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Next Generation of Greenhouses May Be Fully Solar Powered
Many greenhouses could become energy neutral by using see-through solar panels to harvest energy – primarily from the wavelengths of light that plants don’t use for photosynthesis
Many greenhouses could become energy neutral by using see-through solar panels to harvest energy – primarily from the wavelengths of light that plants don’t use for photosynthesis. Those are the findings of a new modeling study conducted by engineering, plant biology and physics researchers at North Carolina State University.
“Plants only use some wavelengths of light for photosynthesis, and the idea is to create greenhouses that make energy from that unused light while allowing most of the photosynthetic band of light to pass through,” says Brendan O’Connor, corresponding author of the study and an associate professor of mechanical and aerospace engineering at NC State. “We’re able to do this by using organic solar cells because they allow us to tune the spectrum of light that the solar cell absorbs – so we can focus on using mostly wavelengths of light that plants don’t use. However, until now it wasn’t clear how much energy a greenhouse could capture if it was using these semitransparent, wavelength selective, organic solar cells.”
To address that question, researchers used a computational model to estimate how much energy a greenhouse could produce if it had semitransparent organic solar cells on its roof – and whether that would be enough energy to offset the amount of energy the greenhouse required to operate effectively. The model was developed to estimate energy use for greenhouses growing tomatoes at locations in Arizona, North Carolina, and Wisconsin.
“A lot of the energy use in greenhouses comes from heating and cooling, so our model focused on calculating the energy load needed to maintain the optimal temperature range for tomato growth,” O’Connor says. “The model also calculated the amount of energy a greenhouse would produce at each location when solar cells were placed on its roof.”
The modeling is complex because there’s a complicated trade-off between the amount of power the solar cells generate and the amount of light in the photosynthetic band that they allow to pass through. Basically, if growers are willing to sacrifice larger amounts of photosynthetic growth, they can generate more power.
What’s more, the solar cells used for this analysis are effective insulators, because they reflect infrared light. This helps to keep greenhouses cooler in the summer while trapping more warmth in the winter.
The end result is that, for many greenhouse operators, the trade-off could be a small one. Particularly for greenhouses in warm or temperate climates.
For example, in Arizona, the greenhouses could become energy neutral – requiring no outside source of power – while blocking only 10% of the photosynthetic band of light. However, if growers are willing to block more photosynthetic light, they could generate twice as much energy as they required to operate the greenhouse. In North Carolina, a greenhouse could become energy neutral while blocking 20% of the photosynthetic light. In Wisconsin, greenhouses couldn’t become energy neutral using the semitransparent solar cells – keeping the greenhouse warm in winter requires too much energy. However, the solar cells could meet up to 46% of the greenhouse’s energy demand.
“While the technology does use some of the light plants rely on, we think the impact will be negligible on plant growth – and that the trade-off will make financial sense to growers,” O’Connor says.
The paper, “Achieving Net Zero Energy Greenhouses by Integrating Semitransparent Organic Solar Cells,” is published in the journal Joule. First author of the paper is Eshwar Ravishankar, a Ph.D. student at NC State. The paper was co-authored by Ronald Booth, a Ph.D. student at NC State; Carole Saravitz, director of the NC State University Phytotron; Heike Sederoff, professor of plant and microbial biology at NC State; and Harald Ade, Goodnight Innovation Distinguished Professor of Physics at NC State. The work was done with funding from the National Science Foundation, under grant number 1639429.
Source: NC State University
Publication date: Mon 10 Feb 2020
Power Generator With Battery Allows Growers To Go Off-Grid
Rolls-Royce offers with its MTU microgrids the company's first eco-friendly and on-site power generation solution suitable for agricultural applications
Rolls-Royce offers with its MTU microgrids the company's first eco-friendly and on-site power generation solution suitable for agricultural applications. These autonomous power grids combine renewable energy sources with battery storage and gas and diesel generators using a microgrid control system developed by Rolls-Royce, thereby reducing CO2 emissions in power generation. Farmers also lose their dependency on the public grid and can integrate existing energy sources such as photovoltaics or biogas plants, which offers financial benefits. Rolls-Royce will be presenting its microgrid solutions for farming applications at the agricultural trade show Agritechnica from 10 to 16 November.
“Many farmers already have large-scale photovoltaic or biogas plants and are therefore ideally equipped to use a microgrid. Our MTU EnergyPack, the battery container, and a smart energy management system allow the various energy sources to be optimally deployed – both technically and in terms of cost,” explains Cordelia Thielitz, Vice President Microgrids at Rolls-Royce.
