Conference Paper

NREL/CP-500-44679

February 2009

Technology, Performance, and 

Market Report of Wind-Diesel 

Applications for Remote and 

Island Communities 

Preprint

I. Baring-Gould

National Renewable Energy Laboratory

M. Dabo

Alaska Energy Authority

To be presented at the European Wind Energy Conference

Marseille, France

March 16-19, 2009
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1 

TECHNOLOGY, PERFORMANCE, AND MARKET 

REPORT OF WIND-DIESEL APPLICATIONS FOR 

REMOTE AND ISLAND COMMUNITIES

E. Ian Baring-Gould

National Renewable Energy 

Laboratory

ian_baring_gould@nrel.gov

Martina Dabo

Alaska Energy Authority

mdabo@aidea.org

ABSTRACT

The rising cost of diesel fuel spurred on by oil 

costs well above $100/barrel and the 

environmental regulation for its transportation, 

use, and storage, combined with the clear 

impacts of carbon emissions are driving remote 

communities dependent on diesel fuel to look at 

alternative methods of providing power. During 

the past few years, wind energy has been 

increasingly used to reduce diesel fuel 

consumption, providing economic, 

environmental, social, and security benefits to 

communities’ energy supplies. 

The market for wind-diesel power systems has 

also recently progressed from a topic discussed 

by researchers to many commercial operating 

systems. From Alaska to Chile, from Australia to 

Spain, from high-penetration wind-diesel plants 

to wind-diesel-hydro systems, the integration of 

wind turbines with conventional isolated 

generation is a commercial reality. The maturing 

wind industry and the advances in controls, 

remote monitoring, storage technologies, and 

diesel generators continue to spur the market for 

wind-diesel applications. Because of the large 

number of isolated diesel mini-grids, specifically 

in island nations such as in the Caribbean and 

the Pacific and the remote northern climates of 

Alaska and Canada, the market for wind-diesel 

systems is substantial. Additionally, the 

similarities between wind-diesel applications and 

large grid-connected wind farms in regard to grid 

stability and other issues can help to develop 

solutions that would also benefit the 

implementation of wind in national grids with 

isolated grid characteristics. 

This paper describes the current status of winddiesel technology and its applications, the 

current research activities, and the remaining 

system technical and commercial challenges. 

System architectures, dispatch strategies, and 

operating experience from a variety of winddiesel systems are discussed, as well as how 

recent development to explore distributed 

energy generation solutions for wind generation 

can benefit from the performance experience of 

operating systems. The paper also includes a 

detailed discussion of the performance of winddiesel applications in Alaska, where 10 winddiesel stations are operating and additional 

systems are currently being implemented. 

Additionally, because this application represents 

an international opportunity, a community of 

interest committed to sharing technical and 

operating developments is being formed. The 

authors hope to encourage this expansion while 

allowing communities and nations to investigate 

the wind-diesel option for reducing their 

dependence on diesel-driven energy sources.

Keywords: Wind, Diesel, Hybrid, Remote, Power

1 Introduction

The use of diesel engines to supply power to 

rural communities has provided light and energy 

services to places where previously there has 

only been darkness. However, the rising cost of 

diesel fuel (brought on by higher oil prices and 

the environmental regulation for its 

transportation, use, and storage) combined with 

carbon emissions concerns is driving remote 

communities to look at alternative methods to 

supplement this power source. During the past 

few years, wind energy has been increasingly 

used to reduce diesel fuel consumption, 

providing economic, environmental, social, and 

security benefits. 

Systems research continues as feedback is 

collected from operators and plant managers 

about how the systems are working. This paper 

describes the current status of wind-diesel 

technology and its applications and the 

remaining system technical and commercial 

challenges. Basic system architectures, dispatch 
2 

strategies, and operating experience from a 

variety of wind-diesel systems are discussed, as 

well as how recent development to explore 

distributed energy generation solutions for wind 

generation can benefit from the performance 

experience of operating systems. The paper 

also includes a detailed discussion of the 

performance of several wind-diesel applications.

Because of the large number of isolated diesel 

minigrids in both the developed and developing 

world, the market for retrofitting these systems is 

substantial. Because this market is international 

in scope, a community of interest has formed 

and is committed to sharing technical and 

operating experiences to expand recent 

successes. 

2 Topography of Power 

Systems Combining Wind 

and Diesel

A wind-diesel power system can be more 

accurately described by the title “hybrid power 

system.” Such a power system can incorporate 

different components, including production, 

storage, power conditioning, and system control 

to supply power to an isolated load [1]. 

The classic hybrid system incorporates 

renewable technology, fossil fuel engine 

generator(s), a battery bank, and a power 

converter. In most cases, this system is based 

on a two-bus system: a DC bus for the battery 

bank and an AC bus for the engine generator 

and distribution. 

Wind-diesel power systems differ from most 

smaller hybrid systems as they are traditionally 

larger and closely integrate the wind and diesel 

technology to provide consistent, high-quality 

AC power. Storage, if used at all, is typically 

provided to smooth power fluctuations, provide 

for short lulls in wind energy production, and 

enable the starting of a diesel engine if one is 

needed. Larger systems usually contain more 

and larger equipment that allows for an 

economy of scale, and thus lower power costs. 

