Learning How to Harness Our Solar Potential
The sun is our main power source on earth. Our planet has always benefitted from solar energy. Without it, the earth would be another cold, dead rock floating in space.
Algae, plants, and trees are the best solar collecting and processing factories known to man. Many animals including humans process sunlight into vitamin D necessary for health. Only fairly recently in our history as a species has mankind begun to realize the importance of the sun as a potential source of clean, renewable power that far exceeds our world-wide energy usage.
There are currently two main ways we collect solar radiation from the sun and turn it into useable power here on earth: with solar thermal and photovoltaic systems.
Solar Thermal Systems
Solar thermal systems collect energy from the sun and convert it into thermal power. The thermal power can then be used for multiple purposes, from providing HV/AC to a residence, to heating a restaurant oven, to providing the intense temperatures necessary for industrial metallurgy.
The thermal energy produced by these systems can be converted into electric power. Solar thermal systems have followed various designs and used various types of solar collectors and solar concentrators. The most efficient design to date, concentrated solar power Stirling system, achieved 30% efficiency, about twice the efficiency of standard PV arrays.
Another plus for solar thermal systems is that whatever thermal energy is excess, not needed for immediate conversion or consumption, can be stored in the form of molten salts. The heat from molten salts can provide direct thermal power or produce electrical power useable or deliverable to the grid long after the sun has set.
Photovoltaic (solar power) systems are components designed to convert light (usually sunlight) into electrical power. PV systems may be configured in one of five ways:
1) Grid tied and battery storage
2) Grid tied without
3) Off-grid and battery storage for both AC and DC appliances
4) Off-grid and battery storage for DC only appliances
5) Off-grid without a battery (system direct)
A PV array is comprised of multiple photovoltaic modules, or solar panels, which convert solar radiation into usable direct current. A very basic photovoltaic system in the US, intended for residential, commercial, or industrial use, typically has one or more solar panels, a DC to AC power converter, hardware for supporting and mounting the solar panels, and electrical wiring. It may also include other task-specific accessories to meet the owner's specific needs, such as a battery system and chargers, or revenue grade metering (generally necessary for participation in solar and other renewable energy tax incentive or sell back programs, or for receiving grid credits.) In some countries, grid ties and metering are mandatory.
The number of solar modules in the array determines the total DC output of a PV system. The converter governs the amount of AC wattage that is distributed for use. Any difference in DC and AC outputs could be stored in a battery or used to run a DC device.
Our Solar Powered Timeline
The history of solar power dates back to the 7th century BC when people first used lenses to magnify and focus sunlight to light their fires.
In 212 BC, Archimedes, the Greek physicist, mathematician, engineer, and inventor, may have been the first to use sunlight as a weapon of war. According to history, the wooden ships of the Roman fleet, at the time besieging Syracuse harbor, were set aflame using highly polished bronze shields as mirrors to reflect and focus sunlight. No hard proof of Archimedes feat has been found supporting the historical record. However, the Greek Navy successfully tested the theory in 1973, setting fire to a tar and plywood mockup at a distance of 50 meters.
In 1839, French scientist Edmond Becquerel, then age 19, invented the first true PV system while experimenting in his father's lab. The system was comprised of an electrolytic cell made up of two metal electrodes placed in an electricity-conducting solution that generated electricity when exposed to light.
In 1878, French inventor Auguste Mouchout became the pioneer of solar cooling when he made ice by attaching a refrigeration device to a solar-fueled steam engine.
In 1954, the first silicon PV cell, precursor to all contemporary PV technology, was invented at Bell Laboratories.
The Benefits of Solar Power Today
Today even a small PV system is capable of providing enough electricity to power a single home, a satellite, an electric car, or a drone aircraft.
Total global solar capacity increased over a three year period (2010-2013) from 40 GW to 139 GW. Germany reported the most solar capacity at 36 GW.
Solar energy technologies continue to advance as does the marketplace for solar power. As of 2013, the solar industry in the US is creating jobs six times faster than the overall job market.
Solar power is increasingly available to qualifying homeowners as a leasing option. The homeowner gets decreased energy bills, while a third party fronts the initial investment and the upkeep of equipment.
The costs associated with producing solar power have plummeted during the past six years. Most of the lower cost is due to increased production of PV modules and improvements in the technology.
In your opinion, which will make the most difference over the next decade?
Obstacles to Solar Power that We Need to Overcome
The obstacles that stand in the way of us reaching our full solar potential are many and varied. Here are some of the major political, economic, and environmental concerns that need to be addressed in the near future.
