Sunday, April 13, 2014

The world must shift to solar and wind power rapidly to avoid catastrophic global warming, say UN scientists in major report | Mail Online

A rapid shift to wind and solar power is needed if the world is to avoid catastrophic global warming, the United Nations warns in a crucial report today.
Emissions of greenhouse gases need to be cut by up to 70 per cent before 2050 to control climate change, the Intergovernmental Panel on Climate Change (IPCC) says.
‘Large-scale changes in energy systems’ are required, with coal power stations to be switched off and replaced by wind and solar.
And the transformation needs to be made in the next 15 years or controlling climate change will become increasingly harder and more expensive.
The report was published in Berlin today after a week of line-by-line drafting and re-drafting.
The final version, written by 235 international scientists and economists, says that efforts so far have failed to stop spiralling emissions of greenhouse gases – which have risen to ‘unprecedented levels’ in the past decade.
Ottmar Edenhofer, co-chair of the authors, said: ‘There is a clear message from science: to avoid dangerous interference with the climate system, we need to move away from business as usual.’
The IPCC report is the first major assessment in seven years of the options for dealing with climate change.



Friday, April 11, 2014

Deconstructing the myths about nuclear power

Peter Bunyard disposes of the argument for nuclear power: it is highly uneconomical, and the saving on greenhouse gas emissions negligible, if any, compared to a gas-fired electricity generating plant
Peter Bunyard will be speaking at Sustainable World Conference, 14-15 July 2005.
References to this article are posted on ISIS members’ websiteDetails here

Limitations due to the quality of uranium ore

A critical point about the practicability of nuclear power to provide clean energy under global warming is the quality and grade of the uranium ore. The quality of uranium ore varies inversely with their availability on a logarithmic scale. The ores used at present, such as the carnotite ores in the United States have an uranium content of up to 0.2 per cent, and vast quantities of overlying rocks and subsoil have to be shifted to get to the 96,000 tonnes of uranium-containing rock and shale that will provide the fresh fuel for a one gigawatt reactor [1].
In addition, most of the ore is left behind as tailings with considerable quantities of radioactivity from thorium-230, a daughter product of the radioactive decay of uranium. Thorium has a half-life of 77 000 years and decays into radium-226, which decays into the gas radon-222. All are potent carcinogens.
Fresh fuel for one reactor contains about 10 curies of radioactivity (27 curies equal 1012 becquerels, each of the latter being one radiation event per second.) The tailings corresponding to that contain 67 curies of radioactive material, much of it exposed to weathering and rain run-off. Radon gas has been found 1 000 miles from the mine tailings from where it originated. Uranium extraction has resulted in more than 6 billion tonnes of radioactive tailings, with significant impact on human health [2].
Once the fuel is used in a reactor, it becomes highly radioactive primarily because of fission products and the generation of the ‘transuranics’ such as neptunium and americium. At discharge from the reactor, a tonne of irradiated fuel from a PWR (pressurized water reactor such as in use at Sizewell) will contain more than 177 million curies of radioactive substances, some admittedly short-lived, but all the more potent in the short term. Ten years later, the radioactivity has died away to about 405 000 curies and 100 years on to 42 000 curies, therefore still 600 times more radioactive than the original material from which the fuel was derived [3].
Today’s reactors, totalling 350 GW and providing about 3 per cent of the total energy used in the world, consume 60 000 tonnes of equivalent natural uranium, prior to enrichment. At that rate, economically recoverable reserves of uranium — about 10 million tonnes — would last less than 100 years. A worldwide nuclear programme of 1 000 nuclear reactors would consume the uranium within 50 years, and if all the world’s electricity, currently 60 exajoules (1018Joules) were generated by nuclear reactors, the uranium would last three years [4]. The prospect that the amount of economically recoverable uranium would limit a worldwide nuclear power programme was certainly appreciated by the United Kingdom Atomic Energy in its advocacy for the fast breeder reactor, which theoretically could increase the quantity of energy to be derived from uranium by a factor of 70 through converting non-fissile uranium-238 into plutonium-239.
In the Authority’s journal [5], Donaldson, D.M., and Betteridge, G.E. stated that, “for a nuclear contribution that expands continuously to about 50 per cent of demand, uranium resources are only adequate for about 45 years.”
The earth’s crust and oceans contain millions upon millions of tonnes of uranium. The average in the crust is 0.0004 per cent and in seawater 2 000 times more dilute. One identified resource, the Tennessee shales in the United States, have uranium concentrations of between 10 and 100 parts per million, therefore between 0.1 and 0.01 per cent. Such low grade ore has little effective energy content as measured by the amount of electricity per unit mass of mined ore [6].
Below 50 parts per million, the energy extracted is no better than mining coal, assuming that the uranium is used in a once-through fuel cycle, and is not reprocessed, but is dumped in some long-term repository. Apart from the self-evident dangers of dissolving spent fuel in acid and keeping the bulk of radioactive waste in stainless steel tanks until a final disposal is found, reprocessing offers very little if at all in terms of energy gained through the extraction and re-use of uranium and plutonium in mixed oxide fuel (MOX) [7].
Grameen Shakti for Renewable Energies