Wind-diesel power systems can vary from 

simple designs in which wind turbines are 

connected directly to the diesel grid with a 

minimum of additional features, to more complex 

systems where advanced controls and 

components are required [1, 2, 3, 4, 5]. Two 

overlapping concepts depict the system design 

and required components: the amount of energy 

that is expected from the renewable sources 

(system penetration) and the methods used to 

control the power system depending on the level 

of renewable contribution. In cold climates, the 

use of waste energy from the diesel engines 

also plays a critical role in determining power 

system design. It should be noted that a 

reduction in standard diesel engine efficiency is 

to be expected in most cases, especially if an 

existing diesel system is retrofitted to allow for 

wind penetration. However, the displacement of 

diesel fuel from wind generation usually 

outweighs this phenomenon.

2.1 Renewable Penetration

In almost all cases, the systems control 

requirements increase with increasing reliance 

on energy from wind turbines. A method 

proposed but not formally published by Steve 

Drouilhet classifies and defines system 

penetration to help characterize the levels of 

system control complexity:

Instantaneous penetration is the product of the 

Wind Turbine Power Output (kW) divided by the 

Primary Electrical Load (kW) while the average 

penetration is a product of the Total Wind 

Turbine Energy Output (kWh) divided by the 

total Primary Electrical Load (kWh) over a given 

time period, typically a month or year.

Instantaneous penetration relates to the power 

system complexity and the required level of 

control to maintain acceptable power quality. 

Power systems with low instantaneous wind 

penetration require limited additional control. 

Devices integrated into diesel generator 

hardware provide system control. As 

instantaneous penetrations increase, more 

caution is required because the variation in wind 

turbine output, driven by the variation of the wind 

resource, may overwhelm the capabilities of 

standard diesel control hardware. At very high 

levels of instantaneous penetration, where wind 

production is on par or even exceeds the system 

energy requirements, additional control must be 

put in place to maximize system performance 

and stability.

Average penetration allows an estimation of fuel 

savings and fuel storage needs, general system 

operation characteristics, and potential longterm monetary impact. Averaged over longer 

periods of time, it provides a record of the total 
3 

amount of system energy coming from wind 

technology.

Drouilhet also proposed a three-level 

classification system for wind penetration that 

separates systems along power and system 

control needs (Table 1). The instantiations and 

average penetration levels provided in the table 

should be considered approximate and will 

depend greatly on the age of the diesel 

generator(s) and associated controls. The 

potential need for additional energy complicates 

the integration since typically space or water 

heating, ice production, or water purification is 

generated through means such as using the 

jacket and exhaust heat from the diesel plant. 

2.2 Low-Penetration Systems

Low-penetration systems are those in which the 

wind energy contribution to the power system is 

limited, requiring no special arrangements or 

control requirements as the energy generated by 

the wind turbines is seen largely as a negative 

load on the diesel plant. The control technology 

required at this level of generation is trivial, 

especially given the control, flexibility, and speed 

of modern electronically controlled and fuelinjected diesel generators and advanced wind 

systems. In systems incorporating older diesel 

engines, especially those using low-speed diesel 

technology, the upper limit of what is considered 

low penetration may shift lower. In some 

instances, individual wind turbines may be shut 

off to reduce the amount of energy from wind to 

prevent grid instability due to a lack of control 

functions in low-penetration systems. However, 

this occurs rarely in well-designed systems. 

Issues of spinning reserve (a term used to 

represent the availability of instantaneous 

system capacity to cover rapid changes in 

system load or energy production) are 

addressed by the allowable capacity of the 

diesel engines, which in many cases can run at 

125% rated power for short periods of time with 

no adverse impact on the diesel or generator.

Many low-penetration systems have been 

installed worldwide. These vary from small to 

relatively large isolated grids, such as those 

found on several Greek islands. The power 

system that has operated in Kotzebue (a coastal 

community of more than 3,000 people in 

northern Alaska) for almost 10 years generally 

classifies as a low to medium-penetration power 

system, with no additional control hardware 

implemented and an average penetration below 

20% but the potential for instantaneous 

penetrations above 100% during times of high 

winds and low system load. [6]

2.3 Medium-Penetration Systems

Systems with larger ratios of renewable energy 

contribution in which some level of power 

system control is required fall into this category. 

In order to maintain minimum load levels on the 

diesel generators in multiple diesel plants when 

a larger portion of the energy is being produced 

by a wind source, some diesels will have to be 

shut off or production switched to a smaller unit. 

This low level of diesel generation makes it 

harder for the operating diesel units to tightly 

regulate system voltage and maintain an 

adequate power balance, especially with older 

diesel generators. 

Several options exist to ensure that the highpower-quality requirements of the power system 

are maintained, even with 50% or more of the 

energy provided by renewable sources. 

Available options are: 

a. power reduction capabilities of the wind 

turbines, 

b. the inclusion of secondary loads, thus 

increasing the overall system load, 

c. use of controlled dump loads to assist in 

clipping the peaks off wind variability, thus 

assisting in the control of frequency, 

d. the use of advanced power electronics and 

turbine control to allow real time power 

specification from the wind turbine, and 

e. diesel governing electronics that allow for 

low-load diesel operation, enabling the 

diesels a faster response time.

Maintaining the proper level of spinning reserve 

in medium-penetration power systems requires 

Penetration 

Class

Penetration

Peak 

Instantaneous

Annual 

Average

Low < 50% < 20%

Medium 50% – 100% 20% – 50%

High 100% - 400% 50% – 

150%

Table 1: Penetration class of wind-diesel 

systems (proposed but not published by 

Steve Drouilhet)
4 

experience with power variability and system 

control but is not considered technically 

complex. Such spinning reserve questions 

should be handled on a case-by-case basis but 

can be solved by using advanced diesel 

controls, modern electronic diesel engines, and 

advanced plant integration. 