The components of a Microgrid can be adapted according to the requirements. The possible applications in agriculture are manifold and offer advantages in terms of return-on-investment (ROI), decentralization and decarbonization. Here are three examples:
Prime power from biomass
Instead of continually pumping all the electrical power won from a biogas plant into the public grid, it can be stored in the MTU-EnergyPack. The smart energy management system then ensures that this energy is only fed into the public grid at times of peak demand when prices are at their highest.
Self-sufficient greenhouses
To flourish and grow, crops cultivated in greenhouses need temperature levels and light exposure to be kept as constant as possible. The heat and power required to achieve that constitute major cost factors for any farmer.
But with combined power generation using a photovoltaic installation and MTU generator linked up to a battery and master controller, the greenhouse can operate independently round-the-clock without recourse to the public grid. Electrical energy generated by photovoltaics and a gas-powered CHP module during the day can be fed into the batteries, where it is subsequently available for lighting the crops and other electrical consumers. Heat from the CHP module is used to heat the greenhouses while CO2 recovered from its exhaust emissions promotes plant growth.
Profitability in times of change
For farmers in Germany who generate power for the public grid using photovoltaics and biogas plants and are subsidized under the German Renewable Energies Act (EEG), the microgrid can be a very worthwhile investment. This is because subsidy rates are falling, with many subsidy schemes soon to reach the end of their twenty-year term. Furthermore, operators of larger-scale PV plants also have to pay an EEG levy on the power they consume themselves.
Integrating these systems with batteries and a smart controller creates new cost benefits for farmers, who reduce their CO2 output at the same time.
“Integrating existing renewable energy sources as a microgrid creates an independent, reliable supply of energy which is gentle on the environment and saves money. For a not inconsiderable number of farmers, microgrids can open up new earning potential,” said Armin Fürderer, head of customer solutions in the power generation section at Rolls-Royce.
For more information:
www.rolls-royce.com/bergen
Publication date: Thu 7 Nov 2019
LA & 8Minute Solar Ink Lowest Cost Solar-Plus-Storage Deal In US History
The Los Angeles Department of Water and Power has signed a groundbreaking 25-year power purchase agreement with 8Minute Solar. The deal will make possible the largest municipal solar plus storage facility in the US
September 11th, 2019 by Steve Hanley
The Los Angeles Department of Water and Power has signed a groundbreaking 25-year power purchase agreement with 8Minute Solar. The deal will make possible the largest municipal solar plus storage facility in the US. But the best part is the combined price for solar energy plus storage is just 3.3 cents per kilowatt-hour, the lowest ever in the US and cheaper than electricity from a natural gas-powered generating plant.
Credit: 8Minute Solar
The electricity will come from a massive solar power plant located on 2000 acres of undeveloped desert in Kern County, just 70 miles from the city. Known as the Eland Solar and Storage Center, it will be built in two stages of 200 MW each, with the first coming online in 2022 and the second phase scheduled to be switched on the following year.
Los Angeles DWP will take 375 MWac of solar power coupled with 385.5 MW/1,150 MWh of energy storage, according to PV Magazine. Neighboring Glendale Water and Power will take 25 MWac of solar plus 12.5 MW/50 MWh of energy. The electricity from Eland I and II is expected to meet between 6 and 7% of Los Angeles’ needs, according to PV Magazine.
The Eland Solar & Storage Center has been engineered by 8minute to provide fully dispatchable power under control of the LA DWP to meet its customers’ demands with reliable and cost-effective power — a capability previously reserved for large fossil fuel power plants. Eland’s ability to provide fully dispatchable power for less than the traditional cost of fossil fuels effectively positions solar PV as an attractive candidate to be the primary source of California’s 100% clean energy future.
In case you didn’t know, the company takes its name from the amount of time it takes the sun’s rays to reach the Earth at the speed of light. In an e-mail to CleanTechnica, Jeff McKay, VP of marketing for the company, says, “Today was a big win for the city of Los Angeles, the people of California and the renewable energy industry as well.
“The project offers a glimpse of the future, with zero-carbon sources providing energy cheaper than fossil fuels to households throughout Los Angeles and the San Fernando Valley — at the lowest combined solar and storage prices on record. While further final regulatory approval is still needed, today was a big step in ensuring this project becomes a reality, and we feel very strongly that this project is a win-win for everyone involved.”
