Item 1.    Business.

Overview

        Capstone Turbine Corporation ("Capstone" or the "Company") develops, manufactures, markets and services microturbine technology solutions for use in stationary distributed power generation applications, including cogeneration (combined heat and power ("CHP"), integrated combined heat and power ("ICHP"), and combined cooling, heat and power ("CCHP")), renewable energy, natural resources and critical power supply. In addition, our microturbines can be used as battery charging generators for hybrid electric vehicle applications. Microturbines allow customers to produce power on-site in parallel with the electric grid or stand alone when no utility grid is available. Several technologies are used to provide "on-site power generation" (also called "distributed generation") such as reciprocating engines, solar power, wind powered systems and fuel cells. For customers who do not have access to the electric utility grid, microturbines provide clean, on-site power with lower scheduled maintenance intervals and greater fuel flexibility than competing technologies. For customers with access to the electric grid, microturbines provide an additional source of continuous duty power, thereby providing additional reliability and potential cost savings. With our stand-alone feature, customers can produce their own energy in the event of a power outage and can use microturbines as their primary source of power for extended periods. Because our microturbines also produce clean, usable heat energy, they provide economic advantages to customers who can benefit from the use of hot water, chilled water, air conditioning and heating. Our microturbines are sold primarily through our distributors. Our distributors install the microturbines. Service is provided primarily by our global distribution network. Together we offer new and remanufactured parts as well as a comprehensive Factory Protection Plan ("FPP"). Successful implementation of microturbines relies on the quality of the microturbine, marketability for appropriate applications, and the quality of the installation and support.

        We believe we were the first company to offer a commercially available power source using microturbine technology. Capstone offers microturbines designed for commercial, industrial, and utility users with product offerings ranging from 30 kilowatts ("kW") to one megawatt in electric power output. Our 30 kW ("C30") microturbine can produce enough electricity to power a small convenience store. The 65 kW ("C65") microturbine can produce enough heat to provide hot water to a 100-room hotel while also providing about one-third of its electrical requirements. Our 200 kW ("C200") microturbine is well suited for larger hotels, office buildings and wastewater treatment plants, among others. By packaging the C200 microturbine power modules into an International Organization for Standardization ("ISO") sized container, Capstone has created a family of microturbine offerings from 600 kW up to one megawatt in a compact footprint. Our 1000 kW ("C1000 Series") microturbines are well suited for utility substations, larger commercial and industrial facilities and remote oil and gas applications. Our microturbines combine patented air-bearing technology, advanced combustion technology and sophisticated power electronics to form efficient and ultra-low emission electricity and cooling and heat production systems. Because of our air-bearing technology, our microturbines do not require liquid lubricants. This means they do not require routine maintenance to change and dispose of oil or other liquid lubricants, as do the most common competing products. Capstone microturbines can be fueled by various sources, including natural gas, propane, sour gas, renewable fuels such as landfill or digester gas, kerosene, diesel and biodiesel. The C65 and C200 microturbines are available with integrated heat exchangers, making them easy to engineer and install in applications where hot water is used. Our products produce exceptionally clean power. Our C65 was certified by the California Air Resources Board ("CARB") as meeting its stringent 2007 emissions requirements—the same emissions standard used to certify fuel cells and the same emissions levels as a state-of-the-art central power plant. Our C65 Landfill and Digester Gas systems were certified in January 2008 by CARB as meeting 2008 waste gas emissions requirements for landfill and digester gas applications. Our C200 Landfill and

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Digester Gas systems were certified in November 2010 by CARB as meeting 2008 waste gas emissions requirements for landfill and digester gas applications.

        On February 1, 2010, we acquired the 100 kW ("TA100") microturbine product line from Calnetix Power Solutions, Inc. ("CPS") and entered into a manufacturing sub-contract agreement and an original equipment manufacturer agreement with selected exclusive rights to package a combined microturbine and waste heat recovery generator product. The TA100 microturbine is most similar to the Capstone product design compared to other microturbine products in the industry and the 100 kW rating fits well between our C65 and C200 microturbines. The 125 kW waste heat recovery generator can be directly fired by the exhaust of six C65 or two C200 microturbines to provide a total of over 500 kW of clean and efficient green power in applications where the microturbine exhaust is not otherwise utilized, such as CHP or CCHP.

        We sell complete microturbine units, subassemblies, components and various accessories. We also remanufacture microturbine engines and provide after-market parts and services. Our microturbines are sold primarily through distributors and Original Equipment Manufacturers ("OEMs"). Distributors purchase our products for sale to end users and also provide application engineering and installation support. Distributors are also required to provide a variety of additional services, including engineering the applications in which the microturbines will be used, installation support of the products at the end users' sites, commissioning the installed applications and providing post-commissioning service. Our distributors perform as value-added resellers. OEMs integrate Capstone's products into their own product solutions.

        To assure proper installation of Capstone microturbine systems, we have instituted a Factory Trained Installer ("FTI") training and certification program. Personnel from our distributors and OEMs, as well as design engineering firms, contractors and end users attend this FTI training. We offer to assist all customers by reviewing their installation designs to confirm that the technical requirements for proper operation have been met, such as electrical interconnections, load requirements, fuel type and pressure, cooling air flow and turbine exhaust routing. As part of the microturbine commissioning process, we also receive a checklist to confirm that the final installation adheres to Capstone technical requirements before we accept any warranty obligations. This is aimed at providing the end user with a proper installation that will operate as expected for the life of the equipment.

