Renewable energy plants: environmental compatibility and external costs assessment at global, regional and local scale

Abstract

In Italy and many European countries energy

production from biomass is encouraged by strong economic

subsidies (in Italy up to 280 €/MWh granted through a feed-in

tariff linked to the electrical production) so that biomass energy

plants are getting large diffusion. Nevertheless, this kind of

energy plant can involve heavy PM10, NOx, ammonia, methane

and N2O emissions, as well as indirect emissions relating to

cultivation, transport, fertilizers’ production. Within the

described outline, the definition of the environmental

compatibility as well as technological and economic issues

dealing with the emerging renewable energy scenario is of

primary importance. This evaluation should take into account

global parameters as well as environmental impacts at regional

and local scale coming from new polluting emissions. The

environmental balances regarding new energy plants are of

primary importance within very polluted areas such as Northern

Italy where air quality limits are systematically exceeded. The

paper analyses the energy and environmental performances of

anaerobic co-digestion of manure and energy crops, wood and

poultry manure combustion, involving the emissive balances,

analysing different possible energy scenarios, using

environmental economics tools like the ExternE methodology,

an approach devoted to the assessment of the externalities

associated to airborne pollution. The most important conclusion

that can be drawn is that the production of renewable energy

from anaerobic digestion, can strongly increase ammonia and

NOx emissions and, in some cases, also GHG emissions could

be worrying, whereas the application of best available

techniques to waste gas cleaning and energy recovery allows

positive environmental balances.