While those who chant "100% renewables" or "no-fossil fuel" or "the democratization of electricity" or threaten to go off-grid while extolling the virtues of distributed energy resources to the grid may sound progressive and attractive, how the electric grid functions as a vital public infrastructure to ensure the safe, affordable and reliable delivery of an essential service to all residents and businesses of a community is rarely discussed. While some decry the monopolistic nature of electric utilities, the fact is, no matter what type of ownership model, the operations of an electric utility and the grid are still governed by same physics and economics within the same framework of rules, laws and policy.
This is the first of a series of articles of my attempt to take on some basic issues to breakdown the complexity of Hawaii's electric system and the challenge to design and make wise investments to optimize both customer and utility assets to achieve cleaner, safe, reliable and equitable electricity service while keeping the cost of electricity affordable. This is critical not only to bolster our economy but to ensure our quality of life. As we achieve higher renewable penetration levels, the decisions of what kinds of technologies we invest in and who pays will become more contentious if we fail to understand the key technical and economic tradeoffs and just rely on aggressive marketing and political soundbites when making new investments.
The following presentation, available on video at the link below, by Hawaii Public Utilities Commissioner Michael Champley is a good way to start off this education effort.
At the March 2016 Maui Energy Conference, when evaluating Hawaii's renewable energy progress, Hawaii PUC Commissioner Mike Champley posed the important question, "What metric do we look at?" In his presentation, as a panelist on "The Hawaii Renewable Energy Experience - What Can Be Replicated Nationally and Internationally," Commissioner Champley said it was important understand two competing metrics, renewable capacity versus energy penetration, or capacity factor, and walked the audience through each of his slides (some shown here) depicting our renewable progress, current challenges, future challenges and new considerations that come into play regarding key technical and economic tradeoffs.
He defined capacity (the red bar) as "the summation of all the renewable energy resources on that island's grid divided by the system peak load regardless of when it occurred, typically for each island in the evening." This is important as the most ubiquitous resource, solar, is not available during the evening system peak.
He said fast forward in a year or so and it is likely that the capacity will soon exceed 100% on the islands of Maui and Kauai and Hawaii Island and rhetorically asked, "What are the implications?" He explained, "Once you hit 100% from a capacity perspective the laws of physics take over. You got a real time match of supply and demand and if your capacity is at 100%, any additional capacity beyond that could lead to curtailment or immediate consideration of some kind of storage or load shifting."
We already see this happening on many circuits with penetration levels ranging from 100 to 250% of daytime minimum load and with the need to move to the self-supply tariff for new rooftop installations.
The logical, economic solutions are there, but it will take the goring of some sacred cows to lay a solid foundation and cost-effective strategy to get to 100%.