        Capstone has a factory direct service offering for commissioning and post-commissioning service. Through our global distribution network, we offer a comprehensive FPP for a fixed annual fee to perform regularly scheduled and unscheduled maintenance as needed. In January 2011, we expanded the FPP to include total microturbine plant operations if required by the end use customer. Capstone provides factory and on-site training to certify all personnel that are allowed to perform service on our microturbines. Individuals who are certified are called Authorized Service Providers ("ASPs") and must be employed by a distributor in order to perform work pursuant to a Capstone FPP. The majority of our distributors provide these services.

        This Annual Report on Form 10-K (this "Form 10-K") refers to Capstone's fiscal years ending March 31 as its "Fiscal" years.

Our Products

        We began commercial sales of our C30 products in 1998, targeting the emerging distributed generation industry that was being driven by fundamental changes in power requirements. In September 2000, we shipped the first commercial unit of our 60 kW microturbine ("C60"), which was replaced by the C65 model during the quarter ended March 31, 2006. We began shipping the C60 Integrated CHP solution in 2003. The first commercial C200 microturbine was shipped on August 28, 2008. Our C1000 Series product was developed based on Capstone's C200 microturbine engine. The C1000 Series product can be configured into 1,000 kW, 800 kW and 600 kW solutions in a single

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ISO-sized container. The first commercial shipment of our C1000 Series product was on December 29, 2008. We began shipping TA100 microturbines in March 2010.

        During Fiscal 2013, we booked total orders of $112.6 million for 765 units, or 107.2 megawatts, compared to $122.5 million for 637 units, or 136.3 megawatts, during Fiscal 2012. We shipped 628 units with an aggregate of 103.2 megawatts, generating revenue of $102.7 million compared to 627 units with an aggregate of 96.1 megawatts, generating revenue of $89.9 million during Fiscal 2012. Total backlog as of March 31, 2013 increased $9.9 million, or 7%, to $148.9 million from $139.0 million at March 31, 2012. As of March 31, 2013, we had 816 units, or 162.8 megawatts, in total backlog compared to 679 units, or 158.8 megawatts, at the same date last year. The timing of the backlog is based on the requirement date indicated by our customers. However, based on historical experience management expects that a significant portion of our backlog may not be shipped within the next twelve months. The timing of shipments is subject to change based on several variables (including customer deposits, payments, availability of credit and customer delivery schedule changes), most of which are not in our control and can affect the timing of our revenue.

        The following table summarizes our backlog:

        Capstone microturbines are compact, lightweight and environmentally friendly generators of electricity and heat compared to competing technologies. They operate on the same principle as a jet engine with the added capability of using a variety of commercially available fuels. For example, our microturbines can operate on low British Thermal Unit ("BTU") gas, which is gas with lower energy content, and can also operate on gas with a high amount of sulfur, known in the industry as sour gas. Examples of these fuel sources include methane from facilities such as wastewater treatment plants, landfills and anaerobic digesters.

        Our microturbines incorporate four major design features:

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advanced combustion technology;



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patented air-bearing technology;



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digital power electronics; and



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remote monitoring capability.

        Our advanced combustion technology allows Capstone microturbines to achieve low emissions with a design geared towards manufacturability. These low emission levels not only provide an environmentally friendly product, but also eliminate permitting requirements in several municipalities for continuously operated onsite power generation. The air-bearing system allows the microturbine's single moving assembly to produce power without the need for typical petroleum-based lubrication.

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Air-bearings use a high-pressure field of air rather than petroleum lubricants. This improves reliability and reduces maintenance such as oil changes. The electronic controls manage critical functions and monitor operations of the microturbine. For instance, our electronics control the microturbine's speed, temperature and fuel flow and communicate with external networks and building management systems. The power electronics coordinate with the grid when the units are operated in a grid-connect mode and with the onboard battery when equipped for stand-alone mode. All control functions are performed digitally. Performance is optimized, resulting in lower emissions, higher reliability and high efficiency over a variable power range.

        The electrical output of our units can be paralleled in multiple unit configurations through our Advanced Power Server product and a digital communications cable to serve larger installations requiring electrical loads up to ten megawatts.

        Our products can operate:

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connected to the electric utility grid as a current source;



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on a stand-alone basis as a voltage source;



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multipacked to support larger loads as a "virtual single" unit; and



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in dual mode, where the microturbine operates connected to the electric utility grid or operates independently.

        We also offer C65 and C200 ICHP systems. These systems combine the standard C65 and C200 microturbine unit with a Heat Recovery Module that provides electricity and heats water.

        Our family of products is offered in the following configurations:

        We offer various accessories for our products including rotary gas compressors with digital controls, heat recovery modules for CHP applications, dual mode controllers that allow automatic transition between grid connect and stand-alone modes, batteries with digital controls for stand-alone or dual-mode operations, power servers for large multipacked installations, protocol converters for Internet access, packaging options and miscellaneous parts such as frames, exhaust ducting and installation hardware. We also sell microturbine components and subassemblies.

        Our electronic controls manage microturbines using Capstone's proprietary software and advanced algorithms. The controls:

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start the turbogenerator and manage its load;



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coordinate the functioning of the microturbine with the grid;



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manage the speed, fuel flow and exhaust temperature of the microturbine;

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convert the variable frequency, up to a maximum of 1,600 Hertz and variable voltage power produced by the generator into a usable output of either 50 or 60 Hertz AC for stationary applications or DC for hybrid electric vehicle applications; and



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provide digital communications to externally maintain and control the equipment.

