What Is The Solar And Who Used It?

Solar energy is the radiant light and heat from the Sun that is harnessed using a range of ever-evolving technologies such as solar heating, photovoltaic panels, and solar thermal energy. Humans have utilized solar energy passively since ancient times to heat dwellings and cook food. Solar innovations progressed gradually over the centuries with early uses including concentrating sunlight to ignite fires. Active solar technology first emerged in the 1860s and developed in the late 19th and early 20th centuries with solar steam engines and photovoltaic array development. The 1973 oil embargo and rising concerns about fossil fuels increased focus on renewable energy sources like solar. Advances in semiconductor technology, manufacturing techniques, and materials science have enabled high performance photovoltaic cells that convert sunlight into electricity at ever lower costs. Solar thermal plants utilize mirrors to concentrate sunlight for generating electricity. Today solar energy powers everything from small gadgets to large power plants with annual solar installations reaching record highs worldwide.

Early Solar Technology

The earliest uses of solar energy date back to ancient times. Before electricity, people relied on passive solar design to heat, cool, and light their structures. This involved orienting buildings and designing openings to maximize sun exposure in the winter and minimize it in the summer.

The ancient Greeks, Chinese, and Romans all oriented their buildings and designed elements like south-facing windows, thermal mass floors, and ventilated roof spaces to capture sunlight for heating. The ancient Pueblo people in North America also designed homes into cliff faces with south-facing entrances to absorb heat.

Early solar devices like the burning mirror and solar furnace also concentrated sunlight for high temperatures to light fires. Beyond heating and lighting, sun-drying was used since ancient times to preserve foods like fruits, vegetables, and meat.

19th Century Developments

In the 19th century, the first solar powered engines were developed to harness the sun’s thermal energy. Auguste Mouchout patented the earliest known solar powered engine in 1860 in France. His engine used a parabolic trough concentrator to heat water and produce steam to power the engine. Mouchout displayed his engine at the 1878 Universal Exposition in Paris.

Other innovators worked to develop solar cookers and water heaters during this time. In 1876, Samuel Langley invented the first solar powered water heater that was able to heat water enough for domestic purposes. Langley’s design used a flat plate collector painted black on the outer side and was enclosed in an insulated box with the water running through it.

By the late 19th century, many solar water heaters were commercially available and increasingly used, especially in sunny parts of the world like California and Florida. These early solar thermal devices proved the efficacy of harnessing the sun’s energy for practical uses.

Photovoltaic Cells

The photovoltaic (PV) cell was invented in 1954 by researchers at Bell Labs. They discovered that shining light on a properly prepared silicon wafer could generate usable electricity. The first PV cells were only a few percent efficient at converting sunlight into power, but they sparked great excitement about the potential of solar energy.

Early PV panels were incredibly expensive, costing over $1,000 per watt in the 1950s and 1960s. This limited their use to niche applications like powering space satellites. But by the 1970s, prices had dropped enough for PV panels to be used more widely for small items like calculators and watches. Still, the panels were far too expensive for widespread residential or commercial use.

Solar Thermal Plants

Largescale solar thermal plants are often cited as an emerging renewable energy technology with substantial potential to meet rising energy demands. Most solar thermal plants use concentrated solar power (CSP) technologies, which concentrate sunlight to generate high-temperature heat that drives an electric power generation cycle. These plants require large, flat areas with strong direct sunlight—hence the tendency to build them in hot desert regions.

Some of the largest solar thermal plants in the world are located in the Mojave Desert region of California and in the Sonoran and Mojave deserts in the Southwestern United States. The Ivanpah Solar Electric Generating System in the Mojave Desert uses 173,500 heliostats (mirrors) to focus sunlight onto boilers located atop three 459 foot towers, generating steam for turbines. With a gross capacity of 392 megawatts, it is one of the largest solar thermal power plants ever built. Other major solar thermal plants in the region include the 250 megawatt Solana Generating Station near Gila Bend, Arizona and the 280 megawatt Mojave Solar Project in the Mojave Desert. In total, nine of the largest solar thermal plants worldwide, each with over 100 megawatts capacity, are located in the deserts of California and the Southwest.

Solar Architecture

Solar architecture refers to the design and orientation of buildings to maximize the use of sunlight. The goal is to harness the sun’s energy to provide natural heating, lighting and ventilation to a structure. This approach is known as passive solar design.

Passive solar makes use of materials, design elements and placement to collect, store and distribute solar energy. For example, large south-facing windows allow sunlight to heat up interior spaces during colder months. Thermal mass materials like stone, concrete and tile absorb and slowly release this warmth. Overhangs block high-angle summer sunlight to prevent overheating. Natural ventilation and light tubes further enhance passive solar capabilities.

