A combination of process and I-O analyses is used to investigate relationships between several kinds of energy uses, product compositions and technical change in Swedish agriculture. Estimates are based on comparisons of three development stages in the transition period from 1956 to 1993, Energy productivity has changed dramatically. Cash crops and non-ruminant animals have been more efficient in their use of support energy, compared to other farm sectors; all sectors have increased their solar energy productivity, Support energy from fertilisers is increasingly a major contributor to solar energy productivity giving 20 kWh biomass per kWh input. Manure has become marginal as a substitute fbr external energy inputs through fertiliser. Transforming a larger population of produced biomass to useful products outside agriculture, changing from ruminants to non-ruminants production or finding fuel uses of manure will increase energy, productivity and sustainability. Contradictions with recent analyses of energy or sustainability may be explained by differences in the perceived influences of technical and structural change or earlier incomplete systems approaches. (C) 1997 Elsevier Science Ltd. All rights reserved.