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  • Climate change puts us all in the same boat. One hole will sink us

     

     

    But despite the mounting evidence of negative impacts, reaching a deal will not be easy. It will require extraordinary political courage – both to cut the deal and to communicate its necessity to the public.

     

    A mindset shift is required. Distrust and competition persist between regions and nations, manifest in a “no, you must show your cards first” attitude that has dogged the negotiations leading up to Copenhagen. This has to be overcome.

     

    A deal that is not based on the best scientific evidence will be nothing better than a line in the sand as the tide comes in. But short-term considerations, including from special interest groups and electoral demands, are working against long-term solutions.

     

    Success in reaching a deal will require leaders to think for future generations, and for citizens other than their own. It will require them to think about inclusive and comprehensive arrangements, not just a patched up compilation of national or regional interests.

     

    A deal that stops at rhetoric and does not actually meet the needs of the poorest and most climate vulnerable countries simply will not work. The climate cannot be “fixed” in one continent and not another. Climate change does not respect national borders. We are all in the same boat; a hole at one end will sink us all.

     

    For it to work, climate justice must be at the heart of the agreement. An unfair deal will come unstuck. Industrialised countries such as the United States must naturally take the lead in reducing emissions and supporting others to follow suit, but developing countries like India or China also have an increasing responsibility to do so as their economies continue to grow.

     

    Tragically, it is the poorest and least responsible who are having to bear the brunt of the climate challenge as rising temperatures exacerbate poverty, hunger and vulnerability to disease for billions of people. They need both immediate help to strengthen their climate resilience as well as long-term support to enable them to adapt to changing weather patterns, reduce deforestation, and pursue low-emissions, clean energy growth strategies.

     

    The deal must include a package of commitments in line with the science and the imperative of reducing global emissions by 50-85% relative to 2000 levels by 2050.

     

    This requires a schedule for richer countries to move to 25-40% emission cuts by 2020 from 1990 baselines; clear measures for emerging economies to cut emissions intensity; and clarity about both immediate and longer term finance and technical support for developing countries, notably the poorest and most vulnerable among them.

     

    Will we get there? The targets that have been proposed for emission reductions by many industrialised countries such as the EU, Japan and Norway are encouraging, as are those being made by the big emerging economies including Brazil, China, India, Indonesia, and South Korea.

     

    Recent announcements by the US on emission targets represent a significant shift and provide a basis for scaling up commitments in the coming years. So does the recognition by emerging economies that they also have a role in supporting the most vulnerable countries.

     

    Welcome too are the proposals for financial support to LDCs and small island states made at the Commonwealth summit in Trinidad, as well as proposals by the Netherlands, France, and the UK, among others.

     

    But much greater specificity on finance is needed. Existing official development assistance (ODA) commitments to help the poorest countries meet the Millennium Development Goals need to be met. And significant additional finance that is separate from and additional to ODA needs to be mobilised to support them meet the incremental costs generated by climate change.

     

    A deal that is not clear on the finance will be both unacceptable to developing countries, and unworkable. Finding the additional resources and communicating its necessity will not be easy, particularly in the current economic climate, but it must be done.

     

    A successful deal could incentivise not only good stewardship of forests and more sustainable land use, but also massive investment into low-carbon growth and a healthier planet, including in sectors such as energy generation, construction and transportation.

     

    And it could usher in an era of qualitatively new international co-operation based on common but differentiated responsibilities – not just for managing climate change, but for human development, social justice and global security.

     

    Ultimately, at stake is whether our leaders can work to help us save ourselves from … well, from ourselves. The legacy of today’s politicians will be determined in the weeks to come.

     

    • Kofi Annan was UN secretary-general from 1997 to 2006. He now chairs the Kofi Annan Foundation and the Africa Progress Panel and is president of the Global Humanitarian Forum

     

    For regular updates on the Copenhagen climate talks and beyond sign up for the Guardian’s email newsletter Greenlight.

