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 alam melimpah) Sustainable (keberlangsungannya terjamin) Enviromental friendly Non-toxic And has good economical feasibility

Renewable energy sources

Renewable energy sources Solar Wind Geothermal Hydropower Biomass Biofuels and waste

Renewable energy in the past Before industrialisation renewable energy had been the only source of energy available: Firewood to provide heat; Biomass for food, for horses and other animals 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 years ago caused an extraordinarily fast rise of the demand on energy and a severe shortage of firewood in many countries. Fossil fuels soon became the dominant source of primary energy. The abundant and steady availability of fossil fuels and especially their low cost satisfied the newly arising additional demand on energy 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 to provide only a rather limited amount of secondary energy, as shown in Table 1. A more extended use of renewable energy at present is mainly handicapped by restricted availability (e.g. hydro power, biomass), strongly fluctuating and intermittent availability of hydro river and wind power and of sunlight, comparatively high investment cost and cost of energy provided (e.g. sunlight, geothermal energy).

Table 1. Use of renewable energy as secondary energy via % global demand Electric energy hydropower 18 Wind power 0.3 Biomass 1 Geothermal Sunlight 0.02 Biofuels Ethanol Transportation sector Biodiesel Heat (mainly for cooking in developing countries) Burning non commercial biomass (mostly firewood) about 7% of the total global demand on primary energy

Transportation fuels

Table 2. Annual Potential of Renewable Energy in units of exajoule, EJ

Table 3. Annual worldwide demand on energy in units of EJ

The future: growing energy consumption Increase due to Population growth Higher welfare levels The highest annual growth of energy consumption is predicted for Asia (3.7%), NON-OECD countries (3%) and Central and South America (2.8%). The lowest annual growth of energy consumption is predicted for Europe with 1%.

Biomass

Biomass is biological material derived from living, or recently living organisms. In the context of biomass as a resource for making energy, it most often refers to plants or plant-based materials which are not used for food or feed, and are specifically called lignocellulosic biomass .

Biomass is any living plant matter Biomass energy is energy made from something that is or once was plant matter

As an energy source, biomass can either be used directly via combustion to produce heat, or indirectly after converting it to various forms of biofuel. Conversion of biomass to biofuel can be achieved by different methods which are broadly classified into: thermal, chemical, and biochemical methods.

Nature is producing vast amounts of biomass driven by sunlight via photosynthesis nCO + H2O (CH2O)n + nO2

Biomass resources can be categorised in many ways, a possible distinction involving: i) agricultural residues ii) forestry products and iii) energy crops The annual global biomass production is estimated at 1.70 x 109 ton

Lignocellulosic biomass consists mainly of carbohydrates and lignin, with variable amounts of proteins, oils, minerals and other minor components. The carbohydrates are generally present in the form of biopolymers like, cellulose, hemicellulose and starch.

Types of Biomass

Biomass is the oldest source of energy

Potential of biomass Only sustainable source for carbon based transportation fuels and chemicals For electricity and heat: Alternatives available (solar, wind, geothermal) biomass may play a role For transportation fuels Biomass expected to be important in the mix

As a fire burns down, it gets hotter

Heat can be used to cook, boil water

We can use fire to make steam, and make steam do work for us

Turning Biomass into Electricity Boiler Biomass High Heat Steam Steam spins the turbine blades Rotating magnets create electricity

Biomass potential and use distribution between regions, 1000 PJ/year

Biomass to biobased chemicals

Methods of Biomass to Energy Conversion Direct combustion Pyrolysis: thermal decomposition into gas or liquid Involves high temperatures (500-900°C), low oxygen Biochemical processes: Anaerobic digestion by methanogens Controlled fermentation produces alcohols: Ethanol (grain alcohol) Methanol (wood alcohol)

Biomass to Fuel Conversions Results: Alcohol (Ethanol) Biogas (Methane) Syngas Gasoline (Biocrude) Diesel Fuel (Plant Oil)