Politically, a large part of the resistance facing the so-called "solar revolution" is basically a PR problem. For years, the potentials of alternative energies have been largely ignored due to lack of political will and short-term economic policies. More conservative governments and entities have viewed alternative energies like solar, at best, as tree-hugging idealism and at worst as threats to big establishment, to traditional ideologies, and even to political stability in general.
Of course, the best cures for the fear of new times and technological progress, are new times and technological progress. Younger generations and the better educated are always less afraid and more accepting that change is inevitable. They also tend to feel more capable of being a part of the positive changes to come.
What can be done now is positive PR campaigning to correct out-of-date information, to educate about the benefits of solar over non-renewables, and to advertise current scientific breakthroughs as heroic and worthy of our aspirations. Society needs to be excited about our bright solar future, not dreading the future in general.
Economically, solar power is becoming more competitive due to lower costs and increased efficiencies. In places like Hawaii, where the costs of energy have always been high, solar power is already far cheaper than fossil fuel non-renewables. In fact, utility companies there have refused to connect new PV systems to the grid because the popularity of solar far exceeds the needs of the grid during peak production hours.
This highlights the main problem facing PV systems at the moment, the lack of storage capacity for saving electric power produced for off-peak and night-time use. Better batteries and super-capacitors, and more affordable thermal storage are our challenges for the future.
On the environmental front, the solar industry has plenty of room for future improvement before it becomes a truly clean industry. While using solar energy produces no greenhouse gases or other pollutants directly, the production of industry-standard solar equipment, including PV modules and batteries, requires the use of many toxic materials which also need to be disposed of safely. Recently some progress has been made on the problem when cheaper and more common substances have been found as viable substitutes for more expensive and harmful ones, but there is still much to do.
Solar collectors if not placed wisely can create loss of habitat to plants and animals as well as cause other types of environmental damage. These too are areas that the industry needs to address in the coming years, along with tackling more basic cost and efficiency issues.
Recent Milestones in Solar and Battery Storage Technologies
In 2011, a solar power plant in Spain becomes the first to produce electricity for 24 hours straight, using molten salt storage.
In 2012, Stanford University Professor Xiaolin Zheng introduces flexible peel-and-stick-solar cells that can adhere like stickers to a window, the case for an electronic device, a car, or virtually any other surface.
In 2014, Scientists from Vanderbilt University announce the development of a strong structural super-capacitor that can be shaped into any form and operate under high mechanical stress. This means roof tiles or the façade of your house could one day soon serve as storage for excess solar power collected at peak hours.
In 2015, scientists from Stanford University reported the invention of an aluminum-ion battery which is rechargeable, safer, less costly, and more environmentally friendly than disposable alkaline or rechargeable lithium-ion batteries. They believe that the new aluminum-ion battery will have a long life cycle with the ability to be recharged tens of thousands of times and thus will be better suited to the storage needs of the grid.
In July 2017, George Washington University researcher unveils a prototype for potentially the most efficient solar cell in the world, a stacked GaSb-based multi-cell device capable of capturing most of the energy across the full solar spectrum. It converts direct sunlight into electricity with 45% efficiency.
In August 2017, A University of Sydney team pioneers the use of a bimetallic oxide-graphene hybrid material as a bi-functional oxygen electro-catalyst, thereby creating a low cost solution for the problem of recharging zinc-air batteries. Zinc-air batteries are cheaper and far safer than lithium-ion batteries and have the potential to store many times more energy.
Where Solar Power May Take Us in the Near Future
The US Department of Energy expects that in the near future all new construction in the US will combine energy efficient design and renewable energies such as solar power to produce net-zero buildings, (buildings with no reliance on traditional non-renewable energy sources like energy from coal or petroleum.)
Exciting new technologies currently under development will change the ways we use solar power. Vanadium batteries, graphene solar cells, and other innovative materials and technologies will allow us to collect and store solar energy more efficiently and at far lower costs.
As solar thermal, photovoltaic, and energy storage research and development continues and more consumers start supporting the industry politically and economically, the costs and harmful environmental impacts of solar thermal and PV energy will decline while the efficiencies will continue to rise. If governments, scientists, and individuals support and advance solar power now, one day photovoltaic systems will be able to supply most of the energy humans use on earth. This will mean safer, more affordable, cleaner, more reliable, non-conflict energy, and a sunnier future for everyone.