However, even with the implementation of 

advanced power conditioning or power 

smoothing technology, diesel engines have a 

minimum load rating under which manufacturers 

state that the diesels should not be operated. 

Not only does operating under these levels 

(typically 40% to 50% of the engines’ rated 

power for older diesels) reduce the diesel 

governor’s ability to control frequency, reactive 

power and to a limited degree voltage, they 

force the engine to run at cooler temperatures, 

thus causing increased engine carbon build up, 

wet stacking, and higher maintenance 

requirements. This minimum diesel-loading 

requirement acts as a glass ceiling, limiting the 

benefit of incorporating increasing amounts of 

wind into a diesel power system. To allow higher 

penetrations of wind into small diesel systems, 

several companies have introduced diesel 

engines that can operate at very low load, 

generally below 10% rated power [7]. These 

low-load diesels maintain their ability to control 

frequency, voltage and reactive power at low 

power levels but also act as spinning reserve 

because of an ability to respond quickly to step 

changes in load.

Medium-penetration systems are more complex, 

which results almost invariably in increased cost. 

These costs must be compared against the 

reduction of plant diesel fuel consumption, 

reduced diesel engine operation, and reduced 

needs for fuel storage and handling, and in 

some cases the reduction of carbon emissions. 

Non-economic beneficial factors of diesel fuel 

reduction include reduced environmental 

impacts and air emissions as well as an 

increase in energy independence. Remote 

communities in Alaska value this increased 

energy independence, especially when semiannual fuel barge deliveries are often threatened 

by weather, and lately, low water levels in rivers.

It should be noted that the amount of required 

spinning reserve is determined by the utility 

operator. Spinning reserve requirements could 

be lowered if an annual system performance 

analysis shows that the local wind resource 

allows for less reserve and if the utility’s diesel 

dispatch and operations strategy allows such 

measures. A reduction in spinning reserve could 

result in expanded diesel fuel savings.

The ability to provide high power quality in 

medium-penetration power systems has been 

demonstrated for years in a number of important 

locations. The most notable examples are the 

military diesel plants on San Clemente Island [8] 

and Ascension Island [9] and the power systems 

in Toksook Bay and Kasigluk, Alaska [6]. 

Several systems have also been installed using 

low-load diesel technology, including power 

systems at Coral Bay and Denham, Australia. 

[10] All of these systems have experienced 

instantaneous penetrations above 50%. 

2.4 High-Penetration Systems

As instantaneous penetrations of renewable 

energy rises, eventually more energy can be 

generated than is needed by the general 

community load. With wind providing a large 

amount of the load, the ability of the diesel 

engines to control frequency, voltage and 

reactive power is significantly reduced. Unless 

there is a large need for additional thermal or 

electrical energy, it makes financial sense to 

shut off as many, and preferably all, of the diesel 

engines when the whole load can be supplied by 

renewable sources (the basic hallmark of a highpenetration wind-diesel system). The operational 

concept behind these systems is that additional 

equipment is installed to ensure power system 

stability and power quality when the diesel 

engine, the device that typically controls these 

parameters, is shut off. In this case, any 

instantaneous power production over the 

required electrical load, an instantaneous 

penetration over 100%, is supplied to a variety 

of controllable secondary loads. In these 

systems, synchronous condensers, load banks, 

dispatchable loads, power converters, advanced 

system controls, and possibly storage in the 

form of batteries or flywheel systems are used to 

ensure power quality and system integrity. 

Additionally a well-designed demand-side load 

management, including load-shedding schemes, 

can be utilized to support grid stability and 

reliability. Recent designs of high-penetration 

wind-diesel systems in Alaska include utilitycontrolled residential electric heating systems 

with thermal storage ability that can be charged 

during low-load and high-wind scenarios.
5 

Spinning reserve is created through the use of 

short-term storage or the maintenance of a 

consistent oversupply of renewable energy. 

This reserve is designed to either ride out short 

lulls in wind power or allow a diesel to be started 

to assume the load if the wind is not adequate. 

Although high-penetration wind-diesel systems 

are being demonstrated commercially, they are 

not yet considered a mature technology and 

have not been demonstrated on systems larger 

than approximately a 300-kW average load. 

High-penetration wind-diesel power stations also 

require a much higher level of system 

integration, technology complexity, and 

advanced control, increasing the project cost, 

but reduce fuel consumption and diesel engine 

operation significantly.

In systems incorporating storage, the storage is 

used to cover short-term fluctuations in 

renewable power. The premise of this design is 

that when the renewable-based generators are 

supplying more power than is needed by the 

load, the engine generators can be shut down 

and the batteries charged with excess wind 

power. During lulls in the renewable power 

generation, discharging the battery bank or other 

storage device supplies any needed power. If 

the lulls are prolonged or the storage becomes 

discharged, an engine generator is started and 

takes over supplying the load. Studies have 

indicated that most lulls in power from the wind 

are of limited duration, and using storage to 

cover these short time periods can lead to 

significant reductions in the consumption of fuel, 

generator operational hours, and reduced 

generator starts [11,12]. 

In recent years two types of storage have been 

successfully demonstrated in operational rural 

power systems: battery storage and flywheels. 

Battery storage has clearly been the most 

commonly used, taking advantage of the long 

operational history of battery technologies. 

