Transcript USE OF BIOGAS FOR RURAL ELECTRIFICATION

Mid-Term Project Presentations – Electrical
Engineering, 13th February 2008
A SUSTAINABLE IMPLEMENTATION OF RURAL
ELECTRIFICATION BY GENERATING ELECTRICITY
FROM BIOGAS
Nelson Mukwaya
David Wakyiku
Project Executive Summary
Problem: Uganda’s current consumption of energy is unsustainable
Goal: To establish the most appropriate system for sustainable generation of
electricity from biogas for rural electrification.
The options being considered are:
• Biogas as an alternative fuel for diesel/Petrol generators through design
modification.
• Steam turbine- generator systems with biogas used for water heating.
The project weighs these options against sustainability issues which
are:
• Technical
• Environment
• Economic
• Climate
Agenda
• Grasping the Current Situation
• Understanding the Problem in Greater Depth
• Presenting the Solution (your project)
Uganda’s Current Energy Consumption is
Unsustainable.
• Five million tones of oil equivalent used
per annum.
–
16%
of this energy consumption is electrical.
– The rest is mainly wood fuel and charcoal
which over 95% of all households use for
cooking.
1Van Nicholas Wamaniala, Develop Management of Hydropower in Uganda.
Electrical Energy Situation in Uganda
SUPPLY SIDE
• Hydro electricity accounts for 95%
Uganda’s electricity generation.
of
• Other sources include Diesel generators, Thermal generators
(3approx. 100MW), Solar power, Biomass (e.g Kakira –
7MW).
• Biogas electrification is yet to be exploited!!
• Liberalisation of the energy sector accommodates suppliers
to the grid.
3CFL
Program Baseline Report, 2007
Electrical Energy Situation In Uganda
DEMAND SIDE
• The current demand measures up to about 4340MW which is
far greater than the supply.
• The drive for rural electrification among others has
increased the demand for electricity now estimated to
increase by about 4-5MW per month.
4CFL
Program Baseline Report, 2007
Electrical Energy Situation In Rural Uganda
• Approximately 2% of rural households are electrified.
• The current sources of electricity are solar, hydro, car batteries, diesel
and petrol generators.
• Rural electrification and increased access to electricity are development
goals for the government.
• The Rural Electrification Agency’s medium –term objective is to add
100,000 new customers within the period 2006-2008.
• Increasing overall generation capacity to service rural electrification
demand is central to the success of the entire Rural Electrification
Strategy.
• Biogas electrification is an option yet to be exploited!
Source: REA 3-Year Business Plan 2005/06-2014/12
What is the project about?
Sustainable systems for small scale(household) and large scale
(community)are being investigated basing on the sustainability
criteria.
Sustainability is being quantified by modelling the criteria. The
criteria are being systematically weighted w.r.t their impact on
sustainability. A weighted index computed will be the pointer to the
system sustainability and will be the basis upon which the more
appropriate option will be determined.
A sustainability model is thus being developed and will be used to
determine the most appropriate biogas-to-electricity system for
both small scale and large scale rural electrification.
PROPOSED PROJECT WORKFLOW
Technical
model
Collect data on
design option
Economical
model
Establish
sustainability
model
Environment
al model
Check the
impact of a
changing
climate on
sustainability
Perform Detailed Implementation
Design using an option that is
sustainable and less impacted by
a changing climate
Technical Model
Reflects the technical sustainability of a particular biogas
electrification option. A sustainable system should be
efficient, reliable, with long maintenance period. The
factors being considered reflect this. They include:
• Energy Conversion Efficiency.
• Maintenance schedule.
• Reliability.
The above factors can easily be quantified, their sum
reflecting the impact of the technical model on the
sustainability model.
Economic Model
The model aims to capture the economic aspects of setting up the
project. It reflects the financial ability of the targeted market.
Factors being considered include the following:
• Project set-up cost per kW capacity.
• Operations and Maintenance (O&M)costs.
• Power Purchasing Power (PPP).
The sum of these factors will be taken as the contribution of the
economic model in the sustainability model.
Environmental Model
Carbondioxide is emitted from the combustion process
involved (burning of the methane). However, since
carbondioxide is more environmentally friendly than methane
(less damaging to the ozone layer), biogas combustion to
generate electricity plays a role in environmental conservation.
A model is being developed that will evaluate the index of
direct Carbondioxide emission – Carbondioxide equivalent of
would be emitted methane .
Climate Model
The model aims to consider project sustainability for a period of 50
to 100 years. Climate effects become influential in determining
sustainability for such periods.
Climate modeling is being done for temperature and rainfall since
temperature and presence of water are essential for biogas
production. There is a particular range of temperatures for which
anaerobic thermophilic bacteria operate optimally.
Quantiles of Probability Density Function for climate change have
been obtained for the East African region. The variables dealt with
include change in temperature, precipitation and percentage change
in precipitation for low emission, medium emission and high
emission scenarios.
Project Weaknesses
• Lack of precedence in Uganda. Absence of
manufacturing workmanship may lead to construction
defects which is a very serious limitation for system
performance.
• Startup capital is large for a rural community or
household. Government subsidies are needed.
• The set up of the entire system including the animal
farm requires a large area as compared to alternative
energy sources of equal capacities.
Project Strengths
• Increased power production in an environmentally
friendly way, promoting sustainable economic growth as
well as better living conditions.
• Increased employment opportunities to mainly the young
population which will reduce the tendency for rural to
urban migration.
• The digestion process is effective in killing dangerous
organisms providing a public health benefit beyond that of
any other treatment in managing the rural health
environment.
Thank You