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International audience; The concept of energy return (EROEI ratio) is widely used in energy science to describe the interactions between energy and the economic system but it is largely ignored in macroeconomics. In order to contribute to bridging a gap between these fields of research, we incorporate these metrics into an endogenous growth model with two sectors (energy and final goods) and use this model to analyze the macroeconomic implications of a transition to lower EROEI resources. An approach in terms of net energy allows us (1) to explicitly link the EROEI to macroeconomic variables, (2) to show how it is related to the growth rate of GDP and (3) to obtain a closed-form solution for its long-run value at a general equilibrium level. There is furthermore a tight and decreasing long-run relationship between the EROEI value and the share of investment that must be allocated to the energy sector. Hence, a transition to lower EROEI resources intensifies the rival use of capital in the energy and non-energy sectors and leads to major economic changes, both in the inter-sectoral capital allocation and in the allocation of final output between consumption and investment. We show that a protracted economic contraction may occur before the completion of the transition to renewable energy. We analyze how (1) the magnitude of this contraction and (2) the possibility of an ulterior recovery depend on the initial stock of non-renewables, the potentials of technical progress in the energy and non-energy sectors and the substitutability between capital and energy.

We reassess Ricardo's conjecture of a secular increase in rent in an endogenous growth model with an essential renewable material resource and rising product quality. The model is consistent with the concept of strong sustainability and thus assumes that the resource productivity is bounded. Hence, only qualitative growth (i.e., a secular increase in the quality of final productions) may persist in the long run. We analyse how the scarcity of the resource affects the rent level and the distribution of national income (between resource, capital and labour) in the short and long runs. In the long run, resource scarcity induces a distributive conflict opposing labour to capital and resource, a lower resource stock implying generally a lower labour share and higher capital and rent shares. The transitory dynamics of the economy is analyzed numerically, starting from initial conditions characterized by a low capital stock and a large potential technical progress. Even if initially the rent share may evolve non-monotonically, simulations tend to confirm that Ricardo's conjecture emerges sooner or later during the transitory dynamics: except in the case of a very high dematerialization potential of final output, the rent share will rise as quantitative growth slows down. JEL: E25, D9, 044, Q0, Q56. / KEY WORDS: Growth, Strong Sustainability, Rent, Functional Distribution of Income, Renewable Resource, Dematerialisation.

International audience; We introduce the concept of product complexity in an endogenous growth model with renewable energy and expanding product variety à la Grossman and Helpman (1991). We describe the complexity of a product as an increasing function of the variety of inputs it consists of. Considering that energy is necessary to all human activities (including research), we highlight what type of long run growth path is possible according to (a) the potential of energy efficiency gains in the various human activities and (b) the effect of the product complexity on the energy intensiveness of its production process. In a finite world, a neoclassical growth path where economic growth can be both quantitative and non-quantitative (i.e. takes the form of an increase in the quantity of produced goods and in the product variety) is only possible if the potential of energy efficiency gains is unbounded in all human activities. If the energy intensiveness of the final production is bounded from below by a strictly positive constant, quantitative growth is not possible in the long run but non-quantitative growth may persist if (i) the impact of product complexity on the energy intensiveness of production is null or weak enough and (ii) the energy intensiveness of research activities tends to zero. If these conditions are not met, no form of long run growth is possible.

In a stochastic dynamic general equilibrium framework, we introduce the concept of capacity utilization (as opposed to capital utilization). We consider an economy where monopolistic firms use a putty-clay technology and decide on their productive capacity and technology under under uncertainty. An idiosyncratic uncertainty about the exact position of the demand curve faced by each firm explains why some productive capacities remain idle and why individual capacity utilization rates differ across firms. A variable capacity utilization allows for a good description of some of the main stylized facts of the business cycle, propagates and magnifies aggregate technological shocks and generates endogenous persistence (i.e., the output growth rate displays positive serial correlation). (Copyright: Elsevier)

We propose a theoretical macroeconomic model where capacity underutilization follows from idiosyncratic demand uncertainty at the time monopolistic firms must choose their productive capacity. After their investment decision, firms facing a low demand will typically prefer to run excess capacities rather than reduce their profit margin; firms at full capacity will respond to demand fluctuations solely by price adjustments. We show that the proportion of firms with idle capacities influences crucially the short-run response of the economy to exogenous disturbances and, in particular, the relative importance of price and quantity adjustments.

This paper proposes a dynamic efficient bargaining model with a putty-clay technology and aggregation over heterogeneous micro markets. We analyse the agents' optimal response to unexpected real changes in their economic environment. The model gives a useful description of the linkages between unemployment and the rate of utilisation of productive equipment.

This paper presents an intertemporal model in which the agents may face different quantity constraints resulting from technological rigidities, microeconomic uncertainty and market segmentation. Its main purpose is to derive the path of the unemployment rate, the rate of capacity utilisation and the proportion of firms reporting demand constraints from a union-firm optimisation programme. The model is calibrated and the impact of different unfavourable shocks is simulated using a new algorithm for solving dynamic non-linear models. The present exercice underlines the need for caution in interpreting business surveys indicators.

We analyse the interactions between investment and local wage bargaining in a putty-clay model where the investment decision commits the firm to a particular capital intensity. This technological pre-commitment is used strategically in order to manipulate the bargaining outcome. We show that this strategic behaviour induces a non-monotonic relationship between the capital-and-labour demands of the firm and most of her environmental parameters (a.o. the bargaining power of the union, her minimum wage requirement, the capital cost,...). The results we obtain in our putty-clay framework thus contradicts several conclusions of the standard literature on wage bargaining and investment.