Learning How to Harness Our Solar Potential
The sun is our prime power source on earth. Our planet has always benefited 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 the vitamin D necessary for health. Only recently in our history as a species has mankind realized the potential of the sun as a clean, renewable source of energy that far exceeds our current power usage.
There are two ways we collect radiation from the sun and turn it into usable energy here on earth: with solar thermal and photovoltaic systems.
Solar Thermal Systems collect energy from the sun and convert it into thermal power. The thermal power itself can then be used for multiple purposes, from providing hot water to a residence or heating a restaurant oven, to generating the intense temperatures necessary for industrial metallurgy.
The thermal energy produced by these systems can also be converted into electric power. Thermal systems have followed various designs and used various types of collectors and concentrators. The most efficient design to date, a solar dish/Stirling system, achieved over 31% efficiency.
Another positive aspect is that molten salts can store the excess thermal power produced. The heat from these salts can provide direct thermal power or produce electrical power for the grid long after sunset.
Photovoltaic 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 incorporates multiple solar panels which convert sunlight into usable direct current. A basic photovoltaic system in the US, intended for residential, commercial, or industrial use, typically has one or more PV panels, a DC to AC power converter, hardware for supporting and mounting the panels and electrical wiring. It may additionally include other task-specific accessories to address the owner's specific needs, such as a battery system and chargers, or revenue-grade metering (necessary for participation in energy tax incentive or sell back programs, or for receiving grid credits.) In some countries, grid ties and metering are mandatory.
The number of panels 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 output and AC usage 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 exploit sunlight as a weapon of war. According to history, by his plan, Greek soldiers angled their highly polished bronze shields, effectively using them as collecting mirrors to concentrate sunlight on each of the wooden Roman ships besieging Syracuse Harbor until all of them were set alight. No definitive proof has been found to support historical records. However, the Greek Navy successfully tested the theory in 1973, setting fire to a tar and plywood mock-up at a 50-meter distance.
- In 1839, French scientist Edmond Becquerel, then age 19, invented the first true PV system while experimenting in his father's laboratory. 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, a 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 capacity at 36 GW. Today worldwide capacity exceeds 500 GW. China reports the most capacity with the US and Japan close behind. The world is expected to exceed 1000 GW in the next 3 years.
Renewable energy technologies continue to advance as does the marketplace for the power produced. In 2013, the solar industry employed over 140,000 Americans and was creating jobs six times faster than the overall job market. Those numbers rose to over 260,000 jobs by 2016 then plateaued, due in part to imposed tariffs against China and other administration policies.
Depending on location, PV rooftop arrays may be available to qualifying homeowners as a leasing option. The homeowner benefits from lower energy bills. A third-party provides the initial investment, installation, and upkeep.
The costs associated with producing solar power plummeted during the past 15 years. Most of the declining cost is due to the increased production of PV modules and improvements in technology.
In your opinion, which will make the most difference over the next decade?
Obstacles We Need to Overcome
The obstacles that stand in the way of us harnessing our solar potential are many and varied. Some of these that need to be overcome in the near future include:
Lack of political will and short-term economic policies have slowed technological improvement in the energy sector. Politically, a large part of the resistance facing the so-called "solar revolution" is a PR problem. Conservative governments and entities have viewed alternative energies like solar, at best, as tree-hugging idealism and at worst as threats to corporation interests, traditional principles, and even to political stability in general.
Of course, the most effective cures for the fear of new times and technological progress, are new times and technological progress. Younger people and the better educated are always less afraid of the future and more accepting that change is inevitable. They also feel more capable of being a part of the positive changes to come.
PR campaigns could update out-dated perceptions, educate about the benefits over non-renewable sources, and promote current technological breakthroughs in the field of greener energy as heroic and worthy of our efforts and aspirations. Society needs to be excited about our promising renewable future, not dreading the future in general.
On the environmental front, the solar industry has plenty of room for future improvement before it becomes a truly clean industry. While using solar power produces no greenhouse gases or other pollutants directly, the production of industry-standard equipment, including PV modules and batteries, requires the use of many toxic materials which need safe recycling and disposal solutions. Recently some progress has been made when cheaper and more common substances proved viable substitutes for more expensive and harmful ones. There is still much to do.
Thermal systems fry unlucky birds in flight. The placement of collectors can create a loss of habitat for plants and animals as well as cause other types of environmental damage. Better wildlife safety and environmental preservation are areas the industry needs to address in the coming years, along with tackling more basic cost and efficiency issues.
Economic and Technical Obstacles
Until recently, the economic potentials of alternative energies have been largely overlooked in favor of greater investment in fossil fuels. Solar power is becoming more competitive due to lower costs and increasing efficiencies. In places like Hawaii, where energy costs have always been high, solar power is already far cheaper than fossil fuel sources. In fact, utility companies have refused to connect new PV systems to the grid because the popularity of home PV systems far exceeds the needs of the grid during peak production hours.
This highlights the main technical problem facing PV systems at the moment, the lack of storage capacity for saving electric power produced for off-peak and night-time usage. Better, cheaper, safer batteries and supercapacitors, and more affordable, and efficient thermal storage are challenges for the future.
Recent Milestones in PV and Battery Storage Technologies
- In 2011, a thermal plant in Spain became the first to produce electricity for 24 hours straight, using molten salt storage.
- In 2012, Stanford University Professor Xiaolin Zheng introduced flexible peel-and-stick PV cells that can adhere like stickers to a window, the case for an electronic device, a car, or any other surface.
- In 2014, Scientists from Vanderbilt University announced the development of a strong structural supercapacitor 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 serve as storage for excess 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 believed that the new aluminum-ion battery combines 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, a George Washington University researcher unveiled a prototype for the most potentially efficient PV module in the world, a stacked GaSb-based multi-cell device capable of capturing most of the energy across the full spectrum of light. It converts direct sunlight into electricity with 45% efficiency.
- In August 2017, A University of Sydney team pioneered the use of a bimetallic oxide-graphene hybrid material as a bi-functional oxygen electro-catalyst, thereby creating an economical solution for the problem of recharging zinc-air batteries. Zinc-air batteries are cheaper and far safer than lithium-ion batteries and potentially store many times more energy.
- In May 2019, physicists at the University of Toledo announced the creation, testing, and tweaking of perovskite solar cells as a possible replacement for current silicon cells. The cells convert sunlight into electricity at 23% efficiency and would be less expensive to produce than industry-standard silicon cells which currently reach 18% efficiency. Unfortunately, the perovskite is a lab-created material that requires lead to produce. They are looking at ways to reduce or replace the lead with other eco-friendly materials and at cleaner methods of recycling.
- In June 2019, Dutch car company Light Year announced the production of the Light Year One, the first solar car available for the public to purchase. The top and hood of the car are made from PV cells embedded in thick safety glass. An adult can stand on top of the car without inflicting damage.
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 energy production.
Exciting innovative technologies currently under development will transform the ways we collect and utilize solar power. Vanadium and organic flow batteries, graphene PV cells, and other new materials and technologies will allow us to harvest and store energy more efficiently, more eco-friendly, and at far lower costs. If governments, scientists, corporations, and individuals support and advance solar power now, within our lifetimes the sun can supply most of our energy needs. This means abundant, safer, cheaper, cleaner, more reliable, non-conflict energy, and a sunnier future for everyone.
This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.