  • DC Arc Faults and PV System Safety

     

    As an industry, we have done a good job of providing adequate system protection and safety mechanisms.  Widespread deployment of PV systems teaches us new lessons.  We must learn from those lessons and continue to improve the safety of PV systems.  Arc fault detection is a necessary next step.

    Aspects of DC Arc Fault and Safety

    Recent proposed changes to the National Electric Code underscore the gravity of DC arc fault risks. The changes (which have NOT yet been adopted as of this writing) will mandate detection of — and preventative measures for — series DC arc faults in systems where the DC voltage exceeds 80VDC. This is a step in the right direction as it addresses the prevention element of DC arc fault safety. There are two elements to the DC arc fault/safety issue:

    1. Prevention – this aspect deals with the mechanism and factors necessary to create an arc, especially one that is capable of becoming the source of ignition of nearby combustible materials. It should be noted that DC arcs can reach temperatures of over 3000 degrees C. Arcs of this temperature can melt metal, which can fall as slag and ignite nearby combustible materials. Preventative measures are therefore necessary to minimize the risk of starting the fire in the first place.
    2. Suppression – this involves all aspects related to extinguishing the fire after it has started. Fires are typically started by some means other than the PV system, but the presence of relatively high DC voltage and high DC current presents a significant risk to the firefighters.

    Types of Arcs

    Three types of arcs are of particular concern:

    Series – A series arc occurs when a connection is pulled apart while the PV is producing current. Any intermittent connection in the DC circuit has the potential for producing a DC arc fault. These connections may include soldered joints within the module, compression type wire connections, or the actual connectors that are commonly used on the wire leads attached to PV modules.

    Parallel – Parallel arcs occur when an insulation system suffers a breakdown. Two conductors of opposite polarity in the same DC circuit are often run in close proximity to each other. The insulation between the two wires can become ineffective due to animals chewing on them, UV breakdown, embrittlement, cracking, moisture ingress and freeze/thaw cycles.

    To ground – This fault only requires the failure of one insulation system.  While GFDI (Ground Fault Detector & Interrupter) provides some measure of protection against this fault, there have been cases of faults to ground that failed to trip the GFDI protection yet created an arc.

    Challenges with Arcs

    Detection of the arc is the first real challenge. It is paramount that the arcs are reliably detected without raising “false alarms.” Many different techniques can be employed, with most relying on voltage, current, radiated energy, or a combination of these.

    Taking appropriate action once the arc has been detected is the second challenge.  Furthermore, the correct action for series arcs is the opposite of the action necessary for parallel arcs.  In fact, the corrective action for a series arc can actually exacerbate a parallel arc.

    To extinguish a series DC arc, power production must be ceased and current flow in the DC circuit must be reduced to a very low level. It is preferable to reduce the DC current flow to zero in order to guarantee that the arc is extinguished. The PV inverter can accomplish this by ceasing exportation of power. 

    A parallel arc requires the opposite action. The two DC conductors must be shorted together to bring the array voltage to zero. Once the voltage is near zero, the arc extinguishes and the protective device must be capable of carrying the array short circuit current indefinitely.

    System Design

    Three aspects of system design contribute to the arc fault risk: high DC voltage, high DC current and large geographic distribution of DC wiring. To sustain an arc of significant temperature, the voltage across the arc gap must be in the range of 20 volts or more. DC short circuit current capabilities below 2 or 3 amps have a difficult time sustaining an arc of any real danger. Wide distribution of wiring systems increases the likelihood of physical damage and increases the degree of exposure to firefighters during the suppression phase of a fire.

    A traditional string/central inverter PV system design is not beneficial in terms of addressing arc fault risk and firefighter safety. Strings are designed for the highest DC voltage to reduce I²R losses, and multiple strings are placed in parallel to increase the DC current. This design also results in a large geographic distribution of DC wiring systems.  All three of these design factors increase the risk of arc faults and make it more difficult to suppress a fault once it occurs.

    The impact of DC-DC converters, which operate at high DC bus voltages and connect to a traditional string/central inverter, resulting in the large geographic distribution of DC wiring, is uncertain.  Certain types of arc faults could fool the control system into taking inappropriate control actions and theoritically worsen the problem.  Some of these systems also rely on communication controls for safety functions.  Without appropriate safety measures similar to those used in aerospace control systems, this is a questionable approach.

