Equipment & Technology

FuelCell Energy announces major European market moves

Wed, 16 May 2012 15:58:00 GMT

US clean energy firm FuelCell Energy, Inc. (Nasdaq:FCEL) has announced that its German subsidiary, FuelCell Energy Solutions GmbH, is acquiring select assets from MTU Friedrichshafen GmbH, a subsidiary of Tognum AG.

The select assets include fuel cell component inventory and fuel cell manufacturing equipment of the former MTU Onsite Energy GmbH Fuel Cell Systems in Ottobrunn, Germany, which was merged with MTU Friedrichshafen GmbH.

Parties to the agreement also include MTU Friedrichshafen GmbH (MTU), and Fraunhofer IKTS (Institute for Ceramic Technologies and Systems).

Under the agreement, MTU will contribute fuel cell related intellectual property to Fraunhofer IKTS and Fraunhofer IKTS will become a minority owner in FuelCell Energy Solutions by June 30, 2012.

FuelCell Energy Solutions, a German company, will develop the market for stationary fuel cell power plants in Europe for commercial, industrial, and utility scale applications.

"This effort is a crucial part of FuelCell Energy's previously announced global growth strategy, leveraging prior relationships with MTU as well as an expanding relationship with Fraunhofer IKTS," said Chip Bottone, President and Chief Executive Officer for FuelCell Energy, Inc. "The agreement with MTU provides assets that will accelerate market development while optimizing current and future capital needs from FuelCell Energy so future investment will be predicated on order flow and a growing installed base."

Mr. Bottone continued, "This agreement and the ramp-up of FCES will enable cost effective large scale fuel cell technology to become available today, for commercial applications throughout Europe. We are building on the strength and leadership shown by the vision of the German government, and bringing the experience which comes from over 180 megawatts of commercial installations and order backlog worldwide."

The scope of FCES will include the continuation of research to further enhance carbonate fuel cell technology, combining the strength of FCE's Direct FuelCell power plants and the carbonate "EuroCell" technology of MTU, which will be licensed into FCES by Fraunhofer IKTS. Local manufacturing capacity will be established at a facility formerly leased by MTU in Ottobrunn, Germany, thus keeping advanced technology fuel cell power plant manufacturing in Germany.

Fuel cells electrochemically convert a fuel source into electricity and heat in a highly efficient process that emits virtually no pollutants due to the absence of combustion.

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Wartsila signs gas power agreement in South Africa

Mon, 14 May 2012 10:53:00 GMT

Wärtsilä has signed three year Operations & Maintenance (O&M) agreement with Sasol New Energy Holdings, a wholly owned subsidiary of Sasol, the integrated global energy and chemical company.

The agreement covers the company's gas engine power plant project in Sasolburg, South Africa.

The Sasol New Energy plant is expected to start producing electricity towards the end of 2012. It will be the largest power plant running exclusively on gas engines to be installed on the African continent, and because of its low emissions, will be a major advance in developing Sasol's electricity business.

The plant has installed capacity of 180 MW and it will provide the energy needed to power the company's major new production facilities, such as the Sasol Wax Expansion and Ethylene Purification Unit 5 projects, that are currently under construction.

"The gas engine power plant employs a cleaner fossil fuel based technology than traditional coal based technology and will reduce the CO₂ emissions by approximately 1 million tons per annum. In addition, it also generates electricity at a higher efficiency," says Kribs Govender, General Manager, Low Carbon Electricity, Sasol New Energy.

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More progress on Canadian biomass plant

Fri, 11 May 2012 13:53:00 GMT

Novia Scotia Power’s 60 MW biomass plant moved another step closer to completion this week in Canada, with the addition of a steam turbine and generator to the facility.

The $208m biomass cogeneration plant has reached a significant milestone with the arrival of the steam turbine generator that will produce electricity.

On operation the plant will provide enough energy to power about 50,000 homes, reports the Cape Breton Post.

The steam turbine generator was constructed by Mitsubishi Power Systems in Japan.

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Californian jail powered by on-site renewables

Wed, 09 May 2012 16:38:00 GMT

S&C Electric Company, a global leader in smart grid solutions and renewable energy integration, has the completion of an energy storage project at the Santa Rita Jail in California, US.

The new energy storage solution features S&C's PureWave® Storage Management System and helps integrate on-site renewable energy sources and storage at the facility.

The battery storage capabilities enable the jail to purchase power during non-peak hours from the local utility and store the reserves—a process that will end up saving the jail nearly $100,000 dollars per year.

The energy storage system is a key component of the jail's smart microgrid that was engineered and built by Chevron Energy Solutions. The microgrid serves a correctional facility that covers 113 acres and combines solar, wind, and fuel cell energy sources, along with emergency diesel backup, to generate electricity for the facility, which uses 3 MW of electricity daily.

During times when the facility is islanded from the local utility grid, the energy storage system balances the microgrid's load with the total power generated from on-site sources by automatically and instantly storing any energy generated in excess of the load requirements.

The energy storage system also supplies electricity if demand exceeds what the onsite generation sources are generating.

To add the needed energy balancing to the microgrid, S&C provided a 2-MW PureWave® Storage Management System to control the charging and discharging of lithium-ion batteries.

