Solar Energy

Is it worth investing in solar PV with batteries at home?

Published

4 years ago

March 21, 2021

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Is it worth investing in solar PV with batteries at home?

Solar energy is a clean, renewable source of electricity that could potentially play a significant part in fulfilling the world’s energy requirements, but there are still some challenges to fully capitalizing on this potential. Researchers looked into some of the issues that hamper the uptake of solar energy and proposed different policies to encourage the use of this technology.

Installing solar panels to offset energy costs and reduce the environmental impact of their homes has been gaining popularity with homeowners in recent years. On a global scale, an increasing number of countries are similarly encouraging the installation of solar photovoltaics (PV) at residential buildings to increase the share of renewable energy in their energy mix and enhance energy security. Despite the promising advantages this mode of electricity generation offers there are still a number of challenges that need to be overcome.

Batteries to store excess electricity

Solar PV electricity generation peaks during the day when electricity demand is low, resulting in overproduction – especially on weekdays when people are usually not at home. Currently, this excess electricity supply is typically exported to the central electricity grid, but ideally, homes that have solar panels should be able to store overproduction of solar electricity, for example, using batteries, and consume it in the evening when demand is high and there is no solar electricity generation.

The problem is that the investment cost for batteries is currently quite high, which makes it economically unprofitable for consumers to pair their solar PV with a battery. In their new study published in the journal Applied Energy, researchers from IIASA, University College London, UK, and Aalto University, Finland, looked into this challenge and proposed different policies to encourage residential electricity consumers to pair solar PV with battery energy storage.

“We wanted to determine whether investing in residential solar PV combined with battery energy storage could be profitable under current market conditions for residential consumers and what kind of support policies can be used to enhance the profitability of stand-alone batteries or PV-battery systems.

On top if this, we also wanted to compare the system (or regulatory) cost of each PV-battery policy to the benefit of that particular policy for residential consumers who invest in these technologies,” explains lead author Behnam Zakeri, a researcher with the IIASA Energy, Climate, and Environment Program.

Benefits of using battery storage

The study shows that without a battery, homeowners only use 30-40% of the electricity from their solar PV panels, while the rest of the electricity is exported to the grid with very little to no benefit for the owner. With a home battery, the self-consumption of solar PV in the building almost doubles, allowing the residents to reduce electricity imports from the grid by up to 84%, which can in turn help the owner to become less dependent on the grid and electricity prices.

In addition, the researchers found that while PV-batteries are presently not really profitable for residential consumers, they can become so with the implementation of slightly different policies and regulations, even in high-latitude countries where solar irradiation is relatively low.

Energy policies for a decentralized energy system

The authors propose some novel energy storage polices that offer a positive return on investment between 40% and 70% for residential PV-battery storage, depending on the policy. These include, among others that national renewable energy policies adopt more innovative incentives to enhance the economic profitability of decentralized green energy solutions based on the contribution of these systems to the grid.

The results indicate that this can be easily achieved by, for example, rewarding consumers for using their solar PV generation onsite, instead of encouraging them to export the excess solar energy they produce to the grid.

The researchers further posit that the way utility companies and electricity distribution firms generate income today may itself be a hindrance to promoting the self-consumption of renewable energy in buildings, as these companies generally charge consumers for each unit of electricity imported from the grid.

If consumers therefore become independent from the grid, grid operators and utility companies would lose a significant part of their income. Such a scenario calls for new business models and operating modes to guarantee that central utilities do not see decentralized solutions as a threat to their revenues.

In today’s renewable electricity generation environment, capital subsidies are one option to partly pay for investment in batteries. The study points out that these policies are costly for the system, and may not automatically result in system-level benefits as they do not reward the optimal use of batteries. In this regard, Zakeri and his colleagues propose a “storage policy” that rewards residential battery owners to store and discharge electricity whenever the system needs it.

The profitability of PV-battery systems of course also depends on the type of retail pricing mechanism in the system. The findings indicate that dynamic electricity pricing at the consumer side, such as hourly electricity prices with an enhanced gap between off-peak and peak prices, will encourage consumers to use home batteries to benefit from charging at low price hours and discharging the battery when the electricity price is high. This way of operating a home battery could help reduce the pressure on the electricity grid at peak times, which has significant benefits for the system.

“Traditional, central energy structures are transitioning to new systems based on decentralized, renewable energy solutions. This requires more flexible, modern, and effective policies that can guarantee the social and economic benefits of the energy transition. We hope our analysis contributes to a better understanding of the role of some energy policies that can promote decentralized energy solutions,” Zakeri concludes.

