and is then used for power generation or energy storage.
'What happens when the sun sets?' - you might ask. The advantage of CSP systems is that they can use fossil fuel during the night and thus generate electricity 24 hrs. This combined system is possible due to the fact that the solar power plants work on the principle of conventional power plants. The only difference is the method of heat generation.

BUT Solar power is not competitive with other energy production methods. For this reason the governments of some countries provide a feed-in tariff (in Spain it is 0.27 EUR/kWh) for investments in solar energy. This is the estimated cost of producing solar electricity. This makes the investment in this business profitable and attracts more interest.

Important issue to consider for every investment is Energy Pay Back: the number of years that the factory must work in orer to repay the initial investment.
For PV, depending on the cells used, it can be from 1 to 3.5 years.
For CSP, only about 0.5 years.

Sounds good to me :)

Conclusion: with solar power you can claim a sustainable production of energy, which has the potential to close the energy gap between today and the year 2060.