Tag Archives: solar energy

Furthest from their Minds: greenhouse gases in Afirca

When sub-Saharan Africa comes up in discussions of climate change, it is almost invariably in the context of adapting to the consequences, such as worsening droughts. That makes sense. The region is responsible for just 7.1% of the world’s greenhouse-gas emissions, despite being home to 14% of its people. Most African countries do not emit much carbon dioxide. Yet there are some notable exceptions.

Start with coal-rich South Africa, which belches out more carbon dioxide than Britain, despite having 10m fewer people and an economy one-eighth the size. Like nearly all of its power plants, many of its vehicles depend on coal, which is used to make the country’s petrol (a technique that helped the old apartheid regime cope with sanctions). A petrochemical complex in the town of Secunda owned by Sasol, a big energy and chemicals firm, is one of the world’s largest localised sources of greenhouse gases.  Zambia is another exception. It burns so much vegetation that its land-use-related emissions surpass those of Brazil, a notorious—and much larger—deforester.

South Africa and Zambia may be extreme examples, but they are not the region’s only big emitters . Nigerian households and businesses rely on dirty diesel generators for 14GW of power, more than the country’s installed capacity of 10GW. Subsistence farmers from Angola to Kenya use slash-and-burn techniques to fertilise fields with ash and to make charcoal, which nearly 1bn Africans use to cook. This, plus the breakneck growth of extractive industries, explains why African forests are disappearing at a rate of 0.5% a year, faster than in South America. Because trees sequester carbon, cutting them counts as emissions in climate accounting.

Other African countries are following South Africa’s lead and embracing coal…A new coal-fired power plant ….Lamu in Kenya is one of many Chinese-backed coal projects in Africa…Africa’s sunny skies and long, blustery coastlines offer near-limitless solar- and wind-energy potential. But what African economies need now are “spinning reserves”, which can respond quickly to volatile demand, says Josh Agenbroad of the Rocky Mountain Institute, a think-tank in Colorado. Fossil fuels deliver this; renewables do not…. Several countries are intrigued by hybrid plants where most electricity is generated by solar panels, but diesel provides the spinning reserves…

Excerpts from  Africa and Climate Change: A Burning Issue, Economist,  Apr. 21, 2018, at 41.

Is Eco-Peace Really Possible?

image from wikipedia

EcoPeace, a joint Israeli, Jordanian and Palestinian NGO thinks it just might. In December it presented an ambitious, if far from fully developed, $30 billion plan to build a number of desalination plants on the Mediterranean shore of Israel and the Gaza Strip. At the same time, large areas in Jordan’s eastern desert would host a 200 square km (75 square mile) solar-energy plant, which would provide power for desalination (and for Jordan) in exchange for water from the coast. “A new peaceful economy can be built in our region around water and energy” says Gidon Bromberg, EcoPeace’s Israeli director. Jordan and the Palestinian Authority are already entitled to 120 million cubic meters of water a year from the Jordan river and West Bank aquifers but this is not enough to meet demand, particularly in Jordan, which regularly suffers from shortages….

The main drawback to making fresh water from the sea is that it takes lots of energy. Around 25% of Jordan’s electricity and 10% of Israel’s goes on treating and transporting water. Using power from the sun could fill a sizeable gap, and make Palestinians less dependent on Israeli power. Renewables supply just 2% of Israel’s electricity needs, but the government is committed to increasing that share to 17% by 2030. Jordan, which has long relied on oil supplies from Arab benefactors, is striving for 10% by 2020.,,, Over the past 40 years there has been a series of plans to build a Red Sea-Dead Sea canal that would have irrigated the Jordan Valley and generated power, none of which have been built.

Beyond many logistical and financial obstacles, the plan’s boosters also have to navigate a political minefield.

Excerpts from Utilities in the Middle East: Sun and Sea, Economist, Jan. 16, 2016, at 54

Nanotechnology and the Environment

Scientists working on the EC-funded research project Monacat,  are looking at how nanomaterials can remove water pollutants such as nitrates. “Nitrate reduction has been studied for decades; it’s very hard to do and it isn’t commercially viable,” says Alexei Lapkin, professor of chemical engineering at the University of Warwick, who works on Monocat.  Nitrates taken into the body through water can block oxygen transport. In severe cases this can starve tissues and organs of oxygen and lead to conditions including heart defects in babies. Nitrate levels are therefore strictly regulated, with an estimated €70bn–€320bn (£60bn –£274bn) spent every year across the EU removing nitrogen waste from water. The Monocat project has developed reactors coated with carbon nanotubes and nanofibres that could potentially remove nitrate pollutants at much lower costs. Lapkin says the most successful reactors will soon be chosen for patenting and further development.

Another European project, NanoGLOWA, is using nanotechnology to tackle global warming. The project aims to develop nanomembranes that can remove carbon dioxide from power plant emissions more efficiently than current methods. These membranes use nanomaterials to physically separate or chemically react with the carbon dioxide in flue gas streams.

As well as cleaning up fossil fuel use, nanotechnology is improving the viability of clean energy. Today, the most widespread photovoltaic solar cells are made of polycrystalline silicon and are relatively expensive, but nanotechnology is working to drive the costs of solar power down.  “It’s quicker and easier to grow a small crystal than a large one, and nanocrystals can be made in large quantities by simple chemical routes,” explains Jason Smith, leader of the Photonic Nanomaterials Group, University of Oxford. Photovoltaic cells made by “printing” nanoparticle inks are already commercially available.  “So far they have reached 17% efficiency,” says Smith. Normal polycrystalline silicon cells are about 20% efficient. “This is a pretty impressive achievement and demonstrates that nanomaterials can be almost as efficient as the standard polycrystalline silicon cells, while produced at a fraction of the cost.” An important next stage of the research will be to continue to improve the efficiency of these cheap nanoparticle cells…

“We will need at some point to replace internal combustion and diesel engines,” says Duncan Gregory, professor of inorganic materials at the University of Glasgow. “Hydrogen is an ideal fuel since one can extract a large amount of energy from it, and the process is green.”  However, storing hydrogen as a gas is both inconvenient and dangerous. “Solid-state storage, by which hydrogen is stored within a host solid, could overcome these problems, in principle making it possible to store a much higher amount of hydrogen in a relatively unreactive form,” Gregory says. He and his team have patented a nanomaterial called lithium nitride, similar in structure to carbon nanotubes and nanofibres, which may provide a way to store hydrogen safely inside a solid.

 

“It might be this material or similar that provides the breakthrough, or a completely different way of thinking,” says Gregory. “How soon this technology becomes ready depends on what the political will for change is. In these challenging economic times, real-terms government spending on research has fallen. Thankfully, energy remains a high UK research priority that will be essential, given all our environmental, economic and political concerns.”

New forms of glass that control the heat, light and glare passing through a surface are emerging. But these are based on nanotechnology procedures that, in some cases, have been around for decades.

Excerpt, Penny Sarchet, Essential matter, Guardian, Nov. 25, 2011