"With the stored energy system, the Santa Rita Jail can use on-site renewable generation to power the facility in the event of a power disruption on the utility grid," says Jim Sember, S&C Vice President—Power Quality Products.

For more on-site renewable news

Chinese and German PMs discuss CHP at MWM meeting

Fri, 04 May 2012 13:02:00 GMT

German Chancellor Angela Merkel and the Chinese prime minister Wen Jiabao visited the MWM at the Hannover Messe in April, and were reminded of the benefits of CHP by the CEO of MWM.

Mr. Schumacher, CEO of MWM GmbH, welcomed the eminent visitors and introduced the company as well as the benefits of combined heat and power (CHP), which MWM is presenting in Hannover.

For more than 140 years, MWM has been developing and manufacturing gas engines and plants for the decentralized generation of power, heat and cold.

The combination of CHP together with gas engines lead the way to an ecological and economical generation of energy for the future.

Chancellor Merkel acknowledged the presentation by stating that ‘combined heat and power is a future technology.’

For more CHP news

Bloom confirmed as fuel cell provider for Apple

Tue, 01 May 2012 12:15:00 GMT

It has been confirmed that California-based Bloom Energy will be supplying fuel cells to Apple to power Apple's North Carolina data centre.

The company will provide 4.8 MW of biogas fuel cells, what the company calls Bloom Boxes, powering the data centre’s servers.

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Construction of $550m combined cycle power plant in Australia

Mon, 30 Apr 2012 16:15:00 GMT

UGL Limited (ASX: UGL) has announced that in a 50:50 joint venture with EPC firm CH2M HILL it has been awarded a $550m contract to construct an on-site power facility.

The award was made by JKC Australia LNG Pty Ltd (a company established by a joint venture between JGC Corporation, KBR and Chiyoda Corporation) for the construction of a combined cycle power plant for the Ichthys liquefied natural gas (LNG) project in the Australian Northern Territory.

As part of the agreement, GE (NYSE: GE) will engineer and supply gas turbines, steam turbines and heat recovery steam generators for the $34bn Ichthys project.

The CH2M HILL-UGL Joint Venture will design and supply the balance of plant based around the GE technology as well as undertake the complete construction of the project.

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Cogeneration system forms part of Honda test house demo

Mon, 23 Apr 2012 15:24:00 GMT

Honda Motor Co., Ltd. today unveiled a house Honda built in the city of Saitama, Japan, for the demonstration testing of the Honda Smart Home System (HSHS).

The house features HSHS, which comprehensively controls in-house energy supply and demand, and helps manage both the generation and consumption of energy for the home such as heat and electricity, while utilizing mobility products.

The house also features Honda’s gas engine cogeneration system.

The gas-engine cogeneration system is an energy device which makes a significant contribution to the reduction of CO2 emissions by enabling efficient generation and consumption of heat which accounts for approximately 60 per cent of the energy consumed in a typical Japanese home, primarily for hot water supply, heating and kitchen needs.

Featuring a unique multi-link type high expansion ratio engine, EXlink (Extended Expansion Linkage Engine), Honda's gas-engine cogeneration system offers combined efficiency -- the combination of power generation efficiency and heat recovery efficiency -- of 92 per cent and enables the efficient use of electricity and heat using city gas or liquid petroleum gas.

In demonstration testing, Honda will study the automatic activation of the cogeneration unit using a battery and verify its effectiveness in the time of an emergency.

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Apple plans largest private fuel cell energy project in the US

Tue, 03 Apr 2012 09:51:00 GMT

In keeping with Apple’s (NASDAQ: AAPL) recent clean energy policy, the company has announced that it is to install the largest private fuel cell energy project in America.

A filing with North Carolina's Utilities Commission reveals that Apple's 4.8 MW fuel cell farm at its North Carolina data center will use Bloom Energy's "Bloom Energy Servers," and is set to be the largest of its kind outside of electric company installations

Apple Insider reports that the project, which should be producing energy by the end of 2012.

The hydrogen fuel is set to be produced from natural gas feedstocks, with Apple hoping to offset the use of natural gas with landfill methane gas or other biogas at its Maiden, North Carolina premises. A provider has yet to be announced.

Bloom Boxes are being used for clean energy production by a number of other large tech firms, including Adobe, eBay, and Google.

Apple's project would be ten times larger than Bank of America's 500 kW
Bloom installation in Southern California.

"That's a huge vote of confidence in fuel cells," said James Warner, policy director of the Fuel Cell and Hydrogen Energy Association in Washington.

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GE gas turbine milestone has had positive impact on on-site power

Wed, 28 Mar 2012 16:16:00 GMT

GE’s (NYSE: GE) fleet of 47 heavy duty gas turbines operating on low British thermal unit (BTU) fuels has accumulated more than 2 million fired hours, an operational milestone.

Low BTU, or low calorific value fuels have significantly less heating values than natural gas. Examples include syngas, steel mill gases and dilute natural gas. These fuels are lighter than natural gas and have less energy per unit volume.

The fuel flexibility inherent in GE’s B, E and F-class turbines has allowed these units to operate on low BTU fuels in a variety of applications, including integrated gasification combined-cycle (IGCC), refinery-based IGCC and steel mills.

