After 40 Years of Hunting, Scientists Identify a Key Flaw in Solar Panel Efficiency

Solar panels are fantastic pieces of technology, but we need to work out how to make them even more efficient – and last year, scientists solved a 40-year-old mystery around one of the key obstacles to increased efficiency.

The 2019 study outlined a material defect in silicon used to produce solar cells that has previously gone undetected. It could be responsible for the 2 percent efficiency drop that solar cells can see in the first hours of use: Light Induced Degradation (LID). Multiplied by the increasing number of panels installed at solar farms around the world, that drop equals a significant cost in gigawatts that non-renewable energy sources have to make up for.

The estimated loss in efficiency worldwide from LID is estimated to equate to more energy than can be generated by the UK's 15 nuclear power plants. The new discovery could help scientists make up some of that shortfall. "An absolute drop of 2 percent in efficiency may not seem like a big deal, but when you consider that these solar panels are now responsible for delivering a large and exponentially growing fraction of the world's total energy needs, it's a significant loss of electricity generating capacity," said Peaker.

Because of the environmental and financial impact, solar panel 'efficiency degradation' has been the topic of much scientific and engineering interest in the last four decades. However, despite some of the best minds in the business working on it, the problem has steadfastly resisted resolution until now.

To find what 270 research papers across four decades had previously been unable to determine, the latest study used an electrical and optical technique called deep-level transient spectroscopy (DLTS) to find weaknesses in the silicon.

Here's what the DLTS analysis found: As the electronic charge in the solar cells gets transformed from sunlight, the flow of electrons gets trapped; in turn, that reduces the level of electrical power that can be produced. This defect lies dormant until the solar panel gets heated, the team found.

The researchers also found that higher quality silicon had charge carriers (electrons which carry the photon energy) with a longer 'lifetime', which backs up the idea that these traps are linked to the efficiency degradation.

What's more, heating the material in the dark, a process often used to remove traps from silicon, seems to reverse the degradation.

The work to push solar panel efficiency rates higher continues, with breakthroughs continuing to happen in the lab, and nature offering up plenty of efficiency tips as well. Now that the Light Induced Degradation mystery has been solved, solar farms across the globe should benefit.

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To cut carbon, Sindh taps into the wind and the sun

As the world grapples with global warming, developing countries like Pakistan face the gravest risk from the adverse impact of climate change. To get a leg up on the challenge, Sindh is preparing to do its part to reduce its environmental footprint.

According to a senior minister, the provincial government is looking to add another 2,485 megawatts of electricity to the national grid using nothing but wind. Some 24 wind-powered electricity plants are already contributing 1,235 megawatts to the national grid, Shaikh said. “These power plants were set up under the federal government’s Alternative Energy Development Board in Thatta district,” he pointed out.

“Some 12 companies have started the construction of new wind-powered electricity plants in the Thatta and Jamshoro districts,” said Sindh Energy Minister Imtiaz Shaikh. “Both districts form a wind corridor that we are working to tap into.”

Wind is not all the Sindh government is looking to tap into to both meet the province’s energy needs and mitigate the climate crisis. The world is doubling down on solar power. In 2017, global investments in solar power projects reached a record $160.8 billion, which was 18 per cent higher than 2016, as per data from Bloomberg New Energy Finance. Solar power currently plays a negligible role in Pakistan’s power generation mix. The country gets 64pc of its energy from thermal power projects which generate electricity by burning fuels — such as furnace oil — that are damaging for the environment.

According to the minister, the provincial government has issued letter of intents for setting up 25 solar power projects in the province.

Once completed, the solar power plants due to be constructed in Thatta, Jamshoro, Shaheed Benazirabad and Sukkur districts will generate as much as 1,550 megawatts, he said. “Four of them have already obtained tariff and are waiting for formal approval from the federal government,” he told The Express Tribune.