Systems incorporating nickel cadmium (NiCad) 

batteries and rotary power converters such as 

those incorporated into the power system for 

Wales, Alaska [13] and the vanadium-based 

flow battery used at Kind Island, Australia 

[14,15] indicate that battery technology can be 

used to smooth out wind power fluctuations, 

both in small and large power systems. Although 

relatively proven, batteries also introduce a host 

of problems, most notably the use of hazardous 

liquids and, in many cases, limited life and a 

consistent maintenance requirement. 

Flywheel technology is becoming more common 

and affordable as a method to provide shortterm power storage and increase system power 

quality. Although flywheels provide only shortterm storage, up to several minutes, they are 

being successfully used in systems such as 

Coral Bay and Flores Island [10,16]. One of the 

key aspects of flywheel technology is the ability 

of the units to supply lower levels of power for 

longer periods of time or short bursts of high 

power for very short periods of time. Although 

several products are on the market, the 

PowerStor® product from PowerCorp Australia 

that was used in the two aforementioned 

projects can provide power up to 1 MW for 15 

seconds or a more reasonable 150 kW for 100 

seconds. These units are also designed in a 

modular fashion and can be stacked to provide 

higher power ratings over longer storage times. 

Although generally still high in cost, their smaller 

system footprint and long operational life make 

them a strong candidate for future storage 

applications. 

This type of system produces a large amount of 

extra energy that must be used if the project is 

to be economic. The power system installed on 

the Alaskan Island of St. Paul to supply the 

airport and co-located industrial complex is an 

example of the configuration of a highpenetration power system.

Unlike flywheels and standard batteries, 

hydrogen and technologies such as flow 

batteries can provide long-term storage. As has 

been found in smaller applications, longer-term 

storage allows the displacement of more fossil 

fuels by using renewable-generated energy 

when the renewable resource is not actually 

available or allow more active optimization of the 

power system dispatch. However, although the 

cost of the renewable-generated energy might 

be relatively low, the efficiency and cost of the 

storage medium is in effect competing against 

the incremental cost of energy from a diesel 

generator, which is also generally low for large 

power plants with defined fuel supply chains. 

The current cost of fuel has limited the 

implementation of wind systems with large 

storage components to technical demonstration 

projects such as the power system on King 

Island [14,15] or the first large-scale remote 

wind-hydrogen development on the remote 
6 

Norwegian Island of Utsira [17]. In locations with 

very high fuel costs, or if standard fuel costs rise 

sharply, longer-term storage may become 

attractive. A proposal to include a re-dox flow 

battery into an expanded wind system is 

currently being evaluated in Kotzebue, Alaska. 

The considered wind generation expansion of 

the exiting system in Kotzebue is contingent on 

the introduction of a storage device that bridges 

longer time periods (over the sub-minute range) 

due to the nature of the local wind resource and 

the utility requirements.

3 Operating Hybrid Power 

Stations

To reduce the cost of rural power generation, 

community vulnerability to rising fuel costs, and 

the environmental impact, many organizations 

have implemented wind-diesel hybrid power 

systems. The following projects provide 

examples of these systems. 

3.1 Kotzebue, Alaska: Low to 

Medium-Penetration Power 

System

Located above the Arctic Circle on a spit of land 

facing the Kotzebue Sound, the coastal 

community of Kotzebue has approximately 

3,000 residents and serves as a regional hub for 

this part of northwest Alaska. The Kotzebue 

Electric Association (KEA) supplies power to the 

community, which has an average load of 

approximately 2.5 MW and a minimum of 700 

kW. The diesel plant has an installed capacity of 

11 MW. [5]

KEA initiated its wind development projects in 

1997, starting with the installation of three 

Atlantic Orient Corporation (AOC) 15/50, 50-kWrated wind turbines on lattice towers on a 

location south of the main town and airstrip. 

Since that time, the wind farm has grown to an 

installed capacity of 915 kW comprised of 17 

turbines: 15 AOC 15/50 or Entegrity EW15 (50 

kW); one remanufactured Vestas V17 (65 kW); 

and one Northern Power Systems Northwind 

100/19 (100-kW) wind turbine. Although the 

annual average wind speed measured at the site 

is quite low (about 5.5 m/s based on data 

collected at the site between 1998 and 2004), 

the wind turbines generated about 667,580 kWh 

last year, saving an estimated 45,500 gallons of 

diesel fuel [18]. Specific penetration values were 

not available from this plant, however based 

simply on system capacity, instantaneous 

penetration up to 100 are clearly possible. 

Currently only turbine curtailment is used to 

control at times of high wind output. Data 

collected by the U.S. Department of Energy 

(DOE) and the Electrical Power Research 

Institute through 2004 showed a relatively high 

system availability of 92%, including wind farm 

down time due to power transmission outages. 

Wind turbine availability is used to describe the 

amount of time that the turbine is in service and 

able to produce energy. Although more current 

assessments have not been published, these 

availability numbers have remained consistent 

on an annual basis [19]. This clearly 

demonstrates the ability for turbines to operate 

in remote communities with high availability, 

primarily due to the KEA’s strong technical 

capabilities and dedication.

3.2 Toksook Bay, Alaska: MediumPenetration Power System

The interconnected communities of Toksook, 

Tununak, and Nightmute have a population of 

approximately 1,160 people and an average 

load just under 370 kW. The power system is 

operated by the Alaska Village Electric 

Cooperative (AVEC) and incorporates three 

Northwind 100/19 100-kW wind turbines that 

were installed in the fall and winter of 

2005/2006. The turbines are dispatched to 

maintain operating levels, and communityheating dump loads were added to address fast 

overload conditions (although in recent 

operations, little energy has been applied to 

heating) [6]. The project, which was 

implemented as part of a complete power 

system upgrade, will help restrain the increased 

costs of electrical generation caused by rising 

fuel prices.

