Solar photovoltaic panels get all the press, with good reason too. They’re shiny. They look the part of a renewable energy technology of the future. That’s great, but people tend to get a little sun-struck and forget that photovoltaic technology is only one way to get clean energy from the sun.
Types of Solar
1. Solar Photovoltaic Panels
Solar-electric panels are the rock stars of the renewable world. Through the power of science and technology, these plates of silica and glass turn everyday sunlight into useful electricity on the fly. But like any legitimate A-list celebrity, they tend to attract a legion of detractors along with their fans and advocates.
For the most part, the arguments against solar photovoltaics have rested primarily on the issue of cost. Specifically, critics call solar an expensive pipe-dream that relies on subsidies to survive. What these solar-haters tend to forget to mention is that subsidies for fossil fuels topped subsidies for all traditional clean energies by a massive margin of 58 billion dollarsover a 7-year period. Detractors claim that solar technology does not deserve taxpayer support. But the same people neglect to inform the public that the oil industry, despite record profits, is also heavily subsidized. Taking into account the other hidden costs of carbon, such as being energy-dependent from countries that despise us, and the costs of environmental degradation, renewables clearly come out ahead.
Photovoltaic technologies continue to improve at a rapid rate. With falling costs, and grid parity status in many areas of the United States, it looks like solar photovoltaics will continue to run the renewable energy show for years to come.
2. Solar Hot Water Heaters
While solar photovoltaics may be the attractive, sleek face of the renewable energy movement, solar water heaters, also known as solar thermal, are the low-tech, functional workhorses that can be found on roofs across the world.
Solar hot water heating systems are especially effective because they are relatively cheaper to purchase and install, and the underlying technology is incredibly simple – the sun superheats a glass box wherein water (or another catalyst) is pumped through, thereby becoming hot in turn. Rather than waste money on an inefficient electric water heater, or burning natural gas, why not take advantage of the energy that falls on your roof every day? Considering that domestic water heating constitutes up to a quarter of a home’s energy consumption, investing in solar hot water heating may be a very good idea.
The solar collector plates of solar hot water systems primarily come in two variations: flat-plate, and evacuated-tube. Flat-plate systems are more cost-effective in warmer regions, while evacuated tube systems work better in colder regions. Considering that both systems can typically provide up to 85 percent of a home’s water heating needs, and offer payback times of five years or less, it’s a wonder that these practical inventions aren’t ubiquitous on American rooftops as they are in several other countries around the world.
Patents for solar water heating systems date as far back as the 1890’s in the United States. However, just like photovoltaics and other renewable technologies originating from the United States, other countries have taken considerable leads in both the development and application of our key technologies. The United States currently has about 2.3 gigawatts-thermal of capacity installed. China has 118 gigawatts-thermal installed across 40 million homes.
3. Solar Passive Heating
Perhaps the most low-tech of the three, passive solar heating is without question the most egregiously overlooked method for getting sun energy. The concept is quite simple: when it’s hot, you want to limit exposure to the sun. But when it’s cold, you want as much of it as you can get – to naturally warm interior spaces. This can be accomplished in a great variety of simple, intelligent, and low-tech ways that really fall more in the realm of “good design” than complex methods or technologies. The reason they call it “passive” heating, after all, is because there are no mechanical systems involved, no shiny technological gadgets, and virtually no monitoring on the side of the occupant (except to open or close window blinds). Sunlight will fall where it will, and it’s up to the architect or designer to work with or against site realities.
For example, sustainability-focused architects and builders tend to place heavy emphasis on preliminary design and building orientation – with good reason. Design experts assert that a building’s final energy consumption and performance is more or less set in stone once a building’s site, orientation, and envelope have been finalized. That makes sense. A house that is heavily exposed to a region’s scorching summer sun will no doubt suffer from equally distressing cooling bills. Likewise, a home that is designed to minimize summer sun exposure, will have substantially reduced cooling costs. The same logic applies to winter conditions where solar penetration into the building would be an ideal thing. Good envelope design and building orientation is all about minimizing sun exposure in the summer, and maximizing heat gain during the winter.
In the end, a climate-appropriate combination of all three types of solar, tempered with some commonsense approaches to house design, can have spectacular energy efficiency results. After all, all three methods of harvesting solar energy aren’t just about finding an alternative to fossil fuels, they’re also about saving money.
Types of Solar
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