EcoRadio

Category: Energy Matters

The twentieth century way of life has been made available, largely due to the miracle of cheap energy. The price of energy has been at record lows for the past century and a half.As oil becomes increasingly scarce, it is becoming obvious to everyone, that the rapid economic and industrial growth we have enjoyed for that time is not sustainable.Now, the hunt is on. For renewable sources of energy, for alternative sources of energy, for a way of life that is less dependent on cheap energy. 

  • Coal crackdown will not reduce emissions

     

    But an analysis by Greenpeace shows that none of the 12 proposed coal plants would be forced into a redesign or be shelved due to the standards.

    The figures show just three of the proposed plants would emit more carbon per megawatt hour of electricity generated than would be allowed under Labor’s promised standards.

    The proposed Bluewaters 3 and Bluewaters 4 coal plants in Western Australia both have emissions intensity rates of 0.92, and the proposed Coolimba plant in WA will have a rate of 0.9 to 1.0. All three have state government approval and would be exempt from federal Labor’s standards.

    The emissions intensity for a new coal generator in South Australia – Altona Energy’s Arckaringa plant, which is in an early stage of development – remains unknown. Calls to Altona Energy’s Australian office went unanswered yesterday.

    A proposed brown coal plant in Victoria with emissions standards of between 0.78 and 0.87 was recently withdrawn for redesign to meet a tougher 0.8 standard set by the Victorian government as part of its climate change white paper.

    The other seven new plants all have estimated emissions intensity rates below Labor’s 0.86 standard. The lowest is the 0.18 at the Wandoan carbon capture project in Queensland.

  • Solar Array Design: Parallel Wiring Opens new Doors

     

    Series: The Old Way

    Series-wired systems are governed by the principles of voltage. A solar array must provide a high enough voltage to enable its inverter to operate at an efficient level; this has traditionally required series wiring, so that panel voltages sum. Similarly it is important to make sure that the system can never go above the maximum voltage permitted by code, usually 600VDC in the U.S.

    However, the inverter is sensitive to operating voltage levels. It can suffer major swings in efficiency when the input voltage varies in relation to its fixed output voltage. The larger the variation, the harder it is for the inverter to operate at optimal efficiency. Currently inverter efficiency is shown at a single operating point when actual operating efficiency varies as system voltage changes, real operating efficiencies can be off several percentage points from the optimal operating efficiency.

    To accommodate these physical demands, all series-architected solar installations must abide by a set of design rules. The result of these rules is to define the minimum-sized building block (string) used for a given installation. Once this is defined, that exact footprint must be used for the entire array. This can lead to serious challenges, as designers are forced to manage the always-unique geometry of the proposed array location. In many cases, these challenges translate into increased cost of deployment, smaller system sizes or even a decision to forego the installation completely.

    The New Parallel Solar Universe

    The enabling technology for parallel solar deployment is a new generation of low-cost, high-efficiency electronic devices that allow a solar module to deliver a fixed DC voltage to a DC power bus. This DC power bus can be set to the single best point for the inverter or can float to whatever level the inverter requires, allowing the inverter to concentrate simply on optimizing its AC-to-DC conversion efficiency, as opposed to worrying about what compromises it might need to make to effectively harvest power from the solar modules. This mechanism provides an effective transport of power to a central inverter where AC conversion efficiencies can be optimized.

    In this parallel solar paradigm, the PV technology of the module no longer matters, as each module operates with complete independence from its neighbors. Because each module can produce the voltage level needed by the inverter, voltage summing with strings of modules is not needed. This means that a solar array can now be designed and installed just like a lighting system. Each module represents a current source and as long as the array’s wiring is sized appropriately and its branches are capable of handling the current produced, the system will work at optimum efficiency; no other design rules apply.

    What does this mean to the system designer? The biggest advantage is that systems can be built using variable-sized blocks of modules ranging from 200 watts to 31,000 watts. This enables designers to maintain installed cost targets while also taking complete advantage of all available space at an installation site. If the geometry or aesthetics of a project require multiple azimuth angles, different angles of tilt or shading, there is no longer a need to incur the costs or design limitations of multiple inverters. The solar power system can accommodate the architecture of the building, rather than requiring the building architecture to provide an ideal platform for the solar array. Different PV module technologies can even be applied to a single inverter (that is, thin film and crystalline).

    But this new technology also allows us to think a little further out of the box. We now have a new tool available for optimizing a system’s production capabilities in multiple environments. We are only scratching the surface of what we can achieve with this new capability. For example, rather than using a technology like a tracker, we might use different materials technologies to optimize production across multiple seasons and environmental conditions.

    Mathematics of Parallel Solar Power System Design

    Parallel solar design reduces the number of variables that need attention during solar power system design. Voltage is no longer a factor, so Voc overhead and temperature drift are no longer concerns. We are also freed from worry about the NEC 600V upper limit and its restrictions on the number of modules we can wire together. This simplifies the calculation of wiring loads.

