Archive for the ‘– renewables’ Category

Solar sails for space voyages

February 18, 2021

Nuclear Rockets to Mars?, BY KARL GROSSMAN– CounterPunch, 16 Feb 21,”………. As for rocket propulsion in the vacuum of space, it doesn’t take much conventional chemical propulsion to move a spacecraft—and fast.

And there was a comprehensive story in New Scientist magazine this past October on “The new age of sail,” as it was headlined. The subhead: “We are on the cusp of a new type of space travel that can take us to places no rocket could ever visit.”

The article began by relating 17th Century astronomer Johanne Kepler observing comets and seeing “that their tails always pointed away from the sun, no matter which direction they were traveling. To Kepler, it meant only one thing: the comet tails were being blown from the sun.”

Indeed, “the sun produces a wind in space” and “it can be harnessed,” said the piece. “First, there are particles of light streaming from the sun constantly, each carrying a tiny bit of momentum. Second, there is a flow of charged particles, mostly protons and electrons, also moving outwards from the sun. We call the charged particles the solar wind, but both streams are blowing a gale”—that’s in the vacuum of space.

Japan launched its Ikaros spacecraft in 2010—sailing in space using the energy from the sun. The LightSail 2 mission of The Planetary Society was launched in 2019—and it’s still up in space, flying with the sun’s energy.

New systems using solar power are being developed – past the current use of thin-film such as Mylar for solar sails.

The New Scientist article spoke of scientists “who want to use these new techniques to set a course for worlds currently far beyond our reach—namely the planets orbiting our nearest star, Alpha Centauri.”……. more

India’s nuclear power programme unlikely to progress. Ocean energy is a better way.

August 18, 2019

The problem is apparently nervousness about handling liquid Sodium, used as a coolant. If Sodium comes in contact with water it will explode; and the PFBR is being built on the humid coast of Tamil Nadu. The PFBR has always been a project that would go on stream “next year”. The PFBR has to come online, then more FBRs would need to be built, they should then operate for 30-40 years, and only then would begin the coveted ‘Thorium cycle’!

Why nuclear when India has an ‘ocean’ of energy,

M. Ramesh – 30 June 19 Though the ‘highly harmful’ source is regarded as saviour on certain counts, the country has a better option under the seas

If it is right that nothing can stop an idea whose time has come, it must be true the other way too — nothing can hold back an idea whose time has passed.

Just blow the dust off, you’ll see the writing on the wall: nuclear energy is fast running out of sand, at least in India. And there is something that is waiting to take its place.

India’s 6,780 MW of nuclear power plants contributed to less than 3% of the country’s electricity generation, which will come down as other sources will generate more.

Perhaps India lost its nuclear game in 1970, when it refused to sign – even if with the best of reasons – the Non Proliferation Treaty, which left the country to bootstrap itself into nuclear energy. Only there never was enough strap in the boot to do so.

In the 1950s, the legendary physicist Dr. Homi Bhabha gave the country a roadmap for the development of nuclear energy.

Three-stage programme

In the now-famous ‘three-stage nuclear programme’, the roadmap laid out what needs to be done to eventually use the country’s almost inexhaustible Thorium resources. The first stage would see the creation of a fleet of ‘pressurised heavy water reactors’, which use scarce Uranium to produce some Plutonium. The second stage would see the setting up of several ‘fast breeder reactors’ (FBRs). These FBRs would use a mixture of Plutonium and the reprocessed ‘spent Uranium from the first stage, to produce energy and more Plutonium (hence ‘breeder’), because the Uranium would transmute into Plutonium. Alongside, the reactors would convert some of the Thorium into Uranium-233, which can also be used to produce energy. After 3-4 decades of operation, the FBRs would have produced enough Plutonium for use in the ‘third stage’. In this stage, Uranium-233 would be used in specially-designed reactors to produce energy and convert more Thorium into Uranium-233 —you can keep adding Thorium endlessly.

Seventy years down the line, India is still stuck in the first stage. For the second stage, you need the fast breeder reactors. A Prototype Fast Breeder Reactor (PFBR) of 500 MW capacity, construction of which began way back in 2004, is yet to come on stream.

