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Category: Energy Matters

  • Solar to provide quarter of electricity by 2050

    Solar to provide quarter of electricity by 2050

    Ecologist

    14th May, 2010

    North Africa expected to become major producer of concentrated solar power (CSP), more than half of which would be exported to meet European electricity demands

    Solar electricity should be able to meet 20 to 25 per cent of global electricity production by 2050, according to analysis by the International Energy Agency (IEA).

    The IEA expects photovoltaic (PV) solar panels to provide 5 per cent of global electricity by 2030 and 11 per cent by 2050, driven by favourable incentive policies for residential and commercial installation. It also expects PV to provide a significant amount of energy for off-grid communities in rural areas.

    Concentrated Solar Power (CSP) is expected to grow to a similar market share – 11 per cent by 2050 – but its expansion will depend largely on the development of dedicated transport lines to bring power from regions with strong sunlight to areas of high population.

    According to the IEA, North America is likely to be the biggest producer of CSP electricty, followed by India and North Africa. The latter is expected to export half its production to Europe through power lines across the Mediterranean. 

    David Matthews, CEO of the Solar Trade Association, said solar PV and CSP would complement each other rather than be in competition.

    ‘The reality is that we need both PV and CSP: PV in northern Europe and CSP in the south where there is the direct sunshine.’

    A market analysis by PricewaterhouseCoopers and due to be published next week says that the installation of solar PV in the UK is likely to increase five fold by the end of 2010, driven by the newly introduced feed-in tariffs.

    PV currrently represents 0.3 per cent of renewable energy in the UK, generating 28 MW. PwC expects that figure to reach 500 MW by 2015.

    In the longer term, Matthews said he expects CSP to have the bigger role in meeting the world’s power needs because of its lower costs per kilowatt, and its ability to store energy overnight as well as transfer it over long distances

  • Bringing Utility-Scale Solar Power to the Grid

     

    Utilities are being challenged to embrace this rapidly evolving wave of change. Some have concerns that integrating a high volume of inverter-based photovoltaic systems and other distributed generation sources will lead to instabilities and the possibility of unsafe grid operations. Variable energy production and the fact that peak production from these sources does not always coincide with peak demand can reduce the value of PV’s impact on utility operating economics.

    The impact of distributed production on fault-protection and system repair safeguards can also be significant. These are valid concerns. It is clear that the old system of “one-way” power flow will not be sufficient in the future. A new paradigm of integrated systems offering two-way power, control and information sharing is required. Not only will the technical issues have to be solved, but utilities will have to adjust their historic view of the grid architecture to embrace distributed generation and work with the other parties involved to create an optimized solution.  (Left: This 100 kW installation by the Oregon DOT is one of the country’s first solar highway projects.  Courtesy PV Powered.)

    DOE Involvement

    Realizing the magnitude of the problems to be solved, the U.S. Department of Energy (DOE) has initiated the Solar Energy Grid Integration System (SEGIS) project. SEGIS brings together utilities with leaders in the field of photovoltaics, energy management and communications to develop the new products and technologies necessary to achieve high penetration of PV systems into the utility grid. Outcomes from this project will include advanced, highly-integrated inverters; new systems of communication; and less costly, more reliable system components, which will easily accommodate the two-way power and information flows required for seamless integration.

    In the current Phase 2 or “Design Phase” of the SEGIS project, five teams composed of industry-leading companies from across the country are working on various aspects of the project. PV Powered Inc., a Bend, Ore.-based maker of solar power inverters, leads a team charged with addressing the project’s core concerns: utility integration and control; system cost, reliability and efficiency; and integration with building monitoring and control systems.

    As an increasing number of utility-scale PV power plants are being connected to the grid, problems are being identified. These relate to the distributed PV resource’s intermittent nature and the inherent conflict between a power generation source and existing grid interconnect standards governing distributed PV system connection to the grid.

    Both problems are complex and their final solution may be realized only when interconnection standards have been changed to embrace PV as a key energy generation asset for utilities. Additionally, smart grid communications infrastructure will likely be required to fully solve these problems at a level that addresses high PV penetration in the case of highly distributed solar generation.

    As first steps toward this goal, SEGIS team members PV Powered and Portland General Electric (PGE) have integrated two-way communications between the solar power plant and PGE’s GenOnSys distributed supervisory control and data acquisition (SCADA) system. This enables the utility to receive status information and assert control commands as necessary, including disconnecting its fleet of distributed resources remotely if needed.

