Biomass (solid)

Biomass:

any plant mass harvestable for conversion to fuel, including animal and human wastes converted to fuel.

  • wood and charcoal

  • crop residues

  • fuel crops

  • aquatic plants

  • animal and human wastes

Biomass: Primary Production

  • (mass/area)

  • Photosynthesis: electromagnetic energy converted to chemical energy (carbohydrate)

  • Geographical variation… ecosystem-based variation… depending on solar radiation, precipitation, etc.

  • Limits to biomass production

  • theoretical total… harvestable total… 1.5 × 10^19 J is <10% of total current energy use

  • But… energy is used to cultivate, harvest, process, and distribute biomass… and energy content (MJ/kg) varies among plant components.

Biomass: First Fuel

Wood in Human History:

  • Rome: wood for silver ore smelting; bathwater heated by wood obtained over long distance.

  • England, 1600s to pre-Ind Rev: charcoal supplied iron furnaces for weapons; wood and charcoal “catchments” for major cities

  • USA mid 1800: biomass (esp wood) +90% energy consumption… breweries, distilleries, furnaces, brickwork, steam engines, iron mills, railroads.

Biomass: 2.1-2.7B people

2.1-2.7B people rely on biomass as primary source of domestic energy

  • Energy poverty… SDG7

  • Location: mainly less developed countries

  • Technology: 3-stone open fire

  • Implications… gender inequality, labor demands, land-use change, human health

Household Fuel choice: why?

  • Income: increasing incomes > move “up” energy ladder

  • Urbanization: limited firewood or dung; distribution better for LPG or electricity

  • Appliance costs: stoves are expensive

  • Relative fuel costs: cost of obtaining wood or dung vs. purchasing kerosene or LPG

Theory: Energy Ladder

  • Increasing income> change in fuel type, increase in energy use

  • From dung or wood to kerosene, then L{G, natural gas, or electricity

  • What policies encourage stepping “up” the ladder? Stove subsidies, Fuel subsidies, urbanization

Biomass: 2.1-2.7B people

Human Health: indoor air pollution

  • PM-10 (particulate matter <10 diameter)

  • US EPA requirements: average daily concentration <150

  • Casual linkages to respiratory infections and pulmonary disease

  • Global mortality: ~1.6M deaths in 2000 (mostly childhood respiratory infections)

Predictions for Sub-Saharan Africa

  • if current trends persist to 2030, ~9.8M people will die prematurely

  • If households switch to charcoal, 1.0-2.8M deaths will be delayed

  • If households switch to petroleum fuels, 1.3-3.7M deaths delayed

Policies: Fuel-stove combinations:

  • switch from wood or dung to charcoal or kerosene

  • improved stoves, ventilation

  • Improved wood fuel preparation

Policies: decentralized (off grid) solar PV:

  • lighting, cooking, refrigeration

Emerging Issues…

Which solution is best?: improved cookstoves or off-grid PV?

  • which policy instruments?

  • Which has higher social acceptance?

  • Less political resistance?

How can we achieve Sustainable Development Goal 7:

  • “affordable, reliable, sustainable and modern energy for all” by 2030> Ensure universal access to affordable, reliable, and modern energy services