Want More Renewable Energy? Store It

ByMichael Vermeer

Editor's note: This story is part of PolicyMic's Millennials Take On Climate Change series this week.

The Mauna Loa monitoring stations in Hawaii reported a daily average atmospheric CO2 concentration over 400 ppm in May – a milestone that passed with relatively little fanfare. With a concentration milestone already well past what has been suggested to be a “safe” level of 350 ppm, there needs to be a renewed urgency in our efforts to combat climate change, as well as a discussion of what is required and what is holding us back.

One of the most significant barriers to effectively addressing climate change is our inability to efficiently store energy on a large scale. While political dysfunction and economic turmoil have certainly plagued our country’s climate efforts, the reality is that we cannot and will not reach a feasible, cost-effective solution to this problem without energy storage. Those concerned with climate change would like to see a greater share of renewable energy in our power supply. Unfortunately, the intermittent nature of renewable sources (e.g. wind turbines do not generate power when it is not windy) severely hinders the feasibility of large-scale implementation. 

The most significant benefits of investing in energy storage are twofold: Our country will be able to source most of our electricity from renewable sources, and we would mitigate our carbon dioxide emissions through more efficient uses of energy. 

The minimum demand for electricity from the grid at any point in the day tends to be 35-40% of that demanded at the peak. As people wake up, turn on their appliances, and increase demand throughout the day, more plants begin electricity generation in order to meet it. In contrast, an intermittent renewable source cannot be depended on to respond to user-driven demand, and can therefore make up only a small portion of the overall generation capacity.

However, were we to integrate large-scale energy storage facilities into the grid, part of our generation could be used at any given time to charge these storage facilities during off-peak hours, and discharge them during peak hours. Intermittent sources such as wind and solar could then be used whenever they begin producing power, and excess generation capacity would be stored. In this way, energy storage would enable us to dramatically increase the percentage of renewable sources in our power supply. 

Energy storage would also mitigate our carbon dioxide emissions and drive down electricity costs whether or not we incorporated any additional renewable energy in our supply. The most efficient (and thus environmentally friendly) power plants tend to be those that also have the least flexibility in starting or stopping generation (e.g. nuclear power plants), and therefore make up the base load. As demand grows throughout the day, the plants that are begin generating power to meet it are those that are increasingly inefficient or expensive, especially the plants used for just a few hours in the late afternoon to meet the peak demand of the day (peaker plants).

However, if energy storage is integrated into our grid, then not only can more plants be operating at all times at peak efficiency, with excess power generation being used to charge the energy stores. The least efficient and dirtiest plants would also be replaced by a discharging of the stored energy. Essentially, it would allow much greater efficiency in our generation by flattening the demand curve, filling in the valleys by charging energy stores, and chopping off the peaks by discharging them. 

If integrating energy storage into our grid would conveniently deliver these benefits, the question is, why haven’t we done it yet?

The most significant reason is, quite simply, because we don’t know how.

We do not currently have adequate technology for it, and the most effective large-scale storage facilities currently in use – facilities that pump water to a reservoir uphill – are efficient but only available in certain topographies. Several technologies have been proposed as potential solutions, including supercapacitors, new battery designs, flywheels, or electrochemical fuel generation (artificial photosynthesis), but a scalable technology currently does not exist. 

Recent investments in research into these technologies to brilliant and ambitious initiatives have been promising, such as the Joint Center for Artificial Photosynthesis at CalTech and Lawrence Berkeley National Laboratory, and the Joint Center for Energy Storage Research at Argonne National Laboratory. While these investments indicate a more forward-thinking and solutions-oriented work on energy issues, we need a combination of more large-scale investments to achieve breakthrough technology and smaller grants to organizations and laboratories doing basic research on energy storage. 

We also need more effective policy to incentivize investments in energy storage technology. A clear regulatory framework for energy storage would help define for utility companies the costs they would save in implementing energy storage – savings they could even pass on to the consumer. Policy incentives would also increase utilities’ overall proportion of renewable energy in their energy mix, spurring their own investment in research and development for energy storage and other renewable power. 

Climate change is a complex problem that will require a multi-faceted approach. There is no magic bullet that will fix it, but investing in efficient, scalable energy storage may be the closest thing we have to it.

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