By optimizing a building’s interaction with the sun, passive solar design can dramatically reduce the need for artificial lighting, heating and cooling. These sustainable features curb energy requirements, costs and environmental impact. Solar architecture even enables some structures to achieve net-zero energy use.

The principles of passive solar design can be applied to new builds as well as renovations. Elements like solar orientation, window placement, insulation and thermal mass should be considered during the planning stage. Careful site selection, landscaping and placement of rooms can further maximize solar gain.

Solar architecture is an elegant approach to reducing energy consumption while providing occupants with optimal natural light and ventilation. When implemented properly, passive solar principles can significantly enhance a building’s sustainability and livability.

Solar Vehicles

Since the 19th century, inventors have experimented with solar powered vehicles. One of the earliest designs was a solar powered steam engine built by Auguste Mouchout in 1860s France. Mouchout demonstrated that the sun’s rays could be concentrated to boil water and power machinery. His work inspired other innovators to build solar powered cars, boats, and even printing presses over the following decades.

The solar car field expanded in the 1950s as photovoltaic cells became more efficient and affordable. In 1955, William Cobb demonstrated the first solar powered model car in the United States. Through the 1950s and 60s, engineers and hobbyists continued to experiment with small-scale solar vehicles.

The 1970s energy crisis stimulated new interest in solar transportation. In 1975, the first practical solar car was built by a team at the University of Delaware. Weighing 380 kg, the car used silicon photovoltaic cells to generate over 500 watts of power on a sunny day. This success led General Motors to develop the Sunraycer solar car and race it in the inaugural 1987 World Solar Challenge across Australia.

Today, solar cars are still more a demonstration of innovation than practical transportation. However, they showcase the potential for solar power to reduce dependence on fossil fuels. Solar plane designs have also been advancing, most notably with the Solar Impulse 2 aircraft’s round-the-world flight in 2015-2016.

Space Applications

Solar power has played an important role in spaceflight and satellite technology since the early days of the space age. In the late 1950s, solar cells were first used to power satellites, starting with the Vanguard 1 satellite launched by the United States in 1958. Solar panels provided this early satellite with just one watt of power, but demonstrated the potential for solar energy in space.

Photovoltaic solar panels are now an essential component of nearly every satellite, spacecraft and space station. They provide renewable power from the sun and allow spacecraft to operate for extended periods without fuel. On manned spacecraft like the International Space Station (ISS), solar arrays can stretch over an area bigger than a football field and generate up to 120 kilowatts of electricity.

Solar energy capabilities steadily improved through the Apollo, Skylab and Space Shuttle programs. Today, advanced solar cells and arrays help power exploration missions far from the sun, such as the Juno and Mars rovers. Solar sails have been proposed as a method of spacecraft propulsion using radiation pressure from the sun. Solar power will continue to enable ambitious space exploration and astronomy projects in the future.

Recent Growth

In the 2000s, solar power saw massive growth globally due to concerns about climate change and energy security. Government incentives like renewable energy targets, feed-in tariffs, tax credits, and rebates helped drive adoption of solar. Costs fell dramatically as manufacturing scaled up, especially in China. Between 2000 and 2013, solar PV capacity grew 200-fold from 1.5 gigawatts to over 139 gigawatts. Some countries now get a substantial portion of their electricity from solar power. For example, Germany produced over 6% of its total electricity consumption from solar in 2013. The solar boom was so large that it caused a supply glut of panels that sent many manufacturers into bankruptcy. However, continued technological improvements and falling costs ensure strong future growth for solar power.

Future Outlook

The future looks bright for solar energy. As technology improves and costs continue to fall, solar is projected to play an increasingly larger role in energy production worldwide.

According to the International Energy Agency (IEA), solar power could generate up to 16% of the world’s electricity by 2050. This is over 20 times more than solar’s contribution in 2018. The IEA predicts solar will dominate renewable energy growth, accounting for nearly 60% of new renewable power capacity worldwide.

One major driver of growth is the continuing cost declines, making solar ever more competitive with fossil fuels. Since 2010, the global average cost of solar power has fallen over 80%. The IEA expects utility-scale solar costs to drop a further 40-70% by 2050. With such economics, solar is anticipated to become the new king of electricity, attracting over $1 trillion in investment through 2050.

China and India are likely to lead the solar boom. These nations face massive energy needs but have polluted air from fossil fuels. Solar offers a clean, cost-effective alternative. The IEA expects China and India will account for over half of new solar installations through 2050. Other sunny regions like the Middle East and Australia will also embrace solar power.

Advances in energy storage and grid management will enable higher penetration of solar electricity. Battery storage capacities are improving while costs are declining, which will allow solar power to be dispatchable 24/7. Smarter grids and interconnections will help balance supply and demand across wider regions.

With such strong tailwinds, the future shines brightly for solar energy worldwide.

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