The problem is apparently nervousness about handling liquid Sodium, used as a coolant. If Sodium comes in contact with water it will explode; and the PFBR is being built on the humid coast of Tamil Nadu. The PFBR has always been a project that would go on stream “next year”. The PFBR has to come online, then more FBRs would need to be built, they should then operate for 30-40 years, and only then would begin the coveted ‘Thorium cycle’! Nor is much capacity coming under the current, ‘first stage’. The 6,700 MW of plants under construction would, some day, add to the existing nuclear capacity of 6,780 MW. The government has sanctioned another 9,000 MW and there is no knowing when work on them will begin. These are the home-grown plants. Of course, thanks to the famous 2005 ‘Indo-U.S. nuclear deal’, there are plans for more projects with imported reactors, but a 2010 Indian ‘nuclear liability’ legislation has scared the foreigners away. With all this, it is difficult to see India’s nuclear capacity going beyond 20,000 MW over the next two decades.

Now, the question is, is nuclear energy worth it all?

There have been three arguments in favour of nuclear enFor Fergy: clean, cheap and can provide electricity 24×7 (base load). Clean it is, assuming that you could take care of the ticklish issue of putting away the highly harmful spent fuel.

But cheap, it no longer is. The average cost of electricity produced by the existing 22 reactors in the country is around ₹2.80 a kWhr, but the new plants, which cost ₹15-20 crore per MW to set up, will produce energy that cannot be sold commercially below at least ₹7 a unit. Nuclear power is pricing itself out of the market. A nuclear power plant takes a decade to come up, who knows where the cost will end up when it begins generation of electricity?

Nuclear plants can provide the ‘base load’ — they give a steady stream of electricity day and night, just like coal or gas plants. Wind and solar power plants produce energy much cheaper, but their power supply is irregular. With gas not available and coal on its way out due to reasons of cost and global warming concerns, nuclear is sometimes regarded as the saviour. But we don’t need that saviour any more; there is a now a better option.

Ocean energy

The seas are literally throbbing with energy. There are at least several sources of energy in the seas. One is the bobbing motion of the waters, or ocean swells — you can place a flat surface on the waters, with a mechanical arm attached to it, and it becomes a pump that can be used to drive water or compressed air through a turbine to produce electricity. Another is by tapping into tides, which flow during one part of the day and ebb in another. You can generate electricity by channelling the tide and place a series of turbines in its path. One more way is to keep turbines on the sea bed at places where there is a current — a river within the sea. Yet another way is to get the waves dash against pistons in, say, a pipe, so as to compress air at the other end. Sea water is dense and heavy, when it moves it can punch hard — and, it never stops moving.

All these methods have been tried in pilot plants in several parts of the world—Brazil, Denmark, U.K., Korea. There are only two commercial plants in the world—in France and Korea—but then ocean energy has engaged the world’s attention.

For sure, ocean energy is costly today.

India’s Gujarat State Power Corporation had a tie-up with U.K.’s Atlantic Resources for a 50 MW tidal project in the Gulf of Kutch, but the project was given up after they discovered they could sell the electricity only at ₹13 a kWhr. But then, even solar cost ₹18 a unit in 2009! When technology improves and scale-effect kicks-in, ocean energy will look real friendly.

Initially, ocean energy would need to be incentivised, as solar was. Where do you find the money for the incentives? By paring allocations to the Department of Atomic Energy, which got ₹13,971 crore for 2019-20.

Also, wind and solar now stand on their own legs and those subsidies could now be given to ocean energy.

How our electricity system of the future could be powered by sun, wind and waves

April 7, 2019

Our electricity system of the future could be powered by sun, wind and waves @nickymison

Response to ‘Burden of proof: A comprehensive review of the feasibility of 100% renewable-electricity systems’

November 3, 2018

Science Direct 18 May 18 

Scientists refute Ben Heard’s paper opposing reneweable energy

November 3, 2018

Can we get 100 percent of our energy from renewable sources? New article gathers the evidence to address the sceptics LAPPEENRANTA UNIVERSITY OF TECHNOLOGY 

Is there enough space for all the wind turbines and solar panels to provide all our energy needs? What happens when the sun doesn’t shine and the wind doesn’t blow? Won’t renewables destabilise the grid and cause blackouts?