To achieve the same heat input as natural gas-fired units, low BTU fuels need increased fuel flow. This flow rate requires the fleet to use GE’s Multi Nozzle Quiet Combustion (MNQC) and standard (single nozzle) syngas combustors, which provide robust and reliable operation on low BTU fuels.

A case in point is the Wuhan Iron & Steel Group Corp. (WISCO) steel mill near Wuhan City in Hubei Province, China. To comply with China’s goals to reduce energy consumption and emissions, WISCO installed a combined-cycle power plant—powered by two GE 9E Gas Turbines—at the Wuhan mill.

Reusing the mill’s own “blast furnace” and “coke oven” waste gases (BFG and COG) as “free” fuel, the two GE 109 combined-cycle systems each generate 164 megawatts of onsite power to support the mill’s activities. Currently, the power plant’s annual output is 1 billion kWh/a, with a guaranteed electrical efficiency greater than 42 percent (LHV).

The key benefits of this project for WISCO include a reduction in emissions associated with the waste gases created during the steel production process and new revenues generated by the sale of some of the power plant’s electricity to the local grid.

GE’s fleet of heavy duty gas turbines operating on low BTU fuels continues to grow, as customers look to do more with less.

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Melbourne district energy project to be powered by GE technology

Mon, 26 Mar 2012 14:58:00 GMT

Melbourne, Australia’s growing energy needs have received a high profile boost witht the news that GE is to provide the technology behind one of the city’s commercial districts.

One of GE’s (NYSE: GE) natural gas-fired Jenbacher gas engines will be powering a cogeneration plant that will provide reliable electricity and thermal energy for a major urban revitalization initiative in Dandenong, Victoria.

Built by Cogent Energy, the plant will play a pivotal role in the VicUrban-lead Revitalising Central Dandenong (RCD) initiative that is rejuvenating the south-east region of Melbourne.

The collaboration marks GE’s first urban district energy project in Australia. Clarke Energy Australia, GE’s authorized distributor for Jenbacher gas engines in Australia, will supply project owner Cogent Energy with a 2-MW, J612 Jenbacher cogeneration unit for Phase 1 of the new power facility, which could be expanded to 6 MW.

The gas engine is expected to save the equivalent of about 9900 tons of carbon emissions a year, which equals the removal of more than 5500 cars from the road.

The cogeneration plant is set to dramatically reduce the emissions and energy use of the Dandedong Commercial District by reducing its reliance on energy from the grid.

The plant also will have the capacity to produce surplus hot water, which Cogent Energy will then sell back to local commercial buildings to provide cooling via building owner-supplied absorption chillers.

“Australia represents an important growth region for GE as more customers embrace various distributed power applications—including industrial cogeneration—to bring the sources of energy production closer to end-users,” said Rafael Santana, CEO and president—Gas Engines for GE Energy.

For more cogeneration power news

OPRA Turbines opens Moscow office

Mon, 26 Mar 2012 12:24:00 GMT

Gas turbine driven power solutions, OPRA Turbines B.V., has announced it will be opening its first office in Moscow, Russia to further strengthen sales activities in Russia and increase local service support to existing and future Russian customers.

The new office will be operational from April 2012.

‘The opening of OPRA Turbines new Moscow office is an important step towards realizing the market potential in Russia for power generation in the 1-10 MW range and increase local service support for the growing fleet of OP16 gensets in the region. The need for gas turbines in the 2MW range to run on flare gas in remote oil fields has been high. Currently almost 50 OP16 gensets are in operation in Russia.’ said Fredrik Mowill, OPRA CEO.

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Opra delivers gas turbine order to Germany

Fri, 23 Mar 2012 16:37:00 GMT

Gas turbine power solutions provider OPRA Turbines B.V. has announced the company will supply an OP16 gas turbine powered genset which will operate in CHP (combined heat and power) mode to Crespel & Deiters, a leading German wheat starch producer with focus on the corrugated-board and paper industries.

Keen to meet the German air regulations requirements with some margin in addition to the need for continuous and reliable heat and power, Crespel & Deiters chose an OP16 genset to replace an existing system. The OP16 genset will provide power for their factory in Ibbenbüren, Germany and the exhaust heat will be utilized for direct drying for the starch production.

'The clean, high temperature exhaust of the OP16 is ideal for industrial CHP applications. The market for low emissions gas turbines in the 2MW range has proven to be significant.' Said Fredrik Mowill (CEO, OPRA Turbines)

OPRA has delivered to customers operating in CHP mode to oil and gas as well as industrial customers including Fuji Film, Krasnaya Polyana Olympic ski resort, Severnefte-Gazprom, and TNK-BP.

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Siemens to supply Diamintina CCPP in Australia

Tue, 13 Mar 2012 11:48:00 GMT

Siemens Energy has received an order from Australia for the supply of two steam turbines and four gas turbines for the Diamantina combined cycle power plant (CCPP).

Following commissioning of the combined cycle plant scheduled for early 2014, the installed capacity of 242 MW will be sufficient to supply ecofriendly electricity to local mines operated by Xstrata and to people living in the region.

The order volume for Siemens is over EUR150m ($196m).