    As PV penetration increases, the problem of how PV systems detect and react to grid variations becomes increasingly critical to overall grid stability. More interactive controls are required to ensure that inverters will disconnect when necessary, but will be able to stay on-line when drops in utility voltage and frequency levels occur. PV can assist in riding through these temporary fluctuations. This function is typically implemented by a sophisticated set of algorithms that perform passive monitoring and active control within an inverter to determine if an unintentional island has been created (where the PV system sends power into a section of the utility grid experiencing an outage). Present-day inverters cannot differentiate between a true utility outage (where anti-islanding is necessary) and a grid disturbance or brownout in which the PV system could actually help support grid stability. Even if these inverters could differentiate between these conditions, current regulations sometimes require the inverter to disconnect from the grid when additional power is most needed.

    A better method for island detection is being developed by the SEGIS team that PV Powered is involved with. This team is using a pioneering application of synchrophasor measurements to enable the inverter to differentiate between a true unintentional island and a situation where grid support from the PV plant is required.

    Synchrophasor measurements are taken at different locations in a power system using the same absolute time base. This provides an accurate and reliable method of correlating values from various locations that take different amounts of time to arrive at a common collection point.

    To accelerate PV penetration, it is essential that the cost of energy from PV systems continues to decline when compared to conventional sources. Here, cost is broadly defined to encompass not only initial cost but reliability, energy harvest and overall lifecycle costs as well embracing the goal of achieving the lowest total cost per kilowatt-hour over a system’s lifetime.

    The inverter/controller is the heart of a PV system. As PV penetration expands and production volumes rise, the cost of inverters is coming down. However, cost is only one part of the equation — inverters can also decrease the lifetime cost per kilowatt-hour (kWh) by offering better performance, higher reliability and more integrated features that improve energy harvest.

    System Reliability

    High reliability is a key part of managing overall lifecycle costs. Frequent service calls and repairs or system component replacements can significantly reduce a system’s value. Some proposals being explored to improve reliability include expanded use of integrated circuits, thermal management, surge protection, self-diagnostics, reduced overall parts count and eliminating the least reliable components or using selective redundancy to ensure inverter uptime. Additionally, data aggregation and analysis protocols are being developed to improve reliability predictions for individual components and each system as a whole. Finally, new design features are being implemented to reduce the cost and complexity of installation and servicing.

    Harsh environmental conditions further tax PV system reliability. Hydroelectric, nuclear and coal- or gas-fired power plants typically reside in a controlled environment such as a building. By contrast, most solar PV power plant components are directly exposed to the outside environment, subjecting them to temperature fluctuations and extremes, humidity, corrosives, dust and other location-influenced stresses. All this must be factored into any reliability analysis. To accurately predict solar inverter component stresses and associated wear-out mechanisms due to natural cycles, a complex time-dependent modeling approach is required. Because temperature cycling contributes to device wear-out, simpler constant hazard rate calculations that might apply in other situations often are not accurate in this case. PV Powered has created a set of time-dependent prediction tools and analytical methods to predict real-world inverter reliability with greater accuracy and granularity than methods commonly used today. (Above: A mobile solar cart used to test different array technologies as part of the SEGIS development project. Courtesy PV Powered)

    Ensuring maximum energy harvest is a function of a number of factors, including a given system’s efficiency, reliability and uptime and the system’s ability to adapt to dynamically changing irradiance conditions. Within an inverter, the maximum power point tracking (MPPT) algorithm (which varies the ratio between the voltage and current delivered by a solar array to deliver maximum power as the array output changes) is a key factor in maximizing overall solar power plant efficiency. As inverter power conversion efficiency from the arrays nears theoretical maximum, the accuracy and efficacy of the MPPT algorithm emerges as one of the few remaining high-value opportunities to increase total energy harvest. Quantifying MPPT efficiency and developing a new MPPT algorithm that provides highly accurate tracking efficiency over static and dynamic irradiance conditions is a challenge in terms being able to adapt MPPT behavior to various PV materials and fast changing environmental conditions. PV Powered is testing an MPPT algorithm that may deliver superior performance under a variety of conditions and PV materials.