    Microinverter and AC module designs work at much lower DC voltages, lower DC current, and limit the distribution of DC wiring to the vicinity of the module. These inverters are Utility-Interactive, which means that the removal of Utility AC power from the system, results in no AC voltage being distributed, and only low voltage DC under each PV module.  This approach reduces arc fault risk and provides the greatest degree of safety for the firefighters.

    In summary, as the concern for fire prevention and suppression rises in the PV industry, more attention is being paid to the threat of arc faults. Challenges with arc faults include understanding the type of arc fault and ensuring that the appropriate corrective action is taken. System design also has a significant effect on both prevention and suppression of fires, with increasing preference being given to AC-based systems that mitigate the risk of fire by avoiding distribution of high DC voltage and high DC current altogether.

  • Queensland residents want to cap population growth

    • As the Government prepares to beef up its population policy credentials, some mayors are protesting that growth is too far ahead of the transport system’s ability to cope.

     

    Allan Sutherland, the Mayor of the Moreton Bay region, which is expected to absorb an extra 84,000 new homes over the next 20 years, said infrastructure was needed to accommodate growth. “You can’t just keep jamming terracotta roofs all over the place and not improve your transport system,” he said.

    The poll found that 59 per cent of those surveyed were in favour of the Government working to limit the region’s population growth.

    Thirty-five per cent were opposed.

    The result was even more emphatic among Labor supporters, with 65 per cent in favour of population limits.

    The poll also found that 59 per cent of Queenslanders thought the forecast population of 6 million for southeast Queensland by the middle of the century was too much, with 33 per cent saying it was about right.

    Concern over the region’s growth has rekindled debate on a population cap for southeast Queensland, despite Premier Anna Bligh and property industry groups dismissing the idea.

    Population growth will be a key issue at today’s Council of Australian Government meeting and Ms Bligh yesterday announced the involvement of scientist Tim Flannery, demographer Bernard Salt and environmentalist Ian Lowe at next year’s South-East Queensland Growth Summit on March 30 and 31.

    Ms Bligh said southeast Queensland had more interstate migrants than any other state.

    But she said she was yet to see “any sensible or legal way” to cap the population.

    “As attractive as a population cap sounds, I think it’s misleading to imply to people that such a thing could be done,” she said.

    The Wells family, who exchanged Yorkshire in the UK for Springfield Lakes, west of Brisbane, are part of the influx that has made southeast Queensland the fastest growing region in the country.

    “We came here on holiday in 2002 and said we’ll be back – we just loved it,” Claire Wells said yesterday.

    Mrs Wells said she and husband Shane had poured over pages on the internet devoted to Springfield Lakes and had liked what they’d seen.

    “We were even more impressed when we saw it in reality,” she said.

    The prospect of further growth didn’t bother Ms Wells so long as the needs of residents were met.

    “There’s room for everybody and with growth comes new opportunities,” she said.

    However, southeast Queensland head of the Sustainable Population Australia lobby group Simon Baltais said there must be a limit.

    “Pro-growth lobbyists are ignoring the science . . . at the expense of the general community and the environment,” he said.

     

  • An Exclusive Look at the New Siemens 3-MW Direct Drive Turbine

    — Henrik Stiesdal, CTO, Siemens

    Proof of Concept

    The first concept prototype was erected in July 2008 and a second in March of this year. The most important functional aspect of this “Proof of concept” test trial was exchanging the gearbox and generator of a conventionally geared 3.6-MW SWT-3.6-107 with a direct-drive generator. The concept turbine drive system also includes a rotating main shaft supported by two bearings, whereby the upwind rotor is located in front and the generator behind the tower.

    Since the test set-up essentially includes only one main variable, a scientifically sound drive-system comparison can be conducted. Stiesdal said that these two machines have proved themselves faster than expected, including a high availability almost from day one and trouble-free operation of the generators with operating temperatures remaining favurably modest.

