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Hybrid Technology

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Tags
2006 IPCC Sector categorization
Energy=20 supply
Energy=20 supply and consumption (excl. industry)
Use=20 of primary energy sources
Scale
= Large=20 scale - long term
Energy Source
Ren= ewables
F= ossil=20 fuels
Renewables=20 and fossil fuels combined
Service
= Electricity
Industrial=20 efficiency

Add=20 your comment

Hybrid technology systems combine two or more technologies with the = aim to=20 achieve efficient systems. Possible combinations are: wind-solar = photovoltaic=20 (PV) hybrid systems, wind-diesel hybrid systems, fuel cell-gas turbine = hybrid=20 systems, wind-fuel cell hybrid systems, etc. (see the short descriptions = below).=20 Hybrid systems combine numerous electricity production and storage units = to meet=20 the energy demands of a given facility or community (Solar Energy = Technologies=20 Program, 2006). They are ideal for remote and isolated applications such = as=20 communications stations, military installations, islands and rural = villages.

Introduction top:

Hybrid technology systems combine two or more technologies with the = aim to=20 achieve efficient systems. Possible combinations are: wind-solar = photovoltaic=20 (PV)=20 hybrid systems, wind-diesel hybrid systems, fuel cell-gas turbine hybrid = systems, wind-fuel cell hybrid systems, etc. (see the short descriptions = below).=20 Hybrid systems combine numerous electricity production and storage units = to meet=20 the energy demands of a given facility or community (Solar Energy = Technologies=20 Program, 2006). They are ideal for remote and isolated applications such = as=20 communications stations, military installations, islands and rural = villages.

Wind-PV=20 hybrid system

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The example of a solar-based hybrid system in combination with wind = energy is=20 shown in the Figure below. In this combination, the wind/engine = generator acts a=20 backup supply for the AC (alternating current) loads which can be = supplied=20 directly to the load without the use of inverter units; the electricity=20 generated from PV is DC (direct current) by nature.

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Figure 1: Solar = hybrid system=20 (Source: Roland Idvps)

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A PV-wind hybrid system is composed of the core part constituting of = PV=20 modules and a wind turbine, a DC-AC inverter, batteries, a charge = controller=20 regulator, and a backup power resource for battery storage systems = (Dayu, no=20 date). PV modules convert sunlight into direct current electricity and = they=20 operate using the semiconductor principles that govern diodes and = transistors=20 (Patel, 1999). The PV modules can be wired together to form a PV array, = which=20 increases the available voltage and increases the available current. = However,=20 the power produced is the same in both combinations. A typical PV module = measures about 0.5 m² and produces about 75 Watts of DC = electricity=20 in full sunlight. It costs about =E2=82=AC 290 and has a lifetime of = over twenty years=20 (Dayu, no date). For detailed descriptions of wind energy technology = (Patel,=20 1999).

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Overcharging of a battery by the PV array and wind turbine is = prevented=20 through a charge controller regulator. Most modern controllers maintain = system=20 voltage regulation electronically by varying the width of DC pulses sent = to the=20 batteries through a phenomenon called pulse width modulation (PWM). = Backup power=20 resource can be maintained either from a generator or from the utility = grid when=20 too much energy is consumed or when there is not enough electricity = generated=20 from the wind-PV hybrid system.

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Wind-Diesel Hybrid Systems

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The Figure below schematically shows how a wind turbine can be = combined with=20 diesel generators in a hybrid configuration. This combination enables = the use of=20 a renewable energy source in remote and isolated areas, where the grid = structure=20 is weak, insufficient or even not existing, and the cost of energy often = constitutes a considerable part of the local economy (Ken Tec Denmark, = no=20 date).