In a review paper last year in the high-ranking journal Renewable and Sustainable Energy Reviews, Master of Science Benjamin Heard (at left) and colleagues presented their case against 100% renewable electricity systems. They doubted the feasibility of many of the recent scenarios for high shares of renewable energy, questioning everything from whether renewables-based systems can survive extreme weather events with low sun and low wind, to the ability to keep the grid stable with so much variable generation.

Now scientists have hit back with their response to the points raised by Heard and colleagues.The researchers from the Karlsruhe Institute of Technology, the South African Council for Scientific and Industrial Research, Lappeenranta University of Technology, Delft University of Technology and Aalborg University have analysed hundreds of studies from across the scientific literature to answer each of the apparent issues. They demonstrate that there are no roadblocks on the way to a 100% renewable future.

“While several of the issues raised by the Heard paper are important, you have to realise that there are technical solutions to all the points they raised, using today’s technology,” says the lead author of the response, Dr. Tom Brown of the Karlsruhe Institute of Technology.

“Furthermore, these solutions are absolutely affordable, especially given the sinking costs of wind and solar power,” says Professor Christian Breyer of Lappeenranta University of Technology, who co-authored the response.

Brown cites the worst-case solution of hydrogen or synthetic gas produced with renewable electricity for times when imports, hydroelectricity, batteries, and other storage fail to bridge the gap during low wind and solar periods during the winter. For maintaining stability there is a series of technical solutions, from rotating grid stabilisers to newer electronics-based solutions. The scientists have collected examples of best practice by grid operators from across the world, from Denmark to Tasmania.

The response by the scientists has now appeared in the same journal as the original article by Heard and colleagues.

“There are some persistent myths that 100% renewable systems are not possible,” says Professor Brian Vad Mathiesen of Aalborg University, who is a co-author of the response.

“Our contribution deals with these myths one-by-one, using all the latest research. Now let’s get back to the business of modelling low-cost scenarios to eliminate fossil fuels from our energy system, so we can tackle the climate and health challenges they pose.”

For more information, please contact:

Tom Brown, Young Investigator Group Leader, Karlsruhe Institute of Technology |

Kornelis Blok, Professor, Delft University of Technology |

Christian Breyer, Professor, Lappeenranta University of Technology |

Brian Vad Mathiesen, Professor, Aalborg University |

The research papers for further information:

T.W. Brown, T. Bischof-Niemz, K. Blok, C. Breyer, H. Lund, B.V. Mathiesen, “Response to ‘Burden of proof: A comprehensive review of the feasibility of 100% renewable-electricity systems’,” Renewable and Sustainable Energy Reviews, DOI:10.1016/j.rser.2018.04.113, 2018.

B.P. Heard, B.W. Brook, T.M.L. Wigley, C.J.A. Bradshaw, “Burden of proof: A comprehensive review of the feasibility of 100% renewable-electricity systems,” Renewable and Sustainable Energy Reviews, DOI:10.1016/j.rser.2017.03.114, 2017.

Response to ‘Burden of proof: A comprehensive review of the feasibility of 100% renewable-electricity systems’

October 9, 2018

Science Direct 18 May 18 

Solar energy: greenhouse emissions becoming lower – will be very low by 2018

February 1, 2017

How clean is solar power?

A new paper may have the answer

Dec 10th 2016 THAT solar panels do not emit greenhouse gases such as carbon dioxide when they are generating electricity is without question. This is why they are beloved of many who worry about the climate-altering potential of such gases. Sceptics, though, observe that a lot of energy is needed to make a solar panel in the first place. In particular, melting and purifying the silicon that these panels employ to capture and transduce sunlight needs a lot of heat. Silicon’s melting point, 1,414°C, is only 124°C less than that of iron.

Silicon is melted in electric furnaces and, at the moment, most electricity is produced by burning fossil fuels. That does emit carbon dioxide. So, when a new solar panel is put to work it starts with a “carbon debt” that, from a greenhouse-gas-saving point of view, has to be paid back before that panel becomes part of the solution, rather than part of the problem. Observing this, some sceptics have gone so far as to suggest that if the motive for installing solar panels is environmental (which is often, though not always, the case), they are pretty-much useless.