Research Report: “Policy options for enhancing economic profitability of residential solar photovoltaic with battery energy storage”

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Solar Energy

China’s solar goes from supremacy to oversupply

Published

1 hour ago

October 10, 2024

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China’s solar goes from supremacy to oversupply

By Oliver HOTHAM

Beijing (AFP) Oct 10, 2024

Strong state support and huge private investment have made China’s solar industry a global powerhouse, but it faces new headwinds, from punitive tariffs abroad to a brutal price war at home.

Officials meeting in Baku next month for the COP29 summit hope to agree on new finance targets to help developing countries respond to climate change, including ditching fossil fuels.

Last year, countries agreed to triple global installed renewable energy capacity by 2030.

China is installing almost twice as much solar and wind power as every other country combined.

And it dominates the market.

It makes eight out of every 10 solar panels and controls 80 percent of every stage of the manufacturing process.

It is also home to the world’s top 10 suppliers of solar panel manufacturing equipment, and its related exports hit a record $49 billion last year, according to Wood Mackenzie.

That supremacy is not accidental: Chinese state support has been key, analysts say.

Beijing invested over $50 billion in new solar supply capacity from 2011 to 2022, according to the International Energy Agency.

The industry has also benefited from access to cheap raw materials, readily available capital from state-owned banks, and huge engineering manpower.

“Chinese producers were ahead of everyone else on cost,” said Lauri Myllyvirta, co-founder of the Centre for Research on Energy and Clean Air, a climate think tank.

“That meant new investment takes place in China, because that’s where it’s most competitive,” he told AFP.

The focus has driven a “steep learning curve… both in solar cell technology and manufacturing know-how”, added Johannes Bernreuter, a longtime solar industry analyst.

That in turn has created “an efficient industry ecosystem”, he said.

– ‘Overcapacity’-

As countries around the world race to convert their power systems, China’s solar supremacy has become a growing concern.

The United States and other Western countries have accused Beijing of deliberate “overcapacity” and flooding global markets with cut-price solar exports intended to undercut competition.

Washington has doubled tariffs on Chinese panels to 50 percent, part of a broader package targeting $18 billion worth of Chinese imports in strategic sectors including electric vehicles, batteries, critical minerals and medical products.

The European Union is also probing Chinese-owned solar panel manufacturers for allegedly receiving unfair subsidies.

Most US solar panel imports now come from Southeast Asia, but Washington says Chinese manufacturers have relocated operations there to circumvent barriers.

China also accounts for almost all of Europe’s imports of solar panels from outside the bloc.

That means many markets will struggle to catch up “with two decades of very forceful and very successful industrial policy in China”, said Myllyvirta.

China’s solar industry faces its own struggles though, beyond trade barriers in the West.

The sector’s supersonic expansion has overleveraged the domestic industry, overloaded China’s grid and sparked a brutal price war, experts say.

Industry leaders have reportedly warned of an “ice age” and urged government intervention to stem slumping prices, but there has been little sign of relief.

This year saw a wave of bankruptcies, and new solar projects fell by over 75 percent in the first half of 2024, an industry group said in July.

– ‘Lots of companies will fail’ –

The price wars, which are so fierce that solar export earnings fell last year despite volumes hitting a new high, are like a “snake eating its own tail”, warned analyst David Fishman.

Companies get stuck “in this circle of competition where whoever is able to endure the pain for longest comes out as the victor,” said Fishman, a senior manager at the Lantau Group specialising in China’s power sector.

“Lots of companies will fail along the way.”

And while the manufacturing glut has helped China hit a wind and solar installation target nearly six years ahead of schedule, the country’s grid is struggling to keep up.

Increasingly, renewable supply is being blocked to prevent the grid from becoming overwhelmed, a process known as curtailment.

Solar curtailment rose four percent in the first quarter of 2024 from a year earlier, according to Fitch Ratings.

Authorities will soon be forced to “stop approving new projects or allowing projects to connect to the grid if it means curtailment rates are at risk of going higher”, Fishman said.

“They’ve got to build,” he added. “They have to catch up.”

Blocked in the West and running out of track at home, China’s solar is seeking new markets, and this year, Europe was overtaken by Asia as the biggest export market for solar products, according to an industry body.

Exports to Africa also soared 187 percent year-on-year in 2023, though the continent still buys a small fraction compared to Europe, according to energy think tank Ember.

The industry is now in a “restructuring and shakeout phase”, said Bernreuter.

After that, “the Chinese solar industry will march on with unperturbed pace and a more global manufacturing footprint”.