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Figure 2: Wind = diesel hybrid=20 system (Source: Wind diesel hybrid)

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By connecting a wind turbine to a diesel generator back-up system, an = uninterrupted power supply can be acquired, thus securing 100% supply. = The=20 diesel generator will take over production when the power generation = from the=20 wind turbines is temporarily insufficient to cover the grid demand. The = wind=20 turbines are virtually always connectable to the existing diesel = generator sets.=20 The new Wind-Diesel concept allows the size of the wind turbine = generators to=20 exceed the size of the diesel generators. The maximum fuel saving is = achieved by=20 declutching and stopping the diesel engine when the supply from the wind = turbine=20 generator exceeds the grid demand. The Wind-Diesel hybrid technology has = the=20 advantage of using standard control systems, implemented with modern = diesel=20 generators that control the voltage and frequency, even when the diesel = engine=20 is not in operation. If the energy production from the wind turbines is = higher=20 than the grid demand, the frequency is controlled by the use of a = dump-load,=20 which can utilise the excessive wind energy for a numerous other = purposes (Ken=20 Tec Denmark, no date).

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Fuel Cell-Turbine (FCT) Hybrid = Systems

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A fuel cell uses hydrogen (or hydrogen-rich fuel) and oxygen from air = to=20 create electricity by an electrochemical process without combustion (US = Climate=20 Change Technology Program, 2005). The absence of a combustion process = eliminates=20 the formation of pollutants such as NOx, SOx, hydrocarbons and = particulates and=20 significantly improves electrical power generation efficiency. Further=20 efficiency gains can be realised by integration of a turbine with the = fuel cell.=20 The Figure below shows the FCT hybrid concept in a simple form to = provide some=20 understanding of the synergy offered and the basic relationships of = components=20 (National Energy Technology Laboratory, no date).

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In this direct operating mode, the fuel cell serves as the combustor = for the=20 gas turbine. Residual fuel in the high temperature fuel cell exhaust = mixes with=20 the residual oxygen in an exothermic oxidation reaction to further raise = the=20 temperature. Both the fuel cell and the gas turbine generate = electricity, and=20 the gas turbine provides some balance-of plant functions for the fuel = cell, such=20 as supplying air under pressure and preheating the fuel and air in a = heat=20 exchanger called a recuperator.

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In an indirect mode, the recuperator transfers fuel cell exhaust = energy to=20 the compressed air supply, which in turn drives the turbine. The = expanded air is=20 supplied to the fuel cell. The indirect mode uncouples the turbine = compressor=20 pressure and the fuel cell operating pressure, which increases = flexibility in=20 turbine selection. Critical issues are the integration of pressure = ratios and=20 mass flows and the dynamic control through start-up, shutdown, = emergency, and=20 load-following operating scenarios.

=20

Figure 3: Direct = FCT hybrid=20 system (Source: NETL)

Feasibility of = technology and=20 operational necessities top:

Several successful examples of the implementation of different types = of=20 hybrid technologies can be observed throughout the world:

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One of the oldest PV hybrid systems and at the same time the first = =E2=80=98large=20 scale=E2=80=99 PV system in Europe was installed in 1983 at island of = Terschelling in=20 the Netherlands (Lysen, 2000). At the Higher Maritime School = =E2=80=98Willem Barentsz=E2=80=99=20 a 43 kWp PV system was coupled to a 75 kW wind turbine and a large = battery=20 bank.

A second example is found on Cura=C3=A7ao, the = Netherlands=E2=80=99 Antilles (National=20 Energy Technology Laboratory, no date). Since March 1984 the local = radio=20 station =E2=80=98Radio Hoyer=E2=80=99 uses a PV powered transmitter, = with a battery and a=20 diesel backup. The system is installed on the top of the mountain = Tafelberg,=20 and is remotely monitored from the capital Willemstad.