The Eland PPA was supposed to close a few months ago, but the IBEW local that represents the workers at the city-operated natural gas power plants complained their needs were not being addressed properly. It now appears those concerns have been addressed, according to the LA Times.
If the transition to renewable energy is to take place in an orderly and expeditious fashion, it is vital that the needs of workers in legacy industries not be ignored and that positive steps are taken to protect the interests of those who will feel the economic impact of the changes coming for the utility industry.
Tags: 8Minute Energy, Eland Solar, and Storage Center, Los Angeles Department of Water and Power
About the Author
Steve Hanley Steve writes about the interface between technology and sustainability from his home in Rhode Island and anywhere else the Singularity may lead him. His motto is, "Life is not measured by how many breaths we take but by the number of moments that take our breath away!" You can follow him on Google + and on Twitter
This Solar-Powered Cannabis Facility Is Biggest In U.S.
Written by Peter McCusker
The first commercial-scale solar-powered cannabis farm is a “green” template for the industry to follow, says the company behind its creation.
Californian cultivator Canndescent spent $3.75 million retrofitting its 11,000-square-foot growing warehouse in Desert Hot Springs. The commercial-scale solar cannabis project uses 734 solar modules, on seven different carport structures, and can now produce enough power to charge an estimated 20% of U.S. smartphones for a day.
Canndescent founder and CEO, Adrian Sedlin, said in a press statement: “We commissioned the solar project because the modern cannabis consumer deserves and demands that we create exceptional products using exceptional practices.”
“As an industry coming of age right now, it’s natural and appropriate for the cannabis industry and Canndescent to lead the business community in addressing some of the world’s pressing challenges,” he continued.
Desert Hot Springs, CA
The state-of-the-art, clean energy system has a capacity of 283 kilowatts and will reduce the facility’s annual carbon emissions by 365 tons. Two-thirds of U.S. commercial cannabis production facilities are indoor operations, while a further 20% are at least partially indoors. Indoor cannabis facilities require large amounts of energy for lighting, heating, air-conditioning, and dehumidification systems, said the press release.
Indoor cannabis greenhouses are said to consume around 1% of US electricity, according to industry experts. Whilst outdoor growers tax local water resources. As the first cannabis company to use renewable power at a large-scale production facility, Canndescent says it has “created a ground-breaking template for sustainability… uniting water efficiency, energy efficiency and pesticide-free growing in an indoor format.”
Canndescent constructed the project in eight weeks after a two-year struggle to win approval and financing. The project consists of custom carport structures since solar could not be installed on the facility roof due to fire codes, reports Solar Power World.
Canndescent’s Chief Compliance Officer Tom DiGiovanni said: “Given the restrictions around cannabis banking and lending and the complexities of energy projects and California civil construction in general, this was extraordinarily difficult to pull off. Nevertheless, we got it done and have established a template for the ‘green industry’ to go greener.”
Canndescent was set up by Harvard Business School graduate Adrian Sedlin and opened the first municipally-permitted facility in California in 2016. Desert Hot Springs, where Canndescent is based, went bankrupt in 2001 and almost did again in 2014. The town then decided to become the first place in California to allow indoor cannabis farming on an industrial scale, and has experienced a renaissance since.
California legalized the sale and use of marijuana for recreational purposes in 2018.
Walmart To Install Solar Panels On 19 Of Its Stores In Illinois
Walmart has reached an agreement with a California company to install solar systems at two distribution centers and 19 stores, including those in Belleville, O’Fallon, Sparta and Litchfield.
This Walmart video shows rooftop and ground-mounted solar panels at some of its stores and distribution centers in the United States. The company recently announced plans to expand its solar program to 21 sites in Illinois.By Teri Maddox
BY TERI MADDOX
November 16, 2018
The nation’s largest retailer is joining the solar boom in Illinois next year.
Walmart has reached an agreement with a California company to install solar systems at two distribution centers and 19 stores, including those in Belleville, O’Fallon, Sparta and Litchfield. It’s billed as a way to save money on electricity and help the environment by reducing carbon emissions.
The move was prompted by the state’s new Adjustable Block Program, which provides incentives for commercial and residential rooftop solar projects, as well as community solar farms.
“We can meet or beat our current cost of energy (under the agreement),” said Katherine Canoy, Walmart’s senior manager for renewable energy, speaking by phone from Bentonville, Arkansas. “From a business perspective, it makes sense for us on a lot of levels.”
