Tag Archives: fossil fuels

Calculating the risk reduction benefits of closing Germany’s nuclear plants

Max Aufhammer at the Energy Institute at Haas posted a discussion of this recent paper reviewing the benefits and costs of the closure of much of the German nuclear fleet after the Fukushima accident in 2011.

Quickly reading the paper, I don’t see how the risk of a nuclear accident is computed, but it looks like the value per MWH was taken from a different paper. So I did a quick back of the envelope calculation for the benefit of the avoided consequences of an accident. This paper estimates a risk of an accident once every 3,704 reactor-operating years (which is very close to a calculation I made a few years ago). (There are other estimates showing significant risk as well.) For 10 German reactors, this translates to 0.27% per year.

However, this is not a one-off risk, but rather a cumulative risk over time, as noted in the referenced study. This is akin to the seismic risk on the Hayward Fault that threatens the Delta levees, and is estimated at 62% over the next 30 years. For the the German plants, this cumulative probability over 30 years is 8.4%. Using the Fukushima damages noted in the paper, this represents $25 to $63 billion. Assuming an average annual output of 7,884 GWH, the benefit from risk reduction ranges from $11 to $27 per MWH.

The paper appears to make a further error in using only the short-run nuclear fuel costs of $10 per MWH as representing the avoided costs created by closing the plants. Additional avoided costs include avoided capital additions that accrue with refueling and plant labor and O&M costs. For Diablo Canyon, I calculated in PG&E’s 2019 ERRA proceeding that these costs were close to an additional $20 per MWH. I don’t know the values for the German plants, but clearly they should be significant.

Repost: A catalog of studies on whether renewables create grid instability | Greentech Media

GTM compiles the studies done over the last month in anticipation of the release of the study ordered by Energy Secretary Rick Perry to examine how increased renewable energy threatens grid reliability.

Source: The Rising Tide of Evidence Against Blaming Wind and Solar for Grid Instability | Greentech Media

Proposed TOU rate revisions are “fighting the last war” in California

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California’s investor-owned utilities (IOUs) have asserted that the underlying costs molding time variant or time of use (TOU) rate structures should be largely, or even exclusively, derived based on conventional fossil generation costs. The IOUs rely on “net load” to determine TOU prices, calculated by subtracting all load met by renewables, nuclear and hydropower generation—the majority of the utilities’ generation fleets.

In theory, net load is the portion of the load served by fossil-fueled generation that has the highest short-run operating costs, and therefore is “marginal.” The infamous “duck curve” shown above depicts the net load (not the metered load.) Yet, the marginal energy generation for most load is no longer served by natural gas; it is now met by renewable energy contracts. The utilities’ net load approach ignores the bulk of their true marginal costs to serve added load, which arise from procuring renewables.[1] The IOUs’ resource procurement has been dominated by adding solar, wind, biofuels, and other renewables since at least 2006 to meet the state’s renewable portfolio standard (RPS), first at 20 percent, then 33 percent, and soon 50 percent.

The tunnel-vision focus on net, rather than the entire, load is especially problematic in the context of State policy to phase-down fossil fuel generation. Eventually, natural gas production will even more significantly diminish, and could disappear from the grid entirely, leaving no price-setting metric under this paradigm. Insistence on the net load approach in the face of this transformation is akin to evaluating the economics of ridesharing based on the exclusive cost of taxis, without consideration of Uber® and Lyft®.

Once fossil-fuel resources are used minimally – an explicit state goal reflected in SB 350 – and potentially no longer on the margin, it is unclear what price benchmark the utilities will propose to set time-variant rates.  Continuing the trend toward fewer fossil-fuel resources is already reflected in pending legislation in Sacramento that proposes a clean-peak standard – AB 1405[2] – and a 100 percent Renewable Portfolio Standard—SB 584.[3] Relying solely on the cost of generation resources that State policy plans to phaseout to define TOU periods is inconsistent with good, long-term, ratemaking principles.  Instead, marginal energy generation costs should be calculated, at least in part, from a set of recent RPS-eligible PPAs, weighted by time of delivery.

Likewise, the marginal energy costs derived using the net load method, which drive the proposed shifts in TOU periods, reflect less than one-third of total average utility rates. The IOUs do not explain why cost differences within a modest component of overall rates should steer determination of TOU periods.

Further, it is not clear why the California Public Utilities Commission (CPUC) should rely on a speculative forecast about load shapes in 2024—seven years from now—to set today’s TOU periods. As the CPUC is well aware, the electricity system is changing rapidly along many dimensions. Infusion of utility-scale renewables, which is driving the IOUs’ rate analyses, is but one factor. Increasing amounts of storage and electric vehicles, shifting work patterns, and other social and economic factors will substantially influence load profiles over the next decade. In 2006, few energy experts foresaw stagnant, or even falling, electricity demand; there is even greater uncertainty today.

[1]This perspective excludes contributions made by utility-scale renewables that meet most of the remaining load, and by customer-side resources.

[2] See http://leginfo.legislature.ca.gov/faces/billTextClient.xhtml?bill_id=201720180AB1405

[3] See https://leginfo.legislature.ca.gov/faces/billNavClient.xhtml?bill_id=201720180SB584