Variable renewable electricity (VRE) is typically located far from load centres. As marginal curtailment is 3+ times average curtailment, unless transmission is expanded commensurately, VRE curtailment will rise rapidly. This article develops a novel closed-form solution to give formulae for the efficient balance of transmission expansion, renewables capacity and voluntary curtailment in a simplified model where VRE is distant from load. Given equilibrium in demand centres, the solutions are independent of market prices, depending only on cost and technology parameters. If local grid-connected storage covers most of its cost, co-located storage increases its profit for onshore wind and lowers optimal export capacity. The model is calibrated for on-shore British wind. Overhead lines, if built sufficiently rapidly, have little effect on desirable levels of curtailment/congestion for

Variable renewable electricity (VRE) is typically located far from load centres. As marginal curtailment is 3+ times average curtailment, unless transmission is expanded commensurately, VRE curtailment will rise rapidly. This article develops a novel closed-form solution to give formulae for the efficient balance of transmission expansion, renewables capacity and voluntary curtailment in a simplified model where VRE is distant from load.

Given equilibrium in demand centres, the solutions are independent of market prices, depending only on cost and technology parameters. If local grid-connected storage covers most of its cost, co-located storage increases its profit for onshore wind and lowers optimal export capacity. The model is calibrated for on-shore British wind.

Overhead lines, if built sufficiently rapidly, have little effect on desirable levels of curtailment/congestion for Scottish wind, but for Britain's proposed undersea links high costs increase efficient curtailment to the point where further Scottish wind expansion becomes unprofitable.