    Another key factor in improving energy harvest is managing weather-related irradiance transients. Unlike other forms of power generation, a solar power system’s inputs are inherently variable due to weather and fluctuations in cloud cover. Without active management power output to the grid can be highly variable and disruptive. This is one of the main barriers to high-penetration PV. Use of irradiance forecasting can mitigate the effects of irradiance transients. SEGIS research is working to develop forecasting methodologies at both the utility level (where forecasting can allow more optimal integration into utility real-time dispatch processes) and the inverter level, where timely insights into cloud position, movement and transparency may be used to “soften” any transients the utility sees.

    From small residential systems to solar farms and utility-scale installations, PV power systems have continued to mature and expand to the point where they are a viable part of the distributed-generation energy future. While significant challenges to successfully implementing high PV power penetration onto the U.S. grid remain, through collaborative efforts such as the SEGIS program, teams of industry and utility experts are working through the issues and developing the technologies that will enable a bright future for distributed utility-scale solar power. 

    Tucker Ruberti joined PV Powered in 2007 and is director of product management. Mr. Ruberti earned a BS in Industrial Engineering from Cornell University and an MS in Environmental Management & Policy from the Rensselaer Polytechnic Institute. He has worked for a range of companies including Westinghouse, General Electric, the New York State Energy Research and Development Authority, Sunlight Solar and IdaTech.

    Sidebar: Solar Energy Grid Integration Systems Projects

    Through industry partnerships, the Solar Energy Grid Integration Systems (SEGIS) initiative is developing advanced systems and technologies to enable the electric power grid to handle large amounts of photovoltaics.

    In 2008, the U.S. Department of Energy Solar Energy Technologies Program (SETP) awarded 12 companies financial assistance to develop a smarter grid. The projects receiving funding include more interactive components and systems that will help solar energy achieve grid parity by 2015. Awardees included Apollo Solar, Edison Materials Technology Center, Enphase, General Electric, NexTek Power Systems, Petra Solar, Premium Power, Princeton Power, PVPowered, SmartSpark Energy Systems Inc., Grid-Smart Inverters (University of Central Florida) and VPT Energy Systems.

    As recipients of Solar Program funding, each company completed Stage 1 conceptual designs and market analysis. Each project then was evaluated prior to receiving a second round of funding on the likelihood of its success and the potential for commercialization. In 2009, five companies were awarded additional funding. These were:

    • Apollo Solar: Advanced Grid-Tied Inverter, Charge Controller, Energy Monitor and Internet Gateway
      Developing advanced modular components for power conversion, energy storage, energy management and a portal for communications for residential-size solar electric systems. Pursuing inverters, charge controllers and energy management systems that can communicate with utility energy portals for implementing two-way power flows of the future.
    • Petra Solar: Economically Viable, Highly Integrated, Highly Modular SEGIS Architecture
      Advancing grid interconnection coupled with lower costs, higher system reliability and safety through low-cost, easy-to-install modular and scalable power architectures. Developing multi-layer control and communication with PV systems to achieve monitoring and control for a cluster of alternating-current module inverters integrated with a strategic energy management system box.
    • Princeton Power: Demand Response Inverter
      Designing innovative commercial-scale demand-response inverter, based on a new, unique circuit and new material, component, and packaging technologies. Developing optimized design for low-cost, high-quality manufacture that will integrate control capabilities (that is, dynamic energy storage and demand-side load response).
    • PV Powered: MPPT Algorithms, EMS Integration and Utility Communications Advancements
      Creating a suite of maximum power point tracking algorithms to optimize energy production from the full range of PV module technologies. Integrating communications with facility energy management systems and utility management networks.
    • University of Central Florida, Grid-Smart Inverters:
      Researching concepts to enhance intelligent grid development with PV that incorporate optional battery storage, utility control, communication, monitoring functions, and building energy management systems. Developing anti-islanding strategy for PV inverters to allow PV generation to remain connected during some grid disturbances, while meeting safety operation requirements. Designing new inverter architectures that bring more stability to the grid.

  • Why would BIG Oil ignore its own demise/

     

    So why do our leaders remain silent? Why does the US push for the truth to be disguised? The risks to a peaceful life are the same for everyone, rich or poor. Why would the great oil companies appear to be so dumb? I suggest they are in fact being extremely canny, and for their own ultimate benefit.

    1. With a sudden and ‘unexpected’ crunch on oil those who control the supply will become powerful forces on the world stage. Countries will be eager to dance their tune. These corporations will, in short, be capable of having such a disproportionate influence on the world that they would be able, over time, to become the major political and economic power on the globe.

    2. If this seems far-fetched, consider the extent to which a medium-sized country would alter its laws in almost every field to maintain their supply of oil.