A push for cleaner renewable energy could have come in Sindh sooner, provincial officials said. They blamed administrative hurdles from the federal government for holding up progress on this front. “The Sindh energy department had finalised agreements from six wind powered electricity plants in 2015,” said one official. “But the federal government imposed a ban on wind and solar power projects through an executive order on April 20 that year.”

The ban was imposed under the recommendation of the Federal Cabinet Committee on Energy. Due to the unilateral action of the federal body, the National Electric Power Regulatory Authority (NEPRA) stopped the process of awarding tariff to companies who had finalised their agreements pertaining to wind and solar projects with the Sindh government.

The move prompted then chief minister of Sindh, Qaim Ali Shah, to write a letter to then prime minister Nawaz Sharif. Shah, in the letter, argued that the cabinet committee’s decision would hold up development in the province.
The share of solar power was so small in the previous fiscal year that it wasn’t highlighted in the Finance Ministry’s report. The Central Power Purchasing Agency’s annual report shows that solar power accounted for less than one per cent of Pakistan’s energy mix.

The rest of the world, on the other hand, has embraced solar power. Germany has invested $200bn in developing various clean energy sources in the past two decades and gets almost a third of its electricity from them.
Although there is no denying the fact that gas, furnace oil, and coal-fired plants are crucial for fulfilling Pakistan’s energy needs, the solar sector certainly deserves more attention.

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Alternative Energy

Researchers Build World’s Most Efficient Solar Cell

Research teams from Australian National University (ANU) and China are closing in on a solar cell design that could revolutionize solar panel efficiency. The breakthrough is the material perovskite, a crystalline structure first found in Russia in the mid-1800s. Studies suggest a perovskite solar panel could achieve efficiencies as high as 35%, while also reducing costs by cutting out some steps in the manufacturing process.

For the past several years, engineers have been focusing on newer materials to build panels that are ultimately more efficient and cost-effective in tandem with silicon-based panels, which are popular and more durable. The material is also much easier to fabricate and use than very high purity silicon, which requires an intricate refinement process. Perovskite is obtained as a powder that can be mixed into a solvent and used to coat glass substrates.

Silicon-based photovoltaic (PV) panels currently have efficiency rates of 16% to 18% absorption, and researchers put the theoretical limit for silicon PV efficiency at 29%.  Thomas White, a researcher and professor at ANU and others note that innovation should be geared to improving energy conversion efficiency—the degree to which a panel converts energy from sunlight directly into electricity. “There’s a lot of emphasis now on improving efficiency, and that’s why there’s suddenly these tandem approaches,” said White.

The largest obstacle remains durability, perovskite crystals break down faster than silicon. The crystals dissolve easily so they are particularly susceptible to moisture and Perovskite also can’t take the heat as well as silicon can. White at ANU acknowledged this deficiency.

“The main challenge at the moment is stability,” he said. “We’re still struggling to make them sufficiently stable that you would want to put them on a rooftop for 25 years. So that’s still an unsolved question.”

In related developments, the Australian Renewable Energy Agency (ARENA) has announced more funding and support towards advanced solar photovoltaic energy applications including a grant of $15 million for R&D teams.

Engineers based at universities in China and the United States have taken an interest in the state of perovskite solar cell research and in a recent edition of the scientific journal Advanced Functional Materials, published a paper acknowledging the problems with heightening stability but also thought there was “astounding progress in the efficiency of perovskite solar cells.” White agreed. “That will make or break perovskite over the next few years,” he said.

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Energy future hinges on Renewable

Under the CCoE decision, renewable energy projects would be accepted only through competitive bidding for specific generation capacities. The new policy was now in final stages, had been supported by lending agencies and could not be held back to accommodate 2006 policy investors who could be considered separately and on examination of their cost-benefit analysis.

The provinces and other private stakeholders wanted the new policy to accommodate those past investors after having spent a lot of time and money in the new policy as had been the case in all the past power policies and petroleum policy to allow existing investors to adopt new regime with cost plus tariff formula subject to certain conditions.

