Sustainable Resilient Longmont is advocating for a goal to be 100% renewable by 2030. Diving into the details, there are a lot of ways to achieve this goal. There are some questions that arise, however, as to what 100% renewable is and how costs to ratepayers can be managed. I have put together a few thoughts.
Are communities that claim to be 100% renewable really at 100%, or are they backed up by coal burning power plants? Intermittency of production when the sun is not shining or the wind is not blowing is a challenge for maximizing these generation sources. Technologies exist today that can utilize various methods of storing energy. Pumped storage, for example, pumps water from one reservoir to a higher reservoir during peak renewable production times. When power is needed the water is released from the higher reservoir through turbines to produce electricity. Efficiencies of 70% to 85% can be achieved through this process (https://thinkprogress.org/why-the-renewables-revolution-is-now-unstoppable-698f8d08cf4c/). Typical coal-fired power plants operate in the 33% to 40% range (https://www.worldcoal.org/reducing-co2-emissions/high-efficiency-low-emission-coal).
Battery storage is also advancing. Tesla Powerwall battery storage is on the market now http://www.energysage.com/solar/solar-energy-storage/tesla-powerwall-home-battery/. Innovation and entrepreneurial efforts will advance batteries to a point where their contribution will lead to lowering our carbon footprint on two fronts, automobile emissions and powerplant emissions.
Is hydroelectric generation renewable? The answer to that question depends on who you ask. According to the Federal Energy Information Administration, hydropower is sustainable. The Sierra Club considers small scale hydropower sustainable. The environmental considerations for large hydroelectric projects are considered unsustainable, therefore not renewable. Even political positions enter into the discussion. Much more information can be found here: https://www.linkedin.com/pulse/20140710135110-294192772-why-hydroelectric-power-isn-t-considered-renewable. One constant comes from hydropower; hydropower is carbon free.
For Longmont, we need to participate with our partners in Estes Park, Loveland and Ft Collins to set policies to reach mutual goals. Platte River Power Authority has an op-ed coming out that outlines what is being done to expand renewable energy options. Any discussion of moving to 100% renewable needs to include a discussion on impact to ratepayers.
So, is setting the goal of becoming 100% renewable by 2030 a bad thing? No. Goals give focus and metrics toward achieving the goal. What happens if we don’t reach the goal? We will have delivered more renewables than we have today.