    3. Then consider that most of this oil comes from Siberia and the Middle East, and from countries that have very different agendas to ours;

    4. and that neither India nor China have significant quantities of oil. Both will become more susceptible to any pressure the suppliers may wish to exert.

    5. Also ask yourself, why is big oil the major owner of alternate energy technology patents and startups? This ensures control over their hegemony.

    6. This has been a long-range plan witnessed by the permanent US presence in Iraq and Afghanistan that is there to ensure the interests of their oil companies are preserved under any future scenario.

    In other words, denial that there is a problem until the last moment ensures that a few corporations will exercise long-term political and financial control over the globe and everyone on it. Its not about money, its about hegemony and power!

    If we were prepared for the crunch then these corporations would lose much of their potential to control the world.

    They will form a world government, or at the least become the world policeman, using their control of a limited resource as the ultimate weapon.

    Scarce oil in an addicted world is the tool of rulership.

    John James

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  • Peak Oil Predictions

     

    The difference between the recovery periods following previous oil shocks and the current one is that a significant proportion of today’s oil demand is in permanent decline. This particularly applies to developed countries where demand for oil is past its peak. In other words, this recession has triggered demand destruction, not demand suppression.

    It’s possible the day of “peak oil” has arrived – but not in the way everyone expected. Instead of peak oil, we’re looking at a peak in demand for oil. The oil age won’t end tomorrow, but the idea that it will go on for ever – with its attendant catastrophes and tragedies – is seriously in question.

    Against this backdrop, the economic case for investing in clean technology becomes as clear as the environmental case. The faster we introduce efficiency in the transport sector, making better cars that use less fuel, adopting cutting-edge hybrid technology and pushing vehicle electrification, the faster the oil industry of the last century will be replaced by the cleaner, safer and economically more sound industries of today.

  • Giant gravel batteries could make renewable energy more reliable

     

     

    Isentopic claims its gravel-based battery would be able to store equivalent amounts of energy but use less space and be cheaper to set up. Its system consists of two silos filled with a pulverised rock such as gravel. Electricity would be used to heat and pressurise argon gas that is then fed into one of the silos. By the time the gas leaves the chamber, it has cooled to ambient temperature but the gravel itself is heated to 500C.

     

    After leaving the silo, the argon is then fed into the second silo, where it expands back to normal atmospheric pressure. This process acts like a giant refrigerator, causing the gas (and rock) temperature inside the second chamber to drop to -160C. The electrical energy generated originally by the wind turbines originally is stored as a temperature difference between the two rock-filled silos. To release the energy, the cycle is reversed, and as the energy passes from hot to cold it powers a generator that makes electricity.

     

    Isentropic claims a round-trip energy efficiency of up to 80% and, because gravel is cheap, the cost of a system per kilowatt-hour of storage would be between $10 and $55.

     

    Howe says that the energy in the hot silo (which is insulated) can easily be stored for extended periods of time – by his calculations, a silo that stood 50m tall and was 50m in diameter would lose only half of its energy through its walls if left alone for three years.

     

    To demonstrate how much less infrastructure his system requires, Howe uses the example of the Bath County Pumped Storage hydro-electric dam in Virginia, US. This is the biggest energy-storage system in the world, with two reservoirs covering 820 surface acres can store up to 30 GWh storage capacity. An Isentropic gravel battery of the same capacity would occupy 1/300th of the area, according to Howe.

     

    John Loughhead, executive director of the UK Energy Research Centre, said that the novelty of the Isentropic system lay in using cheap materials as the heat store, thus making a normally expensive and mechanically complex process very simple. But he said demonstrators would need to be built to prove the idea actually functions. “The question is, does it work? From an engineering standpoint, the temperature differences they mention, +550C to -150C are initially credibility-stretching for a single-pass cycle, and the potential for gravel particles to pass through the engine and damage or clog the inevitable cooling and lubricating systems seems high.”

     

    Howe is in the process of designing a small pilot plant that could store 16MWh at full capacity – enough for the electrical needs of thousands of homes. That energy could be stored in two silos of gravel that are 7 metres tall and 7 metres in diameter. There is no reason why multiple units could not be connected together to store much more power, Howe says several gigawatt hours.

     

    Howe says he is in talks with what he refers to as “a large utility company” to sponsor the construction of a full-storage demonstrator system, something around the 100 kilowatt scale.