The company already has solar systems at about 350 of its 5,000 sites in the United States, including Walmart and Sam’s Club stores. Canoy said installations don’t have a direct effect on prices, but the company’s increasing use of renewable wind and solar energy will help keep them low in the long run.
For Walmart’s first 21 solar projects in Illinois, the retailer is partnering with SunPower, a company based in San Jose, California. It designs, installs and maintains commercial solar systems all over the country, often combining rooftop and ground-mounted solar panels.
Most customers are able to generate 40 to 75 percent of their electricity with solar, said Robert Rogan, SunPower’s senior director of strategy. Walmart generates 5 to 70 percent at its existing solar sites.
“It really varies from store to store, depending on how much of the roof space we can utilize and also how much energy that store is using,” Rogan said.
Some Walmart stores have skylights and air-conditioning units on their roofs, and climate can affect how much electricity is needed to heat and cool buildings.
This photo shows a commercial solar system installed by SunPower, a company based in San Jose, California. It’s designing systems for 19 Walmart stores and two distribution centers in Illinois.
Canada: New Step In Development of Commercial Geothermal Power
Canada: New Step In Development of Commercial Geothermal Power
Climeon receives the world’s first order for a geothermal power plant in Canada from Borealis GeoPower. The order relates to a demonstration project named Sustainaville, in Valemount, British Columbia. It includes delivery of three 150 kW Climeon modules and is valued at approximately EUR 1,000,000.
The municipality of Valemount is situated near the end of a transmission line. The distributed power production from the Climeon Heat Power solution will contribute to Valemount’s economic development by providing additional energy to the area. Borealis GeoPower has conducted extensive field work and is confident that the Climeon Heat Power system can operate at optimal levels even when there are large variations in flow and temperature.
“Our impact goes deeper than the drilling. We provide energy and food security solutions with an emphasis on "please in my backyard" from the local community and Indigenous Peoples. We look forward to working with the low temperature Heat Power market leader Climeon and our myriad stakeholders on bringing the Sustainaville project to life. Thanks goes out to the British Columbia and other governments involved in this project for their continued support,” says Alison Thompson, Co-Founder and CEO of Borealis GeoPower.
”We are very excited about the possibility to work with Borealis on this project. The potential for low-temperature geothermal heat power is substantial and it can be produced almost anywhere in the world. This new order, together with orders from Iceland, USA and Germany earlier positions us as a key player in the transition to renewable energy,” says Ruben Havsed, Head of Sales Geothermal at Climeon.
Natural Resources Canada contributed CAD 1,541,000 through its Energy Innovation Program.
“Geothermal power is an exciting avenue that offers us so much to explore. By bringing this demonstration of renewable power to our country, we have the opportunity to showcase clean reliable energy generation, supporting the transition away from fossil fuels to more sustainable options. Our government is proud to support Borealis and Climeon to discover how this demonstration project may lead to further geothermal energy deployments that will help our country create a brighter future,” says The Honourable Jim Carr, Canada’s Minister of Natural Resources.
“Alberta Innovates is pleased to have played a role in supporting a geothermal company in Alberta,” says John Zhou, Vice President of Clean Energy for Alberta Innovates. “Alberta’s engineering expertise can help in developing geothermal resources in Canada and around the world”.
Drilling of the wells will start in the Spring of 2018 and the delivery of the Climeon Heat Power modules is planned for the end of 2018. Together with Borealis GeoPower, Climeon is taking an important step to demonstrate the viability of commercial geothermal heat power in Canada.
The demonstration project makes Borealis GeoPower a leader in the Canadian geothermal sphere. Longer term, the company aims to make remote communities less dependent on fossil fuels by heating and fully powering them with clean energy from geothermal resources.
Geothermal power is in service day and night throughout the year. It can provide the same regulating power as coal or diesel-fired power plants as part of the heat power category, making it the best option to offer clean power in quantities large enough to replace fossil energy sources.
Canada is the only large country in the volcanic area surrounding the Pacific Ocean, called the Ring of Fire, that still lacks geothermal power production. Canada is estimated to have similar geothermal potential as USA which has 3.5 GW of installed geothermal power production capacity. Canada’s know-how and expertise from the oil and gas industry together with the progressive geothermal sector sets a good foundation for the geothermal market to accelerate in the coming years.
For more information:
Climeon
climeon.com
Publication date: 4/5/2018