Siemens will be responsible for the overall plant design and will also provide technical advisory services during the construction and commissioning phases of the project.

"Diamantina power station is a great example of our ecofriendly power supply solutions for different industries worldwide,” said Markus Tacke, CEO of the Industrial Power Business Unit of Siemens Energy.

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GE’s TM2500+ gas turbine receives ecomagination qualification

Mon, 05 Mar 2012 16:01:00 GMT

GE’s (NYSE: GE) flexible, efficient, trailer-mounted TM2500+™ aeroderivative gas turbine has received ecomagination™ qualification for its ability to help power cities and industries during environmental, economic and emergency power challenges.

When compared with the previous version, the TM2500, it provides customers with faster, more flexible distributed power generation by combining high efficiency, better fuel gas consumption and fuel flexibility, coupled with lower emissions in both the 50 and 60 Hz segments.

The TM2500+is a workhorse in the global aeroderivative mobile fleet. With a GE Aviation CF6-6 engine at its core, the TM2500+ resides on two trailers and can provide up to 31 MW of power generation in days due to its unique roll-on, roll-off capabilities for air, ship or road transportation.

It is the portable version of the LM2500+ aeroderivative gas turbine, which has been the backbone of the global fleet since it was unveiled in 1969.

“GE’s legacy of innovation and American ingenuity is showcased in the TM2500+,” said Darryl Wilson, president and CEO—aeroderivative gas turbines for GE Power & Water. “Our engineers took the successful TM2500 and drove lean, innovative processes to make it even better to meet the needs for fast, emergency or mobile power.”

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Emissions Control for gas turbine energy systems

Thu, 01 Mar 2012 16:44:00 GMT

Cogeneration and district energy, which formed the basis of the world’s very first power plant in New York, can be a prominent solution to energy security and environmental issues. And, as Manfred Klein writes, environmental policies for gas turbine CHP systems are evolving to advance sustainable energy objectives.

There are huge opportunities for industrial and commercial CHP systems. Previous articles in this magazine have discussed solutions to barriers, focusing on the business cases that often do not quantify the many benefits of CHP, and policy drivers that may discourage grid interconnection and local generation. One of these solutions is environmental regulatory policy, which is evolving but often not yet there to provide a balanced health benefit and the required incentives for expansion of ‘clean’ energy in on-site systems for various sectors.

So, what do we mean by ‘clean energy’ – is it just about carbon emissions, or health impacts? See Figure 1. Maybe both – there is more to this, as low air pollution and condenser water impacts have always been important to local regions. Air toxins and CFCs from these same energy systems must also be reduced, and back-end pollution controls have collateral impacts that often affect greenhouse gas (GHG) profiles. Pollution prevention and energy conservation, integrated with system efficiency, are key elements in arriving at balanced and cost-effective long-term solutions that address economic opportunities, energy security and environmental sustainability.

Gas turbine cogeneration systems fuelled by natural gas or synthetic gases have many attributes required by clean energy systems for thermal, electrical and mechanical energy with low air emissions. Smaller machines that can have most of the heat recovered often have the better CHP efficiency and GHG profiles. Best available technology (BAT) considerations will differ greatly, depending on the objectives and environmental issues to be mitigated, and the extent to which prevention and conservation is encouraged rather than controls and NOx emissions dilution. GHG issues may require a completely different environmental assessment (EA) approach than traditional air and water pollution control evaluations.

National guidelines and standards with comprehensive and consistent objectives applied in EAs or BAT determinations can give the best overall approaches. Until recently, GHG emissions and energy efficiency, as a balanced environmental issue, have rarely been studied in permitting and EA processes. Assessments may wish to consider the whole facility as a total energy system, rather than individual components, and may also include the various emissions and efficiency trade-offs in the surrounding region (for example to look for waste heat utilization potential, and water impacts).

Figure 1. Clean energy balancing act

A large fraction of the world’s energy production has been installed using various types of small and large gas turbine systems. Like other nations, Canada has many types of designs, in about 80 active gas turbine CHP plants and over 20 large gas turbine combined-cycle plants.

EMISSION STANDARDS FOR INDUSTRIAL GAS TURBINES

Gas turbines are thermodynamic engines which use a steady inflow of a gas (mostly air), compressed and fired with gaseous or liquid fuel. This high-pressure hot air mixture is expanded through a turbine to generate output power for thrust in an aircraft engine and for marine propulsion, or as shaft power for applications such as pipeline compression, electrical power and CHP heat production. Note that ‘gas turbine’ is a general term regardless of fuel used, as it is the large amount of clean air that produces the turbine power.

Most air pollution NOx measurements are done on a volumetric concentration basis, in parts per million by volume (ppmv) or in some cases in a weight/volume fraction such as mg/m³. Uncontrolled gas turbine NOx emissions are in the 150–300 ppmv range (about 300–600 mg/m³). Sometimes rules are based on a pollutant mass per unit heat input, such as lbs/MMBTU or grams/GJ.

There is little environmental stimulus to conserve energy, and plant output and system efficiency is not directly considered. To some degree they give an incentive to dilute the emission using airflow or stack height, although excess air can be limited by defining a standard oxygen content, such as 15% O2. Back-end controls also tend to encourage parasitic power losses, and plant efficiency objectives are not considered in the analysis. Traditional emission standards and assessment methods do not consider CO₂ emissions, a necessary product of heat release.