    Stiesdal explained that the “main lessons learned underline the long process required from [the] ideas phase to a “Proof of concept” machine. Secondly, the optimization required cost calculation models that are not readily available.”

    He said that the company “discovered that relevant and competent generator suppliers originate from ‘Design to Project’ practices, and not from parties focused at ‘Design to Manufacture.’ All of this took time to get aligned.

    System Layout

    The new highly compact 3-MW IEV WC IA turbine features a 101-metre rotor diameter and a cylindrically shaped nacelle. Visually the turbine is characterized by a large prominent cooling radiator unit located at the nacelle rear, while the characteristic long and tapering Siemens nose cone has been exchanged for a substantially shorter solution.

    A key conceptual difference with the concept turbine is that the annular generator has moved to the front of the tower. This direct-drive system layout is also taken from (earlier) turbine models that were developed by direct drive pioneers like Enercon and Vensys of Germany and former Lagerwey/Zephyros of the Netherlands.

    The main structural element of this 3-MW Siemens direct-drive system is a cast main carrier accommodating eight yaw motors, whereas the generator and rotor assembly as a unit are bolted to its inclined vertical mounting flange. Furthermore, a hollow stationary main pin with the main bearings is an integral part of the generator assembly and provides easy (service) access to the rotor hub internal workings. Both the rotor hub and rotor blades originate from the 2.3-MW SWT-2.3-101 turbine model.

    Inverted Generator

    For this turbine Siemens worked together with partners to develop a new fully enclosed liquid-cooled permanent magnet type generator. Siemens Large Drives based in Berlin, Germany, provided the generator for the prototype for the turbine prototype but in the future there will be additional suppliers.

    The electric machine itself is, in power-engineering terms, known as an inverted radial-flux generator. A key difference with “conventional” radial-flux generators is that the generator-rotor with its magnets facing inside now turns around the stator part. As a consequence this 2-plus-meter-long generator-rotor is directly exposed to the outside environment, and represents a substantial section of total nacelle length.

    Stiesdal explained that there were a number of specific reasons for choosing the inverted generator layout: “Annular generators are by definition big in size, which puts high demand on structural component stiffness, and that in turn is necessary for guaranteeing a constant air gap retention between generator-rotor and stator.”

    He further explained: “adding sufficient structural strength to the stator of a conventional generator by definition results into a substantial outside diameter increase, which potentially contributes to more complex transport logistics. With an inverted generator by contrast, ample space is available for adding stator support structure towards the centre. Our comparative concept analysis clearly showed that inverted generators can be built more compact compared to conventional radial flux equivalents.”

    Lightning Protection

    The compact nacelle cover with integrated lightning protection is further fitted with an onboard crane for easier heavy component exchange, including yaw motors, hydraulic pitch parts, etc. Components as well as people (in case of an emergency) can be lowered to the ground through a hatch located in the nacelle cover’s rear section. Main power electronics, including power cabinets, a full converter and a medium-voltage transformer, are all located at three levels in the tower foot similar to the 2.3-MW turbine series arrangement.

    When asked why Siemens had chosen a new 3-MW class direct-drive turbine, Stiesdal commented: “Some initial findings indicated that the costs per unit of torque (Nm) decrease when power rating goes up and that at a 3.6-MW rating [the] break-even point seems likely. Our expectations were therefore that a direct-drive concept mainly offers a commercially viable alternative for large offshore turbines. However, we now have sufficient indications that the concept might also be feasible for the high-end high-volume market, and do hope that this machine will prove competitive with our 2.3-MW volume turbine series.’

    Early in 2010 Siemens will begin an assembly-line system for the 2.3-MW and 3.6-MW series, the major benefits of which are expected to be substantially reduced assembly time per turbine and optimized factory floor utilization.

    Added Value

    Another key issue Stiesdal explicitly addressed is what a direct-drive solution can offer in terms of added value to customers. He explained that all manufacturers “feel the heat” of press reports on gearbox failures, but also stressed that his company has successfully built geared wind turbines since 1980.

