While Concentrated Solar Power has a great potential for delivering low cost solar power, most initiatives until now suffer from (too) high development costs. As a result these applications are not economically competitive with other sustainable energy generating techniques like wind turbines, PV panels or bio fuel. This initiative uses the “open source” business concept to significantly lower the upfront development costs for Concentrated Solar Power applications, and therefore minimizing the threshold for investors and production companies to move towards this market.
What is concentrated solar power (CSP)?
Most people know the effect of a magnifying glass when held in the sun. At the focus of the light beam there is a very light and hot spot. A CSP application works in the same way. It concentrates solar energy using (parabolic) mirrors. In the focus there is a device to catch the energy by storing it first or convert it directly into electrical energy. A thermal solar collector can only make use of direct sunlight (sunlight that cast shadows). There are several different kinds of CSP applications. The most known types are:
-
Parabolic through collector. A half pipe mirror that tracks the sun only over it’s elevation (from east to west). The heat is concentrated on a pipe in the focus. The energy is transferred by means of oil or direct stream. This technique uses temperatures around 300 degrees Celsius. There are several parabolic collectors installed around the world. Parabolic collectors are used in centralized locations to contribute to the electricity net.
-
Heliostat. Is a system that uses several individual mirrors that focus at the same point. The sun is tracked in both elevation and azimuth. In the focus there is a receiver that collects the heat and stores or converts it the steam, to drive a turbine. Heat can be stored in “solar salt”. Operation temperatures are around 800 to 1000 degrees Celsius. There are several of these installations around the world. The current heliostat technique is always connected to the electricity net.
-
Parabolic dish. This is a large dish or several small parabolic dishes that focus at the same point. The sun is tracked in both elevation and azimuth. With the current parabolic dish installations there is a device in the mirror focus that converts the solar heat directly into electricity (Stirling engine). Operating temperatures are in the range of 700 degrees Celsius. Several of these installation have been operating successfully the past decade.
Concentrated Solar Power vs. Photovoltaic collector.
Photovoltaic collectors use electronics (chips) to convert sunlight into electricity, while thermal solar collectors (CSP) concentrate heat and directly or indirectly convert this to electricity. At first sight, this looks like a more complex way to arrive at the same result, however there are some benefits in the thermal approach.
-
Heat can easily be stored in a cheap and safe medium, to store electricity is more difficult. Electricity can be stored in batteries, but these have to be batteries of considerably size, making the installation more expensive and less environment friendly. The life expectancy of a heat storage is very long. For a battery bank the life expectancy will be much shorter.
-
Thermal solar application are generally more efficient in terms of solar energy to electricity (20-30%) than PV solar applications (10-15%).
-
The stored heat in a thermal solar application can, as mentioned, be used to generate electricity, but also for other applications, like heating, cooling, water purification and water heating. To use heat for this kind of applications is far more efficient than the usage of electricity.
-
A thermal collector is made of relative cheap materials. The production of PV panels is still expensive also when produced in greater numbers. This means that the thermal solar collector has the potential of producing energy cheaper (more than 3 times) than a PV solar installation.
-
CSP uses a generator of some kind to generate the electricity, just like a power plant. This results in a AC current of the right voltage. In PV applications the DC current provided by the pannels must be converted to an AC current and transformed to the right voltage. This is done by a device called an inverter. Inverters are known to be maintenance sensitive and require 10-20% of the energy passing through the device in order to operate.
-
Thermal solar power is a proven technique, with installations generating power since the nineties. Some newly developed PV systems do not have a track record yet. There might be issues with maintenance and durability or other problems on the long run.
Thermal solar collector vs. Wind energy.
Wind energy and solar power are each others complementary. They can be used together or separate depending on the site conditions. Wind energy generally requires more space than solar energy and off cause enough wind. Concentrated solar power on the other hand requires a reasonable amount of direct sunlight to operate. Windy site conditions are not in favor of a thermal solar collector.
Why is this an open source initiative ?.
When someone orders a custom build car, designed from scratch, he can expect it to be a very expensive car. When the same design is build in series, the price of this car will go down considerably. This is also true for the development of a thermal solar collector. Most commercial available thermal solar collectors today, suffer from very high development costs. In most cases the design is also not suitable for mass production. Because of this, one actually purchases a serial build prototype, with a price tag of €120.000, or more, for a 10Kwe machine. This off cause, will never be competitive with traditional power generation, wind energy or PV panels.
