Environmental Engineering Reference
In-Depth Information
criticizes the studies for not including other environmental effects of such expansion, such as
biodiversity, and social factors are also overlooked. These studies give an indication that
biomass utilization could increase substantially; this could, however, lead to environmental
and social problems which are not taken into account when, for example, making a study
where biomass fuel replaces fossil fuel as a compensatory system for district heating
production, hence indicating lower environmental concerns. This is a significant issue, since
it has been shown that these assumptions are often crucial for the results in LCA studies.
One drawback of using MODEST when analyzing waste incineration is that few
environmental effects have been taken into account. In earlier studies (Holmgren and Bartlett,
2004; Holmgren and Gebrenedhin, 2004; Holmgren, 2006), only carbon dioxide emissions
from the analysed DH networks have been calculated. One solution could be to use external
costs of environmental effects, and include these costs in the optimization calculations of the
D networks. This has been done by Carlsson (2002). In that study, external cost data was
obtained from the European Union's ExternE-project.
25
The basic idea behind the concept of
external cost is that electricity and heat production give rise to several negative external
effects,
26
such as climate change, acidification and health impacts. The cost of these effects
should be internalized in the price of the energy supply, otherwise a suboptimal consumption
of energy occurs from a socio-economic perspective. This can be compared to the step of
valuing or weighing in the LCA methodology, since that is essentially also to put a value on
environmental effects. However, this step is not really accepted in LCA methodology since it
is considered to be subjective and the recommendation is to use it with care.
C
ONCLUSION
The double function of waste incineration, both as a waste treatment method and a
supplier of electricity and/or heat is discussed in this chapter. A positive impact in one of the
systems may be negative in the other, and strategies and goals in the two sectors can conflict.
The main findings in this chapter are as follows.
- Sweden has extensive DH networks and therefore better possibilities to efficiently
recover the energy content in the waste than countries with a less developed
infrastructure. There is a correlation between extensive DH networks and substantial
incineration as waste treatment method in Sweden, and the connection is both historical
and organisational. This correlation can not be unambiguously shown to exist in any
other EU country. In this context, Sweden differs from other Western European
countries, since relatively little DH is produced in CHP plants.
- Waste incineration can decrease possibilities for producing CHP in DH networks and this
can be seen as a conflict between the need to treat waste in an acceptable way and the
goal of more CHP production in the energy system.
- There is a conflict in the European Union between the internal market and waste
management policy, for example that waste should be treated close to its origin. This has
been solved by prohibiting exports of waste for disposal but not for recovery. A
25
Information about the ExternE project can be found at http://www.externe.info/
26
Positive external effects, for example on local employment, can also occur.