The Tortoise Head Guest House on French Island, Victoria, = Australia,=20 generates its power from a remote power wind and PV hybrid system that = has=20 been operating since 1995 with support from UNEP (UNEP, 2003). The = Guest House=20 is located 150 m from the seashore, which makes it an ideal site for a = wind=20 turbine. The system includes: 10 kW wind turbine; 840 W PV array; 2 = diesel=20 generators of 15 kW and 25 kW; battery storage (wired to produce a = system=20 voltage of 120 Volts DC); and a 10 kW inverter to convert the DC into = the=20 Australian standard of 240 Volts AC and 50 cycles per second. The = energy=20 uses of the Guest House include: electricity for lighting, water = pumping, cold=20 room, freezer, dish washer, domestic appliances, communication = equipment and=20 some heating, LPG for water heating and cooking, wood from fallen = trees for=20 space heating; solar water heaters to pre-heat water; and diesel for = back up=20 electric generator. The Guest House consists of six large = bedrooms (for=20 2-6 people each), 5 double-bed cabins and meeting/conference = facilities. About=20 68% of the energy comes from wind, 11% from PV and 21% from diesel. = The Guest=20 House continues to reduce diesel and LPG consumption through the use of additional solar water heaters and energy efficiency=20 measures.

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A wind-PV hybrid system is being used at the Samunsan Forest and = Wildlife=20 Sanctuary, 60 KM North of Kuching, in Sarawak, Malaysia (UNEP, 2003). = The=20 population of the community fluctuates between 20-70 people, including = children who return to the community on weekends, tourists, and = scientists.=20 The facilities of the Sanctuary include a dormitory, bungalow, = guestrooms,=20 office, amenities block, store rooms, boat shed and power shed. The = objectives=20 of installing the system were to: provide reliable =E2=80=98grid = quality=E2=80=99 power supply=20 24 hours a day; power refrigerators and freezers for tourist services, = health,=20 and preserving scientific specimens; reduce environmental impacts; = reduce=20 costs; reduce dependence on fossil fuels; minimise potential supply=20 disruptions; enable the community, tourists, and researchers to work = and study=20 in the evenings; and reduce the risk of fire associated with the use = of=20 candles or kerosene lamps. The system includes: 2.5 kW wind = turbines=20 mounted on a 26 m tower; a 900 W PV array; 2 lead acid batteries = storing 2=20 kWhs; 5 kW inverter; 30 kW diesel generator; and remote monitoring = equipment.=20 The community has been trained to perform all maintenance activities, = which=20 has also increased the community=E2=80=99s appreciation of the system. = The wind=20 turbine generates the largest proportion of electricity over the year = while in=20 the summer the PV output is at its maximum. The diesel generator is = mostly=20 used in the summer, due to periods of low windspeed and an increase in = electricity demand arising from tourism, research and community = activities.=20 The system was installed in 1997 at the cost of USD 60,000.

In 1998, a wind/PV hybrid system was installed in Point Hick = lighthouse=20 which was converted to a tourist resort in Southeast Victoria, = Australia=20 (UNEP, 2003). The resort consists of several accommodation cottages = and a=20 low-cost bunkhouse for low budget tourists. The resort is situated in = the Cann=20 River national park. The objectives of this hybrid system were: to = meet all=20 the electricity demands of the managers and tourist cottages; to = reduce the=20 use of diesel operation; to reduce the costs of diesel fuel; and to = reduce the=20 environmental impacts from using fossil fuels. The systems consisted = of a=20 10-kW wind turbine on an 18 m tower with 550 W PV array and a 20-kW = diesel=20 generator. The inverter used had a capacity of 10 kW. The storage = system=20 consisted of a 120-kWh lead acid battery storage. The wind turbine = provided an=20 average of 42 kWh/day at a wind speed of 5-6 m/s while the PV array = generated=20 a daily average of 2.8 kWh under 5 hours of direct sun. The total = system cost=20 amounted to USD 65,000.

