Small Scale Technologies

Introduction

Distributed generation (DG) technologies which are based on small scale technologies can provide energy solutions to customers that are more cost-effective, more environmentally friendly, or provide higher power quality or reliability than conventional solutions. Understanding the wide variety of DG options available in today’s changing electric markets can be daunting. Some of these DG technologies offer high efficiency, resulting in low fuel costs, but emit a fair amount of pollutants (CO and NOx); others are environmentally clean but are not currently cost-effective. Still others are well suited for peaking applications but lack durability for continuous output. With so much to consider, it is often difficult for decision makers to determine which technology is best suited to meet their specific energy needs. As such, a wide range of specifications must take into consideration for choosing and implementing the right technology for each individual energy customer.

(See: Engineering Consultation)

Applications

Continuous Power (where DG is operated at least 6,000 hours per year);

- Combined Heat and Power (CHP) (where DG waste heat is used for heating and or cooling);

- Peaking Power (where DG is operated between 200-3000 hours per year during periods of high electricity price or high site demand);

- Green Power (where DG is operated by a facility to help reduce environmental emissions from its power supply);

- Premium Power (where DG provides a higher level of reliability and/or power quality than typically available from the grid);

- Transmission and Distribution Deferral (where DG is used to delay the purchase of new transmission or distribution systems); and

- Ancillary Service Power (where DG is used to provide ancillary service at a transmission or distribution level; includes spinning/ non-spinning reserves, reactive power, voltage control, and local area security).

Small Scale Power Generators

Main Power Generators which are currently available as DG technologies are mentioned below. It is important to know that each DG technology has its own history and current status, operation, emission control technologies, potential applications, representative manufacturers, and important issues surrounding its development.

1- Reciprocating engines - This DG technology was developed more than a century ago, and is still widely utilized in a broad array of applications. The engines range in size from less than 5 to over 5,000 kW, and use either diesel, natural gas, or waste gas as their fuel source. Development efforts remain focused on improving efficiency and on reducing emission levels. Reciprocating engines are being used primarily for backup power, peaking power, and in cogeneration applications.

2- Microturbines - A new and emerging technology, microturbines are currently only available from a few manufacturers. Other manufacturers are looking to enter this emerging market, with models ranging from 30 to 200 kW. Microturbines promise low emission levels, but the units are currently relatively expensive. Obtaining reasonable costs and demonstrating reliability will be major hurdles for manufacturers. Microturbines are just entering the marketplace, and most installations are for the purpose of testing the technology. Unit sales are expected to increase in 2001 and beyond.

3- Industrial combustion turbines - A mature technology, combustion turbines range from 1 MW to over 5 MW. They have low capital cost, low emission levels, but also usually low electric efficiency ratings. Development efforts are focused on increasing efficiency levels for this widely available technology. Industrial combustion turbines are being used primarily for peaking power and in cogeneration applications.

4- Fuel cells - Although the first fuel cell was developed more than one hundred fifty years ago, this technology remains in the development stage. Currently, fuel cells are commercially available from only one manufacturer, with several others developing units in the 5 to 1000+ kW size range to enter the market in the next year or two. Fuel cell emission levels are quite low, but cost and demonstrated reliability remain major problems for the market penetration of this technology. The few fuel cells currently being used provide premium power or are in applications subsidized by the government or gas utilities.

5- Photovoltaics - Commonly known as solar panels, photovoltaic (PV) panels are widely available for both commercial and domestic use. Panels range from less than 5 kW and units can be combined to form a system of any size. They produce no emissions, and require minimal maintenance. However, they can be quite costly. Less expensive components and advancements in the manufacturing process are required to eliminate the economic barriers now impeding wide-spread use of PV systems. Photovoltaics are currently being used primarily in remote locations without grid connections and also to generate green power.

6- Wind turbine systems - Wind turbines are currently available from many manufacturers and range in size from less than 5 to over 1,000 kW. They provide a relatively inexpensive (compared to other renewables) way to produce electricity, but as they rely upon the variable and somewhat unpredictable wind, are unsuitable for continuous power needs. Development efforts look to pair wind turbines with battery storage systems that can provide power in those times when the turbine is not turning. Wind turbines are being used primarily in remote locations not connected to the grid and by energy companies to provide green power.