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Green Energy
California’s new solar energy proposal removes hefty grid connection fee
California regulators on Thursday revised their proposal for rooftop solar systems credits, a contentious matter as the state tries to expand renewable energy and respond to critics who want more equitable distribution of incentives.
The new proposal offers hundreds of millions of dollars of new support for low-income customers, while excluding a monthly tax for solar homes to connect to the grid, a move critics say effectively favors richer Californians as they own the lion’s share of the clean energy system.
In a 250-page proposed decision, regulators outlined reforms to the so-called “net energy metering”, a state policy that issues credits to solar energy customers for generating excess electricity and feeding it back to the grid.
The proposal will not affect current home solar owners and will maintain their current compensation, the California Public Utilities Commission (CPUC) said. It withdrew a previous proposal from December last year that would have charged Californians with new solar installations a hefty $8 per kilowatt per month to cover the cost of maintaining the grid.
Shares of rooftop solar system providers, including Sunrun Inc (RUN.O), SunPower Corp (SPWR.O) and Sunnova Energy International Inc (NOVA.N), closed 20% to 27% higher on Thursday.
“This has been an overhang for rooftop solar stocks that would be alleviated if passed similar to today’s proposal,” said Morningstar analyst Brett Castelli.
However, the proposal would also reduce export rates, or credits customers receive for feeding their surplus solar power back into utilities.
Though the solar industry is still reviewing the proposed decision, “based on an initial analysis it would cut the average export rate in California from $0.30 per kilowatt to $0.08 per kilowatt,” said the California Solar & Storage Association (CALSSA), a clean energy business group.
“The CPUC’s new proposed decision would really hurt. It needs more work or it will replace the solar tax with a steep solar decline,” the CALSSA added.
Affordable Clean Energy for All spokesperson Kathy Fairbanks said, “It is extremely disappointing that under this proposal, low-income families and all customers without solar will continue to pay a hidden tax on their electricity bills to subsidize rooftop solar for mostly wealthier Californians.”
The CPUC has previously justified its proposals by saying it wants to encourage battery storage so excess power can be stored instead of sold. The state has a target to generate 90% of its electricity from clean sources by 2035, but its grid is barely recovering from record heat waves this year.
The new policy proposals outlined by the CPUC include an additional $900 million to support battery and solar systems, mostly for low-income customers.
Sunrun Chief Executive Mary Powell said while the company is still studying the proposed decision, “customers will not be unduly penalized for generating and storing (in batteries) local clean energy to both participate in modern ways to power their lives and contribute to the fight against climate change, which is an important move in the right direction.”
While the new changes would encourage California’s solar and storage market, the state’s residential solar-only market would become uneconomic, Roth Capital Partners analyst Philip Shen wrote in a note.
The CPUC will vote on the proposal on Dec. 15. If adopted, it will take effect on April 15 next year.
Biofuel combined with advanced engine design shows promise for energy and cost savings
Biofuel is closer to becoming a cost-competitive, climate-friendly solution for slashing carbon emissions in cars and trucks, according to two new studies.
The U.S. Department of Energy’s (DOE) Argonne National Laboratory has collaborated with the DOE’s National Renewable Energy Laboratory (NREL), Pacific Northwest National Laboratory (PNNL) and Idaho National Laboratory (INL) on the research. Results showed that biofuel combined with advanced engine design can reduce greenhouse gas (GHG) emissions by roughly 60% while improving fuel efficiency or reducing tailpipe emissions.
Argonne energy system analyst Pahola Thathiana Benavides, NREL process engineer Andrew W. Bartling and PNNL engineer Steven Phillips were lead analysts for the two studies published in ACS Sustainable Chemistry & Engineering.
Biofuel has significant advantages over petroleum gasoline. But the engines themselves are also critical to energy efficiency. Designing low-carbon fuels and engines to work together can maximize energy use and vehicle performance.