Energy conservation is clearly pollution prevention, and therefore waste heat recovery and CHP should be specifically recognized as an emission prevention technology. An alternative output-based standard such as kg per MWh allows the plant designer and operator to take advantage of all available system efficiencies to reduce fuel consumption, and parasitic losses, or to increase output to offset other emissions. Output-based criteria allow simple and clear comparisons with other technologies, and can readily be used in emissions trading scenarios.

Emission standards should also deal effectively in a balanced fashion with collateral emissions, such as CO, unburned hydrocarbons, particulate matter (PM) and air toxics, as well as GHG emissions of methane and nitrous oxide.

Canada

In 1992, Canadian emission guidelines for stationary combustion turbines were published through a national consultation to promote reasonable pollution prevention technology to achieve a sizeable reduction in NOx emissions. Energy efficiency to minimize CO₂ emissions was also deemed to be important, as well as considerations of operational reliability and cost-effectiveness. We developed an energy output basis for the guideline, with NOx levels directly tied to the demonstrated overall system efficiency. This spring marks the 20th anniversary of the development of that Canadian guideline.

This was the first regulatory standard for the gas turbine sector that used output energy, and helped to establish pollution prevention, combustion modifications and overall system CHP efficiency as ‘Best Available Technology’. The guideline uses an energy output basis for power and heat, in grams of NOx per GJ of energy output. It allows higher efficiency systems to have a higher exhaust ppm NOx concentration. The emission targets in Figure 2 were established at a certain efficiency range in each chosen size category, for gaseous and liquid fuels.

For large units greater than 20 MWe, the power output allowance at 140 g/GJ relates the mass of NOx emitted to the number of GJ or MW of power output (0.5 kg/MWh). This allowance results in large units, fired on natural gas, having to meet a full load NOx emission target of about 27–33 ppmv in simple cycle applications and 37–42 ppmv in a combined-cycle plant. A higher emission level is available through the 40 g/GJ heat recovery allowance to encourage cogeneration applications. Units of 3 to 20 MW have targets set about 70% higher (240 g/GJ, or 0.86 kg/MWh). Revisions are being developed this year to also deal with large gas turbine units in the 70 MWe and greater sizes.

United States

The US Environmental Protection Agency (EPA) has usually used concentration-based ppmv standards, coupled with some state daily, monthly or annual tonnage caps and emission offset rules. Best available control technology (BACT) practices included steam/water injection, dry low NOx combustion technology and add-on selective catalytic reduction (SCR) back-end emission controls. When the lowest achievable NOx emission rate became dominant, these ultra-low NOx control solutions with dry low NOx (DLN) plus SCR were often required, with regional levels set as low as 2 ppmv.

After some years of consultation, the US EPA released in July 2006 a new national NSPS regulation for gas turbines used for pipeline compressors, utility combined-cycle plants and industrial cogeneration plants. Instead of requiring ultra-low NOx stack concentration, the new rules would give a choice for using ppmv criteria, or a new output-based method in kg/MWh, at somewhat higher NOx levels to encourage more energy system efficiency (15–42 ppm, or 0.19 to 1.04 kg/MWh). Local state implementation may be held up by legal challenges due to perceived pitfalls in the loosening up of local NOx permit levels.

Europe

European countries have since 2005 revised the Large Combustion Plant Directive (LCPD), including ‘BAT Reference’ documents (BREFs). However, there is still much debate by industry and government on the various regulatory strategies in EU countries, and to what extent GHGs, system efficiency and other solutions are employed.

Europe has traditionally used concentration-based standards (mg/m³) or fuel input based levels (g/GJ fuel). The Large Combustion Plant Directive from 2005 has required limits for any fuel based plants with more than 50 MW thermal input capacity (between 15–20 MW output). For any gas-fired plants, this was set at a 50 mg/m³ level, but a 25 mg/m³ cogeneration efficiency allowance is a progressive incentive that allows this increased level. The European Commission in 2007 adopted new legislation on industrial emissions to strengthen these provisions, and a new Industrial Emissions Directive of 2011 may combine several impacts into an integrated policy.

AIR POLLUTION AND GHG EMISSIONS

Figure 3 compares approximate air pollution and CO₂ emissions from various fuel-based systems. The multiple pollution prevention benefits of gas turbine and biomass CHP are evident, along with gasification and carbon capture.

Some energy solutions have both low air pollution and low CO₂, including energy conservation, renewables, nuclear, hydro, as well as various industrial gas turbine systems. When GHG emissions are prevented in a system, one finds that all air pollution subsequently falls dramatically as well. There are many synergies and trade-offs in how air pollution and GHG emissions can be prevented and controlled. Some specific examples of balancing various issues are summarized below.

