Renewable Energy Technologies and their Potential

“……the time is running out…soon, there will be nothing left to burn on earth but earth itself…”

Introduction Renewable Energy – “any sustainable energy source that

comes from natural environment.”

It exists perpetually and in abundant in the environment.

Ready to be harnessed, inexhaustible.

It is a clean alternative to fossil fuels.

“energy that is derived from natural process that are replenished constantly” -- defined by the RENEWABLE ENERGY WORKING PARTY of the INTERNATIONAL ENERGY AGENCY

Contribution of Renewable Energy in World Electricity Production

Major Renewable Energy Sources

• Wind Energy• Biomass and Biofuel Energy• Solar Energy• Hydro Energy• Geothermal Energy• Ocean Energy

Installed Capacity from Renewable Energy

Source: Ministry of New and Renewable Energy

Wind Energy•Wind power is the conversion of wind energy into a useful form of energy.

•Wind Turbines are the only present way to harvest wind Energy.

•A wind turbine is a device that converts kinetic energy from the wind into mechanical energy. If the mechanical energy is used to produce electricity, the device may be called a wind generator or wind charger. If the mechanical energy is used to drive machinery, such as for grinding grain or pumping water, the device is called a windmill or wind pump

Wind Energy A wind turbine obtains its power input by

converting the force of the wind into a torque (turning force) acting on the rotor blades.

PLF of Wind Farm is normally in the range of 20 % to 30% depending upon the site conditions and WTG rating.

The amount of energy which the wind transfers to the rotor depends on the density of the air, the rotor area, and the wind speed

P =0.5 AVρ 3

P - Power ρ - Air Density (kg/m3)

A - Blade Area -turbine (m2)V - Wind velocity (m/s)

Generally of two types:1.Can rotate about horizontal axis2.Can rotate about vertical  axis

the former being both older and more common

Types of wind turbine

Design of a Wind Turbine

1. Foundation2. Connection to the electric

grid3. Tower4. Access ladder5. Wind orientation control6. Nacelle7. Generator8. Anemometer9. Brake10.Gearbox11.Rotor blade12.Blade pitch control13.Rotor hub.

Status quo

Alta (Oak Creek-Mojave) 720 USA

Buffalo Gap Wind Farm 523.3 USA

Capricorn Ridge Wind Farm 662.5 USA

Dabancheng Wind Farm 500 China

Fowler Ridge Wind Farm 599.8 USA

Horse Hollow Wind Energy Centre 735.5 USA

Meadow Lake Wind Farm 500 USA

Panther Creek Wind Farm 458 USA

Roscoe Wind Farm 781.5 USA

Sweetwater Wind Farm 585.3 USA

Wind farm(Onshore) Current capacity (MW)

Country

Wind farm(Offshore) Capacity(MW) Country

Walney 367  United Kingdom

Thanet 300  United Kingdom

Horns Rev II 209  Denmark

Rødsand II 207  Denmark

Lynn and Inner Dowsing 194  United Kingdom

Robin Rigg (Solway Firth)

180  United Kingdom

Gunfleet Sands 172  United Kingdom

Nysted (Rødsand I) 166  Denmark

• World wind generation capacity more than quadrupled between 2000 and 2006, doubling about every three years.

Top 10 countries by nameplate wind power capacity (2010)

Country Windpower capacity (MW)

China 44,733

United States 40,180

Germany 27,215

Spain 20,676

India 13,066

Italy 5,797

France 5,660

United Kingdom 5,204

Canada 4,008

Denmark 3,734

Present Scenario Fastest growing renewable energy source.

Globally, it grew at the average rate of 27 % pa over the past 10 years.

In India it grew at the average rate of 33% over the past 9 years.

Presently, India is ranked 3rd in the world in terms of Wind Energy Installed Capacity surpassing Germany and Spain in 2011

Drivers of growth• Environmental Awareness and Sustainable Development• Growing Global Energy Demand • Improving Competitiveness of renewable energy• Security of Supply Concerns• New Markets (e.g. India, China etc)• Carbon Trading• Fiscal Benefits by Govt. (PTC, feed in tariffs, etc)

Wind Energy Potential

• Globally, the long-term technical potential of wind energy is believed to be five times total current global energy production, or 40 times current electricity demand.

• Offshore resources experience average wind speeds of ~90% greater than that of land, so offshore resources could contribute substantially more energy .

• Max Planck Institute in Germany concluded that 18 TW and 68 TW could be extracted.

• A new Carbon Trust study into the potential of small-scale wind energy has found that small wind turbines could provide up to 1.5 terawatt hours (TW·h) per year of electricity saving 0.6 million tonnes of carbon dioxide emission.

Different Aspects of Wind Energy No pollution Can satisfy small and large scale needs

easily. No non-renewable inputs. Noisy. Undesirable appearance. Vulnerable to thunderstorms.

Solar Energy Solar power is by far the Earth's most available energy source, easily

capable of providing many times the total current energy demand.

