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Metso To Supply Biomass Heating Plant In Finland
Taylor Scott International Continue reading
On Board With Energy Crops
By Anna Simet | August 20, 2013 BIOMASS OR BUST: Portland General Electric is in the midst of determining whether it will repower its 600-MW power plant in Boardman, Ore., with biomass or shut down. Photo: Ted Timmons Near the Columbia River just outside of eastern Oregon’s Boardman sits the state’s last operating coal plant, a 600-MW facility built in the late 1970s. Though the plant has plenty of years left in it, the state’s decision to phase out coal left Portland General Electric exploring its options. In 2010, PGE was approved to continue to burn coal at Boardman until 2020, with some temporary emissions controls upgrades. After that, $500 million in additional pollution controls would be required to comply with federal and state sulfur, nitrogen and mercury rules, thus enabling the plant to continue operations until at least 2040. Ultimately, PGE faced three possibilities—closing by 2020, making costly upgrades, or switching to another fuel source. If closed, it would make history as the youngest coal plant in the U.S. to shut down as a result of air quality regulations, but doing so and building a new plant elsewhere makes more economic sense than keeping it open for upgrades. With the upgrade option ruled out, the fate of the plant rests on the feasibility of using torrefied energy crops as fuel, and PGE has spent the past several years conducting in-depth research and rigorous testing to determine what the possibilities are. Exploring Options Initially, PGE looked into repowering with natural gas, but rendered that option unfeasible. “We did a study on natural gas and found the area didn’t have a gas line, but that wasn’t the real issue,” says Jaisen Mody, PGE projects manager. “The issue was that the Boardman boiler was designed for coal combustion, and using gas in the existing boiler made it highly inefficient. The cost wasn’t conducive to running the plant long-term, as we would have to change out the boiler. We decided that converting an old Rankine cycle coal boiler wasn’t the way to go because of the capital expenditure.” Basically, it boiled down to the notion of using gas meant building a new gas plant, adds Steve Corson, PGE spokesman. When PGE began evaluating biomass back in 2010, wood pellets were tested but gummed up the plant’s pulverizers. Crop research began at that point, and arundo donax was chosen as a fuel of interest due to its great growth potential. It’s been found to produce upwards of 35 dry tons per acre per year, compared to switchgrass, which will yield 4 to 13 dry tons per acre per year. PGE has been growing arundo test plots around the Boardman area for the past couple of years—about 92 acres—and has harvested it a few times, storing the crop for test burns, Mody says. He adds that while the initial emphasis was mostly on arundo, that’s changed a bit. On one hand, a single energy crop is attractive because it’s dedicated to producing feedstock volumes needed, but reliance on a single fuel source is risky for a number of reasons, including harsh weather, natural disasters or pests. “So we’re also investigating other biomass sources, including sorghum and ag waste,” says Mody. One thing that’s certain is that if energy crops and biomass are used at Boardman, they will be torrefied first. “Torrefaction is the right way to repower Boardman with biomass, because we’re anticipating no changes to plant equipment,” Mody says. Corson adds that torrefaction would allow the plant to pulverize the fuel just as it is doing with coal, but green biomass would require a lot of changes. Additionally, researchers have found that torrefied biomass is more hydrophobic than Prairie River Basin coal, which is currently used at Boardman. Later this year, PGE is installing a torrefier at Boardman, and will then begin its test burns, according to Mody. “These test burns are critical for us,” he says. “We think running this test will prove to us that we can run torrefied biomass through the plant, and we’ll also collect emissions data. Then we’ll sit down and figure out what it’ll take to run the plant for air permitting and the economics of that.” Mody notes that each feedstock tested—arundo or sorghum—could have a different effect on the boiler, slagging or fouling it, so close attention will be paid as to what source is torrefied and how. According to a study done in 2012 by researchers at the University of Washington, Washington State and Oregon State University, operating at 300 MW and producing power under optimal economic conditions, about 1.25 million tons of torrefied arundo would be used by Boardman, based on the Btu content of torrefied arundo (10,400 Btu per pound). About 794 dry tons of arundo would produce 52.7 tons of torrefied chips, the researchers found, so a total of 67.6 thousand acres of arundo would be required to produce 1.25 million tons of torrefied chips and support torrefaction, assuming 33 dry tons per acre per year. Of course, while multiple sources would be used, Mody admits obtaining necessary quantities remains PGE’s biggest challenge in the quest to repower with biomass. Moving Foward “It’s [repowering] always been one issue—the source of biomass,” says Mody. “How can we procure and move enough in an economic manner that would sustain a large plant? The production of biomass, whether we’re growing or buying it, remains our biggest challenge. That’s why we’re looking at diversity now—one species isn’t the answer. It’s about what we can grow at a reasonable price, and what’s available out there.” If the torrefaction test burns are successful, more work has to be done to calculate the economics and emissions profiles of a full-scale torrefier. Once that data is complete, PGE will bring it to its integrated resource planning process, which is a comprehensive plan presented to the public utility commission that lays out its generating portfolio resource requirements. At that time, the next step for Boardman will be decided, Corson adds. “At this point, what we’ll really be saying is, okay, we know we can do this, is it better than the other options?” Author: Anna Simet Managing Editor, Biomass Magazine asimet@bbiinternational.com Continue reading
Nigeria: Can Bamboo Address Deforestation and Erosion in Nigeria?
