NEW YORK ( TheStreet) -- Solar power, wind power and other clean energy sources are set to form a major portion of global energy supply in the future, thanks to increasing capital investment in the renewable energy sector, a recent United Nations report said.

According to the report, currently almost 13% of the world's energy needs are met through renewable resources. Moreover, decline in prices of solar installations, wind turbines and other such technologies will likely attract more investment in the sector. The report estimates global renewable investments to range between $1.4 trillion and $5.1 trillion from 2010 to 2020.

Global wind market is estimated to grow in 2011 with more than 40 GW of new wind power capacity, according to a report by the Global Wind Energy Council. Further, the report adds that by 2015 the global installed wind power capacity will more than double to 450 GW from 194.4 GW recorded at the end of 2010.

The American Wind Energy Association says the country's wind power industry installed 1,100 MW of new capacity in the first quarter of 2011. For the second quarter, it had another 5,600 MW under construction which is almost twice the megawatts reported in 2010 and 2009.

We have identified six stocks in the alternative energy industry spanning across sectors such as independent power producers, manufacturers of instruments used in energy control, power conversion and supply equipment companies which can leverage the anticipated growth in the sector.

These stocks have potential upsides of anywhere between 11% and 103% based on its latest quarterly earnings and estimates. The average mean upside value is 53%, based on analysts' consensus estimate polled by Bloomberg.

The stocks are stacked based on upside, great to greatest.

6. Ormat Technologies ( ORA), which is involved in the geothermal and recovered energy business, mainly designs, develops, builds, owns and operates geothermal recovered energy-based power plants. Its business activities are divided into two segments, electricity and products.

Of the 18 analysts covering the stock, 22% assign a buy rating, while 50% rate a hold on it. Analysts polled by Bloomberg expect the stock to gain an average 11.2% to $25.8 in the upcoming 12 months.

During first quarter 2011, the company recorded a year-over-year increase of 18% in total revenue to $97.8 million, driven by increases of 18.1% and 18.4% in revenue from product and electricity segment, respectively. Overall, total electricity generation increased by 14.2%. As of March 31, 2011, the backlog in the product segment stood at $104 million, including the contract from New Zealand power plant.

Recently, the company's subsidiary entered into a geothermal power supply contract with New Zealand-based Norske Skog Tasman. The new power plant is to be constructed in the Kawerau Geothermal Field in New Zealand. The contract, valued at approximately $20 million, is scheduled for delivery and completion within 13 months from the contract date. Furthermore, targeting an annual payout ratio of almost 20% of the company's net income, Ormat approved its quarterly dividend payout of 4 cents per share, payable May 25, 2011.

Looking ahead to 2011, the company estimates Electricity Segment revenue to range between $315 and $325 million, while it raised its Product Segment revenue guidance to $80 to $85 million from the earlier forecast of $75 to $85 million. At the end of 2013, Ormat forecasts to add up to 220 MW to its generating capacity through its early and advanced stage projects.

5. Woodward ( WWD) is a designer, manufacturer and service provider of energy control and optimization solutions with major focus on original equipment manufacturers (OEMs) and equipment packagers. With production and assembly facilities located in the U.S., Europe and Asia, the company designs, produces and services components and integrated systems that manage and control the energy of fluid movement, motion, combustion and electricity.

Of the 10 analysts covering the stock, 70% recommend a buy, with the remaining suggesting a hold. There are no sell ratings on the stock. Analysts polled by Bloomberg expect the stock to gain an average 17.8% to $40.6 in the next 12 months.

For its second quarter of 2011, the company recorded net income of $32.1 million or 46 cents per share as compared to $24.1 million or 34 cents per share in the year-ago quarter. Meanwhile, sales increased 20% to $418.9 million. The company topped analysts' estimates who had forecasted earnings of 42 cents per share on sales of $392.7 million.

The company recently declared a quarterly cash dividend of 7 cents per share payable on June 1, 2011. Looking forward to 2011, the company reaffirmed its sales guidance of $1.55 to $1.65 billion with earnings per share in the range of $1.75 to $1.90. The estimates include a projected increase of $26 million or 25 cents per share in variable compensation expense from 2010.

4. Clean Energy Fuels ( CLNE), a provider of natural gas for vehicle fleets in U.S. and Canada, designs, builds, finances and operates fueling stations. It also supplies compressed natural gas (CNG) and liquefied natural gas (LNG) to its customers. Additionally, its wholly owned subsidiary BAF Technologies provides services like natural gas conversions, alternative fuel systems, and application engineering among others for vehicles.

Of the eight analysts covering the stock, 63% recommend a hold, whereas 25% rate a buy. Analysts polled by Bloomberg expect the stock to gain an average 29.8% to $17.3 over the next 12 months.