 Wilfried van Sark, of Utrecht University in the Netherlands, and his colleagues have therefore tried to put some numbers into the argument. As they report in Nature Communications, they have calculated the energy required to make all of the solar panels installed around the world between 1975 and 2015, and the carbon-dioxide emissions associated with producing that energy. They also looked at the energy these panels have produced since their installation and the corresponding amount of carbon dioxide they have prevented from being spewed into the atmosphere. Others have done life-cycle assessments for solar power in the past. None, though, has accounted for the fact that the process of making the panels has become more efficient over the course of time. Dr Van Sark’s study factors this in.

Panel games  To estimate the number of solar panels installed around the world, Dr Van Sark and his team used data from the International Energy Agency, an autonomous intergovernmental body. They gleaned information on the amount of energy required to make panels from dozens of published studies. Exactly how much carbon dioxide was emitted during the manufacture of a panel will depend on where it was made, as well as when. How much emitted gas it has saved will depend on where it is installed. A panel made in China, for example, costs nearly double the greenhouse-gas emissions of one made in Europe. That is because China relies more on fossil fuels for generating power. Conversely, the environmental benefits of installing solar panels will be greater in China than in Europe, as the clean power they produce replaces electricity that would otherwise be generated largely by burning coal or gas.

Once the team accounted for all this, they found that solar panels made today are responsible, on average, for around 20 grams of carbon dioxide per kilowatt-hour of energy they produce over their lifetime (estimated as 30 years, regardless of when a panel was manufactured). That is down from 400-500 grams in 1975. Likewise, the amount of time needed for a solar panel to produce as much energy as was involved in its creation has fallen from about 20 years to two years or less. As more panels are made, the manufacturing process becomes more efficient. The team found that for every doubling of the world’s solar capacity, the energy required to make a panel fell by around 12% and associated carbon-dioxide emissions by 17-24%.

The consequence of all this number-crunching is not as clear-cut as environmentalists might hope. Depending on the numbers fed into the model, global break-even could have come as early as 1997, or might still not have arrived. But if it has not, then under even the most pessimistic assumptions possible it will do so in 2018. After that, solar energy’s environmental credentials really will be spotless.

Solar energy powers South Australia’s desert Sundrop Farms

November 21, 2016

Desert farm grows 180,000 tomato plants using only sun and seawater

Farms that grow food in arid deserts, without groundwater or fossil fuels, could be the future of agriculture. BRYAN NELSON October 10, 2016, No soil, no pesticides, no fossil fuels, and no groundwater. And yet, a thriving farm in the heart of the arid Australian desert. How is this possible?

An international team of scientists has spent the last six years fine-tuning a system that pipes seawater in from the ocean and desalinates it using a state-of-the-art concentrated solar energy plant. The water is then used to irrigate 180,000 tomato plants grown in coconut husks instead of soil, kept in a network of greenhouses.

The result is Sundrop Farms, a commercial-scale facility located just off the Spencer Gulf in South Australia that began construction in 2014. Today it’s producing an estimated 17,000 tons of tomatoes per year to be sold in Australian supermarkets.

Given the increasing demand for fresh water around the world — a problem that’s particularly apparent in the sunburned landscape of South Australia — this might just represent future of large-scale farming, especially in coastal desert regions that have previously been non-arable.

The heart of the farm is the 23,000 mirrors that reflect sunlight towards a 115-meter high receiver tower. All of that concentrated sunlight produces an immense amount of power, up to 39 megawatts. That’s more than enough to cover the desalination needs of the farm and supply all the electricity needs of the greenhouses.

The seawater, too, has other purposes besides just irrigation. During scorching hot summers, seawater-soaked cardboard lines the greenhouses to help keep the plants at optimal temperature. Seawater also has the remarkable effect of sterilizing the air, meaning that chemical pesticides are unnecessary.

