The cost of solar energy remains high despite decades of significant advances in solar collection efficiency. Domestic power generation methods have yet to achieve the low-cost heat and power advantages initially promised. Why is that?
Let's look for some answers and see how change is coming.
The Earth receives more energy from sunlight in a single hour than its entire population consumes in a single year. Around 1000 watts per square meter of bright sunlight falls on the equatorial regions of the Earth during daylight hours.
Yet, only a tiny fraction of that potential energy can get converted into usable electrical power by solar power farms and residential-sized power systems.
Inefficiencies inherent in solar panel design can account for part of the loss. Few of the numerous light photons that hit a photovoltaic (PV) panel will actually dislodge an electron. And only a few of those freed electrons will get to travel through the system as electrical current.
The longer the dislodged electrons can wander around loose the more likely they will flow out of the panel and down the connecting wires to an outlet. "Carrier lifetime" is the name of the effect.
Currently, most solar electricity systems can only attain about 10% to 15% efficiency, but some panel manufacturers have increased the efficiency levels of their product to nearly 20% by extending the carrier lifetime. Such improvements help to lower the cost of solar energy.
In contrast, solar thermal power systems heat saltwater in solar thermal panels to generate steam that powers turbines to produce electricity. The efficiency of these sun-powered generator systems can run nearly 30%.
However, thermal systems are not only expensive to build, but they operate at high risk since the high operating temperature and steam pressure can do considerable damage if the device should ever rupture.
The average consumer still considers the cost of solar energy expensive despite the improvements made in power output efficiency and a the potential for long-term payback. For instance, most PV panels remain costly to buy relative to their power output, though module prices are falling. A typical 230-watt solar panel can cost up to $400.
A solar roof installation for a modest-sized house will require an array of PV panels costing up to $20,000, or possibly more. And if storage batteries and other components are required, the cost can increase.
However, the steady rise in fossil fuel prices has caused manufacturers to respond with an increase in research spending to develop new methods of increasing panel efficiency while lowering production expenses. The marketplace is fast maturing, and even the cost of high efficiency solar panels is lower than it once was.
Thanks to new research, the cost of solar power cells has also been steadily falling by around 15% each year for the past decade. Given that quality PV cells have a lifespan of 20 years, they can easily pay back their initial investment, all the while providing green, renewable electric power.
Significant advances in solar energy continue to be made. At the Université du Québec à Montréal (UQAM) Chemistry Department in Quebec, Canada, Professor Benoît Marsan and his research team have been advancing the design of an electrochemical solar cell with a transparent and non corrosive electrolyte and a relatively inexpensive cobalt sulphide cathode.
Marsan's patented breakthrough offers increased durability with lower manufacturing costs compared to conventionally made solar power cells.
Organic and polymer solar cells (PSCs) are now being developed for applications like computer monitors and keyboards. Flexible plastic-like cells will permit a solar powered tablet computer similar to the iPad to be folded conveniently for the pocket.
A team of UCLA researchers has already developed a visibly transparent solar cell made from a photo-active plastic that enables infrared light to be converted into an electrical current. Unlike conventional cells that mostly absorb visible light, these PSC cells absorb more infrared light making them almost 70% transparent to the eye.
The UCLA team's breakthrough mixture of titanium dioxide nano particles and silver nano wire to create a transparent conductor (electrode) as a composite film replaced the traditional opaque metal electrode and permits the cells to be produced economically by solution processing.
Lightweight and flexible, the transparent cell's potential use is in portable photovoltaic devices and smart screens and in giving home and office windows the ability to generate electricity while still permitting normal see-through capability.
It's expected that polymer solar cells will soon produce electricity for around 20 cents a watt, compared to the $1 per watt or often more for typical panels. This will make the cost of solar energy affordable for almost everyone's budget.
Costs always come down as technology advances. The future of solar photovoltaic energy holds much to look forward to.
The heating of water by solar thermal power has costs that need to improve also. Back in the 1920s, some progressive communities used large sunlight-heated water storage tanks for piping hot water to homes. Once it became cheaper to heat the water with electricity and fossil fuels, solar heated hot water was no longer cost-effective.
However, as non renewable fossil fuels continue to rise in price, old ideas are being reconsidered and improved upon and could prove to be cost-effective again. If the trend continues, and it's likely to, we'll continue to see PV cell efficiency increase and the cost of solar energy significantly decrease.
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