Aula de investigación B. Hobbs 2017/03/15: Crediting Renewables in Electricity Capacity Markets:The Effects of Alternative Definitions upon Market Efficiency
As the penetration of
intermittent renewable energy in electricity markets grows, there is increasing
need for capacity markets to account for the contribution of renewables to
system adequacy. An important issue is the definition of capacity credits
for resources whose availability may be limited. Inconsistencies in capacity
counting methods used by system operators motivate this investigation into the
market efficiency of renewable capacity credits. Inaccurate credits can
distort investment between renewables and nonrenewables, and among different
types and locations of renewables. We quantify the resulting loss of
efficiency, which in simulations based on Texas (ERCOT) data increases total
system generation costs by up to 0.5%. The inefficiency is much larger for more
ambitious renewable portfolio standards. A least-cost capacity market design
should reward marginal capacity contributions by different resources
considering how renewable penetration affects the timing of load peaks,
net of renewable contributions.