Figure 2. Canadian CCME gas turbine guideline, 1992

Water and steam injection for NOx reduction

One method of NOx reduction is the addition of clean water, at a water/fuel mass ratio about 1:1, into the combustion zone to lower the flame temperatures, achieving a 70% NOx reduction. Clean water treatment facilities and combustor maintenance can have high operating costs. Steam injection is often an option on combined cycles and cogeneration plants, where high-pressure steam at a ratio of 1.5:1 is readily available from the heat recovery steam generator (HRSG). Injection into the combustor while producing more power can, however, rob the high-pressure steam cycle of energy, thereby reducing plant efficiency in some cases.

Dry low NOx (DLN) combustors

A more cost-effective pollution prevention method for thermal NOx is to modify the combustion process itself, by changing the airflow and fuel mixture inside the combustor to minimize the occurrence of high local peak flame temperatures, in ‘lean pre-mix’ DLN combustors. Developments since 1990 have successfully resulted in NOx reductions of 60–90%, to a range near 0.7 kg/MWh (15-30 ppm)for small to medium-sized units, and as low as 0.2 kg/MWh (10 ppm) for some very large machines that have more physical combustor design volume and space. The fuel/air ratio must be closely controlled during off-design conditions to prevent instability, combustor pressure oscillations and flameout.

Gas turbine engine vibrations and thermal cracking of hot parts have always been a maintenance challenge, especially for high pressure ratio aeroderivative engines, and now with large gas turbine combined-cycle plants that must be cycled under part load conditions. Transient low fuel/air ratios during low power settings can create the need to bleed away compressor discharge air, or close inlet guide vanes, thereby losing efficiency. Difficulties are faced in designing a reliable fuel control system that maintains good combustion and low CO emissions over a wide range of ambient temperature and loading conditions.

NOx and CO₂ emissions from systems often increase in opposite ‘directions’, with high pressures and temperatures (for efficiency) creating more thermal NOx. Small high-pressure combustors may also have difficult challenges in lean pre-mix design. Smaller units, with smaller combustors, can be allowed a higher NOx level as they can often be more efficient in CHP applications, being able to use most of their exhaust heat output, with a high heat to power ratio.

Figure 3. Air pollution and CO₂ emissions from various fuel-based systems

Large gas turbines have lower NOx emission rates in large DLN combustors for combined-cycle plants. However, the required large steam condensers are an environmental problem for several reasons: large energy losses, thermal pollution of local water bodies, vapour plumes and noise impacts. Large gas turbine systems can be built very quickly, and consume large amounts of fuel from the natural gas delivery infrastructure. The remote siting of a large number of combined cycles will lead to more power transmission lines, condenser energy losses, and gas fuel supply and pricing uncertainty.

Selective catalytic reduction (SCR)

SCR systems use ammonia with a catalyst structure in the waste heat boiler to convert NOx in the exhaust stream to mostly nitrogen and water. Despite the demonstrated 70–80% reduction of NOx, there are several negative collateral issues with SCR systems, including increased fine particulate and ammonia emissions, problems with cycling operation, and the safety and health risks of ammonia handling and transportation. Back-end controls have generally been shown to be less cost-effective than pollution prevention measures, as they often give rise to other collateral air, water or safety impacts, as well as efficiency losses and increased GHGs. When employed after DLN combustion, the resulting safety issues, air emissions plus efficiency loss (more GHGs) can outweigh the marginal benefits of SCR.

Fine particulate and CO emissions

Fine particulate emissions (PM 10 and PM 2.5) can be a serious health issue. There has been discussion on fine PM emissions from gas-fired gas turbines (as per the US EPA AP42 rates of about 0.03 kg/MWh). However, with gas turbine engines swallowing millions of tonnes per year of air for their power output, some of that air may not go through combustion, but as combustor cooling bypass flow. The incoming air might have very fine airborne dust and volatile organic compound (VOC) oils. Can that air which gets by the inlet filter, avoiding combustion, pass through the machine and show up in the exhaust?

It may be that the modern gas turbine system, with higher efficiency air filtration, is cleaning the air from PM by over 99%, and the emission factor could be negative (unless there is an ammonia-based SCR). New DLN combustors also expose more of the airflow to high temperature combustion, possibly incinerating most particles which have survived the air filters.

Combustor design is greatly influenced by how carbon monoxide (CO) emissions are handled, especially for off-design, transient and cold ambient conditions. How important are CO emissions? These emission levels are often set at the same ppm level as NOx emissions. That may not be necessary, as they are much less harmful to human health, rising from an elevated high temperature exhaust stack to oxidize into CO₂ within a day or two.

But the combustor designer is faced with great challenges in mechanical airflow and mixing strategies, with the added complication of transient, start-up and shutdown operating modes. The necessary features of low CO emissions over these conditions will compromise the reliable dry low NOx performance over a suitable operating range.

Specific power

Gas turbine engines have varying amounts of shaft output per kg/sec of air mass flow. This seems to depend on engine size, number of compressor/turbine spools, pressure ratio and bleed air, combustor firing intensity, and the overall resulting efficiency. The value of air mass flow varies from about 200–400 kW per kg/sec air). Traditional gas turbine NOx emissions are measured and studied in term of concentration ppmv. In an efficient unit, at half the air mass flow for a certain power, the same concentration could have only half of the mass emissions.