        In addition, our proprietary Capstone Remote Monitoring Software ("CRMS") allows end users to remotely operate and manage the microturbine. Unlike the technology of other power sources that require manual monitoring and maintenance, the CRMS allows end users to remotely and efficiently monitor performance, power generation and time of operation using our CRMS interface software with standard personal computers. This remote capability can provide end users with power generation flexibility and cost savings. Capstone is currently developing an Internet based system to provide real-time continuous remote monitoring and diagnostics to customers who purchase the service.

        The C30 microturbines were initially designed to operate connected to an electric utility grid and to use a high pressure natural gas fuel source. We have expanded our microturbine's functionality to operate with different fuels. The combustor system remains the same for all fuels except for the fuel injectors, which currently vary between liquid and gaseous fuels. The Capstone microturbine's multi-fuel capability provides significant competitive advantages with respect to some of our selected vertical markets.

        Our C65 grid-connect and stand-alone microturbine power systems are listed by Underwriters Laboratories ("UL") as meeting the UL 2200 stationary engine generator standards and the UL 1741 utility interconnection requirements. Our products are manufactured by processes that are ISO 9001:2000 and ISO 14001:2004 certified.

        In 2002, the California Energy Commission certified our C30 and C60 microturbines as the first products to comply with the requirements of its "Rule 21" grid interconnection standard. This standard streamlines the process for connecting distributed generation systems to the grid in California. The benefits of achieving this standard include avoiding both costly external equipment procurement requirements and extensive site-by-site and utility-by-utility analysis. Our protective relay functionality has also been recognized by the State of New York, which has pre-cleared our microturbines for connection to New York's electric utility grid.

        Our C60 microturbine was the first combustion power generation product to be certified by the CARB as meeting its stringent distributed generation emissions standards that went into effect in 2003. Our C65 microturbine now meets the even more stringent CARB 2007 standard for natural gas.

        The TA100 microturbine offers a digital communication interface which can be connected to an external controller (not sold by Capstone) to provide multiple unit and dual mode dispatching functionality. An external synchronization board is provided to parallel the electrical output in multiple unit configurations for stand-alone operation.

        We are the first microturbine manufacturer to achieve UL Class I, Division 2 certification for operation in hazardous-area oil and gas applications. These specially packaged systems are applied in oil and gas production areas with potentially explosive environments.

        In September 2009, we received UL certification for our C200 grid-connect and stand-alone microturbine as meeting the UL 2200 stationary engine generator standards and the UL 1741 utility interconnection requirements.

        In June 2010, we received UL certification for our C1000 Series grid-connect and stand-alone microturbine as meeting the UL 2200 stationary engine generator standards and the UL 1741 utility interconnection requirements.

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Applications

        Worldwide, stationary power generation applications vary from huge central stationary generating facilities up to 1,000 MW to back-up generators as small as two kW. Historically, power generation in most developed countries such as the United States has been part of a regulated utility system. A number of developments related primarily to the deregulation of the utility industry as well as significant technology advances have broadened the range of power supply choices available to all types of customers.

        Capstone products serve multiple vertical markets worldwide. Within the markets served, we focus on vertical markets that we have identified as having the greatest near-term potential. In the markets we are focusing on, which are energy efficiency, renewable energy, natural resources, critical power supply and mobile products, we have identified specific targeted vertical market segments.

Energy Efficiency—CHP/CCHP

        Energy efficiency maximizes the use of energy produced by the microturbines, reduces emissions compared with traditional power generation and enhances the economic advantage to customers. Energy efficiency uses both the heat and electric energy produced in the power generation process. Using the heat and electricity created from a single combustion process increases the efficiency of the system from approximately 30% to 75% or more. The increased operating efficiency reduces overall greenhouse gas emissions compared with traditional independent sources such as power generation and local thermal generation and, through displacement of other separate systems, can reduce operating costs. Our microturbines' emissions of commonly found air pollutants ("criteria pollutants") such as nitrogen oxides ("NOx"), carbon monoxide ("CO") and volatile organic compounds ("VOCs") are lower than those from the on-site boilers that our CHP system displaces, meaning that local emissions of these pollutants are actually reduced when a Capstone energy efficiency CHP system is installed. This high CHP efficiency also means more efficient use of fuel and can reduce net utility costs for end users. The most common uses of heat energy include space heating and air conditioning, heating and cooling water, as well as drying and other applications. For example, we have used the heat generated by the microturbines to supply hot water solutions for hotels, office buildings and retail, commercial and industrial customers. When our microturbine exhaust drives an absorption chiller, the chiller produces chilled water for air conditioning and other uses.

        There are energy efficiency markets for CHP and CCHP applications worldwide. A study conducted for the US Department of Energy ("DOE") calculated the total potential energy efficiency CHP market in the United States to be over 35.5 gigawatts through 2020. Many governments have encouraged more efficient use of the power generation process to reduce pollution, lower dependence on fossil fuels and control the cost of locally produced goods. To access these markets, we have entered into agreements with distributors which have engineered energy efficiency CHP packages that utilize the hot exhaust air of the microturbine for heating water and also use the hot exhaust to run an absorption chiller for air conditioning. We also offer our own integrated energy efficiency CHP and CCHP product for the C65, C200 and C1000 Series products.