Dipal Barua of Bangladesh had won the 2009 Abu Dhabi government’s Zayed Future Energy Prize in recognition of his work of bringing renewable energy technologies to rural people. The prize included US$1.5 million, which Barua has used to start the Bright Green Energy Foundation. He is intent on making his country one of the world first “solar nations”. He wants to train 100 000 women entrepreneurs to set up their own renewable energy businesses by 2015; and Bangladesh can become a role model for the 1.6 billion energy-starved people all over the world [1].
He has devoted most of his life to finding sustainable, market-based solutions to the social and economic problems of rural people, and came to realize that lack of access to efficient energy sources was one of the major obstacles to their development. “More than 70 percent of my country’s rural population has to depend on primitive energy sources. This limits people’s economic opportunities and damages their health.” He said.

From Grameen Bank to Grameen Shakti

Barua was one of the founding members of the Grameen Bank, the Nobel price-winning micro-finance and community development bank launched in his home village of Jobra in 1976.
In 1996, Barua founded Grameen Shakti (GS), a non-profit organization with a mission to promote, develop and supply renewable energy. As managing director, Barua turned GS into one of the world’s largest and fastest growing renewable energy companies. But attempts to market affordable solar homes initially faced numerous obstacles.
In a country where some 40 percent of the population live on less than US$1.25 a day, the cost of even the most basic solar home system – 15 000 Bangladeshi Taka (US$212)  – was beyond the reach of most rural households; even though for the cost of the kerosene people were buying to light their homes, they could buy a solar home system that would last for 20 years or more, with better, cleaner lighting thrown in along with numerous other uses of the electricity generated.
GS received a big boost in 2002 when low-interest loans from the World Bank and the Global Environment Fund enabled the organization to begin scaling up its provision of micro-finance agreements.  The most popular option was a down-payment of 15 percent and monthly repayments of the remainder over three years.
By the end of 2009, more than 300 000 solar home systems had been installed, bringing electricity to more than 2 million people.

Women the key to success

The key to GS’ success was the deliberate involvement of women in both the take-up of renewable energy, and the installation and servicing of the energy systems.
“Women are the main victims of the energy crisis. They are the ones who suffer most from indoor air pollution, drudgery, and a lack of time because of the onerous task of wood-gathering and cooking.” Barua said. He believes that women should be transformed from passive victim into active forces of good to bring changes in their lives and the communities in which they live.
At more than 40 technology centres based in rural areas, and managed mostly by female engineers, women undergo an initial 15 day course to learn how to assemble charge controllers and mobile phone chargers, and to install and maintain solar home systems. With further training, they are able to repair the systems. Thousands of women technician have come through the programme, and they have been instrumental in the rapid take-up of the solar power systems. For Barua, the success of the women technicians programme is one of his most satisfying achievements.
The women now earn around US$150 a month. “These young women from this most conservative of societies can leave home and operate independently as technicians – this as unimaginable only a few years ago.”

Grameen Shakti for renewable energies

GS was established as a not-for-profit company in 1996 with a mission to empower the rural people with access to green energy and income. The Chairman from the beginning was Professor Muhammed Yunus, and the Managing Director, Dipal Barua [2].
Some 60 percent of the Bangladesh population have no access to grid electricity and rely on kerosene for lighting, while 97 percent of the population depend on biomass for cooking.
The work of GS is mainly focussed on solar energy, biogas, organic fertiliser, and improved cooking stove (ICS) [3]. Apart from selling and providing microcredit for installing solar systems, biogas plants and ICSs, GS also organises technical training, maintenance, after sales service and introduces these products at the mass level.
More than 315 000 units of solar energy system have been installed in remote rural areas of Bangladesh by December 2009, with a combined power generation capacity of 63 MW. Some 13 000 solar energy systems are installed per month. People are saving money that they have had to spend on traditional fuels, and at the same time cutting greenhouse emissions.
GS has been operating biogas plants in different areas of Bangladesh since 2005 [3]. Approximately 8 000 biogas plants have been installed by December 2009, and high quality organic fertiliser is being produced from the slurry of biogas plants.
The ICSs are 50 to 60 percent more efficient than the traditional stoves they replace; and over 45 000 have been constructed so far.