The last two blogs focused on the Netherlands’ leading role in showing the rest of the world strategies for living on an increasingly inhospitable planet, where the terrain is becoming uninhabitable for both humans and agricultural crops and the oceans are consuming ever larger masses of land through sea-level rise. The timing for all of this depends on decisions that we make today. The transition into this bleak future is at work even now, with large land areas already having been declared uninhabitable in places such as India and Africa, resulting in large scale immigration to better terrains.
The last two blogs focused on attempts to adapt to this reality, not through immigration (there are fewer and fewer places where we can go) but by living and growing crops isolated from the physical environment, using indoor agriculture and floating houses.
All of this requires us to realize that there are limits to our ability to adapt to hostile environment; we need to be convinced to completely decarbonize our energy sources. The next few blogs will focus on the issue of energy (with the usual disclaimer for interruptions due to unforeseen events), including a description of where we are in learning how to use the ultimate energy source that all the stars in the Universe use – fusion energy. Since we still don’t know how to use fusion energy for peaceful purposes, today’s blog will instead look at various forms of solar energy. Solar energy supply is intermittent and we need to learn how to adapt our usage to accommodate that flux. (October 21, 2014 and the following blogs, which include active exchanges with Joe Morgan),
Eduardo Porter’s article in The New York Times drew my attention to recent scientific activity and debate on this issue:
Fisticuffs Over the Route to a Clean-Energy Future
By Eduardo Porter
Could the entire American economy run on renewable energy alone?
This may seem like an irrelevant question, given that both the White House and Congress are controlled by a party that rejects the scientific consensus about human-driven climate change. But the proposition that it could, long a dream of an environmental movement as wary of nuclear energy as it is of fossil fuels, has been gaining ground among policy makers committed to reducing the nation’s carbon footprint. Democrats in both the United States Senate and in the California Assembly have proposed legislation this year calling for a full transition to renewable energy sources.
They are relying on what looks like a watertight scholarly analysis to support their call: the work of a prominent energy systems engineer from Stanford University, Mark Z. Jacobson. With three co-authors, he published a widely heralded article two years ago asserting that it would be eminently feasible to power the American economy by midcentury almost entirely with energy from the wind, the sun and water. What’s more, it would be cheaper than running it on fossil fuels.
Jacobson, et al. wrote a related article that was published in PNAS, which was then thoroughly critiqued on the same platform. For more on the exchange, I invite you to check the original references.
Low-cost solution to the grid reliability problem with 100% penetration of intermittent wind, water, and solar for all purposes
Mark Z. Jacobson, Mark A. Delucchib, Mary A. Camerona, and Bethany A. Frewa
Worldwide, the development of wind, water, and solar (WWS) energy is expanding rapidly because it is sustainable, clean, safe, widely available, and, in many cases, already economical. However, utilities and grid operators often argue that today’s power systems cannot accommodate significant variable wind and solar supplies without failure (1). Several studies have addressed some of the grid reliability issues with high WWS penetrations (2–21), but no study has analyzed a system that provides the maximum possible long-term environmental and social benefits, namely supplying all energy end uses with only WWS power (no natural gas, biofuels, or nuclear power), with no load loss at reasonable cost. This paper fills this gap. It describes the ability of WWS installations, determined consistently over each of the 48 contiguous United States (CONUS) and with wind and solar power output predicted in time and space with a 3D climate/weather model, accounting for extreme variability, to provide time-dependent load reliably and at low cost when combined with storage and demand response (DR) for the period 2050–2055, when a 100% WWS world may exist.
Discussion and Conclusions The 2050 delivered social (business plus health and climate) cost of all WWS including grid integration (electricity and heat generation, long-distance transmission, storage, and H2) to power all energy sectors of CONUS is ∼11.37 (8.5–15.4) ¢/kWh in 2013 dollars (Table 2). This social cost is not directly comparable with the future conventional electricity cost, which does not integrate transportation, heating/cooling, or industry energy costs. However, subtracting the costs of H2 used in transportation and industry, transmission of electricity producing hydrogen, and UTES (used for thermal loads) gives a rough WWS electric system cost of ∼10.6 (8.25–14.1) ¢/kWh. This cost is lower than the projected social (business plus externality) cost of electricity in a conventional CONUS grid in 2050 of 27.6 (17.2–54.4) ¢/kWh, where 10.6 (8.73–13.4) ¢/kWh is the business cost and ∼17.0 (8.5–41) ¢/kWh is the 2050 health and climate cost, all in 2013 dollars (22). Thus, whereas the 2050 business costs of WWS and conventional electricity are similar, the social (overall) cost of WWS is 40% that of conventional electricity. Because WWS requires zero fuel cost, whereas conventional fuel costs rise over time, long-term WWS costs should stay less than conventional fuel costs. In sum, an all-sector WWS energy economy can run with no load loss over at least 6 y, at low cost. As discussed in SI Appendix, Section S1.L, this zero load loss exceeds electric-utility industry standards for reliability. The key elements are as follows: (i) UTES to store heat and electricity converted to heat; (ii) PCM-CSP to store heat for later electricity use; (iii) pumped hydropower to store electricity for later use; (iv) H 2 to convert electricity to motion and heat; (v) ice and water to convert electricity to later cooling or heating; (vi) hydropower as last-resort electricity storage; and (vii) DR. These results hold over a wide range of conditions (e.g., storage charge/discharge rates, capacities, and efficiencies; long-distance transmission need; hours of DR; quantity of solar thermal)(SI Appendix, Table S3 and Figs. S7–S19), suggesting that this approach can lead to low-cost, reliable, 100% WWS systems many places worldwide.