All in all, the facility cost around 200 million dollars to get up and running. That might sound excessive, but in the long run the facility should save money compared to the costs of conventional greenhouses that require fossil fuels for power. It’s a self-sustaining, cost-efficient design so long as the initial investment can be provided. Facilities similar to the Australian one are already being planned for Portugal and the U.S., as well as another in Australia. Desert areas like those seen in Oman, Qatar and the United Arab Emirates could be next in line.

“These closed production systems are very clever,” said Robert Park of the University of Sydney, Australia, to New Scientist. “I believe that systems using renewable energy sources will become better and better and increase in the future, contributing even more of some of our foods.”

The future of energy – decentralised renewables

November 21, 2016
Why the Future Belongs to Decentralized Renewables, Not Centralized Hydrogen and Giga-Scale Nuclear November 18, 2016 by Energy Post

“……….Let me develop the real reasons why conventional renewables are likely to emerge as the dominant primary energy sources in the first half of the
21st century. The fundamental advantages of renewables, as revealed by practical experience in China as well as in industrialised countries like Germany where an energy transformation is well under way, are these.As they scale renewable energies do not present greater and greater hazards. Instead they are relatively benign technologies, without serious riskThey are clean (low to zero-carbon); they are non-polluting (important in China and India with their high levels of particulate pollution derived from coal); they tap into inexhaustibleenergy sources; and they have close-to-zero running costs since they do not need fuel. They are also diffuse, which should be viewed as an advantage, since this means that renewable sources are decentralised, and can be harvested by both large and by small operations. So they are eminently practicable.Some advantages of renewables are not at all obvious and need to be made explicit. Fundamentally, they are scalable. They can be built in modular fashion – one solar panel, 100 solar panels, 1000 solar panels. As they are replicated in this fashion so their power ratings continue to rise, without complexity cutting back on efficiency. This cannot be said of nuclear reactors, which have an optimal operational size – below which or above which the plant under-performs.

Moreover as they scale they do not present greater and greater hazards. Instead they are relatively benign technologies, without serious risks.


When they use hazardous materials, such as the cadmium in Cd-Te solar, the solution would be to recycle materials in order to minimise the use and waste of virgin materials.

Most importantly, the superiority of conventional renewables lies in their cost reduction trends which are linked to the fact that they are always the products of manufacturing – and mass production manufacturing, where economies of scale really play a role. This means that they offer genuine energy security in so far as manufacturing can in principle be conducted anywhere. There are no geopolitical pressures stemming from accidents of chance where one country has deposits of a fossil fuel but another does not. Manufactured devices promise an end to the era in which energy security remains closely tied to geopolitics and the projection of armed force. As Hao Tan and I put it in our article published in Nature, manufacturing renewables provides the key to energy security.

Manufacturing is characterised by improving efficiencies as experience is accumulated – with consequent cost reductions captured in the learning or experience curve. Manufacturing generates increasing returns; it can be a source of rising incomes and wealth without imposing further stresses on the earth. Add to these advantages that renewables promise economic advantages of the first importance: they offer rural employment as well as urban employment in manufacturing industry; they offer an innovative and competitive energy sector; and they offer export platforms for the future.

The real driver of the renewable energy revolution is not government policy, or business risk-taking, or consumer demand. It is, quite simply, the reduction of costs

This is to list the advantages of renewables without even mentioning their low and diminishing carbon emissions. Indeed they offer the only real long-term solution to the problem of cleaning up energy systems.

With all these advantages, it is little wonder that China and now India are throwing so much effort into building renewable energy systems at scale. These are not exercises undertaken for ethical or aesthetic purposes, but as national development strategies of the highest priority.

So the real driver of the renewable energy revolution is not government policy, or business risk-taking, or consumer demand. It is, quite simply, the reduction of costs – to the point where renewables are bringing down costs of generating power to be comparable with the use of traditional fossil fuels, and with the promise of reducing these costs further still. Supergrids are also being promoted for renewables, but these are very different conceptions, based on integrating numerous fluctuating sources in IT-empowered grids, offering the same practicable, scalable and replicable energy future.