Solar power is the conversion of sunlight into electricity. Two main commercial ways of conversion of sunlight into electricity.

• Concentrating Solar Thermal Plant (CSP)

• Photovoltaic Plants (PV)

Solar Energy CSP and PV both have their markets. PV is very successful in

decentralized applications, whereas CSP offers advantages

for central and large-scale applications. CSP power plants

are the most cost-efficient way to generate and to store

dispatch able CO2-free electricity. However, there is no

competition between both. Rather, they have to be seen as

complementary technologies.

PLF of CSP – In the range of 20 % to 30 %

PLF of PV – In the range of 15 % to 20 %

Solar Energy Technology Concentrating Solar Thermal Plant (CSP)

It contains;• Collector Field• Turbine• Generator• Cooling Tower• Transformer

Courtsey – ESP solar

Solar Energy Technology Solar Photovoltaic Plants (PV) It contains;

• Solar Arrays• Inverter• Transformer

Solar thermal energy

• It is a technology for harnessing solar energy for thermal energy.

• Solar thermal collectors(STC) are used to serve this.

Types of STC-1. Low-temperature collectors(LTC)2. Medium-temperature collectors(MTC)3. High-temperature collectors(HTC)

Low-temperature collectors(LTC)

• Generally installed to heat swimming pools• Can also be used for space heating. • Collectors can use air or water as the medium to transfer the heat to their

destination.

The two main types of solar air panels are-

1. Glazed 2. Unglazed

Glazed

• designed primarily for space heating.

• Recirculate building air through a solar air panel where the air is heated and then directed back into the building.

• Require at least two penetrations into the building and only perform when the air in the solar collector is warmer than the building room temperature.

Unglazed

• Primarily used to pre-heat make-up ventilation air in buildings with a high ventilation load.

• Turn building walls or sections of walls into low cost, high performance, unglazed solar collectors

• Common designs are pressurized glycol, drain back, batch systems and newer low pressure freeze tolerant systems using polymer pipes containing water with photovoltaic pumping.

• Operational innovations include "permanently wetted collector" operation. This innovation reduces or even eliminates the occurrence of no-flow high temperature stresses called stagnation which would otherwise reduce the life expectancy of collectors.

• Applications in Solar Drying , Cooking , Distillation.

Medium-temperature collectors(MTC)

High-temperature collectors(HTC)

• Solar radiation is concentrated by mirrors or lenses to obtain higher temperatures – a technique called Concentrated Solar Power (CSP) is used.

• CSP plant generates heat first of all, it can store the heat before conversion to electricity. With current technology, storage of heat is much cheaper and more efficient than storage of electricity. In this way, the CSP plant can produce electricity day and night.

Different designs of CSP

Parabolic trough design-A change of position of the sun parallel to the receiver does not require adjustment of the mirrors

(a)

Power Tower Design-Flat mirrors focus the light on the top of the tower. The white surfaces below the receiver are used for calibrating the mirror positions

Dish Design-A parabolic solar dish concentrating the sun's rays on the heating element of a Stirling engine.

Fresnel Reflectors- Wind load is avoided by the low position of the mirrors. Light construction of tracking system due to separation from the receiver

• Photovoltaic (PV) is a method of generating electrical power by converting solar radiation into direct current electricity using semiconductors that exhibit the photovoltaic effect.

• Photovoltaic power generation employs solar panels composed of a number of solar cells containing a photovoltaic material like-

monocrystalline silicon,polycrystalline silicon,amorphous siliconcadmium telluridecopper indium gallium selenide / sulfide.

Photovoltaic Plants (PV)

TECHNOLOGY

• The photovoltaic effect refers to photons of light exciting electrons into a higher state of energy, allowing them to act as charge carriers for an electric current.

• The term photovoltaic denotes the unbiased operating mode of a photodiode in which current through the device is entirely due to the transduced light energy.

• Solar cells produce direct current electricity from sun light, which can be used to power equipment or to recharge a battery

• Photovoltaic panels based on crystalline silicon modules are encountering competition in the market by panels that employ thin-film solar cells (CdTe, CIGS, amorphous Si, microcrystalline Si), which had been rapidly evolving.

• The most efficient solar cell so far is a multi-junction concentrator solar cell with an efficiency of 43.5%.

Potential of Solar technology

Solar Energy Current Scenario The total installed capacity of solar

power (Both CSP and PV) as of 2008 is

2826 MW.

In India the total installed capacity of

solar power is around 2 MW.

In India, various government and

private players have entered into CSP

and PV markets.

MNRE has set a target to establish at

least 50 MW of solar projects during

the 11th plan.

Diffferent Aspects of Solar Energy Saves money. Semi-independent. Low maintenance. High Initial Cost of installation. Can’t work during night. Similarly plants can be installed only where

there is sufficient sunlight.

HOUSE WE NEED!

BIOMASS AND BIOFUEL

• It is a renewable energy source because the energy it contains comes from the sun.

• As long as biomass is produced sustainably, with only as much used as is grown, the battery will last indefinitely.