Renewable Energy

        Our microturbines can use renewable methane gases from landfills, wastewater treatment facilities and other biogas applications such as food processing and agricultural waste, referred to as green waste, and cow, pig and chicken manure. They can burn these renewable waste gases with minimal emissions, thereby, in some cases, avoiding the imposition of penalties incurred for pollution while simultaneously producing electricity from this "free" renewable fuel for use at the site or in the surrounding areas. The microturbines have demonstrated effectiveness in these applications and

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outperform conventional combustion engines in a number of situations, including when the gas contains a high amount of sulfur.

        Capstone released for sale the C65 stand-alone digester product for sale in the renewable energy market segment in 2007. This product is targeted at remote villages in third-world countries with wastewater treatment facilities that offer a valuable source of fuel which can be converted to electricity. A joint applications and engineering team evaluated the performance of the existing C65 digester gas system to ensure that the combustion system would be stable from 0 to 100% power output. Minor controls changes were implemented to increase stability at low power levels. The ability to convert this low BTU fuel to electricity along with the high reliability and low maintenance features of this product make it well suited for this market.

        In February 2010, we entered into an agreement with CPS to purchase 125 kW waste heat recovery generators in exchange for certain minimum purchase requirements through December 2015. Pursuant to this agreement, we have exclusive rights to sell the zero-emission waste heat recovery generator for all microturbine applications and for applications 500 kW or lower where the source of heat is the exhaust of a reciprocating engine used in a landfill application.

Natural Resources—Oil, Natural Gas, Shale Gas & Mining

        On a worldwide basis, there are thousands of locations where the drilling, production, compression and transportation of natural resources and other extraction and production processes create fuel byproducts, which traditionally have been released or burned into the atmosphere. Our microturbines are installed in the natural resource market to be used in oil and gas exploration, production, compression and transmission sites both onshore and offshore as a highly reliable critical source of power generation. In addition, our microturbines can use flare gas as a fuel to provide prime power. Typically these oil and gas or mining operations have no electric utility grid and rely solely on Capstone's microturbine for reliable low emission power supply.

        Many major oil and gas companies are exploring large shale reserves, or plays, in the United States. In mid-2010 Capstone sold its first microturbines into the U.S. shale gas market in the Eagle Ford and Marcellus shale plays. The market for Capstone microturbines in this industry is vast. The shale gas market is expected to grow substantially, especially since the U.S. Environmental Protection Agency's ("EPA") Clean Air Act has strict requirements for emissions levels at natural gas sites.

        The C200 product is offered for sale configured to meet Class 1 Zone 2 hazardous location requirements for the oil and gas market. Hazardous location requirements are met through package ventilation changes for purging and pressurizing package air to avoid potential flammable mixtures as well as controls for emergency disconnect of fuel and electrical sources. The package is upgraded to stainless steel construction to withstand the corrosive offshore environments where these units are installed. Oil and gas customers prefer the low maintenance and high reliability attributes offered by our turbines to ensure continued production. Capstone also offers C30 and C65 microturbine products in similar configurations.

Critical Power Supply

        Because of the potentially catastrophic consequences of even momentary system failure, certain power users such as high technology and information systems companies require particularly high levels of reliability in their power service. Capstone's critical power supply offerings are the world's only microturbine powered Uninterruptible Power Source ("UPS") solutions that can offer clean, IT-grade power produced from microturbines, the utility or a combination of both. We offer two microturbine-powered UPS solutions that support prime and dispatched power options. The Capstone UPSource microturbine-powered UPS solution provides prime or emergency power solutions. Capstone's Hybrid UPS microturbine powered solution provides power when dispatched in high efficiency, standard UPS

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and emergency power solutions. Both critical power supply products offer 99.999999% reliability when the product has at least one independent backup. Dual mode units operating in a prime power configuration can support a 150% overload for 10 seconds during transient conditions. Dual mode units operating in grid parallel mode can provide customers a back-up power system with an economic return. These systems offer high onsite energy efficiency when combined with a heat exchanger (CHP) to create hot water or with a chiller (CCHP) for air conditioning at these facilities. This configuration, when combined with the Capstone Dual Mode Controller, can transition from the grid parallel mode to prime power mode in less than 10 seconds.

Mobile Products—Hybrid Electric Vehicles

        Our technology is also used in hybrid electric vehicle ("HEV") applications. Our customers have applied our products in hybrid electric vehicles such as transit buses and trucks. In these applications the microturbine acts as an onboard battery charger to recharge the battery system as needed. The benefits of microturbine hybrids include extended range, fuel economy gains, quieter operation, reduced emissions and higher reliability compared with traditional internal combustion engines. Internal combustion diesel engine manufacturers have been challenged for the last several years to develop technology improvements, prior to aftertreatment that reduce emissions to levels specified by the EPA and CARB 2007 and 2010 standards. Many manufacturers are incorporating aftertreatment that increases upfront equipment costs, vehicle weight and life cycle costs and may reduce overall engine efficiency.