    Stiesdal quoted the results of a 2008 survey on a substantial number of (former Bonus) turbines installed during the mid 1980’s in California. He said that even after more than 20 years, “96% of these installations were still running well.”  He also said that the systems were so reliable that the company was able to reduce service time from twice per year to only once per year.

    So while it is evident that geared turbines will remain a reliable, competitive alternative for many years to come, it’s important to note that a switch to direct-drive reduces the number of turbine components by 50%. This will make it easier to convince customers of the long-term income stability on their capital investment not to mention that 50% fewer parts to handle also turns into a real cost advantage during high-volume turbine manufacture. 

    Offshore Applications

    Siemens currently has more 450 of the upgraded 3.6-MW SWT-3.6-120 turbines on backlog. In the future Siemens will offer the new 3-MW turbine model for offshore applications, but only after successfully completing a rigorous product testing and optimizing period followed by a careful series production ramp-up.

    Stiesdal said that, “at this moment it is far to early to elaborate on 3-MW series production timing, as we first want to see how the turbine performs in the field. That is the way we always did it, and know based upon these experiences that there will always be issues with a new turbine model, smart design concepts included.”

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  • Rich nations to offset emissions with birth control

     

    The scheme – set up by an organisation backed by Sir David Attenborough, the former diplomat Sir Crispin Tickell and green figureheads such as Jonathon Porritt and James Lovelock – argues that family planning is the most effective way to reduce the likelihood of catastrophic global warming.

    Optimum Population Trust (Opt) stresses that birth control will be provided only to those who have no access to it, and only unwanted births would be avoided. Opt estimates that 80 million pregnancies each year are unwanted.

    The cost-benefit analysis commissioned by the trust claims that family planning is the cheapest way to reduce carbon emissions. Every £4 spent on contraception, it says, saves one tonne of CO2 being added to global warming, but a similar reduction in emissions would require an £8 investment in tree planting, £15 in wind power, £31 in solar energy and £56 in hybrid vehicle technology.

    Calculations based on the trust’s figures show the 10 tonnes emitted by a return flight from London to Sydney would be offset by enabling the avoidance of one unwanted birth in a country such as Kenya. Such action not only cuts emissions but reduces the number of people who will fall victim to climate change, it says.

    “The scheme, called PopOffsets, understands the connection [between population increase and climate change],” says the trust director Roger Martin. “It offers a practical and sensible response. For the first time ever individuals, companies and organisations will have the opportunity to offset their carbon voluntarily by supporting projects to provide family planning services where there is currently unmet demand.”

    In papers released with the launch of the offset scheme, the trust claims that reducing CO 2 by 34 gigatonnes would cost about $220bn with family planning, but more than $1tn with low carbon technologies. The 34 gigatonnes is roughly what the world emits in a year, and would be achieved by cutting the projected global population in 2050 by 500 million.

    The world’s population, presently 6.8 billion, is increasing by nearly 84 million a year. The growth is equivalent to a new country the size of Germany each year, or a city the size of Birmingham every week. It is expected by the UN to peak at about 9 billion people in 2050. By this time, UN scientists say global carbon emissions must have reduced by at least 80% to avoid dangerous rises in temperature, meaning the carbon footprint of each citizen in 2050 will have to be very low.

    “The current level of human population growth is unsustainable and places acute pressure on global resources. Human activity is exacerbating global warming, and higher population levels inevitably mean higher emissions and more climate change victims,” said Martin.

    The giant carbon footprints of developed countries mean prevented births will save far more carbon than those in developing nations.

    However, some development groups opposed the plan. “We are keen that any money raised [from offsets] help the poorest who are most vulnerable to climate change. [But] it would be misleading if it was spent in this way. It should go to [immediate] things like disaster risk reduction, food security and water,” said Paul Cook, advocacy director of Tearfund, a faith-based development group.

    Population control is highly contentious in rich and poor countries alike Some, such as Jonathon Porritt, the former Sustainable Development Commission chair, have said promotion of reproductive health is one of the most progressive forms of intervention. “Had there been no ‘one child family’ policy in China there would now have been 400 million additional Chinese citizens,” he has said.

