The months of April and May have seen negative power prices become more frequent than ever, spurred by good solar and wind output. As we have often noted, negative prices are a strong market signal to develop energy storage, while also representing a threat to further wind and solar developments without that protection. Negative prices are usually one side of general price volatility. But this time there’s also a general lowering of the average price – and it’s quite a dramatic one, first with most European markets below $87 per MWh in the first half of April (per AleaSoft). This was caused in part by President Trump’s tariff disruption, or rather by the lower gas prices those prompted worldwide, with…