The Sun is becoming an increasingly important source of clean electricity. Accurate sunlight forecasts being developed by A*STAR researchers could greatly improve the performance of solar energy plants, making it a viable alternative to carbon-based sources of power.
A photovoltaic power plant can cover up to 50 square kilometers of the Earth’s surface and can generate up to a billion Watts of electricity. This capacity depends on the amount of sunlight at that location, so the ability to predict solar irradiance is crucial for knowing how much power the plant will contribute to the grid on any particular day.
“Forecasting is a key step in integrating renewable energy into the electricity grid,” says Dazhi Yang from A*STAR’s Singapore Institute of Manufacturing Technology (SIMTech). “It is an emerging subject that requires a wide spectrum of cross-disciplinary knowledge, such as statistics, data science, or machine learning.”
Yang, together with Hao Quan from the A*STAR Experimental Power Grid Centre and colleagues from the University of Tennessee at Chattanooga and the National University of Singapore, has developed a numerical approach to weather prediction that efficiently combines multiple datasets to improve the accuracy of solar irradiation forecasts.
Hourly changes in the atmosphere, annual changes in the distance between Earth and the Sun, or 10-yearly changes in the Sun’s internal cycles can all alter the amount of sunlight that reaches the Earth’s surface. These changes occur on very different time scales, and so conventional forecasting methods model variability at different timescales separately, which makes computer processing easier. However, these methods rely on a simple addition of forecasts, with no weighting that makes more use of better forecast sub-series. Moreover, the forecasts they generate are only accurate on the timescale of the original series.
Yang and the team developed a framework that reconciles the different timescales by forming a temporal hierarchy that aggregates forecasts obtained at different timescales, such as high-frequency, hourly data and low-frequency, daily data. “Temporal reconciliation is a type of ensemble forecasting model that forecasts the next day’s solar generation many times, separately, using data of different temporal granularities, hourly, two-hourly, and daily,” explains Yang. “These different forecasts are then combined optimally through statistical models to produce a final forecast.”
The researchers tested their numerical weather prediction method using data from 318 photovoltaic power plant sites in California over a year. Their temporal reconciliation method was shown to significantly outperform other numerical day-ahead forecasts.
UNSW professor Martin Green, who revolutionised photovoltaics, says sun’s power is ‘the best option out there’
By: Sophie Vorrath
The “father of PV” – University of New South Wales professor Martin Green – has become the first Australian to win the global energy prize from a shortlist that included Tesla’s Elon Musk.
UNSW said Green had been selected from 44 contenders from 14 countries by a committee of leading scientists to share the $820,000 prize with Russian scientist Sergey Alekseenko, an expert in thermal power engineering.
It said Green was honoured for revolutionising the efficiency and cost of solar photovoltaics, and making it the lowest-cost option for bulk electricity supply.
Green, the director of the Australian Centre for Advanced Photovoltaics, is a leading specialist in both monocrystalline and polycrystalline silicon solar cells.
In 1989, his team supplied the solar cells for the first photovoltaic system with an energy conversion efficiency of 20%. In 2014 he headed the development team that first demonstrated the conversion of sunlight into electricity with an efficiency of 40%.
Green also invented the PERC solar cell, which accounted for more than 24% of the world’s silicon cell manufacturing capacity at the end of 2017.
The research group he founded at UNSW – the largest university-based PV research group in the world – is broadly credited with driving the enormous reductions in costs in solar PV, largely through the work of Green’s students in establishing manufacturing centres in Asia.
“Not everyone would agree with that attribution,” said Green in an interview with RE on Friday, adding that Tesla’s Musk would have been his pick for the prize for his crucial work of putting electric vehicles on the agenda.
Green was keen to pay tribute to his UNSW solar stablemates, Zhengrong Shi, who left Australia to form Suntech Power in the US, and Stuart Wenham – the “Einstein” of the solar world, who died, aged 60, in December 2017.
“In particular, Stuart created this computer program that was a virtual production line,” Green told RE. “That overcame the language barrier in training hordes of Chinese engineers in setting up these [solar PV] production lines.”
Some 15 to 20 years later, and the global growth of solar PV – now the cheapest new form of energy generation – has soared beyond virtually all predictions.
“If you look at the figures from the last few years, growth has consistently stayed at around 40% a year,” Green said. “If it keeps growing at that rate, we’re looking at hitting a terawatt of solar production in 2024.
“Even if it slows to growth of 20% a year, we are on track to reach production levels of a TW a year in the late 2020s. And that’s the area where you can really start cutting greenhouse gases.”
And that’s what it’s all about – a cheap transition that does not cost more and in fact will likely deliver savings – although some people, and some governments, prefer to remain none the wiser. Which is why awards like this one are so important.
“I think [this is] a good opportunity to get across the message that things have changed with solar and that it’s the best option out there,” Green said. “That’s an important message to get out.
“There’s a growing consensus that we’re going to get most of our energy out of solar down the track. It’s not a matter having to help solar along. It’s not about removing the last remaining barriers – and getting out of the way of [renewable energy].”
