Strøtanker om bæredygtighed

Architecture 2030 er et meget visionært amerikansk initiativ, som har lavet en køreplan for et USA, hvor bygninger er CO₂-neutrale inden 2030, med en tilhørende uddannelsesplan – at alle amerikanske arkitektstuderende i løbet af i år skal være i stand til at designe sådanne CO₂-neutrale bygninger. I samarbejde med forskere fra NASA og National Renewable Energy Laboratory har Architecture 2030 fået udarbejdet et paper, som undersøger mulighederne for et at udfase brugen af kul i USA i 2030. Den endelige artikel vil først udkomme i juni, men er i dag rundsendt i draft form.¹

I den nuværende situation, hvor den amerikanske klimalovgivning og dermed den globale klimaaftale hænger i en endog meget tynd tråd efter et massivt lobby- og støjarbejde fra kul- og olieindustrien, er det et dybt interessant indspark i den amerikanske debat. Alene geotermisk energi vurderes at have 10 gange større energipotentiale end det nuværende amerikanske energiforbrug, og der er masser at spare ved mere hensigtsmæssig indretning af den amerikanske infrastruktur.

Blandt artiklens forfattere finder man også lederen af NASAs klimaforskning, James E. Hansen.

I artiklens abstract hedder det afsluttende: “Vi konkluderer, at USAs emissioner fra kul kan være udfaset i 2030 gennem anvendelse af eksisterende teknologier eller teknologier, som vil være konkurrencedygtige indenfor det kommende tiår. Fjernelsen af subsidier til fossile brændstoffer og en markant øget pris på CO₂-udledninger er de fundamentale forudsætninger for en ren, emissionsfri fremtid.”

Jeg har kopieret artiklens abstract ind nedenfor.

Pushker A. Kharecha et al.: Options for Near-Term Phaseout of CO2 Emissions from Coal Use in the United States, Draft accepted for publication in Environmental Science & Technology (pdf).¹

Abstract

The global climate problem becomes tractable if CO₂ emissions from coal use are phased out rapidly and emissions from unconventional fossil fuels (e.g., oil shale and tar sands) are prohibited. This paper outlines technology options for phasing out coal emissions in the United States by ~2030. We focus on coal for physical and practical reasons, and on the U.S. because it is most responsible for accumulated fossil fuel CO₂ in the atmosphere today, specifically targeting electricity production, which is the primary use of coal. While we recognize that coal emissions must be phased out globally, we believe U.S. leadership is essential.

A major challenge for reducing U.S. emissions is that coal provides the largest proportion of base load power, i.e., power satisfying minimum electricity demand. Because this demand is relatively constant and coal has a high carbon intensity, utility carbon emissions are largely due to coal. The current U.S. electric grid incorporates little renewable power, most of which is not base load power. However, this can readily be changed within the next 2-3 decades. Eliminating coal emissions also requires improved efficiency, a “smart grid”, additional energy storage, and advanced nuclear power. Any further coal usage must be accompanied by carbon capture and storage (CCS).

We suggest that near-term emphasis should be on efficiency measures and substitution of coal-fired power by renewables and third-generation nuclear plants, since these technologies have been successfully demonstrated at the relevant (commercial) scale. Beyond 2030, these measures can be supplemented by CCS at power plants and, as needed, successfully demonstrated breeder reactors.

We conclude that U.S. coal emissions could be phased out by 2030 using existing technologies or ones that could be commercially competitive with coal within about a decade. Elimination of fossil fuel subsidies and a substantial rising price on carbon emissions are the root requirements for a clean, emissions-free future.