The General Evaluation Problem

Free Power Secrets

Making Your Own Fuel

Get Instant Access

The reduction of negative climate change impacts which influence every human activity, in private life as well as in business, is indeed urgently needed. For the improvement of the current situation a broad variety of options is available, or will be developed to fill current gaps. However having such options defined another problem arises. In a concrete situation we have to choose one of the options, and only one, for a definite solution. Which option is to be selected? This is not a simple question and the decision making becomes a complex task.

Let us look at various situations: Some of the solutions proposed by the systems analysis efforts may be of such a character that they lead in the right direction especially if they have extra positive side effects unrelated to climate. Such an example is the reduction of private transport in a city in favour of public transport if it is available. This would result in reduced emissions of carbon dioxide and other greenhouse gases, as well as toxic gases from the combustion of fuel. Traffic noise pollution would be reduced. There would be lower risks of traffic accidents as well as health benefits. Moreover reduced use of fossil fuels lowers its overall consumption.

The above example is not typical of the decision making situation when reducing greenhouse gas burdens: In most cases a certain measure will result in different effects which can be both positive and negative.

Some examples of decision problems related to climate change are given in table 8.1. Details are discussed in the following chapters.

Table 8.1 Interdependence of climate related problem solutions

Problem solution in question

Possible effects

How can financial resources be invested most efficiently for climate protection?

Most measures for climate protection cost money. The more a technical solution costs the better normally the effect is. However the money spent could also be used for other kinds of improvements which may result in better climate protection. The best solution has the highest benefit/cost ratio.

Problem solution in question

Possible effects

The idea is behind CDM (Clean Development Mechanism) on an international scale where expensive measures in one country are substituted by cheaper measures in other countries which result in a larger climate effect for the same cost.

Is the reduction of climate gas emissions more important than the reduction of emissions of cancer causing substances?

Climate gas reduction is influential on a global scale. Cancer causing substances are important factors for human health. Both cannot be compared directly. A decision on the side effects for human beings is necessary.

Under which conditions is the substitution of fossil fuels by biofuels efficient with respect to climate?

Fuels can be produced from fossil or from renewable energy sources. Renewables are generally preferred.

However they are produced by agriculture, and become competitive with human nutrition. Need for land may foster deforestation and stress biodiversity. Production needs would influence input of fertilizers and pesticides which may negatively affect soil and groundwater, and cause air pollution. The production of fertilizers and pesticides consumes fossil fuel. Environmental effects of biofuel production are to be considered.

Should waste be deposited with or without pre-treatment?

Waste pre-treatment reduces the organic matter and separates recyclable materials. Thus methane production in the landfill is lowered. Virgin raw matter as well as production efforts for production of materials can be reduced, thus reducing climate gas emissions in industrial production. Long term landfill effects of liquid leachates and emissions are reduced.

But low methane emissions from landfill also means that there is no possibility of collecting gas in a gas recovery system and using it as an alternative energy source instead of fossil fuels.

Is the reduction of emissions of nitrous oxide (N2O) from a chemical process more climatically effective than the reduction of emissions of CO2?

Both substances are greenhouse gases. But their GWP is different: the reduction potential of one unit in N2O is 298 times larger than one unit in CO2. Such effects can be clearly calculated.

However, the steps to reduce both gases are different and must be taken into consideration.

Problem solution in question

Possible effects

Is it environmentally effective to reduce greenhouse gas emissions with the use of end of pipe technologies?

End of pipe technologies, such as washers, biofilters, or gas incineration are able to reduce direct CO2 emissions.

But this causes extra equipment and may be accompanied by higher energy input for the process which cause indirect climate effects as well as other environmental burdens. Sometimes only environmental effects are transferred from one media to another (e.g. from air to water).

Table 8.1 indicates that a clear decision for a certain option under discussion is only possible if decision criteria are available which focus on climate effects, and at the same time consider other environmental as well as economic and social aspects.

