How will cryptocurrencies affect energy consumption?

Could you elaborate on the potential implications of cryptocurrencies on energy consumption? With the increasing popularity and usage of digital currencies, it's crucial to understand how they might impact our energy resources. Could you discuss the energy-intensive mining processes associated with certain cryptocurrencies? How significant is this impact, and are there any potential solutions or alternative technologies that could mitigate these concerns? Additionally, could you explore the potential energy efficiency gains if cryptocurrencies are widely adopted as a means of payment? Thank you for your insights.