Renewable Energy

Renewable Energy

World energy supply

Current situation

•Ketersediaan energi fosil terbatas

•Emisi CO2 yang meningkat

•Biaya produksi yang semakin tinggi

butuh sumber energi baru yang

dapat diperbarui

Renewable energy should be

•Abundant (ketersediaannya di alammelimpah)

•Sustainable (keberlangsungannya terjamin)

•Enviromental friendly

•Non-toxic

•And has good economical feasibility

Renewable energy sources

Image of Energy Ant surrounded by links to renewable energy fuels: water, solar, wind, geothermal and biomass.

Renewable energy sources

•Solar

•Wind

•Geothermal

•Hydropower

•Biomass

•Biofuels and waste

Renewable energy in the past

Before industrialisation renewable energy hadbeen the only source of energy available:

•Firewood to provide heat;

•Biomass for food, for horses and otheranimals for hauling transportation vehicles;

•Wind for propulsion of sailing boats;

•Wind and water power to run mills.

The past

<1860:wood primary fuel

1890: coal displaced most of the wood

in steam generation

1900:ethanol was competing with

gasoline for cars (Ford T)!

1930:coal primary energy source

1940:the era of oil and gas starts

The onset of industrialisation about 300 to 200 yearsago caused an extraordinarily fast rise of the demandon energy and a severe shortage of firewood in manycountries. Fossil fuels soon became the dominantsource of primary energy. The abundant and steadyavailability of fossil fuels and especially their low costsatisfied the newly arising additional demand onenergy to provide any required fast rising amount of

- heat,

- electric power and

- fuels for propulsion in the transportation sector.

At present, renewable energy can be used toprovide only a rather limited amount of secondaryenergy, as shown in Table 1. A more extended useof renewable energy at present is mainlyhandicapped by

•restricted availability (e.g. hydro power, biomass),

•strongly fluctuating and intermittent availabilityof hydro river and wind power and of sunlight,

•comparatively high investment cost and cost ofenergy provided (e.g. sunlight, geothermalenergy).

Table 1. Use of renewable energy assecondary energy

Secondary energy

via

% global demand

Electric energy

hydropower

Wind power

0.3

Biomass

Geothermal

0.3

Sunlight

0.02

Biofuels

Ethanol

Transportation sector

Biodiesel

Heat (mainly for cooking indeveloping countries)

Burning non commercialbiomass (mostly firewood)

about 7% of the totalglobal demand on primaryenergy

Transportation fuels

Table 2. Annual Potential of Renewable Energy inunits of exajoule, EJ

Table 3. Annual worldwide demand on energy inunits of EJ

The future: growing energyconsumption

•Increase due to

–Population growth

–Higher welfare levels

–The highest annualgrowth of energyconsumption is predictedfor Asia (3.7%), NON-OECD countries (3%) andCentral and SouthAmerica (2.8%). Thelowest annual growth ofenergy consumption ispredicted for Europe with1%.

Biomass

Biomass is biological material derivedfrom living, or recently living organisms.In the context of biomass as a resourcefor making energy, it most often refers toplants or plant-based materials whichare not used for food or feed, and arespecifically called lignocellulosic biomass .

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Biomass is any living plant matter

Biomass energy isenergy made from somethingthat is or once was plant matter

•As an energy source, biomass can eitherbe used directly via combustion toproduce heat, or indirectly afterconverting it to various forms of biofuel.Conversion of biomass to biofuel can beachieved by different methods which arebroadly classified into: thermal, chemical,and biochemical methods.