     

    Isentropic was selected recently by the government-sponsored Technology Strategy Board for a trade mission to meet Silicon Valley investors, one of around 20 of the Britain’s most promising clean technology startup companies.

     

    David Bott, director of innovation programmes at the Technology Strategy Board, one of the sponsors of the 2010 Clean and Cool trade mission said: “Isentropic have done something very exciting, by revisiting scientific theory and coming up with a new technology that answers the need to match the generation of electricity with its use. For instance, the system could enable the more efficient use of wind power, by storing the energy generated by a turbine until it is needed. We need ways to store the energy we generate when we have a surplus, so that it can be used when we need extra and this innovative new system could provide the answer.”

  • Chevron’s solar panels won’t clean up it’s filthy oilfield

     

     

    The company is proud enough of the solar panels to have a promotional video on Operation Brightfield. Chevron’s local vice president, Bruce Johnson, calls the solar facility “a clear example of Chevron’s efforts to find ways to integrate innovative technologies into our business.”

     

    But the Rainforest Action Network, a California-based NGO, put out a natty little video of its own charging the company with “greenwash” in the California sun.

     

    Chevron is the biggest greenhouse-gas emitter in California, according to RAN. And its global green reputation could do with some refurbishing. The company is still living down the environmental damage caused by past involvement of Texaco, a company it bought in 2001, while grabbing oil from the rainforests of Ecuador.

     

    And it faces new criticism for its prominent role in developing tar sands in Canada. This latter is a big problem, as the California governor, Arnold Schwarzenegger, seeks to cut the state’s carbon dioxide emissions.

     

    RAN says last year Chevron hit a “new all-time low in renewable energy investments”, with just 1.96 per cent of its capital and exploratory budget going green.

     

    So the plaudits Chevron has won for its Brightfield test rigs, along with a planned solar project in New Mexico, are green gold dust.

     

    But its dirty old ways still look like the main game at Chevron. You can see its real business down the road from the shiny new solar panels, at the Kern River heavy oil facility. The field is more than a century old and contains some 10,000 “nodding donkey” rigs pumping away. The field is largely exhausted, with production declining every year, but Chevron is reluctant to call a halt to its ancient money-spinner.

     

    But bringing the oil to the surface is increasing difficult, and energy-intensive. The thick tar-like dregs of the oilfield won’t flow on their own. They have to be heated first. So Chevron burns natural gas to make steam, which it pumps underground to raise temperatures and get the gunge moving. They call it “steam flooding”. One reporter invited to Kern River by the American Petroleum Institute describes the scene on The Oil Drum.

     

    Chevron is a specialist in extracting heavy oil round the world. In Venezuela and Indonesia, for instance. But bringing the stuff to the surface has a very large carbon footprint, according to Tony Kovscek of Stanford University’s Energy Resources Engineering department, who has studied Kern River.

     

    He estimates (pdf) that the carbon footprint of producing heavy oil at Kern River is around 50kg of carbon dioxide for every barrel of oil.

     

    That is only half the footprint of tar sands in Alberta, he says, “but the carbon footprint of conventional oil is a great deal smaller.”

     

    The company spokesman Alex Yelland said the 750-kW solar facility, which has an expected lifetime of 25 years, is intended “to evaluate competing next generation solar technologies”. He denied any attempt at greenwash. “That the oil field nearby produces heavy oil was not relevant to the siting of the solar test.”

     

     

     

    Kovscek says, “some of the largest point sources of carbon dioxide in California are from these types of oil field operations.” Solar panels powering the pipeline pumps won’t change that.

     

    But, if Chevron wants to carry on pumping heavy oil from Kern River, there would be a way for the company to make a serious difference, he says. It could harness the power of the sun big time to make the steam.

     

    A lot of entrepreneurs in California want to develop what they call “concentrated solar thermal power”. Rather than covering the desert in photovoltaic panels, they want to install mirrors to concentrate the sun’s rays and boil water to make steam. Their main idea is to use the steam to run turbines. But why not, says Kovscek, use it directly to free up the heavy oil?

     

    “Relatively conservative designs could reduce the heavy-oil carbon footprint by at least 30%,” he told the Guardian. “More aggressive designs could achieve even greater reductions.” Yelland said that the company plans a “solar-to-steam” demonstration facility to replace some of its natural gas needs at another oil field in California.

     

    Now that really will “integrate innovative technologies” into Chevron’s business. It would put Project Brightside in the shade. Until then, Chevron seems to be using a few solar panels to greenwash a thoroughly filthy oilfield.