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Solar Energy

The ZEUS Project to harness solar energy in space with nanowire technology

Published

2 hours ago

October 10, 2024

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The ZEUS Project to harness solar energy in space with nanowire technology

by Hugo Ritmico

Madrid, Spain (SPXR) Oct 10, 2024

The University of Malaga (UMA) is collaborating in an international consortium to advance the collection and transmission of solar energy in space through the ‘ZEUS’ project, part of the Horizon EIC Pathfinder Challenges. This European project, coordinated by Lund University in Sweden, has been awarded nearly euro 4 million to develop innovative nanowire solar cells designed to operate in the harsh conditions of space.

The ZEUS project, or Zero-loss Energy harvesting Using nanowire solar cells in Space, focuses on creating radiation-resistant photovoltaic cells that can efficiently absorb solar energy. Nanowires, which are needle-shaped structures just 200 nanometers in diameter-much thinner than a human hair-allow for high resistance to radiation and optimal light absorption.

“Covering approximately 10 percent of a surface with active material is all that is needed to absorb as much light as a thin layer covering the entire surface of the same material would do,” explained Enrique Barrigon, professor of Applied Physics I at UMA and the project lead at the university.

Currently, nanowire solar cells used in space achieve around 15% efficiency. ZEUS aims to boost this significantly, potentially reaching up to 47% efficiency by utilizing advanced III-V semiconductor materials. The project also explores transferring these solar cells to flexible, lightweight substrates, which could be used to create large deployable photovoltaic panels for space applications.

In addition to its focus on technical innovation, the ZEUS project emphasizes environmental sustainability, including decarbonization and the efficient use of critical raw materials. Professor Barrigon highlighted that the project not only seeks to demonstrate the commercial viability of nanowire solar cells but also to assess their environmental impact, particularly for space-based power generation systems. One potential application is increasing the power output of communications satellites.

The University of Malaga will play a key role in characterizing these advanced solar cells and conducting the tests required to ensure their durability in the space environment.

The Horizon EIC Pathfinder Challenges program supports pioneering technologies like ZEUS that could shape the future by enabling the development of revolutionary technologies. The University of Malaga is also involved in other projects under this program, including ‘BioRobot-MiniHeart’ and ‘SONICOM,’ furthering its contributions to cutting-edge innovation.

Research Project:Zero-loss Energy harvesting Using nanowire solar cells in Space (ZEUS)

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Solar Energy

Photovoltaic upgrade in Jiaxing, China significantly boosts power output

Published

24 hours ago

October 9, 2024

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Photovoltaic upgrade in Jiaxing, China significantly boosts power output

by Simon Mansfield

Sydney, Australia (SPX) Oct 09, 2024

The distributed photovoltaic “trade-in” project at the administrative center in Haining city, Jiaxing, Zhejiang province, has significantly increased power generation capacity without expanding space. Launched on Sept 9, the project marks the first of its kind in Zhejiang, following the release of the “Implementation Plan for Large-scale Equipment Renewal in Key Energy Fields” by the National Development and Reform Commission and National Energy Administration on Aug 21.

As China’s installed photovoltaic capacity grows, the issue of recycling aging photovoltaic panels is becoming increasingly important. The “Plan” emphasizes the need to renew and recycle photovoltaic equipment, enhance grid-forming capabilities, and boost power generation efficiency using advanced digital and power electronics technologies.

Haining city, as part of its ambitious new energy development strategy, has set a goal of installing 300,000 kilowatts of photovoltaic capacity annually, aiming for 350,000 kilowatts. By 2026, the city expects to exceed 2 million kilowatts of installed photovoltaic capacity, with an annual green electricity output surpassing 2 billion kilowatt-hours. A key part of this plan involves upgrading older photovoltaic systems to improve both capacity and efficiency.

In 2023, State Grid Zhejiang Electric Power began mapping and assessing installed photovoltaic systems across Haining, from residential rooftops to commercial buildings. The goal was to develop a trade-in program for these systems. The project on the administrative center’s roof is the first pilot under this initiative. It involves replacing 888 P-type 270-watt modules with 731 N-type 590-watt modules, increasing capacity from 237.6 kilowatts to 431.29 kilowatts.

“This helps improve the power generation efficiency and energy utilization efficiency of photovoltaic power stations,” said Chen Huajie, the project leader. The upgraded system is expected to generate 470,000 kilowatt-hours of electricity annually, enough to meet the needs of 100 households in the region. Over its remaining lifespan, it will produce 4.5 million kilowatt-hours of new green electricity, significantly reducing carbon dioxide and sulfur dioxide emissions.

Zhong Jiewen of State Grid Zhejiang Electric Power commented that this pilot project would serve as a model for future initiatives, promoting sustainable economic and environmental development in the region.

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