Except for some initial issues, including a blade 

failure, the power system is operating quite 

satisfactorily with a first-year turbine availability 

of 92.4%. The array of wind turbines 

experienced an average net capacity factor of 

26.0% from August 2007 to July 2008. The 

average penetration for this system has been 

over 24.2%, with average monthly penetrations 

over 30% during the stronger winter wind 

months. In the year ending September 2008, 

almost 700 MWh of electricity was generated by 

wind, saving almost 46,000 gallons of fuel. 
7 

3.3 St. Paul, Alaska: HighPenetration Power System

The Tanadgusix Corporation (TDX), a native 

Alaskan corporation, needed a stand-alone 

power system for its facility on the island of St. 

Paul in the Bering Sea. The site is an airport and 

industrial complex with airline offices, equipment 

repair, and storage facilities. TDX wanted to 

reduce the overall energy costs for the camp's 

electrical and heating loads while maintaining 

reliable, utility-grade electrical service. In 1999, 

Northern Power Systems installed a highpenetration, no-storage hybrid power system 

that maximizes the contribution of St. Paul's 

abundant wind resource. The primary 

components of the St. Paul plant included a 225-

kW Vestas V27 wind turbine, two 150-kW Volvo 

diesel engine generators, a synchronous 

condenser, a 27,000 liters (6,000 gallon) 

insulated hot water tank with thermal control, 

and a microprocessor-based control system 

capable of providing fully automatic plant 

operation. 

The power system is designed to have all of the 

diesel engines shut off if there is sufficient wind 

to cover the complete load in addition to a 

controllable safety margin. While the diesel 

engines are off the system controller maintains a 

balance between the power generated by the 

wind turbine and total electrical consumption by 

adjusting power going to the thermal heaters in 

the water tank. The synchronous condenser is 

also used to provide reactive power and 

maintain system voltage. By conducting 

continuous monitoring of the load, thermal 

needs and wind power output, if the controller 

determines there is not enough electrical 

headroom between the electrical load and wind 

production, and there is a chance that the wind 

power will drop below the electrical load, a 

diesel engine is started.

The primary electrical load for the facility 

averages about 70 kW, but the system also 

supplies the primary space heating for the 

facility, which it does with excess power from the 

generators and thermal energy from the diesel 

plant. Although the power system has operated 

well over the past 7 years, a few problems have 

been associated with the wind turbine (an early 

failure of the turbine generator, which had to be 

replaced completely). In 2004 for example, the 

wind turbine had a non-scheduled availability of 

100% and a capacity factor of more than 40%.

The average penetration for this system has 

been almost 55%, with significant times when 

the system operates with both of its diesel 

generators off. Since January 2005, the wind 

energy has saved an estimated 150,000 gallons 

of diesel fuel, about 50% of the expected 

consumption without wind energy.

TDX is currently working with the City of St. Paul 

to interconnect two additional Vestas V27 

turbines installed over winter 2007 to the City of 

St. Paul Municipal Electric Utility. This would 

interconnect the industrial complex power 

system with 725 kW of installed wind capacity to 

the cities’ utility electric system, driven by a 2.1-

MW diesel power station and having an average 

load of more than 600 kW. With a minimum load 

close to 400 kW, once interconnected the wind 

will be able to supply a large amount of the 

power for the community, and depending on the 

final selection of control hardware, will represent 

a high-penetration power system for the whole 

community of St. Paul [18, 20].

3.4 Other Projects

Most wind-diesel project development currently 

takes place in Alaska. Currently 10 systems are 

operating in rural Alaska, and an additional six 

are known to be in development. The recent 

release of the Alaska Renewable Energy fund, 

combined with the expected high cost of diesel 

fuel, provide incentives for communities to look 

at alternative technologies that could result in 

the implementation of an additional 20 projects 

over the next few years. The Alaska wind 

screening study [21] identified more than 100 

communities that are considered economically 

and technically viable candidates for wind-diesel 

system development. The high-profile winddiesel projects at the Australian Mawson 

Antarctic base [22], the Ross Island Wind 

Project [23] being implemented at the U.S. 

McMurdo and New Zealand Antarctic Stations, 

the wind project on the Galapagos island of San 

Cristobal [24] and the systems previously 

mentioned along with others completed in 

Western Australia and Canada indicate the 

increased demand.

4 Technical and Commercial 

Challenges

The dominance of fossil-fueled generators to 

provide power to rural areas is well-justified 
8 

based on a strong track record and many years 

of operational experience. However, as 

discussed, many organizations question the 

continued reliance on fossil fuels alone. 

The incorporation of wind technologies into 

remote rural communities adds a host of 

challenges that must be considered as part of 

any rural energy project. Some of these items 

are simply symptomatic of the industry and 

application, while others can be solved by 

expanded research, development, and 

experience with operating power systems.

4.1 Dispatchable Loads

As more wind capacity is installed in an existing 

diesel plant, more excess energy will be created. 

For high-penetration systems, this extra energy 

must be used in a productive way to make 

projects cost-competitive. In temperate and 

arctic climates, this can largely be resolved by 

using the extra energy for space or water 

heating, but in tropical climates, other uses must 

be determined. 