For its first quarter of 2011, the company recorded a year-over-year increase of 67% in total revenue to $65.3 million. Meanwhile, it delivered 35.5 million gallons during the quarter as compared to 28.6 million gallons a year ago. On a GAAP basis, the company's net loss narrowed to $9.8 million or 14 cents as compared to $24.4 million or 41 cents per share in year ago period. During the quarter, the company completed nine station construction or upgrade projects as against two in the year-ago quarter.

Looking ahead, the company has a strong pipeline of 343 projects with 173 of those in the validation and negotiation stage, and 82 have already commenced. Recently, the company was awarded a $40 million contract from Dallas Area Rapid Transit (DART) to design and build four new CNG stations, thereby enabling the transition of DART's fixed route and paratransit bus fleet to 100% CNG power. CLNE estimates to complete DART's first new CNG fueling facility by April 2012.

3. Broadwind Energy ( BWEN) is engaged in providing products and services to the U.S. wind energy industry. Its customers also include wind turbine manufacturers, wind farm developers and wind farm operators. Its operations are divided into four segments -- Towers, Gearing, Technical and Engineering Services, and Logistics.

Of the five analysts covering the stock, 20% recommend a buy and 40% rate a hold. Analysts polled by Bloomberg expect the stock to gain an average 78.6% to $3 in the upcoming 12 months.

For the first quarter of 2011, the company recorded net sales of $43.5 million as compared to $21.7 million in first quarter of 2010. The growth was led by a robust 150% increase in order intake over the year ago quarter. Revenue from Towers segment was up 134% while that of Gearing increased 76%. For the same period, net loss narrowed to $4.1 million or 4 cents per share from $12 million or 11 cents per share. Adjusted EBITDA swung to a positive $0.1 million from negative $7.2 million in year ago period.

With an order backlog of $227 million at the end of March 31, 2011 and cash and marketable securities totaling $22 million, the company believes that the stage has been set for a strong second quarter performance.

2. China Ming Yang Wind Power Group ( MY), a privately owned wind turbine manufacturer in China, is mainly engaged in designing, manufacturing, selling and servicing megawatt-class wind turbines. Its products consist primarily of two wind turbine models, each with a rated power capacity of 1.5 MW. These models are designed and developed to suit the wind and other weather conditions as well as power grids in China.

Of the five analysts covering the stock, 80% recommend buying it while remaining rate a hold. There are no sell ratings on the stock. Analysts polled by Bloomberg foresee the stock gaining an average 78.7% to $14.1 in the upcoming 12 months.

For its first quarter of 2011, the company witnessed an increase of 38.6% in total revenue to $213.4 million as compared to the year-ago quarter. Net income soared 58.6% year-over-year to $33.4 million or 27 cents per share. Gross margin increased significantly to 26% from 20.5% in the first quarter of 2010. Lastly, order backlog increased 23.2% year-over-year to 2,083.5 MW.

For full year 2011, the company forecasts to recognize revenue from Wind Turbine Generators (WTGs) equivalent to wind projects with a total output of 2.3 to 2.4 GW. Additionally, the commercial delivery of the first batch of 2.5/3.0 MW super-compact-driven (SCD) WTGs is likely to begin before end of second quarter of 2011. Also, it estimates to maintain gross margin at its prior year levels.

1. SatCon Technology ( SATC) is a clean energy technology provider of utility grade power solutions for the renewable and distributed energy products. Its power conversion solutions and system design services are used by large-scale renewable energy plants, businesses and utility companies to convert renewable energy sources into electrical power.

Of the 13 analysts covering the stock, 77% recommend a buy and the remaining rate a hold. There are no sell ratings on the stock. Data from Bloomberg has analysts forecasting the stock gaining 103% to $4.8 in the upcoming 12 months.

For the first quarter of 2011, the company recorded revenue of $62 million, a more than threefold increase from $14.7 million recorded in year ago period. Meanwhile, net loss narrowed to $2.1 million or 2 cents per share from $7.2 million or 10 cents per share in first quarter of 2010. Shipments increased to 276 MW of industry-leading solutions as compared to 55 MW in the prior year's quarter. Lastly, bookings totaled $35.5 million, while backlog stood at $72.2 million with North America representing 78.5% of the total.

For the second quarter of 2011, the company estimates revenue to be in the range of $50 to $60 million. With markets in North America and Asia continuing to remain strong, Germany and Italy are likely to establish their long-term strategies in these markets. At the end of 2011, the company targets to achieve a 30% gross margin.

>>To see these stocks in action, visit the 6 Alternative Energy Stocks With Upside portfolio on Stockpickr.