It was assumed that provinces would be left with no option but to raise objections over the new policy when it was taken up for approval at the level of Council of Common Interests (CCI). A dispute at the ultimate forum under the constitution to adopt the policy could have negative repercussions unless the projects awarded by provincial governments under the independent power producer (IPP) mode were covered in the new policy to safeguard the interests of the provinces.

The new renewable energy policy had been developed in the light of present day situation when the technologies on one side were fast developing while on other side the cost was continuously going down. Country’s electricity basket is hugely tilted towards thermal imported fuels and emphasized that the new policy envisages increasing the share of renewable energy from around 4 per cent to 20pc by year 2025 and 30pc by year 2030.

Underscoring the importance of renewable resources and their optimal utilization for generation of electricity, he said that from the prospect of attaining energy security and decreasing the impact of current thermal generation on environment, Pakistan needed to develop and harness to the maximum level its indigenous renewable energy resources.

Danish firms invited to invest in renewable energy

The government of Pakistan is committed to provide sustainable energy solutions in the long-run. And the recent actions are the testament of their claims. Pakistan has a huge potential of energy reserves such as coal, oil, gold etc., which has been untapped for decades. Similarly, solar energy is also one of them which can generate thousands of mega-watts at a cheap price. Minister for Power Omar Ayub Khan has invited Danish companies to invest in the manufacturing of solar panels and wind turbines in Pakistan.

In a meeting with Denmark Ambassador Rolf Holmboe, the minister said Pakistan’s new renewable energy policy would bring opportunities for good returns due to government’s transparent policies. It is pertinent to mention here that the policy was unanimously approved by the Alternative Energy Development Board (AEDB) where all provinces had representation at the highest level.

The minister also acknowledged the lead role Denmark was playing in clean and green energy at the global level. Therefore, Pakistan too had embarked on a drive to tap its huge renewable energy potential.

The renewable energy policy has set ambitious targets, which would soon be presented to the Council of Common Interests (CCI) for final approval and implementation.

He said by the year 2025, the government is planning to enhance to 20% of the current renewable energy share from 4% in the overall energy mix, while by the year 2030 the share would be raised to 30%, or around 20,000 megawatts.

He said the government expected a gradual decrease in electricity prices as new projects with the lowest per unit cost would start power production.

With the reduction in electricity cost, businesses would take benefit, the minister apprised. In turn, overall economic activity would get a boost with creation of thousands of new jobs, he added.

The Danish ambassador also appreciated Pakistan government’s efforts in raising the share of renewable clean and green energy to 60%. He said the new policy was more transparent as it provided a level playing field for all.

He also showed interest in assisting Pakistan’s initiative for renewable and offered capacity building modules to Pakistani experts in renewable energy, adding that Denmark was getting renewable energy at a very low per unit price.

In this regard, Danish companies are closely following developments in Pakistan in the field of renewable energy and they were ready to take part in the competitive process.

Qatar to build new solar power plant

Qatar is also in the race of acquiring solar energy and therefore, has signed an agreement with French energy giant Total and Japan's Marubeni to build a solar power plant capable of generating 800 megawatts, a tenth of country's peak energy demand, according to the country's energy minister. 

The Al Kharsaah plant has an estimated cost of 1.7 billion riyals ($467m) and is expected to be complete by the year 2022 in an anticipation of the grand event FIFA World Cup. 

Energy Minister Saad al-Kaabi told a news briefing on Sunday, said:

"Today is the commencement of the project itself and we expected by the first quarter of 2021 to have half of the [plant's] capacity up and running."

It is assumed that the solar power plant will have the capacity to generate about eight times the size of the solar energy Qatar had pledged to build, helping the organisation of a carbon-neutral event," al-Kaabi continued, referring to the 2022 tournament.

