Solar power technology improvements usher in a new age of renewable energy

Our sun is caught up in a continual frenzy of nuclear reactions, fusing hydrogen into helium. That produces a stupendous amount of energy, which then flows into space. 

Some of that makes it through the Earth’s atmosphere. People get tanned. Plants photosynthesise. The energy drives all manner of life. But, until recently, humanity has been decidedly poor at harnessing it.

Traditional solar technology has performed poorly. Cloud cover and long nights mean photovoltaic panels cannot provide baseload capacity. At best, these turn 20% of the energy coming from the sun into electricity. 

About 95% of solar panels are made from silicon. Making them requires a big energy input and the process requires a great deal of industrial precision. It cannot be easily replicated.  All of this has meant that solar energy has been a small player in the sector. In 1980, there were practically no solar plants in the world. In 2007, solar plants provided 12 000 megawatts (MW) of capacity globally. By 2010, this amount was 40 000MW. Last year, it nudged up to 230 000MW. That’s half as much as wind energy, but it still makes up 1% of global electricity supply. 

This success has seen a drop in the price of electricity from solar panels. In 2011, solar companies bidding in South Africa’s Renewable Energy Independent Power Producer Procurement Programme offered to supply electricity at R3.44 a kilowatt-hour (kWh). By last year, companies were bidding to produce electricity at 85c/kWh. The government of Dubai signed a deal last month for a 800MW solar farm, providing electricity at 44c/kWh.

That price reduction has come about from the sheer scale of global solar growth. More production means more plants and lower production prices. But it has also meant more money for research into innovative solar technologies. That tinkering is happening all over the world, and at some local universities.  The 8 000MW of solar planned for South Africa is already online. Some of these are giants, such as the 94MW Sishen solar energy facility, which can provide power for about 30 000 homes.  

Turning to nature 
Humanity has constantly attempted to transcend nature in its technology. But in recent years this trend has slowed down (it turns out nature is pretty good at the basics). Mimicking nature is now the way forward.  A team at Harvard University has come up with a bionic leaf. This is based on a plant’s photosynthesis and splits sunlight into hydrogen and oxygen. So far, they have been able to turn 1% of the sun’s energy into a liquid fuel, isopropanol. 

Swaying solar panels 
Forests make people happy and make cities liveable. Solar farms take up a lot of space and are visually overwhelming. Researchers in Finland are getting around the problem by studying forests and then growing forests using 3D printers. These use old-fashioned wood for their trunks and make tiny solar panels as their leaves. The process is still inefficient and it cannot replace real trees, given that they produce oxygen, but it is allowing solar technology to blend into the landscape. 

Tweaking existing panels 
About 95% of all solar panels are based on basic technology: sunlight comes in and excites atoms. These generates heat. The glass panels doing this are built from silicon, which is an expensive and highly technical process. But materials with a crystalline structure, perovskites, are being mixed with silicon cells to improve their efficiency. This means panels can capture 6% more energy from the sun. Perovskites are also much cheaper to make.  

Shiny infiltration  
Glass buildings are in. These allow depressed workers to look out across the road at their peers. But that glass is wasted space. 

In the United States some office blocks use coloured solar panels in place of glass. These are a combination of silicon dioxide, which is used to make normal windows, and titanium dioxide, which absorbs the sun’s rays. That means buildings can start generating their own electricity. 

But the technology is still in its infancy. Black windows convert just 9% of the sun’s energy into electricity. Blue window panels convert only 6%. 

The most important thing, however, is that, when things look cool, people tend to adopt them. That will further drive the technology. 

Spray-on solar cells 
In an imagined future, everything people build will be wrapped in solar-receptive cells. Power plants would be a thing of the past because every building would generate its own power. 

Researchers at the University of Toronto are bringing that future closer. Light-sensitive dots, sprayed on to a flexible film, are being wrapped around structures at the university to generate electricity. Similar projects at other institutions are turning out paint that can be sprayed on to any structure to start absorbing energy. 

Floating solar farms 
For many countries, solar farms take up too much space to be feasible. Large-scale solar is a luxury reserved for countries with endless tracts of open space. Not everyone has a Northern Cape at hand. Floating solar plants are an alternative to this. Brazil is building a 350MW plant on a lake in the Amazon. The Indian government is building several plants like this. 

The large-scale game-changer 
The critical failing with solar is in how intermittently it supplies electricity but concentrating solar photovoltaic plants are changing this. Giant towers, surrounded by fields of solar panels, absorb sunlight and store the energy in salt. One such plant in the Northern Cape can provide electricity for the whole night. The world’s biggest plant, in California, provides nearly 400MW of capacity. 

But the plants are still prohibitively expensive to build. Research is therefore going into ways to shrink the towers. Stellenbosch University has built a plant that can be accommodated in a small field. The Helio100 uses 100 panels, clustered around a two-metre high solar tower, which can power a small suburb.

Subscribe to the M&G

These are unprecedented times, and the role of media to tell and record the story of South Africa as it develops is more important than ever.

The Mail & Guardian is a proud news publisher with roots stretching back 35 years, and we’ve survived right from day one thanks to the support of readers who value fiercely independent journalism that is beholden to no-one. To help us continue for another 35 future years with the same proud values, please consider taking out a subscription.

Sipho Kings
Sipho Kings is the acting editor-in-chief of the Mail & Guardian

Related stories

South Africa’s cities opt for clean energy

Efforts to reduce carbon emissions will hinge on the transport sector

How designing ‘green’ buildings can help to combat the climate crisis

South Africa’s buildings account for 40% of the country’s greenhouse gas emissions. But the City of Johannesburg’s new draft green buildings policy aims to change that

The solar energy market will grow if innovative business models are developed

Southern African suppliers should consider entering into partnerships with financiers to offer off-grid, hybrid and prepaid solutions to customers

Is solar power the answer to Southern Africa’s energy crisis?

Africa’s favourable weather conditions means solar energy uptake could be accelerated with a few nudges in the right direction

Renewables will light up the darkness

More than 11 800MW of new electricity capacity from independent power producers will come online in 2022, giving Eskom space to do more maintenance on its unreliable infrastructure

How to stop load-shedding, fast

COMMENT: The rapid roll-out of small-scale solar power will reduce pressure on the grid and and boost SMME sector

Subscribers only

FNB dragged into bribery claims

Allegations of bribery against the bank’s chief executive, Jacques Celliers, thrown up in a separate court case

Dozens of birds and bats perish in extreme heat in...

In a single day, temperatures in northern KwaZulu-Natal climbed to a lethal 45°C, causing a mass die-off of birds and bats

More top stories

North West premier goes off the rails

Supra Mahumapelo ally Job Mokgoro’s defiance of party orders exposes further rifts in the ANC

Construction sites are a ‘death trap’

Four children died at Pretoria sites in just two weeks, but companies deny they’re to blame

Why the Big Fish escape the justice net

The small fish get caught. Jails are used to control the poor and disorderly and deflect attention from the crimes of the rich and powerful.

Koko claims bias before Zondo commission

In a lawyer’s letter, the former Eskom chief executive says the commission is not being fair to him

press releases

Loading latest Press Releases…