Green said removing barriers often meant changing regulations to make them consistent with a solar type of future, as well as overcoming political resistance in places like Australia and the US.
By: Richard Piacentini
The Center for Sustainable Landscapes (CSL) generates all of its own energy and treats all storm and sanitary water captured on-site. An integral part of the Phipps visitor experience, it is the only building to meet four of the highest green certifications: the Living Building Challenge; LEED Platinum; WELL Building Platinum; and Four-Stars Sustainable SITES.
Everything is connected. That is to say, nothing happens in a vacuum. More than 2,000 years ago, Aristotle postulated that nature abhors a vacuum. Nature, like all things, work in systems, where everything is connected.
At Phipps Conservatory and Botanical Gardens, we have celebrated the beauty and importance of the natural world for 125 years and look to it now as inspiration for using systems thinking as a way to help solve the critical challenges that affect us all and provide us with solutions, such as adopting clean energy.
When facing a challenge, we have a tendency to address the symptoms,such as climate change and cancer, rather than the root causes which are often related to our disconnect from nature, our lifestyles and our unsustainable use of natural resources. Addressing symptoms is fragmental and only works in the short-term, as it never corrects the underlying cause. When we strive to understand the interconnectivity of whole living systems, we can appreciate our part within the larger natural and social systems in which we are nested. Only then we can catalyze real and meaningful long-term change.
In her work, regenerative business advocate Carol Sanford describes four paradigms for interacting with the world.
In the extractive model, it is all about “me”; the individual doesn’t care who or what they hurt to get what they want. The world is seen in fragments … there for the taking. This is colonialism.
In the less-bad model, we see a shift in thinking from “me” to “us”; an individual in this paradigm sees the world as fragmented but recognizes the fragments as interconnected and tries to stabilize them. This is where the environmental movement began, as exemplified by the “reduce, reuse, recycle” hierarchy and the first green building certification systems.
The do-good model is also about “us” but recognizes reciprocity; an individual in this model sees the world as fragmented but interconnected and tries to improve it. Some later iterations of green building programs fit this model.
The final paradigm is regenerative. It is about “us,” and seeing the world as a whole interconnected system rather than separate fragments. In a regenerative world, individuals move beyond thinking about themselves in isolation to see the larger social and natural systems that we collectively need to survive. This is the paradigm we need to adopt for the long-term health of ourselves and the planet.
When Phipps Conservatory and Botanical Gardens opened in 1893, most people thought there was no limit to the amount of natural resources we could use or the amount of pollution we could produce. In fact, people thought that humans would conquer nature. Our original conservatory is a great example of that type of mindset; a single-paned glass building designed to grow tropical plants in a temperate climate — from an energy perspective, this is one of the least efficient buildings imaginable.
In the 1990s, Phipps endeavored on a multi-phase master plan to renovate and expand the campus. Through each project, starting with building a Welcome Center, we identified the systemic implications of our actions and evolved our approach. We learned about LEED and discovered how much buildings contribute to the amount of energy and water we use and the pollution we produce.
For over a century, we had been talking about the importance of the environment, so why shouldn’t our buildings reflect that ethos?
This thinking informed the next projects in Phipps’ transformation: the Tropical Forest Conservatory, a giant glasshouse that has no greenhouse effect and is 100 percent passively cooled, and LEED Platinum production greenhouses. Next, we built the Center for Sustainable Landscapes (CSL) a net-positive energy and net-zero water building. The defining standard for the CSL is the Living Building Challenge, which is systems-based and embraces the idea of regenerative thinking. The CSL is remarkable, and five years later, it is still the only building in the world to meet the requirements of the Living Building Challenge, LEED Platinum, WELL Platinum and 4 Stars Sustainable SITES.
Too often, we focus on first costs and fail to align our actions with our values. Take the CSL for example: It cost about 20 percent more than a cheap big-box type of building and not much more than a typical office building; however, it is a much healthier place to work and, in the long run, it will last longer. It uses only a quarter of the energy of a building of comparable size and it generates all the energy it needs onsite without any combustion. It also frees us from the uncertainty of the market, easily outperforming a conventional building in the long run.
We recognize that we operate within living, dynamic, nested systems and that we make reciprocal, mutually beneficial interactions with the larger and lesser systems in which we are nested every day.
This systems-based way of thinking is used to review and design all of our projects, programming and operations. From adopting 100 percent renewable energy campus-wide in 2005 to defining new, socially responsible investment guidelines last year, Phipps is committed to understanding our role in nature and in developing the capacity in everyone we reach to make sustainability a defining component of their lives.
We will not conquer nature. Even if we could, it would be self-defeating, considering human and ecological health are one and the same. We must rethink the status quo and change.
It is not a technology problem and it is not a cost problem; we have the ability and means to solve many of our human and ecological health problems today. We have the capacity, but it is a question of whether we have the will to move beyond short-term symptomatic thinking and do what we know is right. From 2005 to 2016, Phipps reduced carbon dioxide emissions from our buildings by 56 percent per square foot, twice as much and twice as fast as the Paris Climate agreement.