    Three basic decisions must be made at the outset: size of the installation in kWh, modules to be used and inverter to be used. With these in mind, we can start to envision the system. As an example, let’s consider a 180 kW building block using 30 kW units with 230 watt solar modules operating at a Vmp of about 40 VDC. The math here is simple: we will need about 132 modules (30,000/230 ‚âà 132). We will assume that the inverter’s peak efficiency point is at about 330 VDC. From this, we can calculate that at maximum power output, we will have to deal with 92 Amps of current into our inverter (132 modules × 230W/330V = 92 amps (P/V=I)).

    Thinking about this as a lighting circuit, we can look at using six branches of 15 Amps each, a conservative level for #10AWG PV USE-2 or RHW-2 cable outside of conduit. Each branch would have an inline 20 Amp fuse connecting it to a #4 AWG PV backbone that runs directly into the inverter through a 125 Amp fused DC disconnect.

    We can also go a bit larger and design a parallel solar power system for 500kW production capacity: module power density, 230 W; voltage input to the inverter, 330 VDC; total power capacity of system, 550,000 W.

    This will tell us the number of modules we want to use: Total System Capacity/Module Power 500,000/230 = 2,174 modules.

    To figure the total current the system will need to manage we take the total power and divide it by the voltage. Modules×Module Power in Watts = System Power. System Power/Voltage to Inverter = Current. Thus, 2,174×230/330 = 1,516 Amps.

    From here it is a simple matter of working out the number of branches needed to manage the current flow. If we assume use of three of our 180 kW building block circuits (506 Amps each) to connect to our inverter, we can place their terminating points close to the array to minimize our use of conduit. If we want to minimize our terminations, we could use #4 AWG PV wire into our building block combiner units, with each handling 85 Amps.

    To minimize I2R losses we can take a conservative approach and use 20-Amp in-line fuses harnessed into the #4 AWG PV backbone, giving us six branches using #10 AWG PV. Each of our three combiners then will have 167kW of power concentrated into a single pair of conductors, handling a total run of 506 Amps into the central inverter. This array would need just six physical field terminations at the combiners, and six at the inverter. If the combiners are placed strategically at the edge of the array, the conduit runs would likewise be limited to three: one from each combiner to the inverter (see figure 1, below).

    The difference between parallel and series architecture for solar power system design is as simple as the difference between current and voltage. In a series system, the voltage of the module drives the design and therefore the economics of the installation. Parallel wiring lets the voltage be set as a constant, which allows the system to be driven by current.

    Current is a much easier variable to work with on several levels. First, it is a familiar, well-understood design variable for designers and installers; the same one used in all lighting system design. Second, the current variable is much easier to regulate and control with existing safety systems. Third, we can optimize the efficiency of the DC-to-AC conversion by regulating the operational voltage of the solar array to the voltage of the grid that the system is providing power to.

    Perhaps most importantly, parallel solar wiring allows different PV technologies to feed a single inverter. This promises to open new vistas for architects and system designers as they search for better ways to integrate solar technology into our everyday lives. It will allow PV manufacturers to optimize products for very specific environmental conditions without having to carry the load of an entire system’s production capacity. It may also make new materials more feasible by isolating each module from the rest of the system, allowing it to work at whatever native voltage is most efficient for that particular technology. All of these new possibilities open the door for innovation in the solar market.

  • First gas rig headed for NSW coast

     

    This followed an outcry from local councils and residents about a site 25 kilometres off Forresters Beach near Terrigal that was initially slated as Advent’s target and may have played a role in helping the candidates win their seats.

    The office of the federal Environment Minister, Peter Garrett, confirmed that Advent’s previous application for drilling approval was withdrawn.

    However, Mr Breeze said that the site off Forresters Beach was one of four which it was considering in the area and it has now moved its focus over the horizon to the New Seaclem-1 site, which is not visible from the shore.

    The company intends to tow the Ocean Patriot rig from Victoria so it can test the New Seaclem-1 site for the presence of gas 826 metres below the sea floor, Mr Breeze said.

    This would take about 20 days, during which sensors on the drill would send information to a computer aboard the rig and then the hole would be plugged, he said.

    ”You put cement casing into it and you seal it off and have a three foot [0.9 metre] cement plug just under the sea floor,” he said.

    If the exploratory drill is successful, extracting the gas would entail putting a platform out of sight on the sea floor and burying a pipe which would convey it into the existing Newcastle-Sydney gas pipeline ashore, he said.

    The offshore Sydney basin covering 8200 square kilometres could possibly contain almost as much gas as the massive Bass Strait fields, but it has not been explored more extensively because it was so close to a plentiful supply of coal, he said.

    Now that concerns about carbon emissions have come to the fore, there is more interest in gas, a cleaner energy source which as a fuel replacement for coal in power stations could help Australia meet its Kyoto protocol objectives, he said.

    The NSW Minister for Mineral Resources, Paul McLeay, confirmed that this would be the first exploration drilling well ever off the state’s coast if it proceeds.

    The Department of Industry and Investment is awaiting revised application documents from Advent Energy, including a modified environment plan and well design plans, he said.

    Gosford City Council a month ago passed a motion strongly objecting to the company’s plans, saying there had been no social, economic or environmental impact assessment. ”A large proportion of my community rely on the beaches for tourism,” said the mayor, Chris Holstein.

