Three stages of impact
The wider effect of the solar panel came in stages. First it found work in space. Then it supplied remote places that had no grid. Finally, as prices fell, it began to feed ordinary electricity systems, from single rooftops to large power plants. Each stage depended on the previous one, because each brought experience and lower costs.
Satellites and remote power
In the late 1950s, solar cells were too expensive for homes but were perfect for satellites. They were light, had no moving parts and needed no fuel. The Vanguard 1 satellite of 1958 used them, and after that, solar arrays became standard on most spacecraft, from communications satellites to weather satellites and crewed space stations. The long life of the arrays meant that satellites could work for years.
Back on the ground, the first customers who could afford the high price were those who had no good alternative. Panels began to power telephone relay stations, navigation lights and buoys, remote weather instruments and rural water pumps. In the 1970s, oil price shocks stirred interest in a wider use, and companies began to sell cells for these off-grid jobs at lower prices than before.
Rooftops
Rooftop systems grew when two things happened together: lower prices and policies that made it practical to connect to the grid. Programs in Japan in the 1990s and Germany in the 1990s and 2000s are often mentioned as examples. Germany’s feed-in tariff arrangements, which paid owners a set rate for the power they sent to the grid, were influential and copied elsewhere. In the United States, rules such as net metering and various tax incentives helped households. The details varied by country, and these policies were sometimes debated, but they clearly helped build early demand and gave manufacturers a reason to scale up.
For home owners, the change was that they became small producers as well as consumers of electricity. Utilities and regulators had to work out how to count and pay for power flowing in both directions.
Solar farms
Large-scale plants followed. Some early utility projects appeared in California in the 1980s, including a photovoltaic plant at Carrisa Plains, and alongside them were concentrating solar thermal plants in the Mojave Desert that used mirrors to heat fluid and make steam. The thermal approach is a different technology from panels, and a few such plants are still in use.
By the 2010s, falling module prices made photovoltaic solar farms attractive to developers. Today, many sites cover large areas of flat land and produce hundreds of megawatts, and some projects are larger still. They are often built faster than conventional power stations, since the panels are standard units installed in rows, frequently on trackers that follow the sun during the day. Some farms are paired with batteries, floating on reservoirs, or mixed with grazing or crops, though how well such combinations work depends on the site.
Changing how the grid works
Solar power is variable. It stops at night and drops under cloud, and its peak does not always match when people want electricity. This has changed the way grids are managed:
- Operators have to plan for output that rises and falls with weather.
- Midday production in sunny regions can be so high that other plants are asked to reduce output.
- Energy storage, such as lithium-ion batteries, and flexible demand are used to move energy toward the evening.
- Wind farms and solar farms are often considered together, because their output patterns sometimes complement each other.
None of this means solar is a complete answer on its own. Electricity systems vary, and engineers and economists continue to debate how best to balance them. What the history shows is that a technology that was once too expensive for anything but a satellite became an ordinary part of electricity supply in many places.
Other effects
Solar panels also changed energy access in places without grids. Small panels, batteries and lights have provided basic electricity to households and clinics that previously relied on kerosene or diesel, though the scale and cost depend on the region. Manufacturing has shifted, too, with most production now concentrated in a few countries, which has led to discussion of supply chains and trade. And end-of-life management of old panels, including recycling, is an area where practices are still developing.
Takeaway
The impact of the solar panel is not just that it exists. It is that a long chain of uses, starting in orbit and ending in power plants, steadily reduced its cost, and lower cost opened new uses in turn.