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    Mongabay, a leading resource for news and perspectives on environmental and conservation issues related to the tropics, has launched Tropical Conservation Science - a new, open access academic e-journal. It will cover a wide variety of scientific and social studies on tropical ecosystems, their biodiversity and the threats posed to them. Tropical Conservation Science - March 8, 2008.

    At the 148th Meeting of the OPEC Conference, the oil exporting cartel decided to leave its production level unchanged, sending crude prices spiralling to new records (above $104). OPEC "observed that the market is well-supplied, with current commercial oil stocks standing above their five-year average. The Conference further noted, with concern, that the current price environment does not reflect market fundamentals, as crude oil prices are being strongly influenced by the weakness in the US dollar, rising inflation and significant flow of funds into the commodities market." OPEC - March 5, 2008.

    Kyushu University (Japan) is establishing what it says will be the world’s first graduate program in hydrogen energy technologies. The new master’s program for hydrogen engineering is to be offered at the university’s new Ito campus in Fukuoka Prefecture. Lectures will cover such topics as hydrogen energy and developing the fuel cells needed to convert hydrogen into heat or electricity. Of all the renewable pathways to produce hydrogen, bio-hydrogen based on the gasification of biomass is by far both the most efficient, cost-effective and cleanest. Fuel Cell Works - March 3, 2008.

    An entrepreneur in Ivory Coast has developed a project to establish a network of Miscanthus giganteus farms aimed at producing biomass for use in power generation. In a first phase, the goal is to grow the crop on 200 hectares, after which expansion will start. The project is in an advanced stage, but the entrepreneur still seeks partners and investors. The plantation is to be located in an agro-ecological zone qualified as highly suitable for the grass species. Contact us - March 3, 2008.

    A 7.1MW biomass power plant to be built on the Haiwaiian island of Kaua‘i has received approval from the local Planning Commission. The plant, owned and operated by Green Energy Hawaii, will use albizia trees, a hardy species that grows in poor soil on rainfall alone. The renewable power plant will meet 10 percent of the island's energy needs. Kauai World - February 27, 2008.

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Thursday, June 12, 2008

PG&E contracts 107MW of fully renewable solar thermal-biomass hybrid power

California utility PG&E Corp has contracted with a renewable energy unit of Portuguese conglomerate Martifer for 106.8 megawatts (MW) of solar thermal-biomass hybrid power. Solar power is an intermittent source of energy: it cannot deliver reliable baseloads and peakloads, and doesn't work at night. Energy storage systems are currently inefficient or not commercially viable. Therefor, in practise, solar-thermal energy is dependent on other energy sources, most often fossil fuels like coal or natural gas. But when coupled to biomass, which does deliver baseloads, a fully renewable energy system emerges capable of supplying electricity around the clock.

Solar-biomass hybrid concepts can be described in other terms: the solar thermal system converts solar energy directly into electricity, whereas biomass uses solar energy to build cheap but highly efficient structures (strong plant cells) capable of storing this energy for later use.

The two planned solar thermal-biomass hybrid power plants - the first of their kind - will be managed by Martifer subsidiary San Joaquin Solar LLC and will provide enough power for nearly 75,000 homes in northern and central California. They combine solar thermal technology with steam turbines powered by gas made from locally available biomass (agricultural waste and livestock manure.)

The plants will be located near Coalinga, California, in the center of the state, and will help PG&E reach the state-mandated goal of increasing the amount of electricity it produces from renewable sources. The projects are expected to begin operations in 2011. PG&E has already invested heavily in biogas research (more here) and recently it started feeding upgraded biogas (biomethane) into its natural gas pipelines (previous post).

This biogas expertise will now boost the solar thermal power technology. Solar thermal plants use the sun's heat to run steam turbines that produce electricity and are mostly located in sun-drenched states such as California. Advocates say the technology could one day become a viable replacement for fossil-fueled power plants due to their large scale. But critics argue the power produced is too inconsistent because it requires the sun to be shining at all times, which it obviously doesn't. After sunset, when electricity demand can be high, the plants stop working altogether. Therefor solar thermal plants are forced to rely on other, polluting sources to ensure continuous power supplies. The hybrid solar-biomass system effectively solves this problem.
When the sun is shining during peak hours, it will just be the solar facility. As the sun sets, biomass will be available to support the solar generation, and then at night the biomass will run purely on its own. - Andrew Byrnes, project developer
Ricardo Abecassis, president of Martifer Renewables Solar, said that power generated by the solar thermal-biomass hybrid plants would be cost-competitive with energy from conventional power plants, such as those fueled by natural gas or coal:
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Earlier in Germany, a consortium of renewable energy companies and universities demonstrated that in principle an entire country can be powered on the same principles, independently of coal, natural gas or nuclear.