Response to Jacobson et al.:
John E. Bistlinea, and Geoffrey J. Blanforda
Jacobson et al. (1) aim to demonstrate that an all renewable energy system is technically feasible. Not only are the study’s conclusions based on strong assumptions and key methodological oversights, but its framing also omits the essential notion of trade-offs. A far more relevant question is how renewable energy technologies relate to the broader set of options for meeting long-term societal goals like managing climate change. Even if the goal were to maximize the deployment of renewable energy (and not decarbonization more generally), Jacobson et al. still fail to provide a satisfactory analysis by glossing over fundamental implications of the technical and economic dimensions of intermittency. We briefly highlight two prominent examples, and then return to the question of framing.
First, the paper’s “no load loss” assertion is predicated on the large-scale availability of energy storage, demand response, and unconstrained transmission to handle periods of supply surpluses and shortfalls. Its assumptions about the cost and reliability of intertemporal demand flexibility within and across sectors, as well as the electrification of end-use demand, are particularly aggressive. The potential scale and scope of these novel technologies remain highly uncertain and speculative, and the narrow confidence intervals presented in Jacobson et al. (1) do not reflect the full range of possible outcomes. Second, the paper does not account for the regional provision of resource adequacy (i.e., market clearing with spatial heterogeneity) in its reliability results—indeed, the analysis is conducted at the national level. Although geographic smoothing can ameliorate some balancing challenges, seasonal and diurnal variability of wind and solar output cannot be managed through offsetting spatial variability alone. Moreover, these effects require data that reflect renewable output simultaneously with load in each hour of a given year, yet Jacobson et al. (1) use different, nonsynchronous datasets. Consequently, their analysis preserves neither joint temporal nor spatial variability between intermittent resources and demand, which are among the main drivers of decreasing returns to scale for renewable energy (2).
There is an emerging literature on integrated modeling of long-term capacity planning with high-temporal resolution operational detail that effectively incorporates such economic drivers (e.g., ref. 3). By contrast, Jacobson et al. (1) use a “grid integration model” in which investment and energy system transformations are not subject to economic considerations. The resulting renewable dominated capacity mix is inconsistent with the wide range of optimal deep decarbonization pathways projected in model inter-comparison exercises (e.g., refs. 4 and 5) in which the contribution of renewable energy is traded off in economic terms against other low-carbon options.
Jacobson et al. (1) underscore how balancing and fleet flexibility will be important elements of power system design, and that electrification of other demand sectors is a promising option. However, the study underestimates many of the technical challenges associated with the world it envisions, and fails to establish an appropriate economic context. Every low-carbon energy technology presents unique technical, economic, and legal challenges. Evaluating these trade-offs within a consistent decision framework is essential. Such analyses consistently demonstrate that a broad research, development, and deployment portfolio across supply- and demand-side technologies is the best way to ensure a safe, reliable, affordable, and environmentally responsible future energy system.
More recently, Miara et al. provided a different analysis of the changes that are needed in the future of US power supply (Nature Climate Change 7, 793 (2017)). Their analysis incorporates the requirements for cooling water in a constantly warming environment.
Climate and water resource change impacts and adaptation potential for US power supply
Ariel Miara , Jordan E. Macknick , Charles J. Vörösmarty , Vincent C. Tidwell , Robin Newmark & Balazs Fekete
Power plants that require cooling currently (2015) provide 85% of electricity generation in the United States1,2. These facilities need large volumes of water and sufficiently cool temperatures for optimal operations, and projected climate conditions may lower their potential power output and affect reliability3,4,5,6,7,8,9,10,11. We evaluate the performance of 1,080 thermoelectric plants across the contiguous US under future climates (2035–2064) and their collective performance at 19 North American Electric Reliability Corporation (NERC) sub-regions12. Joint consideration of engineering interactions with climate, hydrology and environmental regulations reveals the region-specific performance of energy systems and the need for regional energy security and climate–water adaptation strategies. Despite climate–water constraints on individual plants, the current power supply infrastructure shows potential for adaptation to future climates by capitalizing on the size of regional power systems, grid configuration and improvements in thermal efficiencies. Without placing climate–water impacts on individual plants in a broader power systems context, vulnerability assessments that aim to support adaptation and resilience strategies misgauge the extent to which regional energy systems are vulnerable. Climate–water impacts can lower thermoelectric reserve margins, a measure of systems-level reliability, highlighting the need to integrate climate–water constraints on thermoelectric power supply into energy planning, risk assessments, and system reliability management.
Just as I was about to finish writing this (late afternoon on Friday) my electronic device dinged with the news that the Trump administration had officially approved the recent US Climate Science Report – the result of the Congress-mandated National Climate Assessment. When the draft of this report came out this year many people, including myself, were doubtful that the administration would release it, since it put the responsibility for climate change squarely on humankind and was in complete agreement with almost all the other credible information about climate change, as of the IPCC’s inception more than 20 years ago. I wrote about this draft report earlier (August 15, 2017). I was already using it as the most up-to-date reference in my class and I will refer to it in my next blog, straying away from my intent to focus my attention on future energy needs.