Welcome to the 4th week of the Powering Agriculture MOOC "Sustainable Energy for Food"!
Within that initiative, USAID, the governments
of Sweden and Germany,
as well as Duke Energy and OPIC promote clean energy solutions in the agriculture and food sector.
For the MOOC the Partners are cooperating
with TH Köln, a University of Applied Sciences,
based in Cologne, Germany.
Hello! How are you doing?
Today we are in the fourth week of our MOOC!
And this week's broad content is about
energy efficiency and sustainable energy use.
In this lecture, I first talk about
the general concept of energy efficiency.
Then I will shortly brief you on energy auditing.
Towards the end, we discuss about
the sustainability of energy systems.
So, what does efficiency mean?
Efficiency of any system
is the ratio of output to its input.
This ratio expresses the ability of a process
to utilize different inputs,
such as materials, energy, money or human capital -
to produce a desired output.
Indeed, efficiency of any system, can be measured.
For example: technical processes, economic activities or even administrative processes.
Now, let's talk about energy efficiency.
The International Energy Agency defines
the energy efficiency
as a way of managing and restraining the growth, in energy consumption.
Something is more energy efficient
if it delivers more services for the same energy input.
You may call it a maximization strategy.
Or, the same services for less energy input.
You may call it a minimization strategy.
Let us now think of two different light bulbs:
an incandescent bulb and a LED bulb.
Both bulbs deliver the same brightness,
let's say 1000 lumen.
The conventional bulb needs about 100 watts,
whereas the LED bulb needs only 20 watts
to deliver the same brightness.
In this example, as you can see
the incandescent bulb needs 5 times more energy
to produce the same light effect - compared to the LED.
This example shows that significant amount of energy can be saved, using an energy efficient technology.
And, saving input energy also means saving money as well as reducing environmental impacts.
But please be aware - energy efficiency
is not the same as energy conservation.
Energy conservation is reducing or avoiding a service
in order to save energy.
For example, when you turn off a light in your home,
it is about energy conservation.
But, replacing an incandescent lamp with a LED lamp
is about energy efficiency.
Analysis of energy efficiency, can be extended beyond the end users - such as to the energy production sector.
Let's see an example of a coal power plant
to produce electricity.
Processes involved in such a power plant are:
coal mining, coal cleaning, crushing and
transportation to the power plant,
coal combustion in the furnace, steam generation in boilers, steam turbine operation,
electricity generation via generator,
and electricity transmission via grids to the end users.
As you can see, there are many
intermediate steps in this power system.
In each step, there is a certain form of energy loss.
For example, a large amount of heat loss in a steam turbine, or smaller electrical losses in a generator.
Similar losses take place in other processes, too,
also in the agro-sector. Examples are:
cheese production from milk,
biogas production from agricultural residue,
fertilizer production, irrigation systems, etc.
If you analyze the energy consumption and losses of a complex process chain into its intermediary steps,
we can identify the critical stages.
This procedure is called energy auditing.
An energy audit can be simple:
just having a close look to the process and
observing the areas of energy losses.
Or, it can be a complex analysis,
where every single step of the process is examined, measured and categorized,
according to its impact
and replacement costs.
Here is an example of a milk powder factory.
Throughout the production process chain, multiple motors, refrigerators, heaters and pumps are used.
During an energy audit, we examine the
efficiency of each component.
In the next step we look at the whole system:
The factory uses a refrigerator at the beginning,
and a heater at the end of this process chain.
The cooling process produces heat as a waste product,
while the heater requires it as an input.
By combining these two processes,
we can reuse the waste energy,
and thereby, increase
the overall energy efficiency of the system.
However, just being energy efficient does not necessarily mean,
the product or service we use is sustainable.
Generally, the companies or end users are more concerned with the monetary loss and gain
of implementing the energy efficiency measures.
Environmental aspects are, unfortunately,
of less priority in many cases.
A holistic analysis of such process chains or a system, can be a good instrument to support decision making.
This process is called
sustainable life cycle assessment.
What does sustainability actually mean?
In simple terms it is the ability of a product or a service
to deliver its function in
a better way than its substitute.
We analyze the sustainable life cycle assessment
of a product or a service at its three pillars:
environmental life cycle assessment (often called LCA), life cycle costing, and social life cycle assessment.
In these cases, the whole process chain analysis - or so called cradle to grave analysis - is necessary.
There are not yet international standards developed
for the analysis of life cycle costing, and
social life cycle assessment.
On the other hand, the procedure to carry out the environmental LCA is well developed.
And there are two international standards for this:
ISO 14040 and 14044.
Environmental LCA is the compiling and evaluation of the inputs and outputs
and the potential environmental impacts of a product system during a product's lifetime.
Conducting the LCA involves four phases:
Goal and Scope Definition, Inventory Analysis,
Impact Assessment, and Interpretation.
Goal and Scope Definition phase specifies the objectives and framework,
system boundary, functional unit, etc.
Life Cycle Inventory phase includes data collection for all resources and materials input,
and products and emissions output.
All flows are recorded and compiled
in an inventory table.
Life Cycle Impact Assessment is about the calculation of potential environmental impacts.
Results are summarized into impact categories.
Examples are: global warming potential,
acidification potential, etc.
In the Interpretation Phase the results are checked and evaluated
to see that they are consistent
with the defined goal and scope.
Analysis of sustainable LCA helps you
answer questions such as:
whether to use coal, or solar photovoltaics
to generate 1 kWh of electricity;
or, whether to buy milk in glass
or plastic bottles, or in paper packs.
These and other interesting answers
you can find in the reader.
Now we are at the end of today's lecture.
I hope you enjoyed the time with me!
The quiz is waiting for you!
Have a great time and see you in week 7!