    But other thinkers, such as the Guardian columnist George Monbiot, say global population increase pales into insignificance when compared with the effect of increased consumption and economic growth.

     

  • Designs for new UK nuclear reactors are unsafe

    Designs for new UK nuclear reactors are unsafe

    Terry Macalister

    27th November, 2009

    Major setback for nuclear energy plans as watchdog’s report finds flaws in US and French models

    Britain’s main safety regulator threw the government’s energy plans into chaos tonight by damning the nuclear industry’s leading designs for new plants.

    The Health and Safety Executive said it could not recommend plans for new reactors because of wide-ranging concerns about their safety.

    The leading French and American reactors are central to plans for a nuclear renaissance aimed at keeping the lights on and helping to cut carbon emissions. The government needs to build a number of nuclear power stations in the next 10 years to replace old atomic and coal plants.

    HSE approval

    But the HSE has to approve the safety of the designs before they can be built.

    ‘We have identified a significant number of issues with the safety features of the design that would first have to be progressed. If these are not progressed satisfactorily then we would not issue a design acceptance confirmation,’ the agency concluded following a study of the latest French EPR and US AP1000 reactor designs.

    Kevin Allars, director of new build at the HSE, admitted frustration that the design assessment process was already behind schedule owing to insufficient information from the companies promoting the reactors and a lack of enough trained staff in his own directorate.

    The HSE’s public report expresses ‘significant concerns’ about the lack of separation between the safety protection and control systems on the EPR reactor design promoted by Areva and EDF of France.

    Design faults

    The safety body says another part of the reactor is ‘not entirely in alignment with international good practice’.

    The report says it has raised a number of issues with EDF and Areva relating to the structural integrity of the EPR and it concludes: ‘It is too early to say whether they can be resolved solely with additional safety case changes or whether they may result in design modifications being necessary.’

    The design put forward by Westinghouse, the American firm now owned by Toshiba of Japan, is also criticised, with the HSE saying the safety case on internal hazards has “significant shortfalls”.

    It criticises the company for a “lack of detailed claims and arguments” to support various assertions, while questioning aspects of the civil and mechanical engineering plans as well as the structural integrity and “human factors”.

    It also complains that the reactor design was submitted in feet and inches rather than metric figures.

    Delay

    Industry experts said the HSE was in a pivotal position to make or break the government’s wider plans because it could delay the planned reactors from coming on stream from 2017.

    That is the time that ministers fear an “energy crunch” because most existing reactors will have been retired, many coal plants shut down and renewable power insufficiently advanced to take over.

    John Large, a leading nuclear consultant, said: ‘The HSE as an independent agency will come under tremendous pressure to push through these designs. But if it stands up to [the] government and stops or delays these designs for two or three years until it is satisfied then developers could lose interest and we could fall behind in the queue of countries waiting to build nuclear.’

    Allars said he had not received any pressure so far from the government. While he had beefed up his staff and hoped to quicken the speed of his work, he insisted it was not his problem to worry ultimately about delays.

    Independence

    ‘I am independent of government, and independent of industry and I will do what I need to protect society from any dangers of nuclear power. I will only be in a position to agree a generic design assessment if I get the right information [in future] to do that,’ he said.

    The HSE said it might allow so-called exclusions over some of its concerns under which it would allow construction to proceed on the understanding that the problems would be addressed later.

    Jean McSorley, consultant to Greenpeace’s nuclear campaign, said it was highly likely reactor designs would not be ready for final sign-off at the end of the design process.

    ‘This could leave the utilities and construction companies with real problems finishing projects, and that’s very risky for them financially. Investment companies will also want to delay putting money into these projects until it is decided who takes responsibility for any potential cost overruns and delays,’ she said.

    Areva shrugged off the concerns raised by the HSE.

    ‘It is important to emphasise that this is a normal part of what is a very transparent process and that it is entirely expected, as part of the design assessment process in the UK, for issues to be identified and resolved prior to licensing and construction,’ it said.

    This article is reproduced courtesy of the Guardian Environment Network