Table 8.1 indicates that a clear decision for a certain option under discussion is only possible if decision criteria are available which focus on climate effects, and at the same time consider other environmental as well as economic and social aspects.

This problem is not new, and it is not only true for climate protection. Therefore a variety of evaluation procedures (or assessment tools) has been established, which can be used for such decision tasks. They normally focus on special items or specified groups. A general decision procedure which simultaneously covers all aspects of sustainability does not yet exist. However, climate effects play an important role in most of the procedures. A graphic representation of some assessment tools is given in figure 8.1.

Social aspects

Socio-eco-efficiency analysis

Costs and environmental (climate) effects

Eco-efficiency analysis


Cost efficiency analysis

Environmental effects

Life-cycle assessment

Material intensity

Material flux analysis


Material balance




Energy budgets


Mass budgets

System boundaries

Figure 8.1 Hierarchy of assessment tools (Gohlke, 2006)

Figure 8.1 Hierarchy of assessment tools (Gohlke, 2006)

Obviously all methods are based on matter and energy budgets within certain systems boundaries which are to be defined as a pre-condition for a sensible evaluation process. Economic evaluation is based on costs only. Environmental effects are solely considered in the life cycle assessment. Combinations of economic as well as ecological factors may be assessed using methods such as eco-efficiency or cost-efficiency analysis. The trio of economy, environment, and social aspects is evaluated by the socio-eco-efficiency analysis (BASF, 2004). This method, as well as others of this kind, is relatively close to the needs of a sustainability oriented evaluation criterion but focuses on selected aspects of the item under consideration.

A more detailed description of some practical assessment tools is given in table 8.2.

Table 8.2 Selected environmental assessment tools

Assessment tool

Purpose of application


Environmental audit

Actual ecological performance is analysed, and targets are set for future environmental performance on company levels

Auditing of a production plant, including situation report and target definition

Environmental Impact Assessment (EIA)

Analysis of the environmental impact potentials of a planned facility or other activities

Choosing a production site for a chemical plant or a landfill site

Life-Cycle Assessment (LCA)

Comparison of the environmental effects of the whole life cycle of products, processes, services, or other activities with the same function; identification of improvement and optimisation potentials

Comparison of beverage bottle systems

Identification of key process steps in climate control

Comparison of the climate change potential of different substances

Comparison of climate and health impacts

Risk Assessment

Estimation of impacts of an event and its probability

Assessment of the risks of landfill gas emissions after destruction of a landfill cover

Assessment tool

Purpose of application


Substance and material flow management

(Bringezu, 2QQQ; Brunner, 2QQ4)

Balancing of the material flows in an observation unit (e.g. company, regional, national level)

Identification of flows of dangerous substances and of causes of environmental problems in a region

Control of flows according to given criteria

Analysis of wood balance in a region to find the best use of it as a renewable resource

Sustainable Process Index Assessment (Sandholzer, 2QQ5)

Definition of the impacts of a certain process in terms of the area needed per process unit

Comparison of ethanol production on the basis of renewable or fossil energy sources

Eco-efficiency assessment

Combined assessment of the impacts of a process, a technology, or a service on ecological (LCA) as well as economic criteria

Definition of the best waste management technology for a unit of waste, including deposition, pre-treatment, and waste combustion for a region

Actually used for the estimation of climate effects of processes and services is Life Cycle Assessment (LCA). It is therefore explained in more detail in the following chapter.

Was this article helpful?

0 0
Guide to Alternative Fuels

Guide to Alternative Fuels

Your Alternative Fuel Solution for Saving Money, Reducing Oil Dependency, and Helping the Planet. Ethanol is an alternative to gasoline. The use of ethanol has been demonstrated to reduce greenhouse emissions slightly as compared to gasoline. Through this ebook, you are going to learn what you will need to know why choosing an alternative fuel may benefit you and your future.

Get My Free Ebook

Post a comment