Holwell Farm within the Dartmoor National Park, in Devon, UK, is = using a=20 20-kW Remote Area Power Supply (RAPS) system incorporating a wind = turbine=20 system, 20-kWh battery storage and a backup 25-kW diesel generator = (UNEP,=20 2003). The system provides electricity for agricultural activities, = bed and=20 breakfast tourist accommodation and other domestic uses. The farm is = located=20 2.5 km from the nearest electricity grid. The three-blade wind turbine = has a=20 rotor diameter of 8.8 m, a hub height of 24.4 m and is mounted on a = lattice=20 tower. An automated control system ensures that AC power is always = available=20 and switches to the diesel generator when batteries are 80% discharged = or when=20 electrical demands are high.

Costa de Cocos is a small scuba diving and fishing resort in = Southern=20 Quintana Roo, Mexico, with 12 houses, a restaurant/bar, dive shop, and = a=20 workshop. The resort was previously powered by a succession of small = (5-20 kW)=20 diesel generators operating just four hours each evening. However, in = 1996, a=20 RAPS system consisting of a 7.5-kW wind turbine, battery storage, and = two=20 5.5-kW inverters were installed to provide the resort with electricity = throughout the day (UNEP, 2003). The wind turbine is placed on a 24-m = tower=20 with protection against salt corrosion. The batteries are located in a = specially designed integrated rack assembly. The system cost is = approximately=20 USD 35,000 and has a payback period of 8-10 years.

Another successful example of the hybrid project installation is = the Mexican Hybrid Solar Thermal Power = Project=20 (UNEP, 2003). A solar thermal/natural gas-fired hybrid power plant in = Baja=20 California Norte with a total net installed capacity of about 300 MW,=20 including about 30 MW for the solar component has been constructed = through=20 this project. The plant is a part of the Comisi=C3=B3n Federal de = Electicidad=20 system expansion plan.

The largest European PV wind hybrid system is located on the = Pellworm=20 Island in Germany=20 (see http://www.pvresources.com/en/hybrid.php). The PV array = has the=20 capacity of 600 kW and will be enlarged with an additional 300 kW = array. The=20 first 300 kW array was build in 1983 and the second part was connected = in=20 1992. This hybrid system is grid-connected. The eventual 900-kW = capacity will=20 enable the production of nearly 800 MWh/year.

Another successful example of hybrid technology is a = PV-wind-diesel hybrid=20 system in Kythnos Island of Greece (see http://www.pvresources.com/en/hybrid.php). It = has been=20 in operation since 1983. This plant utilises a 100-kW PV array, a = 100-kW wind=20 turbine, and a 600-kWh battery. The entire system is connected to the = existing=20 distribution grid, which is fed by a 200-kVA diesel generator. Three = 50-kVA=20 inverters operate simultaneously to deliver power to the grid. The = plant is=20 monitored in order to optimise the amount of renewable energy = available to the=20 grid.

The Wilpena Pound power station of South Australia = combines a=20 100-kWp PV system, a battery storage of 400 kWh, an inverter and a = 440-kWp=20 diesel generator = (see http://www.pvresources.com/en/hybrid.php). At=20 night, a computerised smart controller automatically switches between = the=20 battery storage and the most-efficient diesel generator combination to = match=20 the load. A modem-link provides remote monitoring and control=20 facilities.

In Thailand, PV hybrid systems have been installed as pilot = projects since=20 1990 (Phuangpornpitak and Kumar, 2007). Most of them were adapted for = national=20 parks and wildlife preservation areas or rural villages that do not = have=20 access to electricity. Nine off-grid PV hybrid systems ranging from 5 = to 82.5=20 kW, with a total installed capacity of about 285 kW, are in operation = and=20 constitute about 10% of the total PV power installed in Thailand. The = first=20 hybrid power system in a wildlife sanctuary, Huai Kha Khaeng, was set = up by=20 King Mongkut=E2=80=99s University of Technology Thonburi in 1998 with = the aim to=20 assess technological, economic and operating aspects and to study the=20 penetration of PV in remote and preserved areas. During = 1998=E2=80=932003, the system=20 supplied 44,504 kWh (PV supplying about 88.5% of the total demand) or = an=20 average of 24 kWh/day. The PV/diesel hybrid system installed at Huai = Kha=20 Khaeng wildlife sanctuary in 1998 was optimised in order to meet an = increasing=20 demand for a clean and reliable power source. The system can supply=20 electricity to load because the diesel generator works to compensate = any=20 inconvenience caused by photovoltaic. PV-wind-diesel hybrid systems = were=20 installed in 1999 at Phu Kradung, a high-elevation national park in = Loei=20 Province, and at Tarutao, an island in a marine national park in Satun = Province, Thailand.