“We are at the intersection of new innovations in both engines and biofuel,” said Troy Hawkins, Argonne’s group manager, fuels and products group, an author on both ACS Sustainable Chemistry & Engineering studies. “Our goal was to develop new biofuels blended with conventional fuels to improve engine performance. This means a gasoline-powered car or truck could go further on the same amount of fuel. Or a diesel vehicle could meet more stringent emissions standards.”
In both studies, Argonne scientists worked with other national labs to identify promising fuels for different engine types. Researchers considered cost, environmental impact and potential for expanding to commercial markets.
Argonne is part of the Co-Optimization of Fuels & Engines (Co-Optima) initiative jointly led by DOE’s Office of Energy Efficiency and Renewable Energy, Bioenergy Technologies Office and Vehicle Technologies Office. Co-Optima’s consortium consists of nine national laboratories and over 20 university and industrial partners. The consortium studies how simultaneous innovations in fuel and engines can boost fuel economy and vehicle performance while reducing emissions.
Scientists and experts at every DOE laboratory played an important role in each phase of the research, Hawkins said. “This research is a really good example of how laboratories can work together to help the DOE accomplish its mission.”
Finding biofuel pathways
Co-Optima’s research builds on the goal to identify and understand bioblendstocks, or biofuel. Biofuel is produced from biomass—organic materials including plants, agricultural waste and wet waste. Biofuel can be blended with conventional fuel to reduce emissions and improve fuel and engine performance.
Collaborating with Co-Optima fuel experts, researchers used a screening process to develop a list of biofuels for their research, Benavides said.
Argonne scientists developed the list of biofuels working with experts including PNNL technical team manager and Co-Optima Leadership Team member Daniel Gaspar, NREL senior scientist Gina Fioroni, NREL senior research fellow Robert McCormick, and Anthe George, senior manager at DOE’s Sandia National Laboratories (SNL).
“We worked with other experts to use specific criteria to narrow many biofuel candidates down to a short list for our research. This list was developed based on the required properties and the engine’s combustion mode,” Benavides said.
Converting biomass to biofuel is a complex process involving variables in feedstock, conversion technologies and fuel types. It is especially challenging finding biofuel pathways that also meet economic, technology and energy goals.
One study was co-first-authored by Benavides. The team assessed 12 biofuel production pathways for optimizing multimode internal combustion engines. Multimode engines can deliver greater efficiency and cost savings by using different methods of ignition, combustion and/or fuel-preparation, depending on driving demands.
Researchers used renewable biomass feedstock found in forestry byproducts such as wood waste and agricultural byproducts such as corn stover. They used conversion technologies including either fermentation, catalysis under high heat and pressure, or a combination of both.
“We found that not only can seven biofuels be produced cost-competitively, but that these seven are varied in terms of feedstock used and conversion technology,” Bartling said. “This means that biorefineries can be more flexible in choosing where and how to build their facilities.”
NREL and PNNL researchers did a techno-economic assessment of the biofuel production pathways, analyzing cost and technology performance.
“Our findings showed that many of the biofuels are competitive with the current cost of petroleum fuel,” Phillips said.
Researchers also analyzed environmental impact. A life cycle analysis of the pathways using Argonne’s GREET (Greenhouse Gases, Regulated Emissions, and Energy used in Technologies) model showed impressive results. Ten biofuels have the potential to reduce GHG emissions by 60% compared to petroleum gasoline. The list includes alcohols, furan mixtures and olefins.
Biofuel promising for diesel engines
The second study was co-first-authored by Bartling. Researchers analyzed 25 pathways for producing biofuel optimized to improve combustion for mixing-controlled compression ignition engines. These are a type of diesel engine mainly used for freight transportation.
To develop biofuel production pathways, researchers used feedstocks ranging from plant materials such as wood chips or corn stover, to oils from soybean and cuphea, to wet wastes and recycled grease. They used conversion technologies including fermentation, gasification, and hydrothermal liquefaction.