When we have the focus and will to lead the way through regenerative systems thinking, our actions will provide a healthier planet for ourselves and all of the other species that share it.
By: Robbie Harris
The solar energy industry is getting better and better at producing power at lower cost than ever before but storing that energy for a rainy day remains a major roadblock. Batteries have their limitations, but scientists at Virginia Tech are taking a cue from how nature’s plants store energy.
Plants are actually nature’s storage systems for solar energy. They convert it into oxygen on a huge scale. Virginia Tech Chemistry Profess Amanda Morris and her team are working on a way to mimic how plants make that transformation, but instead of oxygen, they want to make methane.
“Methane is a chemical fuel that we use now,” notes Morris. “We can combust it in our boilers at home to heat our houses. There are buses that are powered on methane gas, so you can imagine that we can use that as a direct energy source.”
But, conventionally burning methane sends carbon dioxide into the air. So they’re working on capturing the CO-2 and converting it back to methane, to create an infinitely renewable cycle.
Plants come equipped with that transformation system that begins with oxidizing water, the first step in photosynthesis, but Morris is creating a new kind of molecular scaffold to do it.
“The way that I like to describe it is ‘molecular swiss cheese,’” says Morris. “You can picture a block of cheese with all these holes going through it. Replace the cheese with small chemicals and that’s what we’re working with.”
The goal is to achieve ‘artificial photosynthesis.’ And like the process of photosynthesis in plants, the gases in these methane power plants would be constantly recycled.
“So, we create a recyclable fuel stream. I think that would be a game changer.” But, she adds, “we also could change the way we make every day materials. I mean the plastic that’s on your phone; we could actually think about, how we make precursors to the polymers that are in these plastics. There’s a lot of places where this chemistry could potentially impact our daily lives.”
Morris says several companies are interested in this kind of CO-2 transformation. But her research will take more time.
She gives a shout out to the U.S. Department of Energy. She says she doesn’t mean to be political, but she hopes people will support the DOE for funding this kind of pure research because, this is what it takes to make these kinds of discoveries.
“We can’t necessarily say that our technology is going to be on the market in 10 years,” she says, “but we couldn’t say that about lithium batteries (at one point, either) and now they’re ubiquitous. And it’s really this fundamental research that the Department of Energy supports at universities that pushes our lives further.”
Morris presented her latest findings to DOE a few weeks ago and was told the results are impressive and that this is the first time a Nano molecular structure has shown promise for supporting artificial photosynthesis.
And that means there’s a chance it just might prove to be part of the missing link between creating solar energy and storing it in large quantities.
University of Erlangen-Nuremberg
Storing solar energy is the central challenge facing energy researchers. Alongside traditional solutions such as solar cells or batteries, creative chemical concepts for storing energy are paving the way for entirely new opportunities. Intramolecular reactions are making it possible to transform solar energy and store it in a singular molecule. This may form the basis for constructing energy-storing solar cells.
Electricity from a renewable energy source such as the sun or wind is only available when the wind blows or the sun shines, and it is extremely difficult to store any surplus electricity. New concepts are required—and researchers from the Department of Chemistry and Pharmacy at FAU are counting on chemical concepts for storing energy.
In two joint projects, the scientists are exploring new ideas for using molecules to store solar energy and are investigating molecules and processes that allow energy to be stored efficiently and released in a controlled manner when required. It is even conceivable that stored chemical energy could be converted directly into electrical energy.
The research is based on the so-called norbornadiene-quadricyclane storage system. Norbornadiene (NBD) and quadricyclane (QC) are hydrocarbons and have been under discussion among experts as potential candidates for storing solar energy for some time now. Under the influence of light, a reaction within the norbornadiene molecule is triggered, causing the molecule to transform into quadricyclane. The reaction produces an energy density similar to that of a high-performance battery. Thanks to this property, quadricyclane is also known as “solar fuel.”
The sub-project focusing on photochemical and magnetochemical storage and the release of solar energy in strained organic compounds is led by Prof. Dr. Dirk Guldi and Prof. Dr. Andreas Hirsch. The scientists are working on producing various new groups of NBD and QC derivatives. In addition, they are systematically investigating the influence of photosensitizers and electron acceptors as well as solvents and magnetic fields within this process. The long-term goal of the researchers is to create a closed system-fuel cycle for molecular storage systems.
Prof. Dr. Julien Bachmann, Prof. Dr. Jörg Libuda and Dr. Christian Papp are working together in the sub-project focussing on catalytic and electro-chemical release of solar energy stored in strained organic compounds. The scientists are developing new catalyst systems and electrodes that can be used to convert chemical energy directly into electrical energy. They intend proving the concept behind the functional principle using hybrid boundary surfaces with a suitable electronic structure, chemical structure and electrochemical stability.
The results of both sub-projects could form the basis for building an energy-storing solar cell. The electricity created by solar energy could be stored intelligently and used highly efficiently thanks to intramolecular reactions.