=20

There could be several barriers to the implementation = of hybrid=20 technologies and these need to be overcome for a successful = establishment of=20 projects. Hybrid systems generally have a relatively high investment = cost, which=20 makes smaller projects unattractive to the investors, lenders, project=20 developers, and manufacturers. Similarly, these technologies have = several=20 technical barriers which include: requirement of redundant generation = systems, a=20 time limitation for the generation of electricity, need for = sophisticated=20 control systems, need for storage systems, and transmission line=20 losses.

=20

Other aspects in the implementation chain of these hybrid technology = systems=20 in developing countries could be the limited credit worthiness for = potential=20 investors; absence of a power purchase agreement with energy users (e.g. = through=20 the grid operator); absence of energy or power systems in the villages; = lack of=20 information on market, employment, rural development and other economic=20 information; lack of vocational education, communication availability or = other=20 social development activities; lack of human capital to properly operate = the=20 power plants; and lack of financing partners.

Status of the = technology and its=20 future market potential top:

There are several research programmes on hybrid technologies all over = the=20 world, mainly in developed countries. For instance, Princeton Energy Resources = International=20 (PERI) has undertaken various research programmes on wind power and = other=20 wind-based hybrid technologies. PERI has developed several databases and = analysis tools to track and analyse wind system and subsystem cost, = performance,=20 and other characteristics (Princeton Energy Resources International, no = date).=20 Recent use of these has involved projections of expected technology = development=20 paths over time and evaluation of financing/ownership on both a = corporate=20 balance sheet basis by investor-owned utilities and tax-free public = utilities,=20 and a project finance basis through independent power producers.

=20

To help facilitate adoption of wind/diesel hybrid systems, PERI has = analysed=20 the potential market for replacing existing diesel plants with wind = turbines in=20 rural Alaska (USA) for the National Renewable Energy Laboratory = (Princeton=20 Energy Resources International, no date). The objective of this = assessment was=20 to characterise the size of the wind-diesel hybrid market so that the = State of=20 Alaska and Alaskan rural electricity authorities can determine the level = of=20 effort required to develop wind projects. An initial list of about 90 = Alaskan=20 villages was identified as having outstanding wind resource potential. = The=20 result of this analysis was a ranking that identifies the villages where = wind/diesel hybrids will have the most favourable economic = characteristics.

=20

During 2001, the Photovoltaic fuel cell hybrid systems (PVFC-SYS) project was carried out = as a=20 European Commission research project on the hybrid technology (European=20 Commission, 2001). The main aim of the project was to study and develop = a=20 low-power energy generation system, which would utilise the synergies = between a=20 photovoltaic generator and a Proton Exchange Membrane fuel cell. Such a = system=20 in the range of 5 to 10 kW is intended to be a future competitor to = hybrid=20 PV-Diesel systems, especially from an environmental point of view as = emissions=20 of both exhaust gases and noise will be drastically reduced. The overall = target=20 of the project was the development of a hybrid system based on an = innovative=20 package using hydrogen as a fuel. This can be considered a zero emission = system.=20 The use of the so-called innovative components will open new = possibilities of=20 future cost decrease, both in the investment, operational and = replacement point=20 of view. Since there are no moving parts, less maintenance is required = and the=20 lifetime of the components is expected to be higher.

