What Low-Carbon Energy Technologies Can Do To Improve Water Supply

Low- carbon energy technologies can be thought of as fuels or generation processes that produce fewer greenhouse gasses than traditional fossil fuel (e.g., coal and oil) combustion; although speaking broadly they can also include emission mitigation technologies (e.g., capturing or “scrubbing” greenhouse gas emissions).  The imperative for migrating to low-carbon energy technologies is to reduce greenhouse gas releases to the atmosphere and their attendant impacts on the global climate, humans and the environment.   One of our grand challenges is to create affordable, sustainable supplies of low-carbon energy to meet society’s needs while minimizing its impacts on society and the environment.

Low-carbon energy technologies can help address both water quantity and water quality issues, but none in themselves provide a “silver bullet” that can solve all of our energy, carbon and water challenges.  Each technology has its own set of costs and benefits which must be balanced.  For example, most renewable electricity supplies are clean and “unlimited” supplies, but added costs arise from the intermittent and distributed nature of these resources.  Low-carbon fossil and conventional nuclear are firm sources of electricity, but carbon reduction comes at the cost of higher water demands and either higher energy requirements (e.g., Carbon Capture and Storage [CCS]) or more extensive governmental oversight (e.g., nuclear).  For bioenergy crops, there are emissions reductions, but at the cost of increased water demand, and increased competition with food production and ecosystem services. 

Depending on the energy technology employed, significant quantities of water may be used or saved in upstream processes (e.g., mining, pumping and processing fuels), fuel combustion/energy generation process and downstream processes (e.g., CCS).  And the technology employed may increase or decrease energy production impacts on water quality in each step of the process. 

If energy production and use are to become more sustainable, then future energy systems must provide reliable energy supplies, reduce greenhouse gas emissions and ease the growing strain on global water supplies.  Our challenge is not to decide which energy technology is THE technology that should be employed; this answer will not be the same in all places.  Our challenge is to develop a uniform method for systematically evaluating the full energy supply- carbon-water costs and benefits for each technology and evaluating the various options that can be broadly applied to enable different regions to find the “energy mix” that works best for them.

This discussion will summarize the different water characteristics of commercially deployable forms of low-carbon energy, and the water limitations of different types of environments.  It will then provide examples of how different combinations of low-carbon energy technologies can exacerbate or alleviate local or regional water challenges.  Finally, it will provide a summary of key opportunities and challenges to transitioning towards a more sustainable low-carbon energy future.