HEAT RECOVERY STEAM GENERATORS (HRSGs)

HRSGs are critical to efficient gas turbine CHP systems. They can employ a duct burner at their intake from gas turbine exhaust that has a residual amount of oxygen (13–16%) needed for combustion. This ‘auxiliary firing’ can normally give a large boost to steam production by raising the gas temperature from about 450–500°C to around 900°C, especially for turbine units which have very efficient cycles and low exhaust temperatures. The available oxygen levels will decrease with firing in proportion to the fuel added. Because of the very high preheat from the gas turbine, duct burners are very effective in allowing the HRSG to act as a ~100% efficient ‘boiler’. Sometimes these burners are treated in permitting as a source of increased NOx emissions. There are however many benefits to having them:

avoiding additional traditional boiler fuel used at a 75–85% heat efficiency;
allowing smaller gas turbine engines for the CHP application;
providing good CHP opportunities for aeroderivative gas turbines with low exhaust gas temperatures;
for single-pressure drum units, the higher inlet temperature will increase heat transfer and lower the final stack temperature by 30–50°C, thereby improving overall thermal efficiency;
providing intermittent cycling flexibility for triple the steam production of unfired HRSG systems;
duct firing also allows for improved active control of steam conditions and process optimization.

SYSTEM EFFICIENCY

To evaluate system efficiency and GHG emissions, ‘fuel chargeable to power’ (FCP) is an energy allocation method that can be used for cogeneration calculations. FCP is defined as the net heat rate credited to electricity (or mechanical power) after the thermal load has been served, in GJ/MWh.

Figure 4. Quality of energy

Other more detailed analyses for heat may use ‘exergy’ methods, where the ‘quality’ of energy is determined depending upon temperature and pressure levels, and system losses – see Figure 4. Exergy analysis would allocate more emissions than FCP to the higher quality power portion of a system. Whether FCP or exergy, such methods would allow for a meaningful allocation of various emissions for cogeneration systems.

For fair comparisons, the use of higher heating value (HHV), rather than LHV, could also be considered for all energy systems that can use condensing heat recovery. CHP markets would also be better served if the MWth thermal values were recognized and described at the same time as MWe electrical totals.

GASIFICATION

IGCC and polygeneration should be considered for large projects where natural gas is at a premium, where coal or petcoke is abundant, and where CO₂ capture and storage can be linked to this technology. Because IGCCs are essentially coal plants, they will be unable to meet the very stringent NOx emission levels of natural gas-fuelled plants. Hydrogen-rich fuels must be reliably and safely burned to provide for effective carbon capture and system availability. They have significant flame speed, auto-ignition and flashback characteristics in high-pressure combustion, and are often used with nitrogen or steam dilution to minimize NOx emissions.

CONCLUSION

Identifying comprehensive environmental solutions for GHG and air pollution reductions, with energy reliability and security, make economic sense regardless of the degree of proof in anthropogenic climate change – what used to be termed ‘no regrets’ measures. Energy output, fuel combustion and emissions occur in real, physical facilities. Site visits, training and time spent in the field near actual equipment can be extremely valuable for all in understanding important linkages, collateral impacts and integrated systems.

Rational and clear energy output-based environmental standards can help encourage best practices for many efficient and clean energy opportunities. A balanced economic implementation will be a key consideration among the variety of energy choices that are needed for our long-term infrastructure and job creation needs.

Manfred Klein is a member of the Industrial Application of Gas Turbines Committee, Canada, a technical advisory group to Canadian industry and government. For further information, visit: www.iagtcommittee.com

Engines, turbines and globalization

Thu, 01 Mar 2012 16:28:00 GMT

by David Sweet

The phenomenon of globalization is easier to observe than its root causes and effects are to understand. In the evolution of technology we can also readily observe key milestones, but it is decidedly more complex to connect incremental advances in technology with their global impact. It is the classic example of seeing the many trees in our path but completely missing the forest.

The story of the technology we use to generate power and its impact on our planet has unfolded before our eyes, but is rarely told. In a fascinating examination of this topic, Vaclav Smil brings us Prime Movers of Globalization: The History and Impact of Diesel Engines and Gas Turbines. Smil examines the forest and the trees and awakens us to the impact that these technologies have had in shaping our world today.

While the power generation industry can be segmented between those seeking to advance turbine technologies and those in the reciprocating engine business, Smil points out the profound influence of both technologies: ‘How has it come about that we can fly from virtually any place that has an airport with a runway long enough… to any other similarly equipped place anywhere on the planet, often within just 16 and mostly within 24 hours?’

It was the confluence of these technologies that enabled the waves of migration that reshaped the world in the 20th century. These new engines also facilitated the development of global trade in key commodities such as food, which in turn had an impact on diet and health as: ‘this rising demand for food was best satisfied by specialized producers who had a comparative advantage thanks to mild climate or low labour costs.’

Smil also recognizes the role of decentralized energy and its ‘contributions to the process of economic and social globalization.’ He posits that ‘not all of this new [electricity] demand can be met by large stations… that transmit electricity from a central location by high-voltage lines… By far the most economical choice for generating electricity far from any existing transmission lines… is to install appropriately rated diesel powered generators.’