=20

In 1998, China launched an ambitious =E2=80=98Brightness Programme=E2=80=99 = that targeted household=20 and village-scale applications of solar PV and wind energy in off-grid = regions,=20 particularly in western China. In 2002, the Chinese Government started a = major=20 new rural electrification initiative called the Song Dian Dao Xiang = programme=20 (National Township Electrification Programme). This programme is = directed at=20 electrifying approximately 1000 townships in seven provinces in western = China=20 with about 17 MW of village-scale hybrid systems (mainly PV, with some = wind,=20 combined with batteries and diesel back-up systems). The required = funding=20 amounts to RMB 2 billion (USD 240 million), which covers 50% of the = capital=20 costs of village power systems (in Tibet: 100%) (Martinot and Wallace,=20 2003).

=20

In 2001, 70 village-scale hybrid power systems (wind and/or PV = combined with=20 battery storage and many using backup diesel generators, ranging in size = from=20 5-200 kW) were installed in China (Martinot and Wallace, 2003). A 100-kW = wind-diesel hybrid village power plant was under construction in 2002 in = Zhejiang (Bei Long Dao). A second hybrid system consisting of 80 kW of = wind and=20 20 kW of PV power became operational in Xinjiang in December of = 2002.

=20

Market studies indicate that by 2010 at least 1000 MWp of stand-alone = PV=20 hybrid systems will be installed worldwide, both for remote buildings = and on=20 islands (Lysen, 2000). In order to realise this potential and reduce the = costs=20 of these hybrid systems, still a lot of work remains to be done, for = example,=20 through standardisations and modularity and by developing proper = monitoring=20 systems to reduce maintenance costs.

Technology transfers from industrialised countries could help improve = these=20 implementation chains and demonstrate the working of the hybrid systems. = The=20 aforementioned EU research group study (European Commission, 2001) in = this=20 respect recommends to improve the reliability of systems, reduce their = costs,=20 and reduce maintenance need or make maintenance easier. In order to meet = these=20 targets, the research has focused on different aspects such as = improvement of=20 the methods and techniques to reduce cost for the wind assessment and=20 optimisation of rotor controls along with optimisation of the overall = system=20 layouts and controls. In addition, co-operative R&D projects, = co-ordinated=20 to use the best technology from each member of the EU are required to = improve=20 the technology for all. Directing current testing facilities to develop = norms=20 and standards in their demonstration projects will help in the continued = development of this market for Europe.

For the future development of the international market of the hybrid=20 technologies in developed countries, various stakeholders must be = brought=20 together and appropriate financing modalities used to facilitate = sustainable,=20 decentralised markets for those technologies that have the attributes of = fuel=20 flexibility and hybridisation, particularly with renewable technologies. = The=20 primary challenges for organising and delivering hybrid project = financing will=20 stem from the large number of small projects, which characterise most of = these=20 rural, peri-urban and urban markets.

=20

In developing countries, there is a necessity of creating and = utilising=20 near-term capital and targeted subsidies, reflecting the fact that = hybrid=20 systems are currently pre-commercial and not yet financially viable. The = countries should develop concessional co-financing which uses commercial = methods=20 tied to commercial capacity building and conducting strategic programmes = of=20 hybrid systems.

How the technology = could contribute=20 to socio-economic development and environmental protection top:

Renewable energy sources such as wind and solar used in wind-solar = hybrid=20 systems are sustainable energy sources as they are easily and abundantly = available in nature. Similarly, hydrogen, which is used in fuel cells, = could be=20 by far the most abundant fuel resource since it is part of the water = molecule.=20 Hydrogen used in fuel cells is converted to electricity, but it can also = be=20 combusted as with the space shuttle rocket boosters using liquid = hydrogen. The=20 hybrid systems with combustion turbines and fuel cells can create = systems with=20 exceptionally high efficiency with low emissions. The hybrid systems, in = general, combine generation and storage technologies so that excess of=20 electricity can be generated during optimal times while electricity is = used from=20 the storage at other times. This will help in achieving sustainability = in energy=20 for future.