Against these advantages, the obstacles regularly cited are small indeed. There is the fluctuating nature of renewables, which can be addressed by various forms of systems integration (smart grids, demand response) and of course through energy storage, which is moving into the same kind of cost reduction learning curve that has characterised solar and wind power, promising rapid diffusion of both commercial and domestic energy storage units. With rapidly falling costs of storage providing the buffer that can even out fluctuating levels of generation, there is no further serious argument against renewables……..


This article is based on a scientific paper by John A. Mathews, Competing principles driving energy futures: Fossil fuel decarbonization vs. manufacturing learning curves, which was published in Futures in November 2016 (.

John Mathews is author of the Greening of Capitalism: How Asia is Driving the Next Great Transformation”, published by Stanford University Press: His latest book, “China’s Renewable Energy Revolution” (co-authored with Hao Tan) was published by Palgrave Pivot in September 2015:

See his author’s archive on Energy Post.

Transition from nuclear power to renewables- problems to deal with

September 12, 2016

There are good reasons for California to phase out nuclear power, Huffington Post, Johann Saathoff,MP German BundestagCoordinator of energy policy for the Social Democratic Party in the German Bundestag  07/22/2016 “……..In Germany the transition to renewable energies is proceeding although there are challenges to overcome. Two thirds of electricity in Germany is currently generated from renewables. We do not expect demand for electricity to fall in the future. Coupling the electricity market sector (including electric mobility) and the heat market will create overcapacity. This will be a good thing and any overcapacity can be put to good use in the electricity market.

One of the greatest obstacles at present to expanding renewables is the failure to expand existing and build new power grids. The energy transition and the decentralised production of electricity involves the need to adapt the entire power supply system in Germany and renew large parts. Up to now power stations have been located in the vicinity of the major power consumers; in future power stations will be much smaller and distributed throughout the country. They will also not supply electricity on a continuous basis. Sector coupling between the electricity market, heat market and mobility means that fewer networks have to be built since part of the electricity can be consumed locally.

It is important to ensure, however, that security of supply is guaranteed as the production of renewable energy increases. There is therefore a need for an intelligent grid with intelligent, i.e. controllable, electricity meters at least for the big energy consumers. Up to now the production of electricity has been geared to consumption. In the new energy world it will be possible to adjust the consumption curve to the production curve. It will be possible, as an example, for cold stores to be cooled down further at times when there is too much power in the grid. They will not then need any power if a few hours later there is too little power in the grid. For the operator of the cold store there will be a commercial incentive in the form of lower prices if he adjusts the way he runs his cold store to comply with the electricity market.

The cold store would thus function as a type of energy store. This, along with other storage systems such as pumped hydroelectric and compressed air energy storage, chemical storage and power-to-gas and power-to-heat plants, will become increasingly important with the growth of renewable energy and in the context of supply security. In the transitional phase, security of supply can be ensured locally by small modular gas power stations.

In Germany there is a broad consensus in society in favour of the phasing out of nuclear power by 2022. The reasons for phasing out nuclear power for us are the same as in California and elsewhere: the lack of a solution regarding the storage of nuclear waste, environmental damage and the risk of accidents. The danger of an accident comes from human error in operating the plant, a lack of maintenance and wear. In the past there was also a failure to properly appreciate the danger of terrorist attacks. These dangers apply to the plant itself, to the energy supply for the region in question and to the nation as a whole. Phasing out nuclear power and changing over to decentralised renewable energy removes a central target of attack from potential aggressors. Thus the energy transition also contributes to national security.

There may be a consensus within society in favour of the energy transition and the resulting structural changes that are required, but the state needs to be proactive in the process in order to ensure that this consensus is maintained. This means that people employed up to now in the nuclear sector must be given prospects for the future and those regions which have benefitted in economic terms up to now from nuclear power stations must be shown other options for economic development. One way would be to provide incentives in these regions for building production facilities for storage systems, cabling, wind farms or parts thereof.

One possibility for ensuring people’s support for the energy transition is to encourage them to be actively involved in citizens’ energy companies. This means they have a direct stake in the commercial success of the energy transition. In addition or perhaps alternatively the local authorities as the real agencies responsible for providing public services and representatives of local citizens, should hold large stakes in these energy companies. In this way all citizens participate in the energy transition, not just those who can afford to invest…..