Mobile Products—Marine

        Our technology is also used in marine applications. Our customers have applied our products in the commercial vessel and luxury yacht markets. The most immediate market for our marine products is for use as ship axillaries. In this application, the microturbines provide power to the vessel's electrical loads and, in some cases, the vessel is able to utilize the exhaust energy to increase the overall efficiency of the application, reducing overall fuel consumption and emissions. The other application is similar to our HEV application where the vessel is driven by an electric propulsion system and the microturbine serves as an on board range extender. Our marine customers use both our liquid fueled and natural gas products. Liquefied natural gas (LNG) is in its early stages as a marine fuel, and the number of vessels powered by LNG is forecasted to double every two years over the next decade. Vessel owners can receive the same benefits as users of stationary Capstone products: low emissions with no aftertreatment, long maintenance intervals, high reliability, low noise and no vibration.

Sales, Marketing and Distribution

        We primarily sell our microturbine product, parts and service through distributors. Our typical terms of sale include shipment of the products with title, care, custody and control transferring at our dock, payment due anywhere from in advance of shipment to 90 days from shipment, and warranty periods of approximately 15 to 18 months from shipment. We typically do not have customer acceptance provisions in our agreements.

North America

        We have distribution agreements with a number of companies throughout North America for the resale of our products. Many of these distributors serve multiple markets in their select geographic regions. The primary markets served in this region have been energy efficiency, renewable energy, natural resources and mobile products. The energy efficiency and natural resources vertical markets are expected to grow as a result of an increased supply of low price natural gas.

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        In developing our sales opportunities we have identified the need to address various requirements present in our target localities. These requirements include electric grid interconnection standards, gas utility connection requirements, building and fire safety codes and various inspections and approvals. The costs and scheduling ramifications of these various approvals can be significant to the completion of an installation. Our goal is to work with the applicable regulating entities to establish compliant standards for the installation of our microturbines so that the costs and installation timelines are minimized for our customers. Management believes that we can create market advantages for our products through enhancing the ease of deploying our distributed generation solutions.

Asia and Australia

        Our sales and marketing strategy in Asia and Australia has been to develop and strengthen distributor relationships throughout these continents.

        Our market focus in Asia and Australia is energy efficiency, renewable energy and natural resources. Our historical sales in Southeast Asia and Australia have primarily been in the CHP, CCHP and the oil and gas market. Other areas in Asia and the Pacific Rim offer attractive opportunities as well. South Korea and China are areas where renewable energy applications and CHP and CCHP solutions are expected to experience market growth.

Europe and Russia

        To address the European market, including Russia, we are strengthening our relationships with existing and new distributors and have increased Capstone local sales and service support. We have an office in Europe for the purpose of working with our distributors there on a daily basis to realize growth opportunities. We have established a spare parts distribution center in Europe to make parts readily available to our distributors. Europe has a history of extensive use of distributed generation technologies. We expect revenue from the European market will continue to be soft as a result of general economic conditions. Continued financial instability there could have an adverse effect on our business.

South America

        Our sales and marketing strategy in South America has been to develop and strengthen distributor relationships throughout South America.

        Our market focus in South America is energy efficiency, renewable energy and natural resources. Our historical sales in South America have primarily been in the natural resources market.

Revenue

        For geographic and segment revenue information, please see Note 2—Summary of Significant Accounting Policies—Segment Reporting in the "Notes to Consolidated Financial Statements."

Customers

        Sales to Horizon Power Systems ("Horizon"), one of the Company's domestic distributors, accounted for 27%, 19% and 18% of our revenue for the years ended March 31, 2013, 2012 and 2011, respectively. Sales to BPC Engineering ("BPC"), one of the Company's Russian distributors, accounted for 11%, 26% and 23% of our revenue for the years ended March 31, 2013, 2012 and 2011, respectively. Additionally, BPC and Regatta Solutions, Inc., one of the Company's domestic distributors, accounted for 35% and 11%, respectively, of net accounts receivable as of March 31, 2013. BPC accounted for 44% of net accounts receivable as of March 31, 2012.

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Competition

        The market for our products is highly competitive. Our microturbines compete with existing technologies such as reciprocating engines and may also compete with emerging distributed generation technologies, including solar power, wind-powered systems, fuel cells and other microturbines. Many potential customers rely on the utility grid for their electrical power. As many of our distributed generation competitors are large, well-established companies, they derive advantages from production economies of scale, worldwide presence, brand recognition and greater resources, which they can devote to product development or promotion.

        Generally, power purchased from the electric utility grid is less costly than power produced by distributed generation technologies. Utilities may also charge fees to interconnect to their power grids. However, we can provide economic benefits to end users in instances where the waste heat from our microturbine has value (CHP and CCHP), where fuel costs are low (renewable energy/renewable fuels), where the costs of connecting to the grid may be high or impractical (such as remote power applications), where reliability and power quality are of critical importance, or in situations where peak shaving could be economically advantageous because of highly variable electricity prices. Because Capstone microturbines can provide a reliable source of power and can operate on multiple fuel sources, management believes they offer a level of flexibility not currently offered by other technologies such as reciprocating engines.

        Our reciprocating engine competitors have products and markets that are well developed and technologies that have been proven for some time. A reciprocating engine, also known as an internal combustion engine, is similar to those used in automotive applications. Reciprocating engines are popular for primary and back-up power applications despite higher levels of emissions, noise and maintenance. These technologies, which typically have a lower up-front cost than microturbines, are currently produced by Caterpillar Inc., Cummins Inc., Deutz Corporation, GE Gas Engines which now includes Waukesha, MAN SE, Tecogen, Inc. and Wärtsilä Corporation, among others.