=20

In contrast to conventional power generation systems (diesel = generators, coal=20 power, natural gas combustion), renewable energy technologies can = generate heat=20 and electricity without producing GHG emissions. Utilisation of = renewable energy=20 could play an important role in reducing GHG emissions. Considering the = total=20 life cycle of the energy generation process, it has been demonstrated = that wind=20 turbines are the cleanest and green energy systems and that hydrogen = based fuel=20 cells are environmentally friendly. However, in remote communities wind = or fuel=20 cells as stand-alone systems lack reliability, but when combined they = could=20 become more reliable.

=20

PV and fuel cells represent two very promising industries in term of=20 employment, in particular with respect to the identificaiton and = development of=20 new applications.

Financial requirements = and costs=20 top:

A general assessment of the cost of fuel cell hybrid technology = carried out=20 by Rastler and Lemar (2002) shows that costs of any type of hybrid = technology=20 are expected to fall to USD 600 - 1100 per kW for the period beyond = 2010. The US=20 Department of Energy has made a target of reducing the cost of fuel cell = turbine=20 hybrids to USD 400/ kW by 2010 (Victor, 2003). The life-cycle cost for a = wind=20 energy hybrid system requires the estimation of the following = quantities: system=20 life, component and total capital costs per unit of outputs (e.g., wind = turbine,=20 engine generator, controls, inverter, AC/DC converter), as well as the = battery=20 storage cost per kWh, total hardware cost plus installation and indirect = costs=20 occurring (capital cost), annual operation and maintenance and fuel = costs, and=20 equipment replacement costs occurring during the system lifetime = (Notton, et=20 al., 2001). If the system is a wind PV hybrid system, then the total = cost will=20 include the investment and installation cost of solar panels.

=20

Wind energy systems are one of the most cost-effective home-based = renewable=20 energy systems. A small turbine can cost anywhere between USD 3,000 and = 35,000,=20 depending on size, application, and service agreements with the = manufacturer.=20 According to the American Wind Energy Association (AWEA, 2001), typical = home=20 wind system costs approximately USD 32,000 (10 kW). As a general rule of = thumb,=20 the cost of a residential turbine is estimated at USD 1,000 to USD = 3,000/kW.=20 Hence, the cost of hybrid systems with wind energy systems could = decrease in the=20 near future. In Thailand, most PV hybrid systems were installed through = the=20 co-operation of King Mongkut=E2=80=99s University Technology Thonburi, = the Provincial=20 Electricity Authority and the Electricity Generation Authority of = Thailand. The=20 systems were funded by the Energy Policy and Planning Office, though the = communities have been responsible for operation and maintenance of the = systems.=20 The costs of the systems depend on size, location, customer type and = technical=20 specification. The cost of grid-connected systems amounts to about USD = 2/Watt=20 whereas for standalone systems the costs amount to about USD = 3=E2=80=934/Watt=20 (Pvresources, no date).

=20

The Inner Mongolia Autonomous Region (IMAR) has been working in the = past=20 decade to provide stand-alone renewable power systems to rural area = households:=20 more than 120,000 households have started generating electricity with = 100-300=20 watt wind generators (American Wind Energy Association, 2001). In the = first=20 phase of this project, the University of Delaware, the US National = Renewable=20 Energy Laboratory, and the Inner Mongolia team completed a levelised = cost=20 analysis of rural electrification options for several counties. It was = found=20 that for the output range of 200-640 kWh/yr, levelised cost of energy = produced=20 is USD 0.50-0.63/kWh. In the case of a PV system only, for the output = range of=20 120-240 kWh/yr, the levelised cost of electricity produced would be USD=20 0.77-0.83/kWh. For small hybrid systems in the range of 400-750 kWh/yr, = the cost=20 amounts to USD 0.57-0.72/kWh, and for the large hybrid systems, with an = output=20 range of 560-870 kWh/yr, the costs are USD 0.43-0.57/kWh. For the types = of=20 systems currently being deployed for stand-alone electrical generation = in rural=20 areas of IMAR, wind generators are the least-cost option for household=20 electricity (American Wind Energy Association, 2001).