This so-called 'Kombikraftwerk' project consisted of coupling intermittent renewables like wind and solar power to biomass, which delivered the reliable baseload and kicks in at night. This way, a fully functional renewable energy system was designed capable of supplying electricity around the clock regardless of weather conditions and electricity demand. Peak and baseloads were supplied as reliably as in conventional fossil fuel based systems (previous post).

The PG&E contracts filed with the California Public Utilities Commission are part of the company's broader renewable energy portfolio. Since 2002, PG&E has entered into contracts for over 2,500 MW of renewable power. California law requires each investor-owned utility to increase the share of eligible renewable generating resources in its electric power portfolio to 20 percent by 2010. PG&E has made contractual commitments to have over 20 percent of its future deliveries from renewables. For 2008, PG&E expects to have 14 percent of its energy delivered from renewable sources.

Biopact: Germany is doing it: reliable distributed power based on 100% renewables - December 29, 2007

Biopact: California's Pacific Gas & Electric starts feeding biogas to its natural gas pipelines - March 05, 2008

Biopact: Pacific Gas & Electric Company to research large-scale biomethane resources for its customers - January 25, 2008

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Greening the desert by squeezing water out of gypsum

A group of European scientists has come up with a suggestion on how to green deserts. Gypsum, a rocky mineral abundant in desert regions where fresh water is usually in very short supply, could become a new resource out of which trillions of liters of clean drinking water can be squeezed. The engineers of the 'Holland Innovation Team' describe their proposal in a special issue on 'Macro-Engineering', published in the International Journal of Global Environmental Issues.

Water resources in the world are scarce and unevenly distributed. In deserts, the only source of water is groundwater, often saline and of poor quality. This limits agricultural activities. In those places where farming does occur, groundwater levels have dropped dangerously due to overexploitation.

However, deserts contain several resources which could be combined to help solve this problem in a relatively simple way: ample solar and fossil energy, and the magical ingredient, gypsum. Peter van der Gaag and colleagues have hit the idea of utilizing the untapped energy from oil and gas flare-off, or solar power, to release the water locked in the abundant rocks.

Van der Gaag has already discussed the technology with people in the Sahara who agree that the idea could help combat water shortages, improve irrigation, and even make deserts fertile. As it happens, gypsum is also a very useful agromineral.

So how does the technique to squeeze water out of rocks work? Chemically speaking, gypsum is calcium sulfate dihydrate, with the formula CaSO4.2H2O. In other words, for every unit of calcium sulfate in the mineral there are two water molecules, which means gypsum is 20% water by weight.

The scientists describe both large-scale engineering and micro-scale projects to tap the resource. The process would require energy, but this could be supplied using the energy from oil and gas fields that is usually wasted through flaring. Alternatively, small scale solar thermal systems could provide the necessary heat.

Van der Gaag explains that it takes only moderate heating, compared with many chemical reactions, to temperatures of around 100° Celsius to liberate water from gypsum and turn the mineral residue into bassanite, the anhydrous form.
Dehydration under certain circumstances starts at 60 Celsius, goes faster at 85 Celsius, and faster still at 100 degrees. So in deserts - where there is abundant sunlight - it is very easy to do. - Peter van der Gaag
Van der Gaag points out that the dehydration of gypsum results in a material of much lower volume than the original mineral, so the very process of releasing water from the rock will cause local subsidence, which will then create a readymade reservoir for the water. Tests of the process itself have proved successful and the Holland Innovation Team is planning a pilot study in a desert location:
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So how large are the 'reserves' of this 'stored' water resource? Van der Gaag speaks in terms of billions of tonnes of recoverable gypsum, amounting to a potential to tap off trillions of liters of clean water.

The macro-engineering concept of dewatering gypsum deposits could solve the water shortage problem in many dry areas in the future, for drinking purposes as well as for drip irrigation, he concludes. On a micro-scale, solar thermal technologies could serve small communities with access to deposits of this mineral.

The team collaborated with a state-run mining company in Mauritania and one in France, to test the technique on different types of gypsum. The Sebkha N’Drahamcha mine in Mauritania alone contains 140 million tonnes of recoverable, nearly pure gypsum of which only a few thousand tonnes are mined each year.

Van der Gaag, Peter. "Mining water from gypsum", International Journal of Global Environmental Issues, Special Issue on Macro-Engineering: How to Deal with Global Problems?, 2008 - Vol. 8, No.3 pp. 274 - 281.

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