        Our microturbines may also compete with other distributed generation technologies, including solar power, wind power systems and fuel cells. Solar and wind powered systems produce no emissions. The main drawbacks to solar and wind powered systems are their dependence on weather conditions, the utility grid and high capital costs that can often make these systems uneconomical without government subsidies depending upon geographic locale and application of the technology. Although the market for fuel cells is still developing, a number of companies are focused on markets similar to ours, including FuelCell Energy Inc., ClearEdge Power, Bloom Energy Corporation, LG Fuel Cell Systems, a business unit of LG Electronics, Plug Power Inc. and Ballard Power Systems Inc. Fuel cells have lower levels of NOx, CO, VOCs and other criteria pollutant emissions than our microturbines. Fuel cells, like solar and wind powered systems, have received higher levels of incentives for the same type of applications as microturbines. Management believes that, absent these higher government incentives, microturbines provide a better value to end users in most applications. However, over the medium-to-long term, fuel cell technologies that compete more directly with our products may be introduced.

        We also compete with other companies who have microturbine products, including FlexEnergy and Turbec S.p.A.

        Overall, we compete with end users' other options for electrical power and heat generation on the basis of our microturbine's ability to:

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provide power when a utility grid is not available or goes out of service;



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reduce total cost of purchasing electricity and fuel;



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improve electric power availability and provide high power quality;



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operate on multiple fuel types;



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reduce emissions (both criteria pollutants and greenhouse gases);



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simplify operation; and



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control maintenance costs and associated disposal of hazardous materials.

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Governmental and Regulatory Impact

        Our markets can be positively or negatively impacted by the effects of governmental and regulatory matters. We are affected not only by energy policy, laws, regulations and incentives of governments in the markets in which we sell, but also by rules, regulations and costs imposed by utilities. Utility companies or governmental entities may place barriers on the installation or interconnection of our product with the electric grid. Further, utility companies may charge additional fees to customers who install on-site power generation, thereby reducing the electricity they take from the utility, or for having the capacity to use power from the grid for back-up or standby purposes. These types of restrictions, fees or charges could hamper the ability to install or effectively use our product or increase the cost to our potential customers for using our systems. This could make our systems less desirable, thereby adversely affecting our revenue and profitability. In addition, utility rate reductions can make our products less competitive which would have a material adverse effect on our operations. These costs, incentives and rules are not always the same as those faced by technologies with which we compete. However, rules, regulations, laws and incentives could also provide an advantage to our distributed generation solutions as compared with competing technologies if we are able to achieve required compliance in a lower cost, more efficient manner. Additionally, reduced emissions and higher fuel efficiency could help our customers combat the effects of global warming. Accordingly, we may benefit from increased government regulations that impose tighter emission and fuel efficiency standards.

        Capstone continues to engage with Federal and State policymakers to develop government programs to promote the deployment of Capstone's low emission and energy efficient products. In 2012, President Obama called for 40 GW of additional CHP power generation to be installed in the United States by 2020. Legislation is under consideration by Congress that could stimulate the market for Capstone products by providing incentives to encourage energy efficiency. We cannot provide assurance that any such legislation will be enacted, however, or that it will benefit us if enacted. Several state programs were introduced in 2011 and 2012 that provide financial support to combined heat and power projects, and some of these programs have begun to benefit Capstone's customers. For example, in New York, Capstone systems are pre-qualified for financial incentives available through the NYSERDA CHP Acceleration Program. In Ohio, legislation passed allowing for CHP to qualify as an energy efficiency measure under the state's Energy Efficiency Resource Standard.

        The United States Government is focused on promoting exports of American products with a specific emphasis on clean energy goods. Capstone participates in export promotion activities such as trade missions which help us enter new markets by facilitating interactions with foreign buyers and distributors. Capstone's customers have utilized trade financing through the Export-Import Bank of the United States ("Ex-Im Bank") in the past, and Capstone has seen more customers use Ex-Im Bank financing for projects in 2011 and 2012.

        Government funding can impact the rate of development of new technologies. While we continue to receive development funding, committed amounts remaining are relatively low. Competing new technologies generally receive larger incentives and development funding than do microturbines.

Sourcing and Manufacturing

        We are focused on continuously improving our supply chain effectiveness, strengthening our manufacturing processes and increasing operational efficiencies within our organization. Our microturbines are designed to achieve high volume, low cost production objectives. Our manufacturing designs include the use of conventional technology, which has been proven in high volume automotive and turbocharger production for many years. Many components used in the manufacture of our products are readily fabricated from commonly available raw materials or off-the-shelf items available from multiple supply sources; however, certain items are custom made to meet our specifications. We believe that in most cases, redundant capacity exists at our suppliers and that alternative sources of

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supply are available or could be developed within a reasonable period of time. We also have an on-going program to identify single-source components and to develop alternative back-up supplies and we regularly reassess the adequacy and abilities of our suppliers to meet our needs. We continue to evaluate and implement new systems designed to provide improved quality, reliability, service, greater efficiency and lower supply chain costs. We have substantially increased our focus on process controls and validations, supplier controls, distribution controls and providing our operations teams with the training and tools necessary to drive continuous improvement in product quality. In addition, we remain focused on examining our operations and general business activities to identify cost-improvement opportunities in order to enhance our operational effectiveness. Our ability to leverage these capabilities may be affected by the current variability in our demand volumes and forecasting. Our strategy is to identify primary and secondary sources for critical components when available to minimize factory down time due to unavailability of such parts, which could affect our ability to meet manufacturing schedules.

