ارزش بازار انرژیهای متغیر تجدید پذیر :تاثیر تنوع برق بادی ـ خورشیدی بر قیمت نسبی آنها

This paper provides a comprehensive discussion of the market value of variable renewable energy (VRE). The inherent variability of wind speeds and solar radiation affects the price that VRE generators receive on the market (market value). During windy and sunny times the additional electricity supply reduces the prices. Because the drop is larger with more installed capacity, the market value of VRE falls with higher penetration rate. This study aims to develop a better understanding on how the market value with penetration, and how policies and prices affect the market value. Quantitative evidence is derived from a review of published studies, regression analysis of market data, and the calibrated model of the European electricity market EMMA. We find the value of wind power to fall from 110% of the average power price to 50–80% as wind penetration increases from zero to 30% of total electricity consumption. For solar power, similarly low value levels are reached already at 15% penetration. Hence, competitive large-scale renewable deployment will be more difficult to accomplish than as many anticipate.

Electricity generation from renewables has been growing rapidly during the last years, driven by technological progress, economies of scale, and deployment subsidies. Renewables are one of the major options to mitigate greenhouse gas emissions and are expected to grow significantly in importance throughout the coming decades (IEA, 2012 and IPCC, 2011). According to official targets, the share of renewables in EU electricity consumption shall reach 35% by 2020 and 60–80% in 2050, up from 17% in 2008.1 As hydropower potentials are largely exploited in many regions, and biomass growth is limited by supply constraints and sustainability concerns, much of the growth will need to come from wind and solar power. Wind and solar are variable2 renewable energy sources (VREs) in the sense that their output is determined by weather, in contrast to “dispatchable” generators that adjust output as a reaction to economic incentives. Following Joskow (2011), we define the market value of VRE as the revenue that generators can earn on markets, without income from subsidies. The market value of VRE is affected by three intrinsic technological properties:

Electricity systems with limited intertemporal flexibility provide a frosty environment for variable renewables like wind and solar power. If significant VRE capacity is installed, the merit-order effect depresses the electricity price whenever these generators produce electricity. This implies that the per MWh value of VRE decreases as more capacity is installed. A review of the published literature, regression analysis of market data, and a numerical model of the European power market were used in this study to quantify this drop and identify drivers. We find that the value of wind power is slightly higher than the value of a constant electricity source at low penetration; but falls to 0.5–0.8 at a market share of 30%. Solar reaches a similar level at 15% penetration, because its generation is concentrated in fewer hours. We identify several drivers that affect the value of renewables significantly.