=20

The PURE (Promoting=20 Unst Renewable Energy) project is a pioneering project on the = windswept=20 island of Unst, the most northerly island of the UK (PURE Project, no = date).=20 PURE is a demonstration project that shows how wind power and hydrogen=20 technology can be combined to provide the energy needs for a remote = rural=20 industrial estate. It has been developed by the Unst Partnership Ltd., a = community development agency established by the Unst Community Council = to=20 support local economic development and regeneration. This is the first=20 community-owned renewable energy project of its kind in the world and = thus=20 represents an important milestone in the development of green energy = systems.=20 The Unst Partnership, siGEN Ltd., and the Robert Gordon University, = through the=20 UK Department of Trade and Industry (DTI)=E2=80=99s Knowledge Transfer = Partnership=20 scheme, worked together to deliver the hydrogen system. Significant = differences=20 between the PURE project and other hydrogen energy systems deployed = around the=20 world are the scale and the low budget within which it has been = developed. PURE=20 has uniquely been developed with a comparatively small project budget of = approximately =E2=82=AC475,000 (=C2=A3350,000). This budget also = includes all the engineering=20 and consultancy works surrounding the project, as well as the hardware = (Hutt and=20 Johnstone, 2005).

=20

National Energy Technology Laboratory (NETL) and Fuel Cell Energy = (FCE) are=20 working collaboratively to do large-scale expedient testing of an = atmospheric=20 Direct FuelCell/Turbine (DFC/T) hybrid system. The R&D efforts have = thus far=20 resulted in significant progress in validating the DFC/T cycle concept. = FCE has=20 completed successful proof-of-concept testing of a DFC/T power plant = based on a=20 250-kW DFC integrated initially with a Capstone 30 kW and then a 60 kW = modified=20 mictroturbine. The results of the system tests have accumulated over = 6,800 hours=20 of successful operation with an efficiency of 52% (Williams and Marut,=20 2006).

=20

In 1995, in China, the State Development and Planning Commission = (SDPC), the=20 State Economic and Trade Commission (SETC) and the Ministry of Science = and=20 Technology (MOST) formulated a =E2=80=9CProgramme on New and Renewable = Energy from=20 1996-2010=E2=80=9D and launched the =E2=80=9CSunlight Programme=E2=80=9D, = which will run until=20 2010 and which covers PV systems. It is designed to upgrade the = country=E2=80=99s=20 manufacturing capability of solar technologies, to establish large-scale = PV and=20 PV-hybrid village demonstration schemes, home PV projects for remote = areas and=20 to initiate grid-connected PV projects. The =E2=80=9CBrightness = Project=E2=80=9D, which was=20 first launched in 1996 is aimed at providing electricity from solar and = wind=20 energy in a number of remote regions (WEC, no date).

=20

The Canadian CANMET Energy Diversification Research Laboratory = (CEDRL)=20 addresses the challenges associated to the technical needs via its PV = hybrid=20 Programme (Hybridinfo, 2001). This five-year initiative, which started = in 2001,=20 consists of R&D and technology transfer activities aimed at = improving the=20 performance and cost effectiveness of these systems, and at increasing = the=20 capacity of the solar industry to supply efficient = systems.

References top:

American Wind Energy Association, 2001. Wind Energy Applications = Guide.=20 Available at: http://www.awea.org/pubs/documents/appguideformatWeb.pdf=

=20

Dayu, Y., no date. Local Photovoltaic (PV) =E2=80=93 Wind Hybrid = Systems with Battery=20 Storage or Grid Connection. Available at:

=20

http://www.jyu.fi/Members/juolma/ue-ohjelma/julkaisut/se= minaarit/UEsem2005.pdf

=20

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