In recent years, wind and solar power have decreased dramatically in cost. The same has been true of battery storage technology. When these technologies are used together, they appear to have reached an economic milestone. Specifically, the electricity these renewable technologies produce is now said to be less expensive than that from coal, according to an article in Renew Economy.
This claim may deserve more credence than such optimism has been allowed in the past, as it originates in the energy industry.
In 2017 XCel Energy of Colorado requested bids for new production capacity to take the place of coal units that may close soon. They received offers to produce wind power systems for $21 or less per Megawatt hour, and $36 or less per Megawatt hour for solar. This includes systems including storage capacity. The figure for wind power compares favorably to all coal units in the state. The figure for solar bests roughly three-quarters of coal units.
The article also reported offers of less than $20 per megawatt hour for solar in other countries. ViZn Energy has indicated that it can achieve $23 per megawatt hour solar within 5 to 6 years (this includes storage capacity). The apparently successful operation of the recent Tesla facility has created enthusiasm also.
These prices have been called very bad news for the construction of natural gas plants.
While these bids reflect subsidies, there are reports that within a decade renewables may be cheaper than coal plants even without subsidies. This would rely on the continued decrease in the prices of solar, wind, and storage technologies, but it appears to be a very likely scenario in light of the long-term decreases we have seen for the past several years.