        We assemble and test units as well as manufacture air-bearings and certain combustion system components at our facility in Chatsworth, California. Additionally, we assemble and test our C200 and C1000 Series products and manufacture recuperator cores at our facility in Van Nuys, California. Management believes our manufacturing facilities located in Chatsworth and Van Nuys, California have a combined production capacity of approximately 2,000 units per year, depending on product mix. Excluding working capital requirements, management believes we can expand our combined production capacity to approximately 4,000 units per year, depending on product mix, with approximately $10 to $15 million of capital expenditures. We have not committed to this expansion nor identified a source for its funding, if available.

        Solar Turbines Incorporated ("Solar"), a wholly owned subsidiary of Caterpillar Inc., was our sole supplier of recuperator cores prior to 2001. In 2000, we exercised an option to license Solar's technology, which allows us to manufacture these cores ourselves and we began manufacturing them in June 2001. The cores are subject to a per-unit royalty fee. As of March 31, 2013, cumulative royalties of $0.4 million have been paid under the terms of the licensing agreement with Solar.

        In September 2007, we entered into a Development and License Agreement (the "Development Agreement") with UTCP, a division of United Technologies Corporation. The Development Agreement engaged UTCP to fund and support our continued development and commercialization of our 200 kilowatt ("C200") microturbine. In return we agreed to pay a predetermined fixed rate for each microturbine system covered by the agreement. In August 2009, the Development Agreement was assigned by UTCP to Carrier Corporation ("Carrier"). As of March 31, 2013, cumulative royalties of $9.8 million have been paid under the terms of the licensing agreement with Carrier.

        On April 28, 2011, we purchased from CPS for $2.3 million the remaining TA100 microturbine inventory that was not consumed as part of the TA100 manufacturing process and acquired the manufacturing equipment. On February 1, 2010, the Company and CPS entered into an agreement pursuant to which we agreed to purchase 125 kW waste heat recovery generator systems from CPS, which agreement was subsequently assigned to General Electric Company ("GE") in October of 2010. In exchange for certain minimum purchase requirements through December 2015, we have exclusive rights to sell the zero-emission waste heat recovery generator for all microturbine applications and for applications 500 kW or lower where the source of heat is the exhaust of a reciprocating engine used in a landfill application. As of March 31, 2013, we were not in compliance with the minimum purchase requirements in the agreement. Loss of exclusivity is dependent upon receiving proper notification from GE as set forth in the agreement.

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Research and Development ("R&D")

        For the fiscal years ended March 31, 2013, 2012 and 2011, R&D expenses were $9.0 million, $8.2 million and $7.0 million and were 7%, 7% and 9% of total revenue, respectively. R&D expenses are reported net of benefits from cost-sharing programs, such as DOE grants and the Development Agreement with Carrier. Benefits from cost-sharing programs were $1.7 million, $0.8 million and $0.9 million for Fiscal 2013, 2012 and 2011, respectively. Our R&D activities enabled us to become one of the first companies to develop a commercially available microturbine that operates in parallel with the grid. We were the first company to successfully demonstrate a commercially available microturbine that operates on a stand-alone basis.

        We are focused on making improvements to our C30, C65, and C200 products to be compliant with the new VDE-AR-N 4105 requirements in Europe for decentralized power generation. These improvements require hardware and software changes to our power inverters to allow power that can be fed into the grid smoothly and efficiently. In addition, we continue to work cost reduction activities to improve the direct material costs of our microturbine products. Current cost reduction activities are focused on leveraging the capabilities of our supply base through identification of value added suppliers, working with existing suppliers to identify process and tooling improvements, entering into long term agreements and transitioning parts to low cost manufacturing regions. Cross functional teams, including internal engineering resources and supplier resources, are used to drive changes with a focus on mutually beneficial long-term relationships.

        In September 2011, we received CARB certification to the 2007 Fossil Fuel Standards for our C200 ICHP microturbine power systems. This standard represents the most stringent emissions standard worldwide set to the Best Available Control Technology ("BACT") for large central power plants. To put these emissions levels in perspective, it is challenging to measure the extremely low levels required with today's best emissions measurement equipment. These emissions levels were achieved through scaling and optimization of Capstone existing lean premix combustion technology. Test emissions from both the C30 and C65 natural gas fueled microturbines measured dramatically less than the emissions levels set forth by the CARB standard including NOx at 75% and CO at 96% less than the required levels. The emissions levels are set so low that the California Air Resources Board has not defined any further limit reductions in the foreseeable future.

        We continue to release variants of the C200 product to provide the same features that we offer customers with our C30 and C65 microturbine products. A liquid fuel version of the C200 product has been developed with Capstone's lean premix combustion technology. This technology allows operation on various fuels by changing the injector to achieve the necessary fuel to air ratio mixture, fuel atomization, stability, and exhaust emission levels. The control system is modified to incorporate required algorithm modifications for start/stop sequencing and load state operation. Liquid fuel products are well suited for markets where customers do not have access to gaseous fuels but still demand the low emissions, low maintenance, and high reliability benefits offered by Capstone's microturbine products. Capstone received the 2011 NOVA Award from the Construction Innovation Forum ("CIF") for its C65 Hybrid Uninterruptible Power Supply ("UPS") Microturbine at Syracuse University's data center—labeled one of the greenest data centers in the world. The product utilizes Capstone's inverter electronics and controls technology to provide continuous power quality to the customer critical load. The load inverter is connected through a central power bus to provide power from one of three available power sources including the utility grid, battery storage system, or microturbine generator. Power to the critical load is synchronized to an available utility grid to allow direct bypass of the critical load to the utility grid. This redundant functionality is provided in a single integrated package that can be scaled to a larger seamless power unit through Capstone's multipack feature. These units can also be combined with a heat recovery module or an absorption chiller to provide higher total output efficiency. Unlike current UPS products combined with reciprocating engines for backup, the low emissions of the Capstone Hybrid UPS product allow for continuous