    ”If anything was to impact on our beaches, it would have a major impact not only on the environment, but economically.”

    Wyong Council has also raised issues about possible pollution, the effects on fish and migrating whales and how any subsea rupture would be handled.

    ”We are not against gas. We think it’s a wonderful thing. But we want to be sure the seabed is not disturbed,” said the mayor of Wyong, Bob Graham.

    However, there is a further catch.The federal environment department has no new application for gas drilling off the NSW coast before it, according to Mr Garrett’s spokesman.

    Any proposal likely to have a significant impact on an area protected by environmental law needed approval to go ahead, he said.

    Mr Breeze said his company would fulfil all the requirements of federal government departments.

  • Poison gas leak from Sydney nuclear reactor sparks cover up claims

     

    They were told that 36 hours earlier the first “hot commissioning trials” at ANSTO’s Lucas Heights radioisotope facility for Molybdenum-99 had taken place.

    Molybdenum-99 is produced by the fission technique – the intense neutron-bombardment of a highly purified uranium-235 – and is used in nuclear medicine.

     

    While the nuclear reactor – and the government body that oversees it – insists the release of the radioxenon by-product were no threat to public safety, no one, including neighbours of the suburban Sydney plant, were informed.

    “Xenon gases are highly volatile and, being inert, they are not susceptible to wet or dry atmospheric removal mechanisms,” a scientific report obtained by The Sunday Telegraph says.

    “Consequently, once released to the atmosphere they are simply transported down-wind while radioactively decaying away.”

    Significant amounts of the main gas detected – Xenon-133 – can be released during a nuclear reaction or a nuclear explosion.

    While it is used in medical procedures, specialists are urged not to administer it to pregnant women and children.

    Side effects of its use in medical procedures can include allergic reactions such as itching or hives, swelling of the face or hands, swelling or tingling in the mouth or throat, chest tightness, and trouble breathing.

    The report into the release from Lucas Heights says the doses were “well below the annual limit for public exposure”.

    Officials from the Australian Radiation Protection and Nuclear Safety Agency said it was notified at the time and that the emissions were within public safety guidelines.

    In 2006, ANSTO was forced to allay public fears after a leaked memo revealed xenon and krypton were released into the atmosphere following the rupture of a pipe.

    Read more: http://www.news.com.au/features/environment/poison-gas-leak-from-sydney-nuclear-reactor-spark-cover-up-claims/story-e6frflp9-1225911381815#ixzz0xxZe0IhX

  • Julia Gillard’s carbon price promise

     

    Ms Gillard told The Australian there was a substantive basis to her rejection of same-sex marriage.

    She now rules out any change in her opposition to same-sex marriage during the life of her government. She said she appreciated “our heritage as a Christian country” and believed “the marriage act has a special status in our culture”.

    Like Mr Rudd, she said she would select her own ministry rather than bow to factions.

    And she has rejected proposals for both a parliamentary budget office and a debates commission.

    She said her government would legislate a new funding model for government and private schools across Australia. It would be based upon the review chaired by prominent businessman David Gonski that Ms Gillard branded a “think big” exercise.

    She said a shift to some integration in government and private school funding was a “possibility”. Aware of the explosive political nature of this exercise, Ms Gillard insisted Labor would legislate the new policy to begin from January 2014 – after the next term.

    For the first time, she nominated micro-economic reform in health and education as her most critical economic priorities.

    “In my view, the major economic reform is to focus on health and education, big sections of our domestic economy that make a difference to productivity and participation.”

    This included market design, transparency, consumer choice, quality and regulation. Ms Gillard said health and education were “the two big undone (domestic) pieces of micro-economic reform”.

    She also spelt out her proposals to change immigration policy. “Will there be new criteria that bear upon immigration and numbers? Yes, two – better training policy and sustainability.

    “It is not acceptable to me that states like Western Australia have got companies in the north crying out for skilled workers, and in Perth youth unemployment is more than 10 per cent. That’s not acceptable to me. We will be acting on that.”

    She defended the $43 billion National Broadband Network, saying it had been subjected to “appropriate processes and diligence checks”. This included a strong defence of the network’s operating monopoly.

  • Drilling to begin for Cornwall geothermal power plant in 2011

    Geothermal energy involves pumping water up to 5km underground where it is heated by hot rocks before being pumped back up to the surface to either be converted into electricity or used as a source of renewable heat. In contrast to wind power, geothermal is also able to operate steadily 24 hours a day.

    Cornwall’s big potential

    Most suitable sites for geothermal power are expected to be found in Cornwall, where extensive research in the 1970s and 80s found significant opportunities within the county’s granite bedrock.

    The Department for Energy and Climate has backed both projects with more than £2 million in funding in a bid to kick-start the sector.

    If successful in its exploratory drilling, the Redruth project would produce 10 megawatts (MW) of electricity and 55MW of renewable heat for the local community.

    Ryan Law, managing director of the company behind the project Geothermal Engineering Ltd, said the electricity it could produce over the course of a year was equivalent to 21 wind turbines.