In recent years, globalization has been hotly debated, analyzed, maligned and adored. You can now eat the same food at the same restaurant on virtually every continent. You can connect with people with the click of a mouse from anywhere in the world to anywhere in the world. Whether the world is flat, round, or oval, there is no dismissing the fact that we are a more connected planet as the internet has become the common thread binding the world and the digital divide can begin to close in even the most remote locales.

Decentralized energy has powered the digital world to bring developing economies into the global economy. However, in the rush to embrace digital technology, we have shoved aside this bedrock of globalization. It is the way in which we have powered our industries, homes, electrical grids, planes, trains, automobiles and ships that has brought goods and people from one corner of the earth to another and facilitated the sharing of ideas and cultures across the planet.

Smil reminds us of the significance of these machines that have performed ‘virtually all the work of modern globalization with scant recognition’ and that, because of their many advantages, these engines are here to stay. As Smil incredibly points out, by 2005 over ‘95% of all US freight now moves thanks to Diesel’s engines.’

As I write this comment some 30,000 feet in the air on a 14-hour plane ride, we take for granted the ability to make a journey that would have been impossible but for only the bravest or most foolhardy not that long ago. While many politicians seek new ways to punish and shame us for relying on these engines, they fail to see the complex evolutionary tale that allows us to efficiently power our world.

David Sweet Executive Director, WADE dsweet@localpower.org

FuelCell Energy signs long term service agreement at CSU

Wed, 29 Feb 2012 09:34:00 GMT

FuelCell Energy, Inc. (Nasdaq:FCEL) a leading manufacturer of ultra-clean, efficient and reliable fuel cell power plants, has announced the signing of a multi-year service agreement with Southern California Edison (SCE) to operate and maintain a 1.4 MW Direct FuelCell(R)on-site power plant.

FuelCell Energy will operate and maintain the power plant, which is located at California State University -- San Bernardino.

SCE will sell the ultra-clean electricity produced by the fuel cell power plant to the University under a power purchase agreement and will also provide the high-grade heat generated by the fuel cell to the University.

The utility benefits with ultra-clean power generation that supports clean air initiatives, highly efficient power generation that reduces fuel costs, and on-site power generation, representing incremental capacity that reduces the need to invest in transmission and distribution.

The ultra-clean power generation supports sustainability goals for the University as well as reducing fuel costs due to reduced usage of a boiler for heating. The fuel cell power plant releases virtually zero pollutants and the high efficiency of the power generation process reduces carbon emissions.

The ability of the fuel cell to generate both power and heat from the same unit of fuel lessens the University's usage of a combustion-based boiler for heat, further reducing emissions.

"The fuel cell power plant service agreements that we offer allows our customers to focus on what they do best while we concentrate on our core expertise of delivering ultra-clean power in an efficient and reliable manner," said Chip Bottone, President and Chief Executive Officer, FuelCell Energy, Inc. "Service is a key aspect of our business model as we operate and maintain virtually every Direct FuelCell power plant installation, around the clock."

For more combined heat and power news

GE engines to power China’s power generation project

Fri, 24 Feb 2012 10:43:00 GMT

GE (NYSE: GE) today announced that its ecomagination-qualified Jenbacher gas engines will power China’s largest landfill gas (LFG) power generation project.

The Laogang LFG project is owned by Laogang Renewable Energy Co., a joint venture formed by Veolia and Shanghai Environment Group, and supports the Chinese government’s 12th Five-Year Plan, during which China plans to invest more than RMB$260bn in the waste treatment industry including waste-to-energy initiatives by 2015 ¹.

Chen Hongzhang, general manager, Laogang Renewable Energy Co. “By using GE’s gas engines fueled by LFG, we expect to save emissions by over 340,000 tons of carbon dioxide equivalent per year, significantly improving the local environment in Shanghai.”

Seven of GE’s ecomagination-qualified Jenbacher J420 gas engines, which will provide about 10 MW of electricity, will power the new Laogang LFG facility located in Shanghai.

Each J420 engine combusts 2.7 million cubic meters (m ³) of methane each year, providing an overall yearly reduction of greenhouse gas of around 18.9 million m³ for the seven gas engines.

The Renewable Energy Company will sell any excess electricity generated to the grid.

This project is an example of how GE’s portfolio of innovative distributed power solutions, ranging from 100 kilowatts (kW) to 100 megawatts (MW), gives businesses and communities around the world the ability to generate reliable and efficient power anywhere, whether on or off the grid.

For more on-site renewable power news

Media company adds to its on-site renewable portfolio

Mon, 13 Feb 2012 15:42:00 GMT

Media company Cox Enterprises have announced the installation of five fuel cells at its Cox Communications subsidiary in San Diego.

The fuel cells join nine previous alternative energy projects in the state. Combined, Cox's 14 alternative energy installations in California annually prevent 15,500 tons of carbon emissions from entering the environment, the equivalent of removing 367 cars from the road.

The new fuel cells in San Diego include two 200kW units that power 100 per cent of Cox Communications facility on Copley Drive and three 200kW units that power 90 per cent of its building on N. Cuyamaca Street.

"Twenty-five per cent of Cox Communications' electricity in California is now being generated through our alternative energy projects," said Steve Bradley, Cox Enterprises' director of energy, alternative energy and business continuity. "These projects yield positive results for the environment and the bottom line."

For more on-site power news