In some cases, this extra energy can be directed 

at specific loads that can be turned on or off as 

needed, such as electric water heaters, air 

conditioners, water purification/desalination 

systems, or to power specific devices that by 

their nature have embedded storage, such as 

pumping water or making ice. Additional 

controllable loads, such as electric or plug-in 

vehicles, could also be incorporated to use this 

additional peak energy when it is available.

As an additional complexity, in climates with 

large heating loads it is typical to extract thermal 

energy from the combustion cycle of the diesel 

plant. The inclusion of wind reduces diesel 

operation, thus reducing the amount of thermal 

energy generated. If the plant is using that 

thermal energy, the economics of generating 

that energy by other means must be taken into 

account when assessing the impact of 

incorporating wind. This is especially the case in 

high-penetration wind systems in which all of the 

diesel engines may be shut down, eliminating all 

thermal heat from the diesel system plant. In 

cases of total shut-down of diesel engines, 

excess wind energy might be utilized to keep the 

diesel engines at a certain temperature.

4.2 Lack of Guidelines and 

Standards

A major key to success in the development and 

application of any new technology is proper 

guidelines and standards to ensure that all 

market players can be held accountable for 

products produced and advertised. As with 

many new markets, new organizations are quick 

to advertise capabilities that, in all likelihood, are 

outside of their experience. In the developing 

market for wind-diesel applications, which are 

generally very technically challenging, 

experience is the only sure indication of project 

success. Several organizations are developing 

general guidelines and/or draft standards to 

insure that products advertised meet a specific 

set of requirements or can be designed to pass 

a set of specified tasks, but this is only a start 

and do not rise to the level of dedicated 

international technical standards. To ensure that 

improperly developed projects don’t negatively 

impact public perception, every project 

developed must meet a standard of operation 

and quality. The above-mentioned issues are 

especially important in remote communities, 

where spare part supplies and technical support 

can be delayed by weather or other 

circumstances.

4.3 Lack of an Established 

Technology Track Record

Although wind-diesel applications have been 

operating in various applications for more than 

20 years, limited documentation exists that 

would allow other organizations to accurately 

assess their operation. The only systematic data 

collected up to this point is from the Kotzebue 

wind farm (from January 1999 to July 2004). 

This data, however, only assessed the wind 

farm operation and was not correlated to diesel 

plant operation or output. Additionally, this 

analysis did not include costs for system 

construction, operation, and maintenance. [25] 

This lack of data makes it difficult to perform 

more definitive assessments of technology 

performance and costs, a critical element in the 

assessment of potential future projects or to 

document the benefits of using wind 

technologies. Since many of the existing plants 

are relatively new, even with the limited data that 

are available, its focus on the first few years of 

project operation will skew the results, making 

assessments on the long-term performance and 

costs for system operation and maintenance 
9 

speculative. The absence of data makes it easy 

for technology proponents to brush aside the 

desire to further develop wind-diesel 

applications, even if the best available analysis 

indicates that the projects provide positive 

benefits to everyone involved. As possible, work 

is ongoing to better document the performance 

of the existing wind-diesel applications in Alaska 

to clearly and accurately document their true 

performance.

4.4 Installation and Operation 

Expense

Construction projects in rural and remote areas 

are always more difficult and more expensive. 

The implementation of wind technology that 

typically requires the development of specialty 

foundations (such as permafrost designs) and 

the use of locally unavailable cranes to raise the 

turbines add to the expense. Recent studies 

show that the installation of wind energy projects 

in Alaska typically costs between $2,500 and 

$7,000 per kilowatt of installed wind capacity, 

depending on the community’s size, 

accessibility, and differing soil conditions [26]. 

This is potentially four times the cost of typical 

wind installations in Europe or the United States. 

Only about 30% of these costs relate to the 

actual turbine and tower hardware, a basic 

reversal of most project development costs in 

which the turbine and tower make up 

approximately 70% of the total project costs.

The operation of these systems also poses 

additional challenges. Limited service 

capabilities, harsh climates, and expensive 

travel costs result in higher maintenance 

expenses and increased system or component 

down time. Advances in remote monitoring, 

adaptive system control and condition 

monitoring, and local wind technician training all 

help to reduce these costs and should be 

implemented in projects whenever possible.

5 Next Steps and Research 

Needs

In many locations around the world, wind-diesel 

applications can make financial sense (already 

more than 50 locations have been identified in 

Alaska alone) [25]. If fuel prices return to their 

pre-recession levels, this number will only 

increase. However, this will not guarantee the 

further development of wind-diesel applications 

since there are several policy and technical 

challenges that lay ahead. 

5.1 Policy Challenges

Given the level of state, federal, and 

international funding used to supply energy 

(primarily through the use of diesel engines) to 

rural communities and research stations, policy 

plays a critical role in the development of new 

technology paradigms. The following lists 

several key policy issues that should be 

addressed:

• Creation or streamlining of state policy and 

funding to support the development of 

diesel alternative systems. For example, 

governments in many nations will pay the 

complete cost for a new diesel station but 

require a cost share to implement wind or 

other renewable energy components as 

they are not considered critical.

• Many nations subsidize the cost of diesel 

fuel for power generation, which reduces 

the economic viability of other solutions and 

allows the state to be the primary 

benefactor of any personal reductions in 

fuel consumption. Fuel subsidy policy 

should ensure that projects that reduce fuel 

use should be able to capture at least a 

portion of the state’s cost savings from that 

fuel reduction.

