We are delighted by the fact that we can publish the next issue of our journal despite the pandemic and related issues. This combined volume 3 and 4 is devoted to contributions from the VII Baltic Forum of Biogas and Circular Economy, to papers stimulated by BSR projects LowTemp, ActNOW!, Wasteman as well as to other results proposed by various authors during these two difficult years 2020 and 2021. The published papers deal with environmental issues relating to air pollution, building thermo-modernisation and ventilation and eco-energetics, understood in the context of knowledge concerning the sustainable generation of heat and power.
When considering sustainable energetics, we have in mind its reliance on renewable sources, its increasing efficiency (hence distributed energetics and using where appropriate co- or polygeneration) and reducing the use of all fossil fuels (both as energy resources and those needed for agricultural and other purposes). Another aspect of sustainability is biodiversity — the inverse of the monoculture. Nowadays, much attention is being directed towards concepts of biorefineries and the circular economy, i.e. an integrated approach along with higher recovery rates; issues such as a transition from waste organic residues into marketable products — applying new technological solutions to close the nutrient and carbon cycles. Also the new approach towards utilisation of waste polyolefins is highly recommended, in order to reduce plastic pollution of our oceans, at the same time recovering their value as raw material. Alongside the above, current and future market applications of microalgae and hydrogen production from biowaste are topics of high importance.
When we speak of sustainable energetics, we also emphasize its social (including food security as well as the preservation of cultural goods) and economic aspects (including the influence of bioenergy on the labour market and energy security). According to the current state of knowledge, the development of local, distributed energetics seems to be a very effective way to utilise renewable energy sources, stimulating economic development of regions and increasing energy safety. Also important is that sustainability chimes with the contemporary agenda, with its prosumer (civic) character, drawing attention to the socio-economics of heat and power generation. The once passive energy consumer, voiceless and dependent on large often monopolistic corporations, becomes a partner — an energy co-producer. This extends the scope of their freedom in civil society, as well as enables them to participate in the distribution of various subsidies (in Poland represented, among others, through a system of certificates).