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operation year round allowing customers the ability to receive a payback on their capital equipment investment. In November 2012, we received UL certification for our C65 HUPS microturbine system as meeting the UL 2200 stationary engine generator standards and the UL 1741 utility interconnection requirements.

        We are continuing to work on product improvements to our C30 and C65 microturbine products targeted at the hybrid electric bus and truck market. Because of Capstone's single moving assembly, manufacturers believe there is also the opportunity to produce a lower cost product in larger automotive volumes. Our current focus is on a next generation product that would include existing components and a liquid-cooled set of electronics that are consistent with the size, cost and cooling strategies employed on vehicles today. During the 2011 Hybrid Truck User's Forum in Baltimore Maryland, it was announced that both Kenworth Truck Company and Peterbilt Motors Company are working with Capstone to demonstrate Class 7 and Class 8 microturbine range extended series hybrid trucks. Both vehicles are concept trucks intended to quantify the performance, efficiency, and economic benefits of a microturbine-based series hybrid solution. Future development efforts will be based on the lessons learned from these programs. In the meantime, Capstone has other hybrid vehicle customers that will benefit from continued development of this technology.

        The C65 Liquid Fuel microturbine demonstrated emissions levels which meet the CARB 2010 standards for Heavy Duty Diesel Engines ("HDDE"). These requirements are met using test procedures which evaluate emissions performance through start/stop and load transient cycles. Capstone is able to meet these extremely low emissions requirements using its lean premix combustion technology with no aftertreatment. Competitive reciprocating engine technologies require aftertreatment components that increase system cost, require frequent maintenance, and impact engine efficiency. The C30 Liquid Fuel microturbine met these requirements in March 2009. In August 2011, we announced configurations of the C30 and C65 compressed natural gas ("CNG") fueled microturbines that meet extremely low emission standards, including the U.S. Environmental Protection Agency and CARB 2010 emissions requirements for On-Road Heavy Duty Diesel Engines for Urban Bus. Test emissions from both the C30 and C65 Natural Gas microturbines measured dramatically less than the emissions levels set forth by the CARB standard including NOx at 75% and CO at 96% less than the required levels. We believe that future products will require the implementation of On Board Diagnostic (OBD) controls to gain certification through the CARB.

        Capstone is working with the Department of Energy ("DOE") on two next generation technology roadmap programs, including the Flexible Fuel Turbine System ("FFTS") and High Efficiency Microturbine with integral heat recovery. The FFTS program is aimed at developing a microturbine system for operation on a range of higher BTU gaseous fuels, including synthetic gas ("SynGas") produced by a biomass gasifier and hydrogen. The High Efficiency Microturbine with integral heat recovery is focused on improving microturbine electrical efficiency and overall system efficiency utilizing heat recovery. We are currently focusing efforts on the development of the High Efficiency Microturbine with integral heat recovery system. In March 2013, Capstone successfully completed proof-of-concept testing of the first C250 that produced 270 kW as part of the first phase of development to increase power and electrical efficiency. This milestone validates significant design and aero-performance work and marks the most powerful engine ever produced by Capstone in the lab. Capstone is also working to boost the power capability of the power electronics and electrical system required to support this higher power generator. The second phase of the program is expected to incorporate further engine efficiency improvements, resulting in a product with a projected electrical efficiency of 42% and targeted power output of 370 kW. Improvements in efficiency are key to all markets as improved fuel efficiency benefits users through lower operating costs. We expect to commercialize these products into the C200/C1000 product family upon successful project completion and acceptable technical readiness level.

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Protecting our Intellectual Property Rights and Patents

        We rely on a combination of patent, trade secret, copyright and trademark law and nondisclosure agreements to establish and protect our intellectual property rights in our products. In this regard, we have obtained 106 U.S. and 36 international patents (in certain cases covering the same technology in multiple jurisdictions). The patents we have obtained will expire between 2014 and 2027.

        Management believes that a policy of protecting intellectual property is an important component of our strategy of being the leader in microturbine system technology and will provide us with a long-term competitive advantage. In addition, we implement security procedures at our plants and facilities and have confidentiality agreements with our suppliers, distributors, employees and certain visitors to our facilities.

Organization and Employees

        We were organized in 1988. On June 22, 2000, we reincorporated as a Delaware corporation.

        As of March 31, 2013, we had 217 employees. No employees are covered by collective bargaining arrangements. We consider relations with our employees to be good.

Available Information

        This annual report on Form 10-K ("Annual Report"), as well as our quarterly reports on Form 10-Q, current reports on Form 8-K and amendments to those reports filed or furnished pursuant to section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended (the "Exchange Act") are made available free of charge on the Company's Internet website (http://www.capstoneturbine.com) as soon as reasonably practicable after such materials are electronically filed with or furnished to the Securities and Exchange Commission ("SEC").