• States should mandate the consideration of 

the risks and impacts of investment in diesel 

power generation as compared to other 

generation solutions. For example, since 

fuel is considered an operational cost, 

power plant managers can pass any fueldriven cost increases on to the customers. 

This places all risks of fuel-cost volatility on 

the community and removes any motivation 

by the plant operators, or in many cases 

state regulators, to support lower-risk 

options.

• The development of regional 

implementation approaches to support the 

co-development of systems in a number of 

communities, resulting in economies of 

scale for system implementation and 

leading to a viable operation and 

maintenance infrastructure as compared to 

funding single one-off projects that result in 

higher costs.

• Continued efforts to increase the amount of 

information regarding wind technologies, 

which will help to address the preserved risk 

and associated higher financial costs, with 
10

the deployment of poorly understood power 

generation technologies.

• Streamlining of permitting processes and 

coordination of different permitting agencies 

reduce the time and funding necessary to 

develop projects.

5.2 Technical Challenges

The current high cost of rural wind and winddiesel development clearly indicates that 

technology improvements are needed to ensure 

expanded use for rural electrification. The 

following technical issues form the core of this 

list:

• Collection, analysis, and dissemination of 

wind-diesel power system performance and 

cost information to document a track record 

for the technology and provide a data set to 

better determine where future cost savings 

might be found.

• Development of lower-cost turbine 

foundations and installation processes that 

don’t require the use of cranes, which have 

to be brought to rural communities.

• Expanded development of packaged 

systems that combine all of the needed 

components prior to installation in a rural 

community. This could be developed in 

combination with a more flexible plug-andplay control architecture. 

• Expanded development of lower-cost 

storage technology, allowing highpenetration systems to be implemented at 

lower cost.

• Development of standards or guidelines for 

wind-diesel systems and controllers, 

including defined commissioning 

procedures to ensure acceptable system 

operation following installation.

• Availability of modern wind turbines in the 

appropriate size range to incorporate into 

wind-diesel applications.

• Upgrade re-manufactured turbines with 

performance monitoring equipment to allow 

for early failure detection.

• Increase remote system and health 

monitoring capabilities, both for diesel 

engines and wind turbines.

• A lack of an internationally recognized and 

agreed upon terminology and methodology 

to design, analyze and asses wind-diesel 

systems.

5.3 Institutional Challenges

Institutional and social issues associated with 

the integration of wind technologies into existing 

remote power systems also introduce their own, 

and generally more difficult to solve, challenges. 

The following technical issues form the core of 

this list:

• Poor understanding of the technology, 

specifically in locations where electric power 

is critical to sustaining life as is the case in 

many arctic communities. 

• Lack of trained personnel and the ability to 

keep trained personnel in communities. 

• Organizations and people at all levels with a 

vested interest in maintaining the existing 

infrastructure and systems.

• Environmental, siting or other development 

concerns.

• Requirements to work in typically small, 

remote communities and the potentially 

fractious nature of the politics of those 

communities.

6 Conclusions

There is a clear interest and motivation to add 

wind technologies into the quiver of options to 

provide energy services to remote communities 

and research installations. However, due to a 

lack of knowledge and documentation in many 

cases, the rationale for adopting wind 

technology is rather weak. Analytic studies 

indicate that in locations with good wind 

resources, the life-cycle cost of incorporating 

wind is generally positive (meaning that it will 

save money in the long run), but the calculations 

are usually based on sketchy information 

regarding the performance of existing winddiesel systems, typically in different 

environments. However, the option of waiting for 

another 10 years to “see how the technology 

matures” just guarantees that in 10 years, 

hundreds of diesel plants will have been 

installed or upgraded without consideration of 

alternatives, and little new information will have 

been gained. The result of this course of action 

could be minimal (if fuel prices drop and the 

world decided to tackle climate change directly)

or it could be catastrophic (with fuel prices 

doubling again and the stranding of many rural 

communities due to environmental change). 

Clearly wind, or any other technology for that 

matter, is not going to replace diesel technology 

in providing energy to rural communities in the 

near term, but we must decide whether to invest 

the resources to make sure there are multiple 
11

arrows for this quiver. These decisions are ours 

to make. The true question is whether we make 

them with an eye to the future or looking at the 

past.

7 Acknowledgements

This work was funded by the U.S. Department of 

Energy, Wind and Hydropower Technologies 

Program and the Alaska Energy Authority with 

support from staff of the Alaska Village Electric 

Cooperative, TDX Power, and Kotzebue Electric 

Association.

References

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Chapter 14: Isolated Systems with Wind 

Power. Ackermann, T., ed. Wind Power in 

Power Systems. New York: John Wiley & 

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CH-500-35665. 

[2] Hunter, R.; Elliot, G. Wind/diesel Systems. 

Cambridge, UK: Cambridge University 

Press, 1994. 

[3] Lundsager, P.; Bindner, H. “A Simple, 

Robust, and Reliable Wind/diesel Concept 

for Remote Power Supply.” World 

Renewable Energy Congress III, Reading, 

UK, 11-16 September 1994.

[4] Baring-Gould, E.I.; Flowers, L., Lundsager, 

P.; Mott, L.; Shirazi, M.; Zimmermann J.; 

(2003) “World Status of Wind Diesel 

Applications.” Proceedings of the 2003 

AWEA Conference, Austin TX. June 2003. 

