It doesn’t take much digging to discover that I am a big fan of the Steampunk genre. The idea of steam power being incorporated into modern technology is intriguing, and little did I know that it could actually be more practical than many of the power-generating systems we use today. The science of generating power has undergone remarkable changes over the past 150 years as mankind has developed systems by which energy is derived through harvesting solar and wind energy, capturing and controlling nuclear power, and even through burning coal. Both nuclear and coal-based power generators have one key ingredient in common: steam.
Steam has been a key component in power generation for as long as power plants have been in existence. Even today, steam is in some way responsible for generating the majority of the electricity we use on a daily basis. This steam is generated through the heating of an element (such as coal or a nuclear reaction), which is transferred to water. The steam is then channeled to a turbine, which is connected to a generator. This generator uses rotating magnets to create a flow of electronics that powers our homes, businesses, and anything else running on the power grid.
That said, there are environmental concerns with both coal and a nuclear energy that have stirred controversy over the years. Advocates of either generation’s process have argued that recent technologies including what’s referred to as clean coal have made the process of generating electricity much less harmful to the environment. Unfortunately, natural disasters open up the door to potentially devastating consequences. While the Chernobyl incident may not be repeated thanks to failsafes in modern power plants, a smaller and yet still significant amount of harmful radiation was released in the wake of a tsunami that destroyed significant parts of the Fukushima power plant in Japan last March.
So, aside from burning fossil fuels and using nuclear energy, how is power generated?
How Solar Power Plants Work
We’ve all seen images of fields of solar panels set up to provide clean, renewable energy to homes. Typical power stations can generate enough power to provide electricity to a mid-sized town, with larger stations generating more than enough to power much larger communities, still. When we think of solar energy, we’re typically reminded of panels of silicon cells that convert energy from the Sun’s rays into electricity. What many people don’t know is that there are actually two types of solar generators.
Photovoltaics is the most well-known method for generating electricity from solar energy. This generation method employs the use of solar panels filled with silicon or copper-based elements that facilitate the conversion of raw solar energy into direct current (DC) energy.
Photovoltaics made up 40GW (40,000 MW) of the World’s solar capacity in 2010. That’s enough to power 20 million homes with an average demand of 2Kw. It’s remarkable to think about just how much impact a single alternative energy source can have on the world.
The downside of photovoltaic energy is the cost. Batteries, the panels themselves, and other supporting equipment can run a pretty penny when built in larger scales. DC current isn’t typically used in modern homes, which are usually powered by a more efficient and longer-traveling AC power supply. Because of this, inverters are generally required at solar plants that convert the power into the desired format. Operating costs are higher, which is one reason your local electric company may charge you more for “green” energy harnessed from renewable resources.
Smaller applications, such as individual homes and stand-alone units, employ batteries that store and regulate the energy. These batteries enable the user to benefit from solar power even after the sun has set, though they generally don’t come cheap.
Concentrated Solar Power
Concentrated solar power (CSP) is the lesser-known of the two solar technologies. A CSP system acts more like a traditional power plant in that it uses a heat transfer to generate steam which powers an AC-generating turbine. One interesting difference between CSP and PV energy is that CSP employs mirrors rather than solar cells to reflect the Sun’s energy as opposed to absorbing it.
This reflected energy is channeled to a specific point often using a parabolic mirror or array of mirrors, each targeting a specific hot zone where the energy can be concentrated, generating an immense amount of heat.
You’ve probably seen or heard about the so-called “death ray” invented by Archimedes. The idea of taking multiple mirrors and focusing them on a single point to direct the Sun’s energy is at the heart of CSP technology. By placing a pipe filled with water over the focal point of a parabolic or clustered mirror array, you can actually heat it to boiling fairly quickly. A parabolic mirror roughly the size of an older satellite dish can generate immense amounts of heat at the focal point, and is capable of igniting objects almost instantly.
One derivative of this technology is the solar power tower. By placing a tower in the center of an array of flat mirrors, each motorized to focus the Sun’s reflection on a given central point on the tower, energy can be collected and converted into AC power very efficiently. The tower allows for a liquid (either water or a liquid sodium) to heat up, generating steam. This steam is then channeled to a turbine that generates electricity just as nuclear or coal plants do, but without burning off any fossil fuels to do so.
Trough parabolic mirrors are also used, allowing a long pipe to run along the length of a trough set up on a mechanism that allows it to follow the Sun as it travels from east to west is essential. Perhaps the largest array of solar generators uses this very technology. The Solar Energy Generation Station (SEGS) projects are located in California and currently provide power to over 500,000 people.
The science behind CSP generation has evolved to a level where commercial generation facilities are beginning to gain a lot of press as a viable alternative to more costly renewable sources. One clear advantage of the technology comes in the form of startup costs. By replacing expensive solar cells with a simple reflective mirror, you can concentrate a lot more of the Sun’s energy in a much smaller space, giving you more bang for your buck. Not only that, but you’re not paying a market cost for something that’s specifically labeled for use in solar power generation. Reflective sheeting and basic plumbing equipment can come very cheap, and is easily adapted to the needs of a CSP generator.
Imagine being able to generate electricity without having to use fossil fuels or expensive batteries. One popular hobbyist project out there combines a little of the old-world steam technology with a modern understanding of energy transfer by setting up multiple troughs with parabolic mirrors that follows the sun as it makes its trek across the horizon. The energy produced by a single segment of the array is roughly 1000 watts, which is roughly 1KWh per hour. This particular design is used to heat a swimming pool, though it can be modified to generate steam and power a turbine with some added parts and a little know-how.
Bottom line: If you can make steam, you can make electricity. A little knowledge can take you a long way in this project. This white paper, authored by Robert Saunders, explains the fundamentals of generating electricity using steam created through a solar collection process.
There are several great projects you can find online that can put you on the right path toward building your very own solar generator that creates power with the same basic principals used by the majority of the power companies currently providing electricity to the world. As large power production companies and home hobbyists begin to explore the world of parabolic solar power generation, there’s no denying that this is one cost-efficient technology that could soon have a very big impact on how we power our homes. I, for one, look forward to seeing more companies take advantage of CSP generation, which could result in a lower electric bill and less reliance on expensive fossil fuels.