“The diverse set of biomass resources available in the U.S. has great potential to replace a portion of fuels and chemicals that now come from petroleum,” said Damon Hartley, INL’s Operations Research and Analysis Group lead. “However, one of the largest barriers is the wide variability in quality in the raw materials. This can have a large impact on how the material performs in conversion.”
As with the first study, most of the technologies performed well. Most of the biofuels were cost-competitive with current gas prices.
In terms of environmental impact, GHG emissions were reduced more than 60% in 12 of the 25 pathways, according to the GREET life cycle analysis.
“We evaluated the life cycle GHG emissions for each mixing-controlled compression ignition engine pathway. This included not only the tailpipe emissions but also upstream emissions resulting from biomass cultivation, feedstock transportation, biofuel production and biofuel distribution,” Hawkins said.
Creating a biofuel playbook
Researchers did not intend to produce a definitive list of biofuels, Benavides said. Instead, the studies offer a guide for stakeholders on selecting biofuel pathways that best meet their needs.
“We provide researchers and industry guidance on assessing biofuels based on a number of complex variables,” Benavides said. “The life cycle and techno-economic analysis is important in guiding stakeholders as early as possible. We can’t tell stakeholders what choices to make. But these tools can point them in the right direction from the beginning.”
While many of these biofuel pathways could potentially be cost-competitive, it is too soon to lock in prices in a constantly fluctuating gas market. “The challenge is providing cost-competitive prices in the long term,” Hawkins said.
While these biofuel production pathways target cars and diesel trucks, Argonne researchers are also studying the potential for using these pathways in hard-to-electrify sectors like aviation and maritime industries. The goal is to bring biofuel to market across a range of industries as quickly as possible.
“DOE is constantly working on sustainable solutions for decarbonizing the transportation sector. Biofuel is a big piece of that,” Hawkins said. “We will continue to expand on Co-Optima’s important work.”
Along with Argonne, ORNL, NREL, PNNL, INL, and SNL, other U.S DOE national labs in the Co-Optima Initiative are Los Alamos, Lawrence Berkeley, and Lawrence Livermore national laboratories.
ESA plans to investigate wireless power from space
Solar power gathered far away in space, is seen here being transmitted wirelessly down to Earth to wherever it is needed. ESA plans to investigate key technologies needed to make Space-Based Solar Power a working reality through its SOLARIS initiative. One such technology—wireless power transmission—was recently demonstrated in Germany to an audience of decision makers from business and government.
The demonstration took place at Airbus’ X-Works Innovation Factory in Munich. Using microwave beaming, green energy was transmitted between two points representing “Space” and “Earth” over a distance of 36 meters.
The received power was used to light up a model city, produce green hydrogen by splitting water and even to produce the world’s first wirelessly cooled 0% alcohol beer in a fridge before serving it to the watching audience.
For a working version of a Space-Based Solar Power system, solar power satellites in geostationary orbit would harvest sunlight on a permanent 24/7 basis then convert it into low-power density microwaves to safely beam down to receiver stations on Earth. The physics involved means that these satellites would have to be large, on the order of several kilometers in size to generate the equivalent power of a typical nuclear power station, and the same being true for the collecting “rectennas” down on Earth’s surface.
Achieving this vision would require technical advancements in areas such as in-space manufacturing and robotic assembly, low-cost high-efficiency photovoltaics, high power electronics and radio frequency beam forming. Further research to confirm benign effects of low-power microwaves on human and animal health and compatibility with aircraft and satellites would also be undertaken.
ESA’s SOLARIS—being proposed to Europe’s space ministers at the Agency’s Council at Ministerial Level on 22–23 November—will research these technologies, to allow Agency Member States to make an informed choice on future implementation of Space-Based Solar Power as a new source of clean, always-on “baseload” power supplementing existing renewable power sources, helping Europe to attain Net Zero by mid-century.
In addition, any breakthroughs achieved in these areas will also benefit many other spaceflight endeavors as well as terrestrial applications.