[5] Nelson, V.; Foster, R.; Clark, N.;

Raubenheimer, D. Wind Hybrid Systems 

Technology Characterization, technical 

report, Southwest Technology 

Development Institute, New Mexico State 

University, May 2002. 

http://solar.nmsu.edu/publications/wind_hy

brid_nrel.pdf

[6] Alaska Energy Authority, Wind Program 

operating wind systems in Alaska; 

http://www.akenergyauthority.org/programwi

ndsystem.html

[7] PowerCorp Austrailia, Low Load Diesel – 

Wind/Diesel Product Description and Data 

Sheet 

http://www.pcorp.com.au/images/pcorppdfs/low-load-diesel-productspecification.pdf

[9] Olsen, T.; Gulman, P. J.; McKenna, E. 

(2000). Wind Power Plant Evaluation Naval 

Auxiliary Landing Field, San Clemente 

Island, California; Period of Performance: 24 

September 1999 -- 15 December 2000.

[9] Idaho National Laboratory, power systems 

programs, 

103 

pp.; NREL Report No. SR-500-27527.

http://www.inl.gov/powersystems/ascension

_island.shtml

[10] PowerCorp Australia, project descriptions 

for Coral Bay and Denham (low load diesel) 

and Coral Bay and Flores Island (flywheel), 

http://www.pcorp.com.au/index.php?option

=com_content&task=view&id=83&Itemid=1

32

[11] Beyer, H.G.; Degner, T.; Gabler, H. 

“Operational Behavior of Wind/diesel 

Systems Incorporating Short-Term Storage: 

An Analysis via Simulation Calculations.” 

Solar Energy, Vol. 54, No 6, pp. 429-439, 

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[12] Shirazi, M.; Drouilhet, S. (1997). “An 

Analysis of the Performance Benefits of 

Short-Term Energy Storage in Wind/diesel 

Hybrid Power Systems.” 1997 ASME Wind 

Energy Symposium, Reno, Nevada, 

January 6-9, 1997.

[13] Drouilhet, S.; Shirazi, M. (2002). Wales, 

Alaska High-Penetration Wind/diesel 

Hybrid Power System: Theory of Operation. 

77 pp.; NREL Report No. TP-500-31755.

[14] Australian Greenhouse Office, renewable 

energy enabling technologies, King Island 

Project 

http://www.greenhouse.gov.au/renewable/r

ecp/enabling/three.html and 

http://www.greenhouse.gov.au/renewable/r

ecp/enabling/four.html

[15] VRB Power Systems Incorporated, King 

Island case study 

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A.;Ortjohann, E.; Schultze, E.; Tuckey, A.; 

Zimmermann, J. “Increasing Renewable 

Energy Penetration in Isolated Grids Using 

a Flywheel Energy Storage System.” 2007, 

International Conference on Power 

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(POWERENG), Portugal, April 2007.

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Hydrogen & Fuel Cell Letter, August 2004, 

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169-1.html
12

[18] Alaska Energy Authority (2007), Statistical 

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Program, Fiscal year 2006. 

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7PCEStatisticsFY06.pdf

[19] Conover, K.; VandenBosche, J.; Rhoads, 

H.; Smith, B. (2000). Review of Operation 

and Maintenance Experience in the DOEEPRI Wind Turbine Verification Program. 

13 pp.; NREL Report No. CP-500-28620. 

[20] Web site for Wind Powering America, 

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merica/wkshp_2002_wind_diesel_4.html. 

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Economic Wind Development in Rural 

Alaska – Part I Technical Potential, the 

Arctic Energy Summit, Anchorage Alaska, 

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[22] The Mawson wind farm, Australian Antarctic 

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[23] The Ross Island Wind Energy – Stage 1 

Project, Meridian Energy, 

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80%93+Stage+1+Project.htm

[25] Rhoads, H.; VandenBosche, J.; McCoy, T.; 

Compton, A.; Smith, B. (2000). Comparison 

of Projections to Actual Performance in the 

DOE-EPRI Wind Turbine Verification 

Program. 14 pp.; NREL Report No. CP500-28608. 

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Wind Energy in Alaska: Progress, Barriers, 

and the Path Forward Proceedings of the 

2006 AWEA Conference, Austin TX. June, 

2006.
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4. TITLE AND SUBTITLE

Technology, Performance, and Market Report of Wind-Diesel 

Applications for Remote and Island Communities: Preprint

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14. ABSTRACT (Maximum 200 Words)

The rising cost of diesel fuel has been spurred on by oil costs well above $100/barrel and the environmental 

regulation for its transportation, use, and storage. Rising costs combined with the clear impacts of carbon emissions 

are driving remote communities dependent on diesel fuel to look at alternative methods of providing power. During 

the past few years, wind energy is increasingly used to reduce diesel fuel consumption, providing economic, 

environmental, social, and security benefits to communities’ energy supplies. This paper describes the current status 

of wind-diesel technology and its applications, the current research activities, and the remaining system technical and 

commercial challenges. System architectures, dispatch strategies, and operating experience from a variety of winddiesel systems will be discussed, as well as how recent development to explore distributed energy generation 

solutions for wind generation can benefit from the performance experience of operating systems. The paper also 

includes a detailed discussion of the performance of wind-diesel applications in Alaska, where 10 wind-diesel stations 

are operating and additional systems are currently being implemented. Additionally, because this application 

represents an international opportunity, a community of interest committed to sharing technical and operating 

developments is being formed. The authors hope to encourage this expansion while allowing communities and 

nations to investigate the wind-diesel option for reducing their dependence on diesel-driven energy sources. 

15. SUBJECT TERMS

wind energy; wind turbine; Alaska; wind-diesel; wind hybrid system; hybrid; remote; power 

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