• As an energy source, biomass can either be used directly, or converted into other energy products such as biofuel.

Biomass sources

Biomass energy is derived from five distinct energy sources: Garbage Wood waste landfill gases alcohol fuels

• The largest source of energy from wood is pulping liquor or “black liquor,” a waste product from processes of the pulp, paper and paperboard industry.

• Biomass alcohol fuel, or ethanol, is derived primarily from sugarcane and corn. It can be used directly as a fuel or as an additive to gasoline.

• Rotting garbage, and agricultural and human waste, release methane gas—also called "landfill gas" or "biogas”.

• Biomass to liquids (BTLs) and cellulosic ethanol are still under research.

TECHNOLOGIES FOR BIOMASS CONVERSION TO USEFUL ENERGY

Thermal conversion-These are processes in which heat is the dominant mechanism to convert the biomass into another chemical form.• hydrothermal upgrading(HTU) - converts a large

variety of biomass feedstock into a liquid fuel that can be upgraded to a high quality diesel fuel.

• Hydro processing• combined heat and power (CHP) -  use of a heat

engine or a power station to simultaneously generate both electricity and useful heat.

• co-firing -  combustion of two different types of materials at the same time

Chemical conversion-A range of chemical processes may be used to convert biomass into other forms.

A microbial electrolysis cell can be used to directly make hydrogen gas from plant matter

• Biochemical conversion makes use of the enzymes of bacteria and other micro-organisms to break down biomass.

In most cases micro-organisms are used to perform the conversion process : anaerobic digestion, fermentation and composting.

• Another way of breaking down biomass is by breaking down the carbohydrates and simple sugars to make alcohol. However, this process has not been perfected yet. Scientists are still researching the effects of converting biomass.

Biomass Energy Overview

Bio Mass Resource

s

•Agricultural Crops and Residues

•Oil Bearing Plants

•Woody Biomass

•Industrial and Municipal Waste

Supply

System

•Harvesting

•Collection•Handling•Storage

Conversio

n•Thermo

chemical•Physical/

Chemical

End Products

•Heat Electricity

•Transport Fuels

•Solid Fuels

BIOENERGY POTENTIAL

20 GW of power may be generated from 300 MT of agro waste (currently produced)

50% currently burnt in the open Less than 3% potential realized Can revolutionize pace of rural electrification Better technologies Dual usage of cattle dung (fuel + manure)

• High initial cost despite subsidy

• Space requirement & slurry handling difficulties

• High water requirement

• Lack of proper maintenance infrastructure

Limitations for wider adoption

Recent developments

• Compact biogas plants

• Alternative feedstock

Need of Technical Work for

• Increasing efficiency of cattle dung based plants

• Low cost, user-friendly, optimal plant designs

Development of training & service infrastructure

HYDROPOWER

• Conversion of kinetic energy of flowing water into useful energy.

• Water from the reservoir flows due to gravity to drive the turbine.

• Turbine is connected to a generator.

• Power generated is transmitted over power lines.

Technology

HydropowerTechnology

Impoundment Diversion Pumped

Storage

Impoundment facility

Potential THEORETICAL- The maximum potential that exists.

TECHNICAL- It takes into account the cost involved in exploiting a source (including the environmental and engineering restrictions)

ECONOMIC- Calculated after detailed environmental, geological, and other economic constraints.

REGION THEORETICAL POTENTIAL (TWh)

TECHNICAL POTENTIAL (TWh)

AFRICA 10118 3140

N. AMERICA 6150 3120

LATIN AMERICA 5670 3780

ASIA 20486 7530

OCEANIA 1500 390

EUROPE 4360 1430

WORLD 44280 19390

Continent Wide distribution

COUNTRY POWER CAPACITY (GWh)

INSTALLED CAPACITY (GW)

TAJIKISTAN 527000 4000

CANADA 341312 66954

USA 319484 79511

BRAZIL 285603 57517

CHINA 204300 65000

RUSSIA 160500 44000

NORWAY 121824 27528

JAPAN 84500 27229

INDIA 82237 22083

FRANCE 77500 77500

Top ten countries (in terms of capacity)

United Nations Development Program estimates Theoretical potential is about 40,500 TWh per year. The technical potential is about 14,300 TWh per year. The economic potential is about 8100 TWh per year. The world installed hydro capacity currently stands at 694 GW. In the 1980s the percentage of contribution by hydroelectric

power was about 8 to 9%. The total power generation in 2000 was 2675 Billion KWh or

close to 20% of the total energy generation. Most of the undeveloped potential lies in the erstwhile USSR

and the developing countries. Worldwide about 125 GW of power is under construction. The largest project under construction is the Three Gorges at

the Yangtze river in China. Proposed potential is 18.2 GW and the proposed power output is 85 TWh per year

Different Aspects of Hydro Energy

Flexible. Long Economic lives. Suitable for industrial applications. Failure risk. Methane Emission. High initial and maintenance cost. Loss of Land.