AU in der HALLERTAU, Germany — Bright green vines snake upwards 20 feet toward an umbrella of solar panels at Josef Wimmer’s farm in Bavaria.
He grows hops, used to make beer, and in recent years has also been generating electricity, with solar panels sprawled across 32 acres of his land in the small hop-making town of Au in der Hallertau, an hour north of Munich in southern Germany.
The pilot project — a collaboration between Wimmer and local solar technology company Hallertauer Handelshaus — was set up in last fall. The electricity made at this farm can power around 250 households, and the hops get shade they'll need more often as climate change turbocharges summer heat.
Solar panels are mounted July 19 on poles above a hops field near Au in der Hallertau, Germany. The use of solar panels atop crops has been gaining traction in recent years as incentives and demand for clean energy skyrocket.
Solar panels atop crops has been gaining traction in recent years as incentives and demand for clean energy skyrocket. Researchers look into making the best use of agricultural land, and farmers seek ways to shield their crops from blistering heat, keep in moisture and potentially increase yields. The team in Germany says its effort is the first agrivoltaic project that's solely focused on hops, but projects have sprouted around the world in several countries for a variety of grains, fruits and vegetables.
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Beer-making hops can suffer if exposed to too much sun, said Bernhard Gruber, who's managing the project's solar component — and since there were already solar installations on the farm, it made sense to give them a second purpose by mounting them on poles above the crops.
In addition to shielding plants from solar stress, the shade could mean “water from precipitation lasts longer, leaving more in the soil” and that “the hops stay healthier and are less susceptible to diseases,” Gruber said. A scientific analysis of the benefits for the plants will be concluded in October.
The farm is working with researchers to understand how to get the balance right, so the hops get enough shade and sunlight for the best harvests each year.
Solar panels are mounted on poles above a hops field July 19 near Au in der Hallertau, Germany. The use of solar panels atop crops has been gaining traction in recent years as incentives and demand for clean energy skyrocket.
In the U.K., where weather is also getting hotter and more variable, a team of researchers is looking at how to retrofit solar panels onto greenhouses or polytunnels — frames covered in plastic where crops grow underneath — with semi-transparent or transparent installations.
“You can get your renewables from the land that you do have covered and you don’t need to do these massive solar arrays on good agricultural land, which is what you’ve tended to see around to date," said Elinor Thompson, a reader at Greenwich University who’s leading the research.
Thompson, a plant biologist, and her team are working with a fruit farm in Kent in southern England to make sure the plants also get the best out of solar structures.
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“Nobody can afford to lose crop, especially in current conditions,” she said. “We are assuming that British summers are going to get hotter, we have a problem with water shortages, we need to be efficient in all parts of agriculture.”
Having shade where it's useful and monitoring the effects of different arrangements of solar panels on a variety of crops will help the world prepare for a more climate-variable future, Thompson said.
In East Africa, which has suffered from a long and punishing drought that scientists said was worsened by human-caused climate change, solar panels can also help keep moisture in plants and soil and reduce the amount of water needed, said Richard Randle-Boggis, a research associate at the University of Sheffield who's developing two agrivoltaic systems in Kenya and Tanzania.
Randle-Boggis said the systems can be used for “climate change resilience and a way of improving the growing environment for crops, while also providing low carbon electricity.” He said that some of the crops under the partial shade of solar panels are using around 16% less irrigation.
The solar-covered farms saw increased yields for maize, Swiss chard and beans, and while growers experienced lower yields for onions and sweet peppers, they still had the added benefit of clean electricity generation.
But crop yields can also “vary depending on the weather conditions because we’re seeing the climate changing,” said Randle-Boggis, although he added he was “really surprised and impressed with some of the results that we’re seeing” for solar-covered crops.
“Maize is grown by about 50% of farmers in Tanzania. Maize is also a sun-loving plant. So the fact that we had an 11% yield increase in maize … is a phenomenal result,” he said.
Solar panels above a hops field near Au in der Hallertau, Germany.
And Randle-Boggis said these projects can continue to be replicated around the world for many different crops, as long as systems are “designed with the local context in mind.”
A future with more crops under solar is Gruber's hope for beer-making hops, too.
“At the end of the year we will set up another solar park over hops,” which will have about 10 times the electricity-generating potential as the current project, Gruber said.
But that's still just the beginning.
“We're getting lots of inquiries from hop farmers," he said, "even from abroad.”
How the cost of solar panels has fallen
How the cost of solar panels has fallen
The energy the earth absorbs from the sun in just hour is enough to power the planet for a year. Why, then, is the world not taking greater advantage of this renewable energy source?
Despite the detrimental environmental effects, fossil fuel infrastructure is well-established and difficult to phase out. On top of that, humans have only recently managed to harness the sun's energy in a way that is also efficient, scalable, and relatively affordable. About 80% of the world's energy still comes from fossil fuels like oil, coal, and natural gas.
Solar energy capacity in the United States is made up of large- and small-scale systems. Solar energy at utility scale—large facilities that generate at least 1 megawatt of power for the grid—represents the largest solar market in the U.S. The second largest market is residential, followed by commercial and community.
Rocket Solar cited data from the Energy Information Administration to look at how the cost of solar panels has fallen and what that means for electric power in the U.S.
At one time, solar-generated electricity was cost-prohibitive; however, it became increasingly attainable as its price decreased by about 90% between 2009 and 2019. One of the main reasons the costs have fallen so dramatically is that the photovoltaic solar panels became more efficient and less expensive. Similarly, as efforts to increase solar energy production have grown, the cost of necessary components has decreased. Private and government-funded research and development also played a key role in reducing solar costs.
Keep reading to discover how the cost of solar panels has fallen.
Solar panel shipments have grown significantly in the last 15 years
Solar panels shipped to the U.S., measured in electricity-generating capacity, rose to a record 28.8 million peak kilowatts in 2021, according to the EIA. This unprecedented high was achieved despite supply chain constraints and higher-than-usual material costs over the last several years.
About 80% of solar panels shipped in the U.S. were imported from Asia. California, Texas, Florida, Georgia, and Illinois accounted for roughly half of all received shipments in 2021. Utility-scale and residential solar installations have grown substantially year over year, up 25% and 34%, respectively.
Lower prices have followed that growth
Today, solar panels are 94% cheaper than they were in 1989. As the production and energy-generating capacity of solar panels has improved over the last few decades, the cost has dropped significantly.
This is a quintessential example of economies of scale in manufacturing. Dating back even further to the mid-1970s, every time the global cumulative capacity of photovoltaic cells doubled, prices saw the same relative decline, according to cost and capacity data analyzed by Our World in Data.
Over the last several years, construction costs for renewable energy have increased in line with record-high demand and project delays, rising raw material costs, supply chain and shipping constraints, and increased solar construction contracts. This has made new solar construction more expensive than other forms of renewable energy at a utility scale, despite dramatic cost reductions.
Falling prices made solar a competitive electricity source with fossil fuels
The efficiency and affordability of solar, combined with the skyrocketing costs of fossil fuels, have made solar a competitive electricity source on a large and small scale.
Roughly 50 years ago, solar technology was so expensive that it could only be used on satellites. Over the next 20 years, costs fell dramatically. In 1976, solar panels cost $106 per watt and had a capacity of 0.3 megawatts—enough to provide electricity for only 20 people annually—which was highly impractical.
Today, they cost less than 50 cents per watt with a capacity of more than 100,000 megawatts. While solar energy has become more affordable, global events over the last several years have created huge volatility in the crude oil market, driving up the cost of energy derived from fossil fuels.
This story originally appeared on Rocket Solar and was produced and distributed in partnership with Stacker Studio.
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