The “open source” approach is different. Instead of spending large amounts of money up front, the initial investments are kept very low. The development costs are carried by several companies and organizations (sponsors). Standardized parts can be produced by a multitude of companies around the world, resulting in lower material costs.
What is the advantage of open source development over traditional design?
Open source has a number of advantages over traditional development. Fist of all there is the lower or lack of development costs, as mentioned earlier. This makes it more interesting for manufactures around the globe, to start an endeavourer in the CSP business, since the risks are calculable. Secondly open source is more likely to have a worldwide brand awareness, making it easier to get products certified and assisting in a commercializing campaign. Finally there is the market force. Every company around the world is able to start manufacturing parts and/or complete systems. Parts are standardized and exchangeable. This will result in low part prices and high availability, again resulting in low system overall costs.
What is open source?
Open source describes the principles and methodologies to promote open access to the production and design process for various goods, products, resources and technical conclusions or advice. The term is most commonly applied to the source code of software that is made available to the general public with either relaxed or non-existent intellectual property restrictions. This allows users to create user-generated software content through either incremental individual effort, or collaboration.
Some consider open source as one of various possible design approaches, while others consider it a critical strategic element of their operations. Before open source became widely adopted, developers and producers used a variety of phrases to describe the concept; the term open source gained popularity with the rise of the Internet and its enabling of diverse production models, communication paths, and interactive communities. Subsequently, open source software became the most prominent face of open source practices. (source Wikipedia http://en.wikipedia.org/wiki/Open_source )
What is distributed power generation?
Distributed generation, also called on-site generation, dispersed generation, embedded generation, decentralized generation, decentralized energy or distributed energy, is a method of generating electricity from numerous small sources, such as solar panels on the roofs of buildings and natural gas-fired microturbines and reciprocating engines located in homes and office buildings, which produce waste heat that can be used for space or water heating. Currently, industrial countries generate the vast majority of their electricity in large power plants, which have excellent economies of scale, but often have to transmit electricity long distances and most do not allow for the usage of waste heat. Distributed generation reduces the amount of energy lost in transmitting electricity because the electricity is usually generated close to the place that it is used. It also reduces the number of power lines that have to be constructed. (source Wikipedia: http://en.wikipedia.org/wiki/Distributed_generation ). Typically the biggest part of the grid electricity price is made of costs to install and maintain the grid itself. Power generated close to the point where it is going to be used, does not suffer from there extra costs.
Is a CSP application useful in all parts of the world?
Concentrated Solar Power makes use of direct sunlight to operate. Therefore there must be a reasonable amount of direct sunlight present at the site. The amount of sunlight on a specific site is called the insolation level http://en.wikipedia.org/wiki/Insolation and is expressed in Thermal Kilowatts per square meter per day/year (KWth/m2/day). When used with a thermal storage device a insolation level of 4 should make the application competitive to traditional (net) power (depending on the local energy prices)
What will be the environmental impact of this enterprise?
In terms of the effect upon the environment, one needs to put measures into C02 equivalents. C02 is the primary, but not the worst, of the greenhouse gasses. (Methane is said to be 21 times as potent in terms of its greenhouse effect.) . Because electricity is generated in several diffent ways, we have to use an average in the conversion. This average is set on 0.63 Kg C02 for every kWh. Thermal solar applications are build to last for at least 20 years. As an example, the thermal solar collector proposed in the Archimedes project, with a daily average of 50 kWhe, will produce in it’s lifetime 356.000 kWhe or saving the exhaust of 224280 Kg of C02. If the secondary heat that the collector produces, is also put into good use, this number can be doubled.
How can I participate in a CSPOSI project?
All the CSPOSI projects are “open source” projects, what means that anybody can use the information on this site and/or contribute to it, as long as the rules stated in the “open source” license (under construction) are followed. It is also possible to sponsor a project, both financially or by simply helping to promote this initiative. Open source exists on a wide awareness. The internet is a very good medium to reach many companies, individuals and organizations around the world. If you want to contribute in one of these ways, visit the forum.