BY ALEX ABUTU, 21 AUGUST 2013 Every year, according to statistics from the Centre for International Forestry Research, Africa loses forest cover equal to the size of Switzerland and Nigeria alone is estimated to lose about 350,000 – 4000,000 ha of its forest reserve annually and this is regarded as one of the highest rates of deforestation in the world. As the trees across the country vanish, the land dries; the soil erodes and becomes barren leading to low agricultural yield, alarming desert encroachment, desertification and uncontrollable erosion. Experts at a recent meeting on the state of the nation’s forest identified firewood and charcoal as the leading drivers of deforestation but the country lacked alternatives to firewood and charcoal which have become the energy sources for middle class and low income Nigerians especially those in the rural areas. A lot of propositions have been advanced as options government should consider in addressing the drivers of deforestation and this include the need to articulate policy framework that address the out-dated forest laws in operations in the country, better mechanism for the implementation/enforcement of best forest management practices, reduce firewood and charcoal consumption and forest tenure system for local communities. However, Mr Badru Ola Muyideen of the forest department of the Federal Ministry of Environment is of the view that the introduction and massive cultivation of bamboo remained Nigeria’s best option to reduce deforestation, address desertification as well as cushion the impact of climate change on Nigeria. According to him, bamboo can serve as firewood and can be burnt as charcoal. “This way we don’t have to cut down trees which take forever to grow but we can harvest bamboo yearly and use it as we want.” Bamboo is a common plant which the country is currently not exploiting in the quest to address the mirage of environmental challenges confronting the country. Bamboo is a tribe of flowering perennial evergreen plant in the grass family Poaceae. Giant bamboos are the largest members of the grass family. In bamboos, the internodal regions of the stem are hollow and the vascular bundles in the cross section are scattered throughout the stem instead of in a cylindrical arrangement. The dicotyledonous woody xylem is also absent. The absence of secondary growth wood causes the stems of monocots, even of palms and large bamboos, to be columnar rather than tapering. Bamboos are some of the fastest-growing plants in the world, due to a unique rhizome-dependent system. Bamboos are of notable economic and cultural significance in South Asia, Southeast Asia and Sun-Saharan Africa, being used for building materials, as a food source, and as a versatile raw product. Bamboo is one of the fastest-growing plants on Earth, with reported growth rates of 100 cm (39 in) in 24 hours. However, the growth rate is dependent on local soil and climatic conditions, as well as species, and a more typical growth rate for many commonly cultivated bamboos in temperate climates is in the range of 3-10 centimetres per day during the growing period. Some of the largest timber bamboo can grow over 30 m (98 ft) tall, and be as large as 15-20 cm in diameter. However, the size range for mature bamboo is species dependent, with the smallest bamboos reaching only several inches high at maturity. A typical height range that would cover many of the common bamboos grown in the United States is 15-40 feet, depending on species. Bamboo is a kind of grass which explains the speed of growth. This means that there’s lots of it, and when it’s harvested it grows itself back again quickly enough not to leave a dent in the eco-system. Unlike all trees, individual bamboo stems, or culms, emerge from the ground at their full diameter and grow to their full height in a single growing season of three to four months. During these several months, each new shoot grows vertically into a culm with no branching out until the majority of the mature height is reached. Here in Nigeria conscious effort have not been paid to the importance or relevance of bamboo in addressing erosion, desertification nor deforestation. Nigerians still rely heavily on hardwood as source of energy and this according to medical experts is dangerous. It is a women and children’s job to collect firewood and as the demand increases so they have to walk farther distances to find. Most of the firewood cooking is done indoors resulting in air pollution which kills over a million Nigerian women and children annually according to the Bureau of Statistics. Dr Samuel Ike, conservationist said that Nigeria can solve most of the environmental challenges it is facing with the introduction of bamboo into the affroestation programme. “You cut down a hard tree and it takes decades to grow back but cut down a bamboo and before you know it has grown back. Unlike hardwood, bamboo is renewable and regrows after harvesting just as grass regrows after cutting,” he said. According to him, the bamboo roots have the potentials to grab onto the soil and hold it fast, “plant bamboo on a steep slope or riverbank and it prevents mudslides and erosion.” “This is the plant needed for the afforestation programme and even the Great Green Wall project where millions of trees are expected to be planted. A meeting of stakeholders on sustainable development of bamboo and rattan in Nigeria recently urged the federal government to implement a Food and Agriculture Organisation’s recommendation that each country set aside 25 per cent of its total land mass for forest conservation through the establishment of bamboo plantations. According to the stakeholders, such development would ensure that all relevant research institutes in the country work on how the country would benefit maximally from the plant. As the nation move to address flood, erosion and other environmental challenges, the inclusion of bamboo in the aforestation programme would go a long way in saving the soil and provide jobs and incomes for rural dwellers. Continue reading