Other companies such as Qatar's Siraj Energy, a joint venture owned by Qatar Petroleum (QP) and Qatar Electricity and Water Company (QEWC), hold a 60 percent stake in the solar plant. The remaining 40 percent will be owned by both Marubeni and Total. Marubeni will take 51 percent of the minority stake, while Total will have 49 percent.

Patrick Pouyanne, Total's chief executive, said the solar plant, once complete, will be the largest ever built by the French conglomerate. In the past, Gulf States, have heavily dependent on oil and gas, but now they are investing billions of dollars in clean energy projects, mainly in solar and nuclear.

But critics say many such projects are slow to get off the drawing board.

On the other hand, the United Arab Emirates (UAE) said last week its first nuclear power plant would start operating within months after repeated delays to meet safety and regulatory conditions. It is pertinent to mention here that UAE will have the first operational nuclear reactor in the Arab world.

Saudi Arabia, the world's top crude oil exporter, has said it plans to build up to 16 nuclear reactors, but the projects have yet to be materialised.

Critics say the addiction to oil is hard to kick, particularly when supplies remain abundant and the high costs of investment in infrastructure needed to switch to renewable.

Solar - the Untapped Potential in Pakistan

In the last few decades, energy demand has surged as a function of industrialisation, population growth, inhabitant density amplification, commercial activity intensification, enhanced space mobility, de-forestation, etc.

Member states working on renewable energy around the world are allotted year-on-year Green House Gas (GHG) emission mitigation targets for reducing the impact of global warming. These communal gatherings for emission consensus are a result of 0.2-degree Celsius projected rise in temperature per decade globally due to emissions in the next two decades.

Even so, if the concentrations of GHGs were not to change, rise in sea level and anthropogenic warming would occur for centuries.

Whereas Pakistan is concerned, it’s current energy mix includes fossil fuels (furnace oil, natural gas and coal) and renewables (hydroelectric power, wind and solar) across its geographical vertices. The country stands at 169th place in the Environmental Performance Index (EPI) out of the 180 countries included in the study, and this is quite alarming.

With several policies being passed, frameworks introduced and consultancies being sought over the last 10+ years, we as a nation have not been able to fully maximise this energy source as a value addition to the national grid.

Although, past and present governments consistently claim supply-demand parity, what remained unanswered is the lack of:

·        Rural electrification due to a low transmission/distribution network spread or grid proximity (70% of Pakistan is rural and overall grid connectivity stands at 42% to date)

·        High cost of well-to-consumer for a multitude of reasons (dilapidated development infrastructure, shortage of investment, lack of intrinsic resources, security, etc)

·        Rising fuel import bill

·        Under-utilisation of existing power plant capacities

·        Shortage of fuel transport civil linkages

All of these sources of energy generation are dirty, especially coal, and except solar.

Solar is one such clean energy resource that has made strong headway in recent years. For a country like Pakistan, solar energy is particularly suitable due to its optimal geographical location. In comparison with many European countries, most cities in Pakistan receive about 1,500-2,500 hours of sun annually, which is twice more than that of Europe. Baluchistan is particularly rich in solar energy with annual mean sunshine duration of 8-8.5 hours per day and these values are one of the highest in the world.

Unfortunately, with the technology being clean, cheap and abundant and climate platform ideal, it is a surprise that solar adoption to this day remains low in Pakistan. It is pertinent to mention here that solar energy is by far the most popular renewable energy resource relative to its peers due to its low operational/maintenance cost, ease of installation/use and zero GHG emissions.

One of the main challenges comes not from government regulations, theft or mismanagement, but from the technology itself. Solar has the good fortune and a bad omen of being relatively easy to set up, compared to other renewables (such as biogas, hydro, wind, etc).

From street vendors in Rawalpindi to SMEs all are equally to blame for the muddle in the solar energy price control, incomplete installations, workforce misuse, misappropriation of public wealth, indecisive policymaking and unaccountable billing. The Quaid-e-Azam Solar Park is one prime example of such public-private partnership conundrum, which was hailed as a symbolic beacon of clean energy in the country.

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