Alternative to aviation fuel based on an oxygenated nanofluid
Aviation is a big user of fossil fuels and, as such, is a heavy producer of carbon emissions. Sustainability is high on the agenda. New work in the International Journal of Sustainable Aviation has reviewed the thermo-physical properties of an alternative to aviation fuel based on an oxygenated nanofluid.
Selçuk Sarıkoç of the Department of Mechanical Engineering at Amasya University in Turkey, and Nwabueze Emekwuru of the School of Mechanical, Aerospace, and Automotive Engineering at Coventry University, Coventry, United Kingdom, point out that oxygen additives make for a leaner burn in internal combustion engines and reduce pollution. The additives ensure complete and efficient combustion of the fuel. They point out that additives in the form of nanoparticles of metal and non-metal oxides can improve the combustion processes still further. Alumina, zinc oxide, titania, ceria, and silica have all been investigated as nanoparticle additives for fuels.
The team’s survey of the state-of-the-art in nanofluid-based aviation fuels reveals that oxygenated additives, such as alcohol and metal oxide nanoparticles improve the thermal and physical properties of fuels even boosting total calorific value of the fuel, accelerating the combustion process, and reducing soot formation through cleaner burning of the fuel. Overall engine performance is improved with such additives. The presence of oxygen within the fuel itself contributes significantly to the improvement in combustion.
However, the team also points out that the presence of the nanoparticles leads to better heat transfer and their high surface area to volume ratio allows for more effective interaction between oxygen and the fuel molecules to boost the combustion reactions at high altitude through a catalytic effect.
Improvements in engine performance are always welcome in aviation. Such improvements can effectively boost useful load-carrying capacity, extend flight range, allow higher altitude flying, and improve fuel economy.
Check out this offshore wind farm’s massive gravity-based foundations
All 72 of the 5,000-tonne gravity-based foundations for France’s 500-megawatt (MW) Fécamp offshore wind farm are now complete.
All about the Fécamp offshore wind farm
The €2 billion ($2.25 billion) Fécamp wind farm features 71 offshore wind turbines with a capacity of 7 MW each. It will generate electricity for around 770,000 people in Normandy.
Each of Fécamp’s 71 gravity-based foundations, which were built at the Grand Port Maritime site in Le Havre, measures between 48m (157 feet) and 54m (177 feet) in height.
The Consortium of Bouygues Travaux Publicis, Saipem, and Boskalis (BSB) supplied and installed the foundations for the Fécamp offshore wind farm, which is sited between 13 and 22 km (8 and 13.6 miles) off the coast of Normandy. The first foundation was transported out to sea by barge and installed in August.
The three companies were awarded the €552 million contract in early 2020 by EDF Renewables, Canadian energy infrastructure company Enbridge, and German clean energy developer wpd Offshore. The started manufacturing Fécamp’s gravity-based foundations in December 2020.
Check out the load-out operations for these giant foundations in this short video:
Meanwhile, the wind turbines were made at the Siemens Gamesa Renewable Energy (SGRE) manufacturing plant in Le Havre and assembly is done at the Port of Cherbourg.
The Fécamp wind farm is expected to come online in 2023.
What’s a gravity-based foundation?
Gravity-based foundations for offshore wind farms are made on land of precast concrete, and they’re either taken to sea by ship or floated out. They can be sited in depths up to 30m (98 feet). The NRDC explains:
Once offshore, the gravity-based foundation is filled with water and sand, sinking the base so that it sits firmly on a layer of gravel that has been prepared on the seabed. It is then ready for the wind turbine to be installed on top of the foundation.
Windpower Engineering explained the advantages of gravity-based foundations:
- Uses lower-cost materials like concrete and steel.
- Proven technology borrowed from oil and gas industries.
- Some designs do not need crane installation.
- Tugboats can move port-assembled floated-to-fixed GBFs into place, reducing costs and risk.
And they also explained what’s not so good:
- Seabed preparation, like dredging, is typically required. This can disturb a significant amount (up to 7%) of the wind farm’s site.
- A larger installed footprint may increase the turbine